BGC-Argo Satellite matchup to compute variability in the Chl:C ratio of phytoplankton.

This dataset provides matchups between BGC-Argo and MODIS satellites (both atmospheric and ocean color products). This dataset allows users to compare the variability of the Chlorophyll (Chl) to Phytoplankton Carbon ratio from BGC-Argo floats depending on the light in the mixed layer and link to information obtained from satellites about cloud coverage. 

Quality control previously performed on this dataset and matchup criteria are described in the associated publication.

Here are some of the column headers detailed for clarity:

Columns 1-25 represent data from the BGC-Argo floats:

• ID: Float WMO ID number
• dt: Datetime in datenum format.
• biomes: Biomes according to Fay & McKinley, 2014 (with West Mediterranean biome 18 and East Mediterranean biome 19)
• zenith: Sun zenith angle at time of surfacing.
• kd_490_Xing: Downwelling diffuse attenuation coefficient at 490nm from Xing et al.,2021 method. 
• kd_PAR_Xing: Downwelling diffuse attenuation coefficient of PAR  from Xing et al.,2021 method. 
• chla: Median chlorophyll from fluorescence in the mixed layer (corrected for Non-Photochemical Quenching following Xing et al., 2012)
• F_indiv: Calibration factor for chla (chlorophyll from fluorescence) according to the method described in Xing et al., 2011. 
• F_median: Median Correction factor (F) for all the floats in a biome
• F_median_season: Median Correction factor (F) for all the floats in a biome in a given season
• Chl_cor: Chla from floats corrected using the F_median factor according to Xing et al., 2011. 
• PAR_0_Argo: PAR(0-) right below the surface also from Xing et al., 2021.
• Z_iso : Depth of the 0.415 mol/quanta/m-2/d-1 isolume. 
• Zeu: Euphotic depth, 1% of surface light.
• Eg_Argo: Median light level in the mixed layer during a float's profile, bounded by the surface and the MLD (in mol quanta m^-2 h^-1).
• MLD: Mixed layer depth, determined using the 0.03 density criteria from de Boyer Montégut, et al.,2004.
• bbp_XXX: Backscattering at a specific wavelength
• Cphyto: Median Phytoplankton Carbon in the mixed layer computed from Bbp following Graff et al., 2015.
• Cphyto_B: Median Phytoplankton Carbon in the mixed layer computed from Bbp following Behrenfeld et al., 2005.
• Cphyto_M: Median Phytoplankton Carbon in the mixed layer computed from Bbp following Martinez-Vincente et al., 2013.
• ratio_cor: Chl_cor /Cphyto.

Columns 26-45 have products from matchups with ocean-color MODIS files:

• sat_dt: Datetime of satellite overpass in datenum format. 
• chlor_a: Satellite chl obtained from NASA's OBPG hybrid algorithm.
• sat_IPAR: Instantaneous PAR at time of overpass.
• sat_PAR: MODIS Daily PAR product above the surface.
• sat_Daily_PARminus: MODIS Daily PAR product propagated right below the surface (0-)
• sat_Daily_Eg: Daily median light in the mixed layer computed as sat_DailyPAR_minus * exp(-Kd_PAR*MLD/2) ( in mol quanta m^-2 d^-1).

Columns 46-49 have products from matchups with atmospheric MODIS files: 

• a_lat, a_lon, a_dt: Same as above but for the atmospheric file
• Confident Cloudy: Number of pixels (Out of 25) with the Confident Cloudy flag.