Ocean Acidification Product Suite

Scientists within the ACCRETE (Acidification, Climate, and Coral Reef Ecosystems Team) Lab of AOML_s Ocean Chemistry and Ecosystems Division (OCED) have constructed a tool to monitor ocean acidification over the wider Caribbean and Gulf of Mexico. This tool utilizes satellite data and a data-assimilative hybrid model to map the components of the carbonate system of surface water. This effort represents an update to the experimental Ocean Acidification Product Suite (OAPS) developed by Coral Reef Watch (http://coralreefwatch.noaa.gov/satellite/oa/index.php). To resolve the seawater carbonic acid system, we use the partial pressure of CO2 (pCO2) and pH. Surface pCO2 is approximated by taking total tropospheric column CO2 from the AIRS mid-tropospheric CO2 and AMSU instruments on board the Aqua satellite (http://disc.sci.gsfc.nasa.gov/AIRS/data-holdings/by-data-product-v5/AIRX3C2M) and adjusting it for the marine boundary layer by replacing the annual cycle of the observed AIRS data with that from the NOAA Marine Boundary Layer (http://www.esrl.noaa.gov/gmd/ccgg/mbl/). Following this adjustment, seawater pCO2 is estimated using an empirical model relating the differential between sea surface and atmospheric CO2 partial pressure to changes in CO2 gas solubility (K0). Total alkalinity (TA) is calculated using the Subtropical/Tropical algorithm from Lee et al. (2006). Sea surface temperature is derived from an optimal interpolated product at 9km resolution (http://www.remss.com/measurements/sea-surface-temperature/oisst-description) and salinity is obtained from a data-assimilative hybrid model (HYCOM https://hycom.org/). These measurements, together with pCO2 and TA, allow calculation the complete carbonate system. Data are updated monthly at a 9km resolution. Initial results indicate good agreement with observed values from cruises and MAPCO2 buoys, but further testing and refinement of algorithms is planned.