SeaFlux v2023: harmonised sea-air CO2 fluxes from surface pCO2 data products using a standardised approach

BE SURE TO DOWNLOAD 2023.02 See the additional notes for updates on the Fluxes calculated using the standardized approach: \(F\text{CO}_2=K_0 \cdot K_w \cdot (p\text{CO}_2^\text{sea} - p\text{CO}_2^\text{atm})\ \cdot (1 - [ice])\). We provide each of the components to this equation to reduce the potential for errors in fluxes due to methodological differences. The netCDF files contain the following data (note that only bold names have been updated in v2023): fgco2_all_winds_products: the sea-air CO2 flux for all spCO2 products (6) and kw from all wind products (5). fgco2_global: the globally integrated sea-air CO2 fluxes for all spCO2 products (6) and kw from all wind products (6) sol: \(K_0\) is calculated using the Weiss (1974) parameterization with EN4 salinity and OISST temperatures kw: \(k_w\) is calculated for winds with each being scaled independently to a 14-C bomb flux estimate of 16.5 cm/hr using the quadratic formulation by Wanninkhof (1992). CCMPv2 ERA5 JRA55 NCEP1 NCEP2 spco2_SOCOM_unfilled: \(p\text{CO}_2^\text{sea}\) downloaded from various sources contains the following products: CMEMS_FFNN CSIR_ML6 JENA_MLS JMA_MLR MPI_SOMFFN NIES_FNN spco2_filler: scaled version of the Landschützer et al. (2020) climatology used to fill missing regions of spco2_SOCOM_unfilled fco2atm: \(p\text{CO}_2^\text{atm}\) is calculated from NOAA's marine boundary layer product with ERA5 mean sea level pressure corrected for pH2O. The virial coefficient is then applied to pCO2atm ice: \([ice]\) is the ice fraction from the OISST product area_ocean: the surface area of the ocean including the fractional area of the coastal regions seafrac: the fraction of a pixel that is ocean Units are listed in the metadata of each of the netCDF variables.

version 2023.02: fixed a bug where sol was 1e3 too large for the units (mol m3 uatm). Now corrected to the right order of magnitude. Mean for sol = 4.547e-5 version 2023.01: released alongside the GCBv2023. Note that I have not provided NCEPv2 since this was dropped during the analysis of the paper. Further, the salinity for the solubility is the same as that used in OceanSODA-ETHZ (see the documentation of that product). Temperature is still NOAA's OISST. I do not provide pco2atm but rather fco2atm since the GCB now requests fco2 instead of pco2. Note that the alpha (coefficients of gas transfer) are still the same as before. version 2021.04.03: includes globally integrated fluxes including all wind and pco2 products. version 2021.04.02: removed some files that remained from v2021.02 that I didn't delete in v2021.04 version 2021.04 now extends the variables to calculate fluxes from 1982-2020. The comparison period for fluxes is now limited to 1990-2019 (30 years). The area contains coastal fraction coverage. A missing strip along the longitude 179.5°E is filled in. Negative values of pCO2 are limited to 50 µatm (primarily affects JENA in Hudson Bay). version 2021.02 calibrates kw with 14-C bomb estimated global average kw (16.5 ± 3.2 cm/hr) where the average is calculated without ice weighting (v2021.01 included ice weighting). Further, the date range of the data has been increased from 1982 to 2020 where possible (not possible for the scaling factor and pCO2 product).