| Contributors | Affiliation | Role |
|---|---|---|
| Takahashi, Taro | Lamont-Doherty Earth Observatory (LDEO) | Principal Investigator |
| Sutherland, Stewart C. | Lamont-Doherty Earth Observatory (LDEO) | Contact |
| Copley, Nancy | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Carbonate chemistry data gridded to 4 degree latitude by 5 degree longitude by monthly grid in the reference year 2005.
For detailed information, see final report.
Associated dataset: LDEO global surface ocean carbon.
Maps of global estimated pH
Gridded data for salinity, sea surface temperature, nitrate, phosphate, and silicate were regridded to our 4 degree latitude by 5 degree longitude grid. pCO2 were interpolated to the same grid in the manner described in the Final Report by Taro Takahashi to NSF for Grant OCE-10-38891 'Climatological Mean Distribution in the Global Ocean Surface Waters in the Unified pH Scale and Mean Rate of Their Changes in Selected Areas' (Dec. 31, 2012) pp. 34. The method will be described in detail in a paper in preparation.
Working on a 4 degree latitude by 5 degree longitude by monthly grid, Potential Alkalinity (PALK) was calculated using a series of linear equations relating PALK to salinity. Total alkalinity was obtained by removing the nitrate component of PALK using climatological data. TCO2 was calculated from Total Alkalinity, and pCO2 using an updated global pCO2 map. The other carbonate chemistry values such as pH, CO3=, calcite and aragonite saturation were calculated at the same time as TCO2.
| File |
|---|
pH_grid.csv (Comma Separated Values (.csv), 2.35 MB) MD5:94ef71f7de17d1db45f68f968bf56869 Primary data file for dataset ID 3961 |
| Parameter | Description | Units |
| month | Calendar month, e.g. 1 = Jan, 2=Feb | |
| lat | Latitude; North is positive | decimal degrees |
| lon_360 | Longitude of the center point of the box in degrees East (i.e. 75 degrees W = -75 + 360 = 285) | decimal degrees |
| lon | Longitude; East is positive | decimal degrees |
| slope | Slope of linear relation between Salinity and Potential Alkalinity | unitless |
| intercept | Intercept of linear relation between Salinity and Potential Alkalinity | unitless |
| temp_ss | Climatological Sea Surface Temperature | degrees Celsius |
| sal | Climatological Sea Surface Salinity (Practical Salinity Scale) | unitless |
| PALK | Potential Alkalinity. PALK = Total Alkalinity + Nitrate estimated from salinity: PALK = SLOPE * Salinity + INTERCEPT | microequivalents per kilogram seawater |
| NO3 | Climatological Nitrate | micromoles per kilogram seawater |
| PO4 | Climatological Phosphate | micromoles per kilogram seawater |
| SIO3 | Climatological Silicate | micromoles per kilogram seawater |
| TALK | Total Alkalinity calculated from Potential Alkalinity: TALK = PALK - NO3 | microequivalents per kilogram seawater |
| PCO2_SST | Partial Pressure of CO2 at sea surface temperature; adjusted to year 2005 | microatmospheres |
| TCO2 | Total CO2 calculated from TALK and pCO2 | micromoles per kilogram seawater |
| CO3 | Carbonite ion concentration | micromoles per kilogram seawater |
| pH | Total hydrogen ion concentration scale | unitless |
| HION | Total hydrogen ion concentration | 10^-9 moles per kilogram seawater |
| OMGARAG | Degree of saturation (Omega) of Aragonite | unitless |
| OMGCALC | Degree of saturation (Omega) of Calcite | unitless |
| Website | |
| Platform | LDEO |
| Start Date | 2011-01-01 |
| End Date | 2013-12-31 |
In this project, researchers at the Lamont-Doherty Earth Observatory of Columbia University will obtain the global distribution of surface ocean pH in a single unified scale based on the observations for pCO2, total alkalinity and total CO2 ion concentration (DIC) in surface waters. They will utilize three decades of their own pCO2 and DIC data, which are based on David Keeling's (and successor Pieter Tans at ERL/NOAA) WMO manometric CO2 standard, and the well-calibrated alkalinity data from the WOCE program (Dickson et al., 2003) and the time-series stations including BATS, HOT and ESTOC. These data will allow establishment of a global ocean pH and carbonate concentration baseline anchored firmly to the international CO2 standards common to the atmospheric and oceanic CO2 measurements. The pCO2 and DIC data obtained in different years will be corrected to a reference year 2000, and a climatological distribution of monthly mean pH in the total hydrogen ion scale and carbonate ion concentrations will be computed using the dissociation constants for carbonic and boric acids of Lueker et al. (2000) and Dickson (1990). This will serve as a world ocean baseline distribution for the characterization of future ocean acidification. In some data-rich areas of the North Atlantic, North Pacific and Southern Ocean, the rate of change will be demonstrated.
Because of calibration problems associated with direct pH measurements, an observation-based global ocean pH distribution map is not possible; presently the information is based on ocean GCM studies without land interactions. The research team's ongoing analysis of the alkalinity data shows, however, that its distribution differs from the open oceans in the broad regions of land interactions such as in the Bay of Bengal, Arabian Sea, Gulf of Alaska and Bering Sea. This suggests that the model results are biased by the omission of rivers and land interactions. The results of our proposed investigation will be used for the validation of global biogeochemical ocean models and will help to place the global ocean acidification study on a much firmer base.
Broader Impacts: Baseline information is needed for accurate characterization of global environmental changes. The purpose of this study is to provide a global surface ocean baseline for pH and carbonate ion concentration in waters computed in a uniform pH scale using an extensive pCO2, alkalinity and DIC database obtained for past several decades. This should serve as a reference level, against which the future and past changes may be referenced.
NSF Climate Research Investment (CRI) activities that were initiated in 2010 are now included under Science, Engineering and Education for Sustainability NSF-Wide Investment (SEES). SEES is a portfolio of activities that highlights NSF's unique role in helping society address the challenge(s) of achieving sustainability. Detailed information about the SEES program is available from NSF (https://www.nsf.gov/funding/pgm_summ.jsp?pims_id=504707).
In recognition of the need for basic research concerning the nature, extent and impact of ocean acidification on oceanic environments in the past, present and future, the goal of the SEES: OA program is to understand (a) the chemistry and physical chemistry of ocean acidification; (b) how ocean acidification interacts with processes at the organismal level; and (c) how the earth system history informs our understanding of the effects of ocean acidification on the present day and future ocean.
Solicitations issued under this program:
NSF 10-530, FY 2010-FY2011
NSF 12-500, FY 2012
NSF 12-600, FY 2013
NSF 13-586, FY 2014
NSF 13-586 was the final solicitation that will be released for this program.
PI Meetings:
1st U.S. Ocean Acidification PI Meeting(March 22-24, 2011, Woods Hole, MA)
2nd U.S. Ocean Acidification PI Meeting(Sept. 18-20, 2013, Washington, DC)
3rd U.S. Ocean Acidification PI Meeting (June 9-11, 2015, Woods Hole, MA – Tentative)
NSF media releases for the Ocean Acidification Program:
Press Release 10-186 NSF Awards Grants to Study Effects of Ocean Acidification
Discovery Blue Mussels "Hang On" Along Rocky Shores: For How Long?
Press Release 13-102 World Oceans Month Brings Mixed News for Oysters
| Funding Source | Award |
|---|---|
| NSF Division of Ocean Sciences (NSF OCE) |