MODIS/Aqua Ocean Color Reprocessing 2022.0

Introduction

Reprocessing 2022.0 is a multi-mission reprocessing to incorporate updates in instrument calibration, vicarious calibration, new ancillary sources and algorithm improvements. The affected missions are CZCS, SeaWiFS, OCTS, MERIS, MODIS on Aqua and Terra, VIIRS on SNPP and NOAA-20, OLCI on Sentinel-3A and Sentinel-3B, GOCI, and HICO. Here we describe the changes and results specific to MODIS Aqua (MODISA).

Instrument Calibration

In this reprocessing, the instrument calibration follows the same general approach developed and employed by the MODIS Calibartion Support Team (MCST) and OBPG for previous ocean color reprocessings, but with a few differences. Reprocessing 2022.0 page provides more details on the instrument and vicarious calibration, and product and algorithm changes.

Results

Time Series Comparison

The comparison of the MODISA time series for global deep water (>1000m) generated for the R2022 configuration to the corresponding R2018 time series is shown below (left panels). The ratio of R2022 to R2018 is also shown on right panels.

Comparison with In Situ Measurements

Validation of the chlorophyll, apparent optical properties (Rrs, Kd490), inherent optical properties (a_giop, aph_giop, adg_giop, bbp_giop), PAR, PIC, and POC retrievals was performed relative to all available match-ups from SeaBASS and the Aerosol Robotic Network - Ocean Color (AERONET-OC). Statistical analysis, scatter plots and frequency distribution comparisons of the satellite to in situ match-ups are provided below.

Chlorophyll a (chlor_a)

^* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
chlor_a	1347	1.16723^*	1.68849^*	0.02107, 58.28675	0.01900, 58.09900

Apparent Optical Properties

Remote Sensing Reflectance (Rrs)

Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
Rrs412	5704	-0.00015	0.00106	-0.00302, 0.05000	-0.00000, 0.03266
Rrs443	5937	-0.00014	0.00083	-0.00105, 0.02847	0.00007, 0.03920
Rrs488	5515	-0.00066	0.00097	0.00020, 0.03530	0.00039, 0.04753
Rrs531	3272	-0.00070	0.00090	0.00081, 0.02918	0.00113, 0.03797
Rrs547	5320	-0.00065	0.00094	0.00085, 0.02926	0.00114, 0.03610
Rrs555	5184	-0.00088	0.00109	0.00068, 0.02839	0.00081, 0.03680
Rrs667	5299	-0.00019	0.00034	-0.00059, 0.02279	0.00000, 0.02355
Rrs678	547	-0.00020	0.00032	-0.00053, 0.00996	0.00004, 0.00904

Diffuse Attenuation Coefficients (kd490)

^* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
kd490	498	1.10909^*	1.35517^*	0.01942, 6.03211	0.01597, 9.07948

Inherent Optical Properties

Total Absorption Coefficients (a_giop)

^* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
a_giop412	64	0.78340^*	1.72102^*	0.01482, 1.69616	0.01119, 1.52649
a_giop443	64	0.82284^*	1.47815^*	0.01553, 1.66059	0.01177, 1.11421
a_giop488	64	0.83745^*	1.36270^*	0.01953, 1.35619	0.01728, 0.64664
a_giop531	64	0.87438^*	1.28878^*	0.04064, 0.85137	0.04443, 0.41927
a_giop547	64	0.88657^*	1.26463^*	0.03390, 0.72239	0.05660, 0.33654
a_giop555	64	0.91193^*	1.22304^*	0.04088, 0.64077	0.05983, 0.31630
a_giop667	64	1.01769^*	1.11437^*	0.17181, 1.57861	0.43027, 0.63570

Phytoplankton Absorption Coefficients (aph_giop)

^* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
aph_giop412	66	1.02262^*	1.77602^*	0.00020, 1.73762	0.00106, 0.42967
aph_giop443	66	1.06495^*	1.75135^*	0.00024, 1.93807	0.00139, 0.39176
aph_giop488	66	1.14385^*	1.77244^*	0.00016, 1.32626	0.00080, 0.27172
aph_giop531	66	1.16659^*	1.94150^*	0.00006, 0.80036	0.00006, 0.15537
aph_giop547	66	1.38076^*	2.12851^*	0.00004, 0.66369	0.00001, 0.11235
aph_giop555	66	1.27884^*	2.08061^*	0.00004, 0.57652	0.00015, 0.09717
aph_giop667	66	1.43855^*	2.06679^*	0.00010, 1.14408	0.00028, 0.18520

Absorption Coefficient of Non-algal Material plus CDOM (adg_giop)

^* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
adg_giop412	64	0.54221^*	2.75342^*	0.00492, 1.99047	0.00539, 1.23065
adg_giop443	64	0.49526^*	2.90104^*	0.00282, 1.13925	0.00268, 0.77597
adg_giop488	64	0.42602^*	3.15297^*	0.00126, 0.50682	0.00105, 0.40048
adg_giop531	64	0.35003^*	3.51926^*	0.00059, 0.23371	0.00055, 0.22245
adg_giop547	64	0.35889^*	3.69613^*	0.00043, 0.17522	0.00005, 0.16707
adg_giop555	64	0.33423^*	3.90359^*	0.00038, 0.15173	0.00004, 0.15553
adg_giop667	64	0.20556^*	5.32914^*	0.00008, 0.02020	0.00012, 0.03245

backscattering coefficient of particles (bbp_giop)

^* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product Name	#	Mean Bias	Mean Absolute Error (MAE)	Aqua Range	In situ Range
bbp_giop412	78	0.93191^*	1.36138^*	0.00082, 0.01194	0.00072, 0.01019
bbp_giop443	78	0.93253^*	1.34208^*	0.00071, 0.01094	0.00067, 0.00928
bbp_giop488	78	0.92903^*	1.32858^*	0.00059, 0.00973	0.00057, 0.00876
bbp_giop531	78	0.92447^*	1.32353^*	0.00050, 0.00931	0.00049, 0.00836
bbp_giop547	78	0.92902^*	1.32696^*	0.00047, 0.00919	0.00045, 0.00818
bbp_giop555	78	0.92400^*	1.32714^*	0.00046, 0.00914	0.00045, 0.00814
bbp_giop667	78	0.91136^*	1.35350^*	0.00032, 0.00848	0.00031, 0.00732
bbp_giop678	3	0.62566^*	1.59831^*	0.00030, 0.00295	0.00058, 0.0048