ACS Publications. Most Trusted. Most Cited. Most Read
Salinity from Space Unlocks Satellite-Based Assessment of Ocean Acidification
My Activity

Figure 1Loading Img
  • Free to Read
Feature

Salinity from Space Unlocks Satellite-Based Assessment of Ocean Acidification
Click to copy article linkArticle link copied!

View Author Information
Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, U.K.
University of Exeter, Penryn Campus, Cornwall TR10 9FE, U.K.
§ Institut Francais Recherche Pour ĹExploitation de la Mer, Pointe du Diable, 29280 Plouzané France
Telespazio-Vega U.K. for European Space Agency (ESA), ESTEC, Noordwijk, The Netherlands
Ocean Processes Analysis Laboratory, University of New Hampshire, Durham, New Hampshire 3824, United States
# Norwegian Institute for Water Research, Thormøhlensgate 53 D, N-5006 Bergen, Norway
Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur 741 246, West Bengal India
Open PDF

Environmental Science & Technology

Cite this: Environ. Sci. Technol. 2015, 49, 4, 1987–1994
Click to copy citationCitation copied!
https://doi.org/10.1021/es504849s
Published January 8, 2015

Copyright © 2015 American Chemical Society. This publication is available under these Terms of Use.

Abstract

Click to copy section linkSection link copied!

Approximately a quarter of the carbon dioxide (CO2) that we emit into the atmosphere is absorbed by the ocean. This oceanic uptake of CO2 leads to a change in marine carbonate chemistry resulting in a decrease of seawater pH and carbonate ion concentration, a process commonly called “Ocean Acidification”. Salinity data are key for assessing the marine carbonate system, and new space-based salinity measurements will enable the development of novel space-based ocean acidification assessment. Recent studies have highlighted the need to develop new in situ technology for monitoring ocean acidification, but the potential capabilities of space-based measurements remain largely untapped. Routine measurements from space can provide quasi-synoptic, reproducible data for investigating processes on global scales; they may also be the most efficient way to monitor the ocean surface. As the carbon cycle is dominantly controlled by the balance between the biological and solubility carbon pumps, innovative methods to exploit existing satellite sea surface temperature and ocean color, and new satellite sea surface salinity measurements, are needed and will enable frequent assessment of ocean acidification parameters over large spatial scales.

This publication is licensed for personal use by The American Chemical Society.

Copyright © 2015 American Chemical Society

Synopsis

Approximately a quarter of the carbon dioxide (CO2) that we emit into the atmosphere is absorbed by the ocean. This oceanic uptake of CO2 leads to a change in marine carbonate chemistry resulting in a decrease of seawater pH and carbonate ion concentration, a process commonly called “Ocean Acidification”. Salinity data are key for assessing the marine carbonate system, and new space-based salinity measurements will enable the development of novel space-based ocean acidification assessment. Recent studies have highlighted the need to develop new in situ technology for monitoring ocean acidification, but the potential capabilities of space-based measurements remain largely untapped. Routine measurements from space can provide quasi-synoptic, reproducible data for investigating processes on global scales; they may also be the most efficient way to monitor the ocean surface. As the carbon cycle is dominantly controlled by the balance between the biological and solubility carbon pumps, innovative methods to exploit existing satellite sea surface temperature and ocean color, and new satellite sea surface salinity measurements, are needed and will enable frequent assessment of ocean acidification parameters over large spatial scales.

1 Introduction

Click to copy section linkSection link copied!

Each year global emissions of carbon dioxide (CO2) into our atmosphere continue to rise. These increasing atmospheric concentrations cause a net influx of CO2 into the oceans. Of the roughly 36 billion metric tons of CO2 that is emitted into our atmosphere each year, approximately a quarter transfers into the oceans. (1) This CO2 addition has caused a shift in the seawater–carbonate system, termed ocean acidification (OA), resulting in a 26% increase in acidity and a 16% decrease in carbonate ion concentration since the industrial revolution. (2) Recently there has been recognition that this acidification is not occurring uniformly across the global oceans, with some regions acidifying faster than others. (3, 4) However, the overall cause of OA remains consistent: the addition of CO2 into the oceans, and as such, it remains a global issue. Continual emissions of CO2 into the atmosphere over the next century will decrease average surface ocean pH to levels which will be deleterious to many marine ecosystems and the services they provide. (5)
While the seawater–carbonate system is relatively complex, two parameters have been suggested as pertinent to the monitoring and assessment of OA through time and space. These are pH (the measure of acidity) and calcium carbonate (CaCO3) mineral saturation state, with aragonite generally considered to be an important CaCO3 mineral to be monitored because of its relevance to marine organisms (e.g., corals) and its relative solubility. Thermodynamically, CaCO3 is stable when the saturation state (an index of the concentrations of calcium and carbonate ions) is greater than one and becomes unstable when seawater becomes undersaturated with these ions (saturation <1). While there is significant variability between types of organism, there is ample experimental evidence that many calcifying organisms are sensitive to OA, (6) and that thresholds exist below which some organisms become stressed and their well-being and existence becomes threatened. (7) Increasingly evidence suggests that the physiology and behavior of calcifying and noncalcifying organisms can be impacted by increasing OA, (8) with cascading effects on the food chain and protein supply for humans, (3) and alterations to the functioning of ecosystems and feedbacks to our climate. (9)
In 2012 the Global Ocean Acidification Observing Network (GOA-ON, www.goa-on.org) was formed in an attempt to bring together expertise, data sets and resources to improve OA monitoring. At present, OA monitoring efforts are dominated by in situ observations from moorings, ships and associated platforms. While key to any monitoring campaign, in situ data tend to be spatially sparse, especially in inhospitable regions, and so on their own are unlikely to provide a comprehensive, robust and cost-effective solution to global OA monitoring. The need to monitor and study large areas of the Earth has driven the development of satellite-based sensors.
Increasingly, as in situ data accumulate, attempts are being made to use in situ hydrographic data (10-13) and/or remotely sensed data (14, 15) to provide proxies and indicators for the condition of the carbonate system, enabling data gaps to be filled in both space and time. The increased availability of in situ data creates a substantial data set to develop and test the capabilities of satellite-derived products, and we suggest that the recent availability of satellite-based salinity measurements provides new key insights for studying and assessing OA from space.

2 The Complexities of the Carbonate System

Click to copy section linkSection link copied!

The oceanic carbonate system can be understood and probed through four key parameters: total alkalinity (TA), dissolved inorganic carbon (DIC), pH, and fugacity of CO2 (fCO2). The latter may be replaced with the related partial pressure of CO2, pCO2, from which fCO2 can be calculated, and the two are often used interchangeably. In principle, knowledge of any two of these four is sufficient to solve the carbonate system equations. However, overdetermination, the process of measuring at least three parameters, is advantageous.
The relationships between the different carbonate system parameters are fundamentally driven by thermodynamics, hence influenced by temperature and pressure, and knowing these is fundamental for calculating the carbonate system as a whole. (16) Water temperature is the major controller of the solubility of CO2, (17) so seasonal changes in sea temperature can, depending on the region, be significant for driving changes in fCO2 (and consequently DIC and pH). Salinity affects the coefficients of the carbonate system equations. Hence to solve the equations, it is necessary to estimate temperature, salinity and pressure along with carbonate parameters.
The ratio between ions (the constituents of salinity) will tend to remain constant anywhere in the global oceans, resulting in a strong relationship between TA and salinity. (18) Unfortunately, a universal relationship between TA and salinity does not apply in certain regions, for instance in areas influenced by freshwater outflows from rivers, (7) or areas where calcification and/or CaCO3 dissolution occurs, such as where calcifying plankton are prevalent. (19) In these regions, it is therefore critical to gain additional local knowledge. For example, different rivers will have different ionic concentrations (and therefore different TA concentrations) depending on the surrounding geology and hydrology.
For DIC, fCO2 (or pCO2), and pH, the other important process is biological activity. (19) Removal or addition of CO2 by plankton photosynthesis or respiration can be a significant component of the seasonal signal. (20) Biological activity, in turn, is driven by factors such as nutrient dynamics and light conditions, which again are regionally specific. Measurements of chlorophyll (a proxy for biomass) and/or oxygen concentration can be useful for interpreting the biological component of the carbon signal.
The combination of these processes means that it is extremely challenging to produce a global relationship between any component of the carbonate system and its drivers. To enable us to understand these dynamics, extrapolation from collected data points to the global ocean is needed, and along with model predictions, empirical relationships and data sets are important and need to be studied and developed. OA needs to be assessed using these relationships on a global scale, but regional complexities, particularly where riverine and coastal processes dominate, (21, 22) cause significant challenges for global empirical relationships.

3 Current in Situ Approaches and Challenges

Click to copy section linkSection link copied!

Laboratory measurements are the gold standard for assessing the carbonate system in seawater, with accuracy far in excess of that achievable from satellites. (23-25) However, research vessel time is expensive and limited in coverage, so autonomous in situ instruments are also deployed, for example, on buoys, with less accuracy. (26) A notable example is the Argo network of over 3000 drifters, which measure temperature and salinity throughout the deep global ocean. Interpolation of Argo data is much less challenging than for most in situ measurements. Argo is the closest in situ data have come to the global, synoptic measurements possible with satellites, but shallow or enclosed seas are not represented (there are as yet no Argo instruments in the open Arctic Ocean). Table 1 lists more examples. Of the four key parameters, only fCO2 (or pCO2) and pH are routinely monitored in situ. As yet there are limited capabilities to measure DIC and TA autonomously, hence these parameters must be measured either in a ship-based laboratory or on land.
Table 1. In Situ Datasets and Programs than Can Be Used for the Development and Validation of OA Remote Sensing Algorithms
data set name and referencetemporal periodgeographic locationvariablesno. of data points
SOCAT v2.0 (27)1968–2011global*fCO2, SSS, SST6 000 000+
LDEO v2012 (28)1980-presentglobal*pCO2, SSS, SST6 000 000+
GLODAP (29)1970–2000globalTA, DIC, SSS, SST, Nitrate10 000+
CARINA AMS v1.2 (30)1980–2006ArcticTA, DIC, SSS, SST1500+
CARINA ATL v1.0 (31)Atlantic
CARINA SO v1.1 (32)Southern Ocean
AMT (33)1995-presentAtlanticpCO2W, SSS, SST, Chl, pH1000+
NIVA Ferrybox (34)2008-presentArcticpCO2W, TA, DIC, SSS, SST1000+
OWS Mike (35)1948–2009ArcticTA, DIC, SSS, SST, Chl1000+
RAMA Moored buoy array (36)2007-presentBay of BengalSSS, SST1000+
ARGO buoys (37)2003-presentglobalSSS, SST1 000 000+
OOI (38)2014 onwardglobal (six sites)pCO2, SSS, SST, nitratenew program
SOCCOM (39)2014 onwardSouthern OceanSSS, SST, pH, nitratenew program

4 Potential of Space Based Observations

Click to copy section linkSection link copied!

4.1 Advantages and Disadvantages

While it has proven difficult to use remote sensing to directly monitor and detect changes in seawater pH and their impact on marine organisms, (22) satellites can measure sea surface temperature and salinity (SST and SSS) and surface chlorophyll-a, from which carbonate system parameters can be estimated using empirical relationships derived from in situ data. Although surface measurements may not be representative of important biological processes, for example, fish or shellfish, observations at the surface are particularly important for OA because the change in carbonate chemistry due to atmospheric CO2 occurs in the surface first. Thus, satellites have great potential as a tool for assessing changes in carbonate chemistry.
SST has been measured from space with infrared radiometry since the 1960s, but the data are only globally of sufficient quality for climate studies since 1991. (40) Satellite measurements of chlorophyll-a in the visible are more recent, starting in 1986 and delivering high quality global data since 1997. (41) Both measurements are made globally at high spatial and temporal resolution, but with data gaps due to effects such as cloud, which can greatly affect data availability in cloudy regions. SST is measured in the top few microns, and chlorophyll-a is generally measured to depths around 1–100 m, depending on water clarity. Data quality can be affected by many issues, for example, adjacent land or ice may affect both SST and chlorophyll-a retrievals, and suspended sediment may affect chlorophyll-a retrievals.
Only since 2009 has a satellite-based capability for measuring SSS existed. Increasing salinity decreases the emissivity of seawater and so changes the microwave radiation emitted at the water surface. ESA Soil Moisture and Ocean Salinity (SMOS) and NASA-CONAE Aquarius (launched in 2009 and 2011 respectively, both currently in operation), are L-band microwave sensors designed to detect variations in microwave radiation and thus estimate ocean salinity in the top centimeter. The instruments are novel and the measurement is very challenging, and research is ongoing to improve data quality. (42) The instruments can measure every few days at a spatial resolution of 35–100 km, but single measurements are very noisy, so the instantaneous swath data are generally spatially and temporally averaged over 10 days or a month, with an intended accuracy around 0.1–0.2 g/kg for monthly 200 km data. A particular issue close to urban areas is radio frequency interference from illegal broadcasts, which are gradually being eliminated but still result in large data gaps, particularly for SMOS. The signal can be affected by nearby land or sea ice, and the sensitivity to SSS decreases for cold water, by about 50% from 20 to 0 °C. (43)
With these challenges, a central question is whether satellite SSS can bring new complementary information to in situ SSS measurements such as Argo for assessing OA. Direct comparisons (44, 45) indicate differences of 0.15–0.5 g/kg in a 1° × 1° region over 10–30 days. The two are difficult to compare directly, however, as Argo measures 5 m or more from the surface, so some differences are expected even in the absence of errors, especially where the water column is stratified. A better strategy might be to compare their effectiveness in estimating OA. How the uncertainties propagate through the carbonate system calculations is the subject of ongoing research.
Despite biases and uncertainties, satellite measurements of SSS in the top centimeter contain geophysical information not detected by Argo. (46, 47) In addition, Argo coverage can be much poorer than satellite SSS in several regions such as the major western boundary or equatorial currents and across strong oceanic fronts. The use of interpolated Argo products presents an additional source of uncertainty due to the interpolation scheme. (48) Satellite SSS can also resolve mesoscale spatial structures not resolved by Argo measurements, (49) and unlike Argo, satellites provide a synoptic “snapshot” of a region at a given time.
Regular mapping of the SSS field with unprecedented temporal and spatial resolution at global scale is now possible from satellites. The impact of using satellite SSS for carbonate system algorithms can now be tested, where previously there was a reliance on climatology, in situ or model data. For example, this provides the means to study the impact that freshwater influences (sea ice melt, riverine inputs and rain) can have on the marine carbonate system. The use of satellite SSS data will also allow evaluation of the impact on the carbonate system of the inter- and intra-annual variations in SSS.
Recent advances in radar altimetry (e.g., Cryosat-2 and Sentinel 1 satellites and sensors) are already enabling significant improvements in satellite sea-ice thickness measurements. (50) Thin sea ice thickness can now also be determined from SMOS, complementing altimeter estimates mostly valid for thick sea ice. (51) Sea ice thickness is important for OA research as it indicates whether ice is seasonal or multiyear, supporting the interpretation of carbonate parameters. Altimetry is also used to measure wind speeds and increases the coverage of scatterometer estimates in polar regions. It provides higher-resolution (along track) estimates of surface wind stress, which can potentially be used to indicate regions of upwelling. Wind-driven upwelling causes dense cooler water (with higher concentrations of CO2 and thus more acidic) to be drawn up from depth to the ocean surface. This upwelling can have significant impacts on local OA and ecosystems, (4, 52) especially at eastern oceanic boundaries. (53, 54)
It is important to emphasize that the use of Earth observation data to derive carbonate parameters should not be seen as a replacement for in situ measurement campaigns, especially due to the current reliance on empirical and regional algorithms. Earth observation algorithms need calibration and validation with in situ data such as those taken by GOA-ON, and if the carbonate system response changes over time, empirical and regional algorithms tuned to previous conditions may become less reliable.

4.2 Algorithms for Estimating Carbonate Parameters

The four key OA parameters (pCO2, DIC, TA, pH) are largely driven by temperature, salinity and biological activity, allowing empirical relationships to be developed using in situ measurements of OA parameters. Table 2 shows a range of published algorithms based on such relationships, while Figure 1 shows their geographical coverage. Both illustrate that most of the literature has focused on the northern basins of the Pacific and Atlantic and the Arctic, especially the Barents Sea, with all other regions only attracting algorithms for a single parameter or none at all.. (55)
Table 2. Example Regional Algorithms for Each Carbonate Parameter Illustrating the Variable Dependencies. Chl is Chlorophyll-a and MLD is Mixed Layer Depth
parameterdependenciesregion and references
pCO2SSTglobal, (56) Barents Sea (57)
SST, SSSBarents Sea, (58) Caribbean (14)
SST, ChlNorth Pacific (59)
SSS, ChlNorth Sea (60)
SST, SSS, ChlNorth Pacific (61)
SST, Chl, MLDBarents Sea (62)
 
TASSSBarents Sea (57)
SST, SSSglobal, (18, 63) Arctic (15)
SSS, nitrateGlobal (55)
 
DICSST, SSSEquatorial pacific (64)
SST, SSS, ChlArctic (15)
 
pHSST, ChlNorth Pacific (10)

Figure 1

Figure 1. Number of key carbonate parameters (fCO2 or pCO2, TA, DIC, pH) for which regional algorithms exist in the literature that can be implemented using just satellite Earth observation data. Regions are indicative of open ocean areas, as implementation of algorithms in coastal areas may be problematic.

NOAA’s experimental Ocean Acidification Product Suite (OAPS) is a regional example of using empirical algorithms with a combination of climatological SSS and satellite SST to provide synoptic estimates of sea surface carbonate chemistry in the Greater Caribbean Region. (14)pCO2 and TA were derived from climatological SSS and satellite SST, then used to calculate monthly estimates of the remaining carbonate parameters, including aragonite saturation state and carbonate ion concentration. In general the derived data were in good agreement with in situ measured data (e.g., mean derived TA = 2375 ± 36 μmol kg–1 compared to a mean ship-measured TA = 2366 ± 77 μmol kg–1). OAPS works well in areas where chlorophyll-a is low, however in regions of high chlorophyll-a, where net productivity is likely to perturb the carbonate system, and in areas where there are river inputs, the approach tends to underestimate aragonite saturation state, for example. (21)
A quite different approach is the assimilation of satellite data into ocean circulation models. (65) The model output carbonate parameters can then be used directly. This allows satellite-observed effects to be extended below the water surface, albeit with the uncertainties inherent in model data. Here we seek to assess the direct use of satellite data through empirical algorithms to improve OA estimates.

4.3 Regions of Interest for Earth Observation

Arctic Seas

It is increasingly recognized that the Polar Oceans (Arctic and Antarctic) are particularly sensitive to OA. (66) Lower alkalinity (and thus buffer capacity), enhanced warming, reduced sea-ice cover resulting in changes in the freshwater budget, (67) and nutrient limitation make it more vulnerable to future OA. (68) Retreating ice also provides increased open water for air-sea gas exchange and primary production. (69)
The remote nature of the Arctic Ocean provides difficulties for collecting in situ data sets, with limited ship, autonomous vehicle and buoy access, and in situ data collection during winter months is often impossible. Therefore, the use of remote sensing techniques is very attractive, if sufficient in situ data can be found to calibrate satellite algorithms, and if the challenges of Arctic remote sensing can be overcome. These waters are very challenging regions for satellite remote sensing. For instance, low water temperatures reduce the sensitivity range of SSS sensors, (43) and sea ice can complicate retrievals of SSS and chlorophyll-a. (70, 71) Improvement in the accuracy of high latitude satellite SSS is expected soon by combining observations from SMOS, Aquarius and the upcoming SMAP sensor, all polar-orbiting L-band radiometers.

The Bay of Bengal

This region is clearly a focus of current OA research with unique characteristics due to the large freshwater influence. The flow of fresh water from the Ganges Delta into Bay of Bengal (42 000 m3/sec) represents the second greatest discharge source in the world. Additionally, rainfall along with freshwater inputs exceeds evaporation, resulting in net water gain annually in the Bay of Bengal. Collectively these provide an annual positive water balance that reduces surface salinity by 3–7 g/kg compared to the adjacent Arabian Sea, (72, 73) resulting in distinctly different biogeochemical regimes. (74) Biogeochemically, the Indian Ocean is one of the least studied and most poorly understood ocean basins in the world. (74) This is particularly true for the Bay of Bengal where a relatively small number of hydrographic sections and underway surface observations have been undertaken, despite the notable influence of freshwater on particle dynamics, air-sea carbon flux and surface carbonate chemistry. (75-79) North of 15° S, TA increases relative to salinity, (80) indicating the presence of an important land source that can broadly affect acidification dynamics.
To date there is little work on acidification dynamics and air sea exchange of CO2 in the Bay of Bengal. (81-83) In 2013, the Bay of Bengal Ocean Acidification (BOBOA) Mooring was deployed for the first time in Bay of Bengal (15°N, 90°E) by PMEL (NOAA) and the Bay of Bengal Large Marine Ecosystem Program (BOBLME). Data from the buoy will improve our understanding of biogeochemical variations in the open ocean environment of the Bay of Bengal.
It is an open question whether SSS can be used to estimate TA in the Bay of Bengal. An important step toward answering this question would be to investigate the spatial variability of the TA to salinity relationship in the region. Use of satellite SSS in the region is also challenged by heavy radio frequency interference.

The Greater Caribbean and the Amazon plume

The reefs in the Greater Caribbean Region are economically important to the US and Caribbean nations with an estimated annual net value of US$3.1–4.6 billion in 2000. (84) At least two-thirds of these reefs are threatened from human impacts including OA. The skeleton of a coral is made of aragonite and the growth of their skeletons is reduced by OA, (6) and numerous studies have shown a net decline in coral calcification (growth) rates in accordance with declining CaCO3 saturation state. (85) The waters of the Greater Caribbean region are predominantly oligotrophic and similar to the subtropical gyre from which it receives most of its water. (14) While the often shallow water environments of coral reefs and the plethora of small islands can make it challenging for Earth observation instruments to collect reliable data, the oligotrophic nature and the similarities in water type across the whole region make it ideal for the development of novel products. This region therefore provides an ideal case study to develop and evaluate algorithms representative of a shallow, oligotrophic environment.
The Amazon plume, south of the Greater Caribbean, is the largest freshwater discharge source in the world (209 000 m3/sec). It can cause SSS decreases of several units many hundreds of kilometers from land, and has an area that seasonally can reach 106 km2. These characteristics make it an ideal case study for testing and evaluating remote sensing algorithms, particularly to study the space-time resolution trade-offs using SSS sensors.

5 Future Opportunities and Focus

Click to copy section linkSection link copied!

The Copernicus program is a European flagship initiative, worth more than €7 billion, which aims to provide an operational satellite monitoring capability and related services for the environment and security. (86) The launch of the Sentinel-1A satellite in 2014 signaled its start. Of the five Sentinel satellite types, Sentinels 2 and 3 are most appropriate for assessment of the marine carbonate system. (87-89) These satellites will provide chlorophyll-a and SST with unprecedented spatial and temporal coverage. The development of higher spatial resolution geostationary sensors that continually monitor chlorophyll-a and SST over the same area of the Earth also holds much potential for the future of OA assessment and research. (90) These satellites and sensors are able to provide 10 or more observations per day, allowing the study of the effect of tidal and diurnal cycles on OA. The societal importance of measuring and observing the global carbon cycle was further highlighted with the launch of the NASA Orbiting Carbon Observatory (OCO-2) in 2014. This satellite and its sensors are designed to observe atmospheric CO2 concentrations, but its potential for marine carbon cycle and OA is likely to be a focus of future research.
SMOS and Aquarius have recently passed their nominal lifetimes, with SMOS now extended until 2017. Based on the lifetimes of previous satellite Earth observation sensors, they may well operate until the early 2020s. NASA’s SMAP satellite, to be launched in January 2015, should provide short-term continuity. The development of the technology and the clear importance of monitoring ocean salinity are likely to support the development of future satellite sensors. Also, historical time series data from alternative microwave sensors hold the potential for a 10+ year time series of satellite based SSS observations, (91) and this sort of measurement record is likely to extend into the future as it forms the basis of a global SSS monitoring effort.
In summary, satellite products developed up to now in the OA context have been regional, empirical or derived with a limited variety of satellite data sets, rendering an effort to systematically exploit remote sensing assets (capitalizing on the recent advent of satellite salinity measurements) absolutely timely. To-date there is only regional application of satellite SST to address the issue of assessing OA, (62) along with two nonpeer-reviewed attempts to calculate carbonate system products using satellite SSS data. (92, 93) Supported by good in situ measurement campaigns, especially in places with currently poor in situ coverage such as the Arctic, satellite measurements are likely to become a key element in understanding and assessing OA.

Author Information

Click to copy section linkSection link copied!

  • Corresponding Author
    • Peter E. Land - Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, U.K. Email: [email protected]
  • Authors
    • Jamie D. Shutler - University of Exeter, Penryn Campus, Cornwall TR10 9FE, U.K.
    • Helen S. Findlay - Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth PL1 3DH, U.K.
    • Fanny Girard-Ardhuin - Institut Francais Recherche Pour ĹExploitation de la Mer, Pointe du Diable, 29280 Plouzané France
    • Roberto Sabia - Telespazio-Vega U.K. for European Space Agency (ESA), ESTEC, Noordwijk, The Netherlands
    • Nicolas Reul - Institut Francais Recherche Pour ĹExploitation de la Mer, Pointe du Diable, 29280 Plouzané France
    • Jean-Francois Piolle - Institut Francais Recherche Pour ĹExploitation de la Mer, Pointe du Diable, 29280 Plouzané France
    • Bertrand Chapron - Institut Francais Recherche Pour ĹExploitation de la Mer, Pointe du Diable, 29280 Plouzané France
    • Yves Quilfen - Institut Francais Recherche Pour ĹExploitation de la Mer, Pointe du Diable, 29280 Plouzané France
    • Joseph Salisbury - Ocean Processes Analysis Laboratory, University of New Hampshire, Durham, New Hampshire 3824, United States
    • Douglas Vandemark - Ocean Processes Analysis Laboratory, University of New Hampshire, Durham, New Hampshire 3824, United States
    • Richard Bellerby - Norwegian Institute for Water Research, Thormøhlensgate 53 D, N-5006 Bergen, Norway
    • Punyasloke Bhadury - Department of Biological Sciences, Indian Institute of Science Education and Research-Kolkata, Mohanpur 741 246, West Bengal India
  • Author Contributions

    The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.

  • Funding

    This work was funded by the European Space Agency Support to Science Element Pathfinders Ocean Acidification project (contract No. 4000110778/14/I-BG).

  • Notes
    The authors declare no competing financial interest.

Biography

Click to copy section linkSection link copied!

Peter Land is a remote sensing scientist at Plymouth Marine Laboratory (PML), specializing in atmosphere-ocean gas exchange and carbonate chemistry. Jamie Shutler is an oceanographer and former European Space Agency (ESA) fellow specializing in atmosphere-ocean gas exchange at the University of Exeter. Helen Findlay is an oceanographer at PML specializing in ocean acidification and carbonate chemistry. Fanny Girard-Ardhuin is a remote sensing scientist specializing in sea ice at l’Institut Français de Recherche pour l’Exploitation de la Mer (Ifremer). Nicolas Reul is a remote sensing scientist at Ifremer and member of the SMOS scientific team. Jean-Francois Piolle is a computer scientist at Ifremer. Bertrand Chapron leads remote sensing research at Ifremer. Yves Quilfen is an altimetry remote sensing scientist at Ifremer. Joseph Salisbury and Douglas Vandemark are oceanographers at the University of New Hampshire focusing on biogeochemistry and ecology in coastal areas. Richard Bellerby is a chemical oceanographer at the Norwegian Institute for Water Research, a member of the GOA-ON executive committee, and leader of the AMAP and SCAR ocean acidification working groups. Punyasloke Bhadury is a coastal ecologist at the Indian Institute of Science Education and Research-Kolkata. Roberto Sabia is a specialist in remote sensing of salinity working for ESA.

Acknowledgment

Click to copy section linkSection link copied!

This work was enabled by European Space Agency (ESA) Support to Science Element (STSE) Pathfinders Ocean Acidification project (contract No. 4000110778/14/I-BG). The authors gratefully acknowledge the assistance of Diego Fernandez (STSE programme manager).

References

Click to copy section linkSection link copied!

This article references 93 other publications.

  1. 1
    Stocker, T. F., Qin, D., Plattner, G. K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P. M.Climate Change 2013: The Physical Science Basis. Intergovernmental Panel on Climate Change, Working Group I Contribution to the IPCC Fifth Assessment Report (AR5); Cambridge Univ. Press: New York, 2013.
  2. 2
    Fabry, V. J.; Seibel, B. A.; Feely, R. A.; Orr, J. C. Impacts of ocean acidification on marine fauna and ecosystem processes ICES J. Mar. Sci. 2008, 65 (3) 414 432
  3. 3
    Turley, C.; Eby, M.; Ridgwell, A. J.; Schmidt, D. N.; Findlay, H. S.; Brownlee, C.; Riebesell, U.; Fabry, V. J.; Feely, R. A.; Gattuso, J. P. The societal challenge of ocean acidification Mar. Pollut. Bull. 2010, 60 (6) 787 792
  4. 4
    Feely, R. A.; Sabine, C. L.; Hernandez-Ayon, J. M.; Ianson, D.; Hales, B. Evidence for upwelling of corrosive “acidified” water onto the continental shelf Science 2008, 320 (5882) 1490 1492
  5. 5
    Bellerby, R. G. J. UN biodiversity and OA report. http://www.cbd.int/ts.
  6. 6
    Kroeker, K. J.; Kordas, R. L.; Crim, R.; Hendriks, I. E.; Ramajo, L.; Singh, G. S.; Duarte, C. M.; Gattuso, J. P. Impacts of ocean acidification on marine organisms: Quantifying sensitivities and interaction with warming Global Change Biol. 2013,  DOI: 10.1111/gcb.12179
  7. 7
    Salisbury, J.; Green, M.; Hunt, C.; Campbell, J. Coastal acidification by rivers: A threat to shellfish? Eos, Trans. Am. Geophys. Union 2008, 89 (50) 513
  8. 8
    Widdicombe, S.; Spicer, J. I. Predicting the impact of ocean acidification on benthic biodiversity: What can animal physiology tell us? J. Exper. Mar. Biol. Ecol. 2008, 366 (1) 187 197
  9. 9
    Ridgwell, A.; Schmidt, D. N.; Turley, C.; Brownlee, C.; Maldonado, M. T.; Tortell, P.; Young, J. R. From laboratory manipulations to Earth system models: Scaling calcification impacts of ocean acidification Biogeosciences 2009, 6 (11) 2611 2623
  10. 10
    Nakano, Y.; Watanabe, Y. W. Reconstruction of pH in the surface seawater over the north Pacific basin for all seasons using temperature and chlorophyll-a J. Oceanogr. 2005, 61 (4) 673 680
  11. 11
    Juranek, L. W.; Feely, R. A.; Peterson, W. T.; Alin, S. R.; Hales, B.; Lee, K.; Sabine, C. L.; Peterson, J. A novel method for determination of aragonite saturation state on the continental shelf of central Oregon using multi-parameter relationships with hydrographic data Geophys. Res. Lett. 2009, 36 (24) L24601
  12. 12
    Midorikawa, T.; Inoue, H. Y.; Ishii, M.; Sasano, D.; Kosugi, N.; Hashida, G.; Nakaoka, S.-i.; Suzuki, T. Decreasing pH trend estimated from 35-year time series of carbonate parameters in the Pacific sector of the Southern Ocean in summer Deep Sea Res., Part I 2012, 61, 131 139
  13. 13
    Bostock, H. C.; Mikaloff Fletcher, S. E.; Williams, M. J. M. Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere Oceans Biogeosci. Discuss. 2013, 10 (4) 6225 6257
  14. 14
    Gledhill, D. K.; Wanninkhof, R.; Millero, F. J.; Eakin, M. Ocean acidification of the greater Caribbean region 1996–2006 J. Geophys. Res. 2008, 113 (C10) C10031
  15. 15
    Arrigo, K. R.; Pabi, S.; van Dijken, G. L.; Maslowski, W. Air-sea flux of CO2 in the Arctic Ocean, 1998–2003 J. Geophys. Res. 2010, 115 (G4) G04024
  16. 16
    Dickson, A. G.; Goyet, C. Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water, 1992; Vol. 2.
  17. 17
    Weiss, R. F. Carbon dioxide in water and seawater: The solubility of a non-ideal gas Mar. Chem. 1974, 2 (3) 203 215
  18. 18
    Lee, K.; Tong, L. T.; Millero, F. J.; Sabine, C. L.; Dickson, A. G.; Goyet, C.; Park, G. H.; Wanninkhof, R.; Feely, R. A.; Key, R. M., Global relationships of total alkalinity with salinity and temperature in surface waters of the world’s oceans. Geophys. Res. Lett. 2006, 33, (19).
  19. 19
    Smith, S. V.; Key, G. S. Carbon dioxide and metabolism in marine environments Limnol. Oceanogr 1975, 20 (3) 493 495
  20. 20
    Sarmiento, J. L.; Gruber, N. Ocean Biogeochemical Dynamics; Cambridge University Press, 2006; Vol. 503.
  21. 21
    Gledhill, D. K.; Wanninkhof, R.; Eakin, C. M., Observing ocean acidification from space. Oceanography 2009, 22.
  22. 22
    Sun, Q.; Tang, D.; Wang, S. Remote-sensing observations relevant to ocean acidification Int. J. Rem. Sensing 2012, 33 (23) 7542 7558
  23. 23
    Dickson, A. G., The carbon dioxide system in seawater: Equilibrium chemistry and measurements. In Guide to Best Practices for Ocean Acidification Research and Data Reporting, Riebesell, U.; Fabry, C. J.; Hansson, L.; Gattuso, J.-P., Eds.; European Commission: Brussels, 2011; pp 17 40.
  24. 24
    Dickson, A. G.; Sabine, C. L.; Christian, J. R.Guide to Best Practices for Ocean CO2 Measurements, PICES Special Publication 3, 2007
  25. 25
    Byrne, R. H. Measuring Ocean Acidification: New Technology for a New Era of Ocean Chemistry Environ. Sci. Technol. 2014, 48 (10) 5352 5360
  26. 26
    Martz, T. R.; Connery, J. G.; Johnson, K. S. Testing the Honeywell Durafet® for seawater pH applications Limnol. Oceanogr. Methods 2010, 8, 172 184
  27. 27
    Bakker, D. C. E.; Hankin, S.; Olsen, A.; Pfeil, B.; Smith, K.; Alin, S. R.; Cosca, C.; Hales, B.; Harasawa, S.; Kozyr, A. An update to the surface ocean CO2 Atlas (SOCAT version 2) Earth Syst. Sci. Data 2014,  DOI: 10.5194/essd-6-69-2014
  28. 28
    Takahashi, T.; Sutherland, S. C.; Kozyr, A. Global Ocean Surface Water Partial Pressure of CO2 Database: Measurements Performed During 1957–2012 (Version 2012), ORNL/CDIAC-160, NDP-088(V2012); Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2013.
  29. 29
    Key, R. M.; Kozyr, A.; Sabine, C. L.; Lee, K.; Wanninkhof, R.; Bullister, J. L.; Feely, R. A.; Millero, F. J.; Mordy, C.; Peng, T. H., A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Global Biogeochem. Cycles 2004, 18, (4).
  30. 30
    CARINA group. Carbon in the Arctic Mediterranean Seas Region—The CARINA Project: Results and Data, Version 1.2; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2009.
  31. 31
    CARINA group. Carbon in the Atlantic Ocean Region—The CARINA Project: Results and Data, Version 1.0.; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2009.
  32. 32
    CARINA group. Carbon in the Southern Ocean Region—The CARINA Project: Results and Data, Version 1.1.; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2010.
  33. 33
    Robinson, C.; Holligan, P.; Jickells, T.; Lavender, S. The Atlantic Meridional Transect Programme (1995–2012) Deep Sea Res., Part II 2009, 56 (15) 895 898
  34. 34
    Yakushev, E. V.; Sørensen, K. On seasonal changes of the carbonate system in the Barents Sea: Observations and modeling Mar. Biol. Res. 2013, 9 (9) 822 830
  35. 35
    Skjelvan, I.; Falck, E.; Rey, F.; Kringstad, S. B. Inorganic carbon time series at Ocean Weather Station M in the Norwegian Sea Biogeosciences 2008, 5, 549 560
  36. 36
    McPhaden, M. J.; Meyers, G.; Ando, K.; Masumoto, Y.; Murty, V. S. N.; Ravichandran, M.; Syamsudin, F.; Vialard, J.; Yu, L.; Yu, W. RAMA: The Research Moored Array for African–asian–australian Monsoon Analysis and Prediction, 2009
  37. 37
    ARGO Argo - part of the integrated global observationstrategy. http://www.argo.ucsd.edu (14/12/ 2014) ,.
  38. 38
    OOI Ocean Observatories Initiative. http://oceanobservatories.org (14/12/ 2014) ,.
  39. 39
    SOCCOM, Southern Ocean Carbon and Climate Observations and Modeling. http://soccom.princeton.edu (accessed December 14, 2014).
  40. 40
    Merchant, C. J.; Embury, O.; Rayner, N. A.; Berry, D. I.; Corlett, G. K.; Lean, K.; Veal, K. L.; Kent, E. C.; Llewellyn-Jones, D. T.; Remedios, J. J., A 20 year independent record of sea surface temperature for climate from Along–Track Scanning Radiometers. J. Geophys. Res.: Oceans 2012, 117, (C12).
  41. 41
    McClain, C. R.; Feldman, G. C.; Hooker, S. B. An overview of the SeaWiFS project and strategies for producing a climate research quality global ocean bio-optical time series Deep Sea Res., Part II 2004, 51 (1) 5 42
  42. 42
    Font, J.; Boutin, J.; Reul, N.; Spurgeon, P.; Ballabrera-Poy, J.; Chuprin, A.; Gabarró, C.; Gourrion, J.; Guimbard, S.; Hénocq, C. SMOS first data analysis for sea surface salinity determination Int. J. Rem. Sens. 2013, 34 (9–10) 3654 3670
  43. 43
    Font, J.; Camps, A.; Borges, A.; Martín-Neira, M.; Boutin, J.; Reul, N.; Kerr, Y. H.; Hahne, A.; Mecklenburg, S. SMOS: The challenging sea surface salinity measurement from space Proc. IEEE 2010, 98 (5) 649 665
  44. 44
    Boutin, J.; Martin, N.; Reverdin, G.; Morisset, S.; Yin, X.; Centurioni, L.; Reul, N. Sea surface salinity under rain cells: SMOS satellite and in situ drifters observations J. Geophys. Res.: Oceans 2014, 119 (8) 5533 5545
  45. 45
    Reul, N.; Chapron, B.; Lee, T.; Donlon, C.; Boutin, J.; Alory, G. Sea surface salinity structure of the meandering Gulf Stream revealed by SMOS sensor Geophys. Res. Lett. 2014, 41 (9) 3141 3148
  46. 46
    Boutin, J.; Martin, N.; Reverdin, G.; Yin, X.; Gaillard, F. Sea surface freshening inferred from SMOS and ARGO salinity: Impact of rain Ocean Sci. 2013, 9, 183 192
  47. 47
    Sabia, R.; Klockmann, M. Fernández-Prieto, D.; Donlon, C., A first estimation of SMOS-based ocean surface T-S diagrams J. Geophys. Res.: Oceans 2014, 119 (10) 7357 7371
  48. 48
    Hosoda, S.; Ohira, T.; Nakamura, T. A monthly mean dataset of global oceanic temperature and salinity derived from Argo float observations JAMSTEC Rep. Res. Dev 2008, 8, 47 59
  49. 49
    Reul, N.; Fournier, S.; Boutin, J.; Hernandez, O.; Maes, C.; Chapron, B.; Alory, G.; Quilfen, Y.; Tenerelli, J.; Morisset, S. Sea surface salinity observations from space with the SMOS satellite: A new means to monitor the marine branch of the water cycle Surv. Geophysics 2014, 35 (3) 681 722
  50. 50
    Laxon, S. W.; Giles, K. A.; Ridout, A. L.; Wingham, D. J.; Willatt, R.; Cullen, R.; Kwok, R.; Schweiger, A.; Zhang, J.; Haas, C. CryoSat-2 estimates of Arctic sea ice thickness and volume Geophys. Res. Lett. 2013, 40 (4) 732 737
  51. 51
    Kaleschke, L.; Tian-Kunze, X.; Maaß, N.; Mäkynen, M.; Drusch, M., Sea ice thickness retrieval from SMOS brightness temperatures during the Arctic freeze-up period. Geophys. Res. Lett. 2012, 39, (5).
  52. 52
    Mathis, J. T.; Pickart, R. S.; Byrne, R. H.; McNeil, C. L.; Moore, G. W. K.; Juranek, L. W.; Liu, X.; Ma, J.; Easley, R. A.; Elliot, M. M., Storm-induced upwelling of high pCO2 waters onto the continental shelf of the western Arctic Ocean and implications for carbonate mineral saturation states. Geophys. Res. Lett. 2012, 39, (7).
  53. 53
    Mahadevan, A.; Tagliabue, A.; Bopp, L.; Lenton, A.; Memery, L.; Lévy, M. Impact of episodic vertical fluxes on sea surface pCO2 Philos. Trans. R. Soc., A 2011, 369 (1943) 2009 2025
  54. 54
    Mahadevan, A. Ocean science: Eddy effects on biogeochemistry Nature 2014, 506, 168 169
  55. 55
    Takahashi, T.; Sutherland, S. Climatological Mean Distribution of pH and Carbonate Ion Concentration in Global Ocean Surface Waters in the Unified pH Scale and Mean Rate of Their Changes in Selected Areas, OCE 10-38891; National Science Foundation: Washington, D. C., USA,, 2013.
  56. 56
    Goddijn-Murphy, L. M.; Woolf, D. K.; Land, P. E.; Shutler, J. D.; Donlon, C. Deriving a sea surface climatology of CO2 fugacity in support of air-sea gas flux studies Ocean Sci. Discuss. 2014, 11, 1895 1948
  57. 57
    Årthun, M.; Bellerby, R. G. J.; Omar, A. M.; Schrum, C. Spatiotemporal variability of air–sea CO < sub> 2</sub> fluxes in the Barents Sea, as determined from empirical relationships and modeled hydrography J. Mar. Syst. 2012, 98, 40 50
  58. 58
    Friedrich, T.; Oschlies, A., Basin-scale pCO2 maps estimated from ARGO float data: A model study. J. Geophys. Res.: Oceans 2009, 114, (C10).
  59. 59
    Ono, T.; Saino, T.; Kurita, N.; Sasaki, K. Basin-scale extrapolation of shipboard pCO2 data by using satellite SST and Chla Int. J. Rem. Sens. 2004, 25 (19) 3803 3815
  60. 60
    Borges, A. V.; Ruddick, K.; Lacroix, G.; Nechad, B.; Asteroca, R.; Rousseau, V.; Harlay, J., Estimating pCO2 from remote sensing in the Belgian coastal zone. ESA Spec. Publ. 2010, 686.
  61. 61
    Sarma, V. V. S. S.; Saino, T.; Sasaoka, K.; Nojiri, Y.; Ono, T.; Ishii, M.; Inoue, H. Y.; Matsumoto, K., Basin-scale pCO2 distribution using satellite sea surface temperature, Chl a, and climatological salinity in the North Pacific in spring and summer. Global Biogeochem. Cycles 2006, 20, (3).
  62. 62
    Lauvset, S. K.; Chierici, M.; Counillon, F.; Omar, A.; Nondal, G.; Johannessen, T.; Olsen, A. Annual and seasonal fCO2 and air–sea CO2 fluxes in the Barents Sea J. Mar. Syst. 2013,  DOI: 10.1016/j.jmarsys.2012.12.011
  63. 63
    Millero, F. J.; Lee, K.; Roche, M. Distribution of alkalinity in the surface waters of the major oceans Mar. Chem. 1998, 60 (1) 111 130
  64. 64
    Loukos, H.; Vivier, F.; Murphy, P. P.; Harrison, D. E.; Le Quéré, C. Interannual variability of equatorial Pacific CO2 fluxes estimated from temperature and salinity data Geophys. Res. Lett. 2000, 27 (12) 1735 1738
  65. 65
    Anderson, D.; Sheinbaum, J.; Haines, K. Data assimilation in ocean models Rep. Prog. Phys. 1996, 59 (10) 1209
  66. 66
    Steinacher, M.; Joos, F.; Frölicher, T. L.; Plattner, G. K.; Doney, S. C. Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model Biogeosciences 2009, 6 (4) 515 533
  67. 67
    Peterson, B. J.; Holmes, R. M.; McClelland, J. W.; Vörösmarty, C. J.; Lammers, R. B.; Shiklomanov, A. I.; Shiklomanov, I. A.; Rahmstorf, S. Increasing river discharge to the Arctic Ocean Science 2002, 298 (5601) 2171 2173
  68. 68
    Shadwick, E. H.; Trull, T. W.; Thomas, H.; Gibson, J. A. E., Vulnerability of polar oceans to anthropogenic acidification: Comparison of arctic and antarctic seasonal cycles. Sci. Rep. 2013, 3.
  69. 69
    McGuire, A. D.; Anderson, L. G.; Christensen, T. R.; Dallimore, S.; Guo, L.; Hayes, D. J.; Heimann, M.; Lorenson, T. D.; Macdonald, R. W.; Roulet, N. Sensitivity of the carbon cycle in the Arctic to climate change Ecol. Monogr. 2009, 79 (4) 523 555
  70. 70
    Zine, S.; Boutin, J.; Font, J.; Reul, N.; Waldteufel, P.; Gabarró, C.; Tenerelli, J.; Petitcolin, F.; Vergely, J. L.; Talone, M. Overview of the SMOS sea surface salinity prototype processor IEEE Trans. Geosci. Rem. Sens. 2008, 46 (3) 621 645
  71. 71
    Bélanger, S.; Ehn, J. K.; Babin, M. Impact of sea ice on the retrieval of water-leaving reflectance, chlorophyll a concentration and inherent optical properties from satellite ocean color data Rem. Sens. Environ. 2007, 111 (1) 51 68
  72. 72
    Varkey, M. J.; Murty, V. S. N.; Suryanarayana, A. Physical oceanography of the Bay of Bengal and Andaman Sea Oceanogr. Mar. Biol.: Annu. Rev. 1996, 34, 1 70p
  73. 73
    Vinayachandran, P. N.; Murty, V. S. N.; Ramesh Babu, V. Observations of barrier layer formation in the Bay of Bengal during summer monsoon J. Geophys. Res.: Oceans 2002, 107 (C12) SRF-19
  74. 74
    International CLIVAR Project Office Understanding The Role Of The Indian Ocean In The Climate System—Implementation Plan For Sustained Observations; International CLIVAR Project Office: 2006.
  75. 75
    Sarma, V. V. S. S.; Krishna, M. S.; Rao, V. D.; Viswanadham, R.; Kumar, N. A.; Kumari, T. R.; Gawade, L.; Ghatkar, S.; Tari, A. Sources and sinks of CO2 in the west coast of Bay of Bengal Tellus B 2012, 64, 10961
  76. 76
    Madhupratap, M.; Gauns, M.; Ramaiah, N.; Prasanna Kumar, S.; Muraleedharan, P. M.; De Sousa, S. N.; Sardessai, S.; Muraleedharan, U. Biogeochemistry of the Bay of Bengal: Physical, chemical and primary productivity characteristics of the central and western Bay of Bengal during summer monsoon 2001 Deep Sea Res., Part II 2003, 50 (5) 881 896
  77. 77
    Ittekkot, V.; Nair, R. R.; Honjo, S.; Ramaswamy, V.; Bartsch, M.; Manganini, S.; Desai, B. N. Enhanced particle fluxes in Bay of Bengal induced by injection of fresh water Nature 1991, 351 (6325) 385 387
  78. 78
    Ramaswamy, V.; Nair, R. R. Fluxes of material in the Arabian Sea and Bay of Bengal—Sediment trap studies Proc. - Indian Acad. Sci., Earth Planet. Sci. 1994, 103 (2) 189 210
  79. 79
    Gomes, H. R.; Goes, J. I.; Saino, T. Influence of physical processes and freshwater discharge on the seasonality of phytoplankton regime in the Bay of Bengal Continental Shelf Research 2000, 20 (3) 313 330
  80. 80
    Sabine, C. L.; Key, R. M.; Feely, R. A.; Greeley, D. Inorganic carbon in the Indian Ocean: Distribution and dissolution processes Global Biogeochem. Cycles 2002, 16 (4) 1067
  81. 81
    Biswas, H.; Mukhopadhyay, S. K.; De, T. K.; Sen, S.; Jana, T. K. Biogenic controls on the air-water carbon dioxide exchange in the Sundarban mangrove environment, northeast coast of Bay of Bengal, India Limnolo. Oceanogr. 2004, 49 (1) 95 101
  82. 82
    PrasannaKumar, S.; Sardessai, S.; Ramaiah, N.; Bhosle, N. B.; Ramaswamy, V.; Ramesh, R.; Sharada, M. K.; Sarin, M. M.; Sarupria, J. S.; Muraleedharan, U. Bay of Bengal Process Studies Final Report; NIO: Goa, India, 2006; p 141.
  83. 83
    Akhand, A.; Chanda, A.; Dutta, S.; Manna, S.; Hazra, S.; Mitra, D.; Rao, K. H.; Dadhwal, V. K. Characterizing air–sea CO2 exchange dynamics during winter in the coastal water off the Hugli-Matla estuarine system in the northern Bay of Bengal, India J. Oceanogr. 2013, 69 (6) 687 697
  84. 84
    Burke, L. M.; Maidens, J. Reefs at Risk in the Caribbean; World Resources Institute: Washington, DC, 2004.
  85. 85
    Langdon, C.; Atkinson, M. J., Effect of elevated pCO2 on photosynthesis and calcification of corals and interactions with seasonal change in temperature/irradiance and nutrient enrichment. J. Geophys. Res.: Oceans 2005, 110, (C9).
  86. 86
    Aschbacher, J.; Milagro-Pérez, M. P. The European Earth monitoring (GMES) programme: Status and perspectives Rem. Sens. Environ. 2012, 120, 3 8
  87. 87
    Berger, M.; Moreno, J.; Johannessen, J. A.; Levelt, P. F.; Hanssen, R. F. ESA’s sentinel missions in support of Earth system science Rem. Sens. Environ. 2012, 120, 84 90
  88. 88
    Drusch, M.; Del Bello, U.; Carlier, S.; Colin, O.; Fernandez, V.; Gascon, F.; Hoersch, B.; Isola, C.; Laberinti, P.; Martimort, P. Sentinel-2: ESA’s optical high-resolution mission for GMES operational services Rem. Sens. Environ. 2012, 120, 25 36
  89. 89
    Donlon, C.; Berruti, B.; Buongiorno, A.; Ferreira, M. H.; Féménias, P.; Frerick, J.; Goryl, P.; Klein, U.; Laur, H.; Mavrocordatos, C. The global monitoring for environment and security (GMES) sentinel-3 mission Rem. Sens. Environ. 2012, 120, 37 57
  90. 90
    IOCCG. http://www.ioccg.org/sensors/GOCI.html (accessed August 27, 2014).
  91. 91
    Reul, N.; Saux-Picart, S.; Chapron, B.; Vandemark, D.; Tournadre, J.; Salisbury, J., Demonstration of ocean surface salinity microwave measurements from space using AMSR-E data over the Amazon plume. Geophys. Res. Lett. 2009, 36, (13).
  92. 92
    Sabia, R.; Fernández-Prieto, D.; Donlon, C.; Shutler, J.; Reul, N. In A Preliminary Attempt to Estimate Surface Ocean pH from Satellite Observations; IMBER Open Science Conference: Bergen, Norway, 2014.
  93. 93
    Willey, D. A.; Fine, R. A.; Millero, F. J. Global surface alkalinity from Aquarius satellite. In Ocean Sciences Meeting, Honolulu, HI, 2014.

Cited By

Click to copy section linkSection link copied!

This article is cited by 32 publications.

  1. David S. Trossman, Robert H. Tyler, Helen R. Pillar. Physical oceanographic factors controlling the ocean circulation-induced magnetic field. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2024, 382 (2286) https://doi.org/10.1098/rsta.2024.0076
  2. Susan L. Ustin, Elizabeth McPhee Middleton. Current and Near-Term Earth-Observing Environmental Satellites, Their Missions, Characteristics, Instruments, and Applications. Sensors 2024, 24 (11) , 3488. https://doi.org/10.3390/s24113488
  3. Jamie D. Shutler, Nicolas Gruber, Helen S. Findlay, Peter E. Land, Luke Gregor, Thomas Holding, Richard P. Sims, Hannah Green, Jean-Francois Piolle, Bertrand Chapron, Shubha Sathyendranath, Cecile S. Rousseaux, Craig J. Donlon, Sarah Cooley, Jessie Turner, Alexis Valauri-Orton, Kaitlyn Lowder, Steve Widdicombe, Jan Newton, Roberto Sabia, Marie-Helene Rio, Lucile Gaultier. The increasing importance of satellite observations to assess the ocean carbon sink and ocean acidification. Earth-Science Reviews 2024, 250 , 104682. https://doi.org/10.1016/j.earscirev.2024.104682
  4. C. Frangoulis, N. Stamataki, M. Pettas, S. Michelinakis, A. L. King, L. Giannoudi, K. Tsiaras, S. Christodoulaki, J. Seppälä, M. Thyssen, A.V. Borges, E. Krasakopoulou. A carbonate system time series in the Eastern Mediterranean Sea. Two years of high-frequency in-situ observations and remote sensing. Frontiers in Marine Science 2024, 11 https://doi.org/10.3389/fmars.2024.1348161
  5. Hannah L. Green, Helen S. Findlay, Jamie D. Shutler, Richard Sims, Richard Bellerby, Peter E. Land. Observing Temporally Varying Synoptic‐Scale Total Alkalinity and Dissolved Inorganic Carbon in the Arctic Ocean. Earth and Space Science 2023, 10 (12) https://doi.org/10.1029/2023EA002901
  6. Smitha Ratheesh, Neeraj Agarwal, Rashmi Sharma. An observing system experiment framework for the tropical Indian Ocean salinity: A case study using a constellation of three satellites. Deep Sea Research Part II: Topical Studies in Oceanography 2023, 212 , 105345. https://doi.org/10.1016/j.dsr2.2023.105345
  7. Nadezhda Drumeva, Milen Chanev. STUDYING OF THE SATELLITE BASED MODELS FOR LOCAL SPATIO-TEMPORAL MONITORING OF OCEAN ACIDIFICATION IN COSTAL SEA WATER IN BLACK SEA. Ecological Engineering and Environment Protection 2023, 2023 (2/2023) , 34-41. https://doi.org/10.32006/eeep.2023.2.3441
  8. Hanisha Mamidisetti, Ritesh Vijay. Dynamics of sewage outfall plumes based on Landsat-8-derived sea surface salinity and tidal characteristics. Environmental Science and Pollution Research 2023, 30 (34) , 82311-82325. https://doi.org/10.1007/s11356-023-28137-0
  9. Robert J.W. Brewin, Shubha Sathyendranath, Gemma Kulk, Marie-Hélène Rio, Javier A. Concha, Thomas G. Bell, Astrid Bracher, Cédric Fichot, Thomas L. Frölicher, Martí Galí, Dennis Arthur Hansell, Tihomir S. Kostadinov, Catherine Mitchell, Aimee Renee Neeley, Emanuele Organelli, Katherine Richardson, Cécile Rousseaux, Fang Shen, Dariusz Stramski, Maria Tzortziou, Andrew J. Watson, Charles Izuma Addey, Marco Bellacicco, Heather Bouman, Dustin Carroll, Ivona Cetinić, Giorgio Dall’Olmo, Robert Frouin, Judith Hauck, Martin Hieronymi, Chuanmin Hu, Valeria Ibello, Bror Jönsson, Christina Eunjin Kong, Žarko Kovač, Marko Laine, Jonathan Lauderdale, Samantha Lavender, Eleni Livanou, Joan Llort, Larisa Lorinczi, Michael Nowicki, Novia Arinda Pradisty, Stella Psarra, Dionysios E. Raitsos, Ana Belén Ruescas, Joellen L. Russell, Joe Salisbury, Richard Sanders, Jamie D. Shutler, Xuerong Sun, Fernando González Taboada, Gavin H. Tilstone, Xinyuan Wei, David K. Woolf. Ocean carbon from space: Current status and priorities for the next decade. Earth-Science Reviews 2023, 240 , 104386. https://doi.org/10.1016/j.earscirev.2023.104386
  10. Richard P. Sims, Thomas M. Holding, Peter E. Land, Jean-Francois Piolle, Hannah L. Green, Jamie D. Shutler. OceanSODA-UNEXE: a multi-year gridded Amazon and Congo River outflow surface ocean carbonate system dataset. Earth System Science Data 2023, 15 (6) , 2499-2516. https://doi.org/10.5194/essd-15-2499-2023
  11. Kunal Madkaiker, Vinu Valsala, M. G. Sreeush, Anju Mallissery, Kunal Chakraborty, Aditi Deshpande. Understanding the Seasonality, Trends, and Controlling Factors of Indian Ocean Acidification Over Distinctive Bio‐Provinces. Journal of Geophysical Research: Biogeosciences 2023, 128 (1) https://doi.org/10.1029/2022JG006926
  12. Aadidev Sooknanan, Patrick Hosein. Estimating the carbon content of oceans using satellite sensor data. Journal of Big Data 2022, 9 (1) https://doi.org/10.1186/s40537-022-00647-7
  13. Meisam Amani, Farzane Mohseni, Nasir Farsad Layegh, Mohsen Eslami Nazari, Farzam Fatolazadeh, Abbas Salehi, Seyed Ali Ahmadi, Hamid Ebrahimy, Arsalan Ghorbanian, Shuanggen Jin, Sahel Mahdavi, Armin Moghimi. Remote Sensing Systems for Ocean: A Review (Part 2: Active Systems). IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 2022, 15 , 1421-1453. https://doi.org/10.1109/JSTARS.2022.3141980
  14. J. Boutin, N. Reul, J. Koehler, A. Martin, R. Catany, S. Guimbard, F. Rouffi, J. L. Vergely, M. Arias, M. Chakroun, G. Corato, V. Estella‐Perez, A. Hasson, S. Josey, D. Khvorostyanov, N. Kolodziejczyk, J. Mignot, L. Olivier, G. Reverdin, D. Stammer, A. Supply, C. Thouvenin‐Masson, A. Turiel, J. Vialard, P. Cipollini, C. Donlon, R. Sabia, S. Mecklenburg. Satellite‐Based Sea Surface Salinity Designed for Ocean and Climate Studies. Journal of Geophysical Research: Oceans 2021, 126 (11) https://doi.org/10.1029/2021JC017676
  15. Y. Quilfen, J. Shutler, J.-F. Piolle, E. Autret. Recent trends in the wind-driven California current upwelling system. Remote Sensing of Environment 2021, 261 , 112486. https://doi.org/10.1016/j.rse.2021.112486
  16. Robert J.W. Brewin, Shubha Sathyendranath, Trevor Platt, Heather Bouman, Stefano Ciavatta, Giorgio Dall'Olmo, James Dingle, Steve Groom, Bror Jönsson, Tihomir S. Kostadinov, Gemma Kulk, Marko Laine, Victor Martínez-Vicente, Stella Psarra, Dionysios E. Raitsos, Katherine Richardson, Marie-Hélène Rio, Cécile S. Rousseaux, Joe Salisbury, Jamie D. Shutler, Peter Walker. Sensing the ocean biological carbon pump from space: A review of capabilities, concepts, research gaps and future developments. Earth-Science Reviews 2021, 217 , 103604. https://doi.org/10.1016/j.earscirev.2021.103604
  17. Bijeesh Kozhikkodan Veettil, Raymond D. Ward, Mariana Do Amaral Camara Lima, Milica Stankovic, Pham Ngoc Hoai, Ngo Xuan Quang. Opportunities for seagrass research derived from remote sensing: A review of current methods. Ecological Indicators 2020, 117 , 106560. https://doi.org/10.1016/j.ecolind.2020.106560
  18. N. Reul, S.A. Grodsky, M. Arias, J. Boutin, R. Catany, B. Chapron, F. D'Amico, E. Dinnat, C. Donlon, A. Fore, S. Fournier, S. Guimbard, A. Hasson, N. Kolodziejczyk, G. Lagerloef, T. Lee, D.M. Le Vine, E. Lindstrom, C. Maes, S. Mecklenburg, T. Meissner, E. Olmedo, R. Sabia, J. Tenerelli, C. Thouvenin-Masson, A. Turiel, J.L. Vergely, N. Vinogradova, F. Wentz, S. Yueh. Sea surface salinity estimates from spaceborne L-band radiometers: An overview of the first decade of observation (2010–2019). Remote Sensing of Environment 2020, 242 , 111769. https://doi.org/10.1016/j.rse.2020.111769
  19. Oliver Legge, Martin Johnson, Natalie Hicks, Tim Jickells, Markus Diesing, John Aldridge, Julian Andrews, Yuri Artioli, Dorothee C. E. Bakker, Michael T. Burrows, Nealy Carr, Gemma Cripps, Stacey L. Felgate, Liam Fernand, Naomi Greenwood, Susan Hartman, Silke Kröger, Gennadi Lessin, Claire Mahaffey, Daniel J. Mayor, Ruth Parker, Ana M. Queirós, Jamie D. Shutler, Tiago Silva, Henrik Stahl, Jonathan Tinker, Graham J. C. Underwood, Johan Van Der Molen, Sarah Wakelin, Keith Weston, Phillip Williamson. Carbon on the Northwest European Shelf: Contemporary Budget and Future Influences. Frontiers in Marine Science 2020, 7 https://doi.org/10.3389/fmars.2020.00143
  20. Jamie D Shutler, Rik Wanninkhof, Philip D Nightingale, David K Woolf, Dorothee CE Bakker, Andy Watson, Ian Ashton, Thomas Holding, Bertrand Chapron, Yves Quilfen, Chris Fairall, Ute Schuster, Masakatsu Nakajima, Craig J Donlon. Satellites will address critical science priorities for quantifying ocean carbon. Frontiers in Ecology and the Environment 2020, 18 (1) , 27-35. https://doi.org/10.1002/fee.2129
  21. Peter E. Land, Helen S. Findlay, Jamie D. Shutler, Ian G.C. Ashton, Thomas Holding, Antoine Grouazel, Fanny Girard-Ardhuin, Nicolas Reul, Jean-Francois Piolle, Bertrand Chapron, Yves Quilfen, Richard G.J. Bellerby, Punyasloke Bhadury, Joseph Salisbury, Douglas Vandemark, Roberto Sabia. Optimum satellite remote sensing of the marine carbonate system using empirical algorithms in the global ocean, the Greater Caribbean, the Amazon Plume and the Bay of Bengal. Remote Sensing of Environment 2019, 235 , 111469. https://doi.org/10.1016/j.rse.2019.111469
  22. Daniele Ciani, Rosalia Santoleri, Gian Liberti, Catherine Prigent, Craig Donlon, Bruno Buongiorno Nardelli. Copernicus Imaging Microwave Radiometer (CIMR) Benefits for the Copernicus Level 4 Sea-Surface Salinity Processing Chain. Remote Sensing 2019, 11 (15) , 1818. https://doi.org/10.3390/rs11151818
  23. Nadya Vinogradova, Tong Lee, Jacqueline Boutin, Kyla Drushka, Severine Fournier, Roberto Sabia, Detlef Stammer, Eric Bayler, Nicolas Reul, Arnold Gordon, Oleg Melnichenko, Laifang Li, Eric Hackert, Matthew Martin, Nicolas Kolodziejczyk, Audrey Hasson, Shannon Brown, Sidharth Misra, Eric Lindstrom. Satellite Salinity Observing System: Recent Discoveries and the Way Forward. Frontiers in Marine Science 2019, 6 https://doi.org/10.3389/fmars.2019.00243
  24. Moacyr Araujo, Carlos Noriega, Carmen Medeiros, Nathalie Lefèvre, J. Severino P. Ibánhez, Manuel Flores Montes, Alex Costa da Silva, Maria de Lourdes Santos. On the variability in the CO2 system and water productivity in the western tropical Atlantic off North and Northeast Brazil. Journal of Marine Systems 2019, 189 , 62-77. https://doi.org/10.1016/j.jmarsys.2018.09.008
  25. Roberto Sabia, Estrella Olmedo, Antonio Turiel, Justino Martinez, A. Alvera-Azcarate. SMOS Satellite Inference of Alkalinity Over Mediterranean Basin. 2018, 1519-1522. https://doi.org/10.1109/IGARSS.2018.8518407
  26. William Ouellette, Wondifraw Getinet. Remote sensing for Marine Spatial Planning and Integrated Coastal Areas Management: Achievements, challenges, opportunities and future prospects. Remote Sensing Applications: Society and Environment 2016, 4 , 138-157. https://doi.org/10.1016/j.rsase.2016.07.003
  27. Claudia H. Fry, Toby Tyrrell, Eric P. Achterberg. Analysis of longitudinal variations in North Pacific alkalinity to improve predictive algorithms. Global Biogeochemical Cycles 2016, 30 (10) , 1493-1508. https://doi.org/10.1002/2016GB005398
  28. Linlin Wang, Qiang Li, Hongsheng Bi, Xian-zhong Mao. Human impacts and changes in the coastal waters of south China. Science of The Total Environment 2016, 562 , 108-114. https://doi.org/10.1016/j.scitotenv.2016.03.216
  29. B. Buongiorno Nardelli, R. Droghei, R. Santoleri. Multi-dimensional interpolation of SMOS sea surface salinity with surface temperature and in situ salinity data. Remote Sensing of Environment 2016, 180 , 392-402. https://doi.org/10.1016/j.rse.2015.12.052
  30. Jamie D. Shutler, Graham D. Quartly, Craig J. Donlon, Shubha Sathyendranath, Trevor Platt, Bertrand Chapron, Johnny A. Johannessen, Fanny Girard-Ardhuin, Philip D. Nightingale, David K. Woolf, Jacob L. Høyer. Progress in satellite remote sensing for studying physical processes at the ocean surface and its borders with the atmosphere and sea ice. Progress in Physical Geography: Earth and Environment 2016, 40 (2) , 215-246. https://doi.org/10.1177/0309133316638957
  31. Feng-Jiao Liu, Shun-Xing Li, Bang-Qin Huang, Feng-Ying Zheng, Xu-Guang Huang. Effect of excessive CO2 on physiological functions in coastal diatom. Scientific Reports 2016, 6 (1) https://doi.org/10.1038/srep21694
  32. Roberto Sabia, Diego Fernandez-Prieto, Jamie Shutler, Craig Donlon, Peter Land, Nicolas Reul. Remote sensing of surface ocean PH exploiting sea surface salinity satellite observations. 2015, 106-109. https://doi.org/10.1109/IGARSS.2015.7325709

Environmental Science & Technology

Cite this: Environ. Sci. Technol. 2015, 49, 4, 1987–1994
Click to copy citationCitation copied!
https://doi.org/10.1021/es504849s
Published January 8, 2015

Copyright © 2015 American Chemical Society. This publication is available under these Terms of Use.

Article Views

10k

Altmetric

-

Citations

Learn about these metrics

Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.

Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.

The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.

  • Abstract

    Figure 1

    Figure 1. Number of key carbonate parameters (fCO2 or pCO2, TA, DIC, pH) for which regional algorithms exist in the literature that can be implemented using just satellite Earth observation data. Regions are indicative of open ocean areas, as implementation of algorithms in coastal areas may be problematic.

  • References


    This article references 93 other publications.

    1. 1
      Stocker, T. F., Qin, D., Plattner, G. K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P. M.Climate Change 2013: The Physical Science Basis. Intergovernmental Panel on Climate Change, Working Group I Contribution to the IPCC Fifth Assessment Report (AR5); Cambridge Univ. Press: New York, 2013.
    2. 2
      Fabry, V. J.; Seibel, B. A.; Feely, R. A.; Orr, J. C. Impacts of ocean acidification on marine fauna and ecosystem processes ICES J. Mar. Sci. 2008, 65 (3) 414 432
    3. 3
      Turley, C.; Eby, M.; Ridgwell, A. J.; Schmidt, D. N.; Findlay, H. S.; Brownlee, C.; Riebesell, U.; Fabry, V. J.; Feely, R. A.; Gattuso, J. P. The societal challenge of ocean acidification Mar. Pollut. Bull. 2010, 60 (6) 787 792
    4. 4
      Feely, R. A.; Sabine, C. L.; Hernandez-Ayon, J. M.; Ianson, D.; Hales, B. Evidence for upwelling of corrosive “acidified” water onto the continental shelf Science 2008, 320 (5882) 1490 1492
    5. 5
      Bellerby, R. G. J. UN biodiversity and OA report. http://www.cbd.int/ts.
    6. 6
      Kroeker, K. J.; Kordas, R. L.; Crim, R.; Hendriks, I. E.; Ramajo, L.; Singh, G. S.; Duarte, C. M.; Gattuso, J. P. Impacts of ocean acidification on marine organisms: Quantifying sensitivities and interaction with warming Global Change Biol. 2013,  DOI: 10.1111/gcb.12179
    7. 7
      Salisbury, J.; Green, M.; Hunt, C.; Campbell, J. Coastal acidification by rivers: A threat to shellfish? Eos, Trans. Am. Geophys. Union 2008, 89 (50) 513
    8. 8
      Widdicombe, S.; Spicer, J. I. Predicting the impact of ocean acidification on benthic biodiversity: What can animal physiology tell us? J. Exper. Mar. Biol. Ecol. 2008, 366 (1) 187 197
    9. 9
      Ridgwell, A.; Schmidt, D. N.; Turley, C.; Brownlee, C.; Maldonado, M. T.; Tortell, P.; Young, J. R. From laboratory manipulations to Earth system models: Scaling calcification impacts of ocean acidification Biogeosciences 2009, 6 (11) 2611 2623
    10. 10
      Nakano, Y.; Watanabe, Y. W. Reconstruction of pH in the surface seawater over the north Pacific basin for all seasons using temperature and chlorophyll-a J. Oceanogr. 2005, 61 (4) 673 680
    11. 11
      Juranek, L. W.; Feely, R. A.; Peterson, W. T.; Alin, S. R.; Hales, B.; Lee, K.; Sabine, C. L.; Peterson, J. A novel method for determination of aragonite saturation state on the continental shelf of central Oregon using multi-parameter relationships with hydrographic data Geophys. Res. Lett. 2009, 36 (24) L24601
    12. 12
      Midorikawa, T.; Inoue, H. Y.; Ishii, M.; Sasano, D.; Kosugi, N.; Hashida, G.; Nakaoka, S.-i.; Suzuki, T. Decreasing pH trend estimated from 35-year time series of carbonate parameters in the Pacific sector of the Southern Ocean in summer Deep Sea Res., Part I 2012, 61, 131 139
    13. 13
      Bostock, H. C.; Mikaloff Fletcher, S. E.; Williams, M. J. M. Estimating carbonate parameters from hydrographic data for the intermediate and deep waters of the Southern Hemisphere Oceans Biogeosci. Discuss. 2013, 10 (4) 6225 6257
    14. 14
      Gledhill, D. K.; Wanninkhof, R.; Millero, F. J.; Eakin, M. Ocean acidification of the greater Caribbean region 1996–2006 J. Geophys. Res. 2008, 113 (C10) C10031
    15. 15
      Arrigo, K. R.; Pabi, S.; van Dijken, G. L.; Maslowski, W. Air-sea flux of CO2 in the Arctic Ocean, 1998–2003 J. Geophys. Res. 2010, 115 (G4) G04024
    16. 16
      Dickson, A. G.; Goyet, C. Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water, 1992; Vol. 2.
    17. 17
      Weiss, R. F. Carbon dioxide in water and seawater: The solubility of a non-ideal gas Mar. Chem. 1974, 2 (3) 203 215
    18. 18
      Lee, K.; Tong, L. T.; Millero, F. J.; Sabine, C. L.; Dickson, A. G.; Goyet, C.; Park, G. H.; Wanninkhof, R.; Feely, R. A.; Key, R. M., Global relationships of total alkalinity with salinity and temperature in surface waters of the world’s oceans. Geophys. Res. Lett. 2006, 33, (19).
    19. 19
      Smith, S. V.; Key, G. S. Carbon dioxide and metabolism in marine environments Limnol. Oceanogr 1975, 20 (3) 493 495
    20. 20
      Sarmiento, J. L.; Gruber, N. Ocean Biogeochemical Dynamics; Cambridge University Press, 2006; Vol. 503.
    21. 21
      Gledhill, D. K.; Wanninkhof, R.; Eakin, C. M., Observing ocean acidification from space. Oceanography 2009, 22.
    22. 22
      Sun, Q.; Tang, D.; Wang, S. Remote-sensing observations relevant to ocean acidification Int. J. Rem. Sensing 2012, 33 (23) 7542 7558
    23. 23
      Dickson, A. G., The carbon dioxide system in seawater: Equilibrium chemistry and measurements. In Guide to Best Practices for Ocean Acidification Research and Data Reporting, Riebesell, U.; Fabry, C. J.; Hansson, L.; Gattuso, J.-P., Eds.; European Commission: Brussels, 2011; pp 17 40.
    24. 24
      Dickson, A. G.; Sabine, C. L.; Christian, J. R.Guide to Best Practices for Ocean CO2 Measurements, PICES Special Publication 3, 2007
    25. 25
      Byrne, R. H. Measuring Ocean Acidification: New Technology for a New Era of Ocean Chemistry Environ. Sci. Technol. 2014, 48 (10) 5352 5360
    26. 26
      Martz, T. R.; Connery, J. G.; Johnson, K. S. Testing the Honeywell Durafet® for seawater pH applications Limnol. Oceanogr. Methods 2010, 8, 172 184
    27. 27
      Bakker, D. C. E.; Hankin, S.; Olsen, A.; Pfeil, B.; Smith, K.; Alin, S. R.; Cosca, C.; Hales, B.; Harasawa, S.; Kozyr, A. An update to the surface ocean CO2 Atlas (SOCAT version 2) Earth Syst. Sci. Data 2014,  DOI: 10.5194/essd-6-69-2014
    28. 28
      Takahashi, T.; Sutherland, S. C.; Kozyr, A. Global Ocean Surface Water Partial Pressure of CO2 Database: Measurements Performed During 1957–2012 (Version 2012), ORNL/CDIAC-160, NDP-088(V2012); Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2013.
    29. 29
      Key, R. M.; Kozyr, A.; Sabine, C. L.; Lee, K.; Wanninkhof, R.; Bullister, J. L.; Feely, R. A.; Millero, F. J.; Mordy, C.; Peng, T. H., A global ocean carbon climatology: Results from Global Data Analysis Project (GLODAP). Global Biogeochem. Cycles 2004, 18, (4).
    30. 30
      CARINA group. Carbon in the Arctic Mediterranean Seas Region—The CARINA Project: Results and Data, Version 1.2; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2009.
    31. 31
      CARINA group. Carbon in the Atlantic Ocean Region—The CARINA Project: Results and Data, Version 1.0.; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2009.
    32. 32
      CARINA group. Carbon in the Southern Ocean Region—The CARINA Project: Results and Data, Version 1.1.; Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy: Oak Ridge, TN, 2010.
    33. 33
      Robinson, C.; Holligan, P.; Jickells, T.; Lavender, S. The Atlantic Meridional Transect Programme (1995–2012) Deep Sea Res., Part II 2009, 56 (15) 895 898
    34. 34
      Yakushev, E. V.; Sørensen, K. On seasonal changes of the carbonate system in the Barents Sea: Observations and modeling Mar. Biol. Res. 2013, 9 (9) 822 830
    35. 35
      Skjelvan, I.; Falck, E.; Rey, F.; Kringstad, S. B. Inorganic carbon time series at Ocean Weather Station M in the Norwegian Sea Biogeosciences 2008, 5, 549 560
    36. 36
      McPhaden, M. J.; Meyers, G.; Ando, K.; Masumoto, Y.; Murty, V. S. N.; Ravichandran, M.; Syamsudin, F.; Vialard, J.; Yu, L.; Yu, W. RAMA: The Research Moored Array for African–asian–australian Monsoon Analysis and Prediction, 2009
    37. 37
      ARGO Argo - part of the integrated global observationstrategy. http://www.argo.ucsd.edu (14/12/ 2014) ,.
    38. 38
      OOI Ocean Observatories Initiative. http://oceanobservatories.org (14/12/ 2014) ,.
    39. 39
      SOCCOM, Southern Ocean Carbon and Climate Observations and Modeling. http://soccom.princeton.edu (accessed December 14, 2014).
    40. 40
      Merchant, C. J.; Embury, O.; Rayner, N. A.; Berry, D. I.; Corlett, G. K.; Lean, K.; Veal, K. L.; Kent, E. C.; Llewellyn-Jones, D. T.; Remedios, J. J., A 20 year independent record of sea surface temperature for climate from Along–Track Scanning Radiometers. J. Geophys. Res.: Oceans 2012, 117, (C12).
    41. 41
      McClain, C. R.; Feldman, G. C.; Hooker, S. B. An overview of the SeaWiFS project and strategies for producing a climate research quality global ocean bio-optical time series Deep Sea Res., Part II 2004, 51 (1) 5 42
    42. 42
      Font, J.; Boutin, J.; Reul, N.; Spurgeon, P.; Ballabrera-Poy, J.; Chuprin, A.; Gabarró, C.; Gourrion, J.; Guimbard, S.; Hénocq, C. SMOS first data analysis for sea surface salinity determination Int. J. Rem. Sens. 2013, 34 (9–10) 3654 3670
    43. 43
      Font, J.; Camps, A.; Borges, A.; Martín-Neira, M.; Boutin, J.; Reul, N.; Kerr, Y. H.; Hahne, A.; Mecklenburg, S. SMOS: The challenging sea surface salinity measurement from space Proc. IEEE 2010, 98 (5) 649 665
    44. 44
      Boutin, J.; Martin, N.; Reverdin, G.; Morisset, S.; Yin, X.; Centurioni, L.; Reul, N. Sea surface salinity under rain cells: SMOS satellite and in situ drifters observations J. Geophys. Res.: Oceans 2014, 119 (8) 5533 5545
    45. 45
      Reul, N.; Chapron, B.; Lee, T.; Donlon, C.; Boutin, J.; Alory, G. Sea surface salinity structure of the meandering Gulf Stream revealed by SMOS sensor Geophys. Res. Lett. 2014, 41 (9) 3141 3148
    46. 46
      Boutin, J.; Martin, N.; Reverdin, G.; Yin, X.; Gaillard, F. Sea surface freshening inferred from SMOS and ARGO salinity: Impact of rain Ocean Sci. 2013, 9, 183 192
    47. 47
      Sabia, R.; Klockmann, M. Fernández-Prieto, D.; Donlon, C., A first estimation of SMOS-based ocean surface T-S diagrams J. Geophys. Res.: Oceans 2014, 119 (10) 7357 7371
    48. 48
      Hosoda, S.; Ohira, T.; Nakamura, T. A monthly mean dataset of global oceanic temperature and salinity derived from Argo float observations JAMSTEC Rep. Res. Dev 2008, 8, 47 59
    49. 49
      Reul, N.; Fournier, S.; Boutin, J.; Hernandez, O.; Maes, C.; Chapron, B.; Alory, G.; Quilfen, Y.; Tenerelli, J.; Morisset, S. Sea surface salinity observations from space with the SMOS satellite: A new means to monitor the marine branch of the water cycle Surv. Geophysics 2014, 35 (3) 681 722
    50. 50
      Laxon, S. W.; Giles, K. A.; Ridout, A. L.; Wingham, D. J.; Willatt, R.; Cullen, R.; Kwok, R.; Schweiger, A.; Zhang, J.; Haas, C. CryoSat-2 estimates of Arctic sea ice thickness and volume Geophys. Res. Lett. 2013, 40 (4) 732 737
    51. 51
      Kaleschke, L.; Tian-Kunze, X.; Maaß, N.; Mäkynen, M.; Drusch, M., Sea ice thickness retrieval from SMOS brightness temperatures during the Arctic freeze-up period. Geophys. Res. Lett. 2012, 39, (5).
    52. 52
      Mathis, J. T.; Pickart, R. S.; Byrne, R. H.; McNeil, C. L.; Moore, G. W. K.; Juranek, L. W.; Liu, X.; Ma, J.; Easley, R. A.; Elliot, M. M., Storm-induced upwelling of high pCO2 waters onto the continental shelf of the western Arctic Ocean and implications for carbonate mineral saturation states. Geophys. Res. Lett. 2012, 39, (7).
    53. 53
      Mahadevan, A.; Tagliabue, A.; Bopp, L.; Lenton, A.; Memery, L.; Lévy, M. Impact of episodic vertical fluxes on sea surface pCO2 Philos. Trans. R. Soc., A 2011, 369 (1943) 2009 2025
    54. 54
      Mahadevan, A. Ocean science: Eddy effects on biogeochemistry Nature 2014, 506, 168 169
    55. 55
      Takahashi, T.; Sutherland, S. Climatological Mean Distribution of pH and Carbonate Ion Concentration in Global Ocean Surface Waters in the Unified pH Scale and Mean Rate of Their Changes in Selected Areas, OCE 10-38891; National Science Foundation: Washington, D. C., USA,, 2013.
    56. 56
      Goddijn-Murphy, L. M.; Woolf, D. K.; Land, P. E.; Shutler, J. D.; Donlon, C. Deriving a sea surface climatology of CO2 fugacity in support of air-sea gas flux studies Ocean Sci. Discuss. 2014, 11, 1895 1948
    57. 57
      Årthun, M.; Bellerby, R. G. J.; Omar, A. M.; Schrum, C. Spatiotemporal variability of air–sea CO < sub> 2</sub> fluxes in the Barents Sea, as determined from empirical relationships and modeled hydrography J. Mar. Syst. 2012, 98, 40 50
    58. 58
      Friedrich, T.; Oschlies, A., Basin-scale pCO2 maps estimated from ARGO float data: A model study. J. Geophys. Res.: Oceans 2009, 114, (C10).
    59. 59
      Ono, T.; Saino, T.; Kurita, N.; Sasaki, K. Basin-scale extrapolation of shipboard pCO2 data by using satellite SST and Chla Int. J. Rem. Sens. 2004, 25 (19) 3803 3815
    60. 60
      Borges, A. V.; Ruddick, K.; Lacroix, G.; Nechad, B.; Asteroca, R.; Rousseau, V.; Harlay, J., Estimating pCO2 from remote sensing in the Belgian coastal zone. ESA Spec. Publ. 2010, 686.
    61. 61
      Sarma, V. V. S. S.; Saino, T.; Sasaoka, K.; Nojiri, Y.; Ono, T.; Ishii, M.; Inoue, H. Y.; Matsumoto, K., Basin-scale pCO2 distribution using satellite sea surface temperature, Chl a, and climatological salinity in the North Pacific in spring and summer. Global Biogeochem. Cycles 2006, 20, (3).
    62. 62
      Lauvset, S. K.; Chierici, M.; Counillon, F.; Omar, A.; Nondal, G.; Johannessen, T.; Olsen, A. Annual and seasonal fCO2 and air–sea CO2 fluxes in the Barents Sea J. Mar. Syst. 2013,  DOI: 10.1016/j.jmarsys.2012.12.011
    63. 63
      Millero, F. J.; Lee, K.; Roche, M. Distribution of alkalinity in the surface waters of the major oceans Mar. Chem. 1998, 60 (1) 111 130
    64. 64
      Loukos, H.; Vivier, F.; Murphy, P. P.; Harrison, D. E.; Le Quéré, C. Interannual variability of equatorial Pacific CO2 fluxes estimated from temperature and salinity data Geophys. Res. Lett. 2000, 27 (12) 1735 1738
    65. 65
      Anderson, D.; Sheinbaum, J.; Haines, K. Data assimilation in ocean models Rep. Prog. Phys. 1996, 59 (10) 1209
    66. 66
      Steinacher, M.; Joos, F.; Frölicher, T. L.; Plattner, G. K.; Doney, S. C. Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model Biogeosciences 2009, 6 (4) 515 533
    67. 67
      Peterson, B. J.; Holmes, R. M.; McClelland, J. W.; Vörösmarty, C. J.; Lammers, R. B.; Shiklomanov, A. I.; Shiklomanov, I. A.; Rahmstorf, S. Increasing river discharge to the Arctic Ocean Science 2002, 298 (5601) 2171 2173
    68. 68
      Shadwick, E. H.; Trull, T. W.; Thomas, H.; Gibson, J. A. E., Vulnerability of polar oceans to anthropogenic acidification: Comparison of arctic and antarctic seasonal cycles. Sci. Rep. 2013, 3.
    69. 69
      McGuire, A. D.; Anderson, L. G.; Christensen, T. R.; Dallimore, S.; Guo, L.; Hayes, D. J.; Heimann, M.; Lorenson, T. D.; Macdonald, R. W.; Roulet, N. Sensitivity of the carbon cycle in the Arctic to climate change Ecol. Monogr. 2009, 79 (4) 523 555
    70. 70
      Zine, S.; Boutin, J.; Font, J.; Reul, N.; Waldteufel, P.; Gabarró, C.; Tenerelli, J.; Petitcolin, F.; Vergely, J. L.; Talone, M. Overview of the SMOS sea surface salinity prototype processor IEEE Trans. Geosci. Rem. Sens. 2008, 46 (3) 621 645
    71. 71
      Bélanger, S.; Ehn, J. K.; Babin, M. Impact of sea ice on the retrieval of water-leaving reflectance, chlorophyll a concentration and inherent optical properties from satellite ocean color data Rem. Sens. Environ. 2007, 111 (1) 51 68
    72. 72
      Varkey, M. J.; Murty, V. S. N.; Suryanarayana, A. Physical oceanography of the Bay of Bengal and Andaman Sea Oceanogr. Mar. Biol.: Annu. Rev. 1996, 34, 1 70p
    73. 73
      Vinayachandran, P. N.; Murty, V. S. N.; Ramesh Babu, V. Observations of barrier layer formation in the Bay of Bengal during summer monsoon J. Geophys. Res.: Oceans 2002, 107 (C12) SRF-19
    74. 74
      International CLIVAR Project Office Understanding The Role Of The Indian Ocean In The Climate System—Implementation Plan For Sustained Observations; International CLIVAR Project Office: 2006.
    75. 75
      Sarma, V. V. S. S.; Krishna, M. S.; Rao, V. D.; Viswanadham, R.; Kumar, N. A.; Kumari, T. R.; Gawade, L.; Ghatkar, S.; Tari, A. Sources and sinks of CO2 in the west coast of Bay of Bengal Tellus B 2012, 64, 10961
    76. 76
      Madhupratap, M.; Gauns, M.; Ramaiah, N.; Prasanna Kumar, S.; Muraleedharan, P. M.; De Sousa, S. N.; Sardessai, S.; Muraleedharan, U. Biogeochemistry of the Bay of Bengal: Physical, chemical and primary productivity characteristics of the central and western Bay of Bengal during summer monsoon 2001 Deep Sea Res., Part II 2003, 50 (5) 881 896
    77. 77
      Ittekkot, V.; Nair, R. R.; Honjo, S.; Ramaswamy, V.; Bartsch, M.; Manganini, S.; Desai, B. N. Enhanced particle fluxes in Bay of Bengal induced by injection of fresh water Nature 1991, 351 (6325) 385 387
    78. 78
      Ramaswamy, V.; Nair, R. R. Fluxes of material in the Arabian Sea and Bay of Bengal—Sediment trap studies Proc. - Indian Acad. Sci., Earth Planet. Sci. 1994, 103 (2) 189 210
    79. 79
      Gomes, H. R.; Goes, J. I.; Saino, T. Influence of physical processes and freshwater discharge on the seasonality of phytoplankton regime in the Bay of Bengal Continental Shelf Research 2000, 20 (3) 313 330
    80. 80
      Sabine, C. L.; Key, R. M.; Feely, R. A.; Greeley, D. Inorganic carbon in the Indian Ocean: Distribution and dissolution processes Global Biogeochem. Cycles 2002, 16 (4) 1067
    81. 81
      Biswas, H.; Mukhopadhyay, S. K.; De, T. K.; Sen, S.; Jana, T. K. Biogenic controls on the air-water carbon dioxide exchange in the Sundarban mangrove environment, northeast coast of Bay of Bengal, India Limnolo. Oceanogr. 2004, 49 (1) 95 101
    82. 82
      PrasannaKumar, S.; Sardessai, S.; Ramaiah, N.; Bhosle, N. B.; Ramaswamy, V.; Ramesh, R.; Sharada, M. K.; Sarin, M. M.; Sarupria, J. S.; Muraleedharan, U. Bay of Bengal Process Studies Final Report; NIO: Goa, India, 2006; p 141.
    83. 83
      Akhand, A.; Chanda, A.; Dutta, S.; Manna, S.; Hazra, S.; Mitra, D.; Rao, K. H.; Dadhwal, V. K. Characterizing air–sea CO2 exchange dynamics during winter in the coastal water off the Hugli-Matla estuarine system in the northern Bay of Bengal, India J. Oceanogr. 2013, 69 (6) 687 697
    84. 84
      Burke, L. M.; Maidens, J. Reefs at Risk in the Caribbean; World Resources Institute: Washington, DC, 2004.
    85. 85
      Langdon, C.; Atkinson, M. J., Effect of elevated pCO2 on photosynthesis and calcification of corals and interactions with seasonal change in temperature/irradiance and nutrient enrichment. J. Geophys. Res.: Oceans 2005, 110, (C9).
    86. 86
      Aschbacher, J.; Milagro-Pérez, M. P. The European Earth monitoring (GMES) programme: Status and perspectives Rem. Sens. Environ. 2012, 120, 3 8
    87. 87
      Berger, M.; Moreno, J.; Johannessen, J. A.; Levelt, P. F.; Hanssen, R. F. ESA’s sentinel missions in support of Earth system science Rem. Sens. Environ. 2012, 120, 84 90
    88. 88
      Drusch, M.; Del Bello, U.; Carlier, S.; Colin, O.; Fernandez, V.; Gascon, F.; Hoersch, B.; Isola, C.; Laberinti, P.; Martimort, P. Sentinel-2: ESA’s optical high-resolution mission for GMES operational services Rem. Sens. Environ. 2012, 120, 25 36
    89. 89
      Donlon, C.; Berruti, B.; Buongiorno, A.; Ferreira, M. H.; Féménias, P.; Frerick, J.; Goryl, P.; Klein, U.; Laur, H.; Mavrocordatos, C. The global monitoring for environment and security (GMES) sentinel-3 mission Rem. Sens. Environ. 2012, 120, 37 57
    90. 90
      IOCCG. http://www.ioccg.org/sensors/GOCI.html (accessed August 27, 2014).
    91. 91
      Reul, N.; Saux-Picart, S.; Chapron, B.; Vandemark, D.; Tournadre, J.; Salisbury, J., Demonstration of ocean surface salinity microwave measurements from space using AMSR-E data over the Amazon plume. Geophys. Res. Lett. 2009, 36, (13).
    92. 92
      Sabia, R.; Fernández-Prieto, D.; Donlon, C.; Shutler, J.; Reul, N. In A Preliminary Attempt to Estimate Surface Ocean pH from Satellite Observations; IMBER Open Science Conference: Bergen, Norway, 2014.
    93. 93
      Willey, D. A.; Fine, R. A.; Millero, F. J. Global surface alkalinity from Aquarius satellite. In Ocean Sciences Meeting, Honolulu, HI, 2014.