The SNPP mission has restored data collection following a spacecraft anomaly that occurred on 26 July 2022. The VIIRS calibration team is evaluating the data to determine any impacts the two-week outage may have had on data quality. This evaluation may take several weeks to complete. Until such time as this analysis is complete and any calibration adjustments can be made, users are cautioned against using these data for scientific analyses.

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.

Deep water time series comparisons of Aqua R2022 to R2018
Figure 1: Global deepwater time series comparisons of R2022 to R2018

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
Aqua Range In situ Range#Mean Bias Mean Absolute Error (MAE)
chlor_a13471.16723*1.68849*0.02107, 58.286750.01900, 58.09900

Apparent Optical Properties

Remote Sensing Reflectance (Rrs)
Product
Name
#Mean BiasMean Absolute Error (MAE)Aqua Range In situ Range
Rrs4125704-0.000150.00106-0.00302, 0.05000-0.00000, 0.03266
Rrs4435937-0.000140.00083-0.00105, 0.028470.00007, 0.03920
Rrs4885515-0.000660.000970.00020, 0.035300.00039, 0.04753
Rrs5313272-0.000700.000900.00081, 0.029180.00113, 0.03797
Rrs5475320-0.000650.000940.00085, 0.029260.00114, 0.03610
Rrs5555184-0.000880.001090.00068, 0.028390.00081, 0.03680
Rrs6675299-0.000190.00034-0.00059, 0.022790.00000, 0.02355
Rrs678547-0.000200.00032-0.00053, 0.009960.00004, 0.00904







Diffuse Attenuation Coefficients (kd490)
* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product
Name
#Mean BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
kd4904981.10909*1.35517*0.01942, 6.032110.01597, 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 BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
a_giop412640.78340*1.72102*0.01482, 1.696160.01119, 1.52649
a_giop443640.82284*1.47815*0.01553, 1.660590.01177, 1.11421
a_giop488640.83745*1.36270*0.01953, 1.356190.01728, 0.64664
a_giop531640.87438*1.28878*0.04064, 0.851370.04443, 0.41927
a_giop547640.88657*1.26463*0.03390, 0.722390.05660, 0.33654
a_giop555640.91193*1.22304*0.04088, 0.640770.05983, 0.31630
a_giop667641.01769*1.11437*0.17181, 1.578610.43027, 0.63570






Phytoplankton Absorption Coefficients (aph_giop)

* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product
Name
#Mean BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
aph_giop412661.02262*1.77602*0.00020, 1.737620.00106, 0.42967
aph_giop443661.06495*1.75135*0.00024, 1.938070.00139, 0.39176
aph_giop488661.14385*1.77244*0.00016, 1.326260.00080, 0.27172
aph_giop531661.16659*1.94150*0.00006, 0.800360.00006, 0.15537
aph_giop547661.38076*2.12851*0.00004, 0.663690.00001, 0.11235
aph_giop555661.27884*2.08061*0.00004, 0.576520.00015, 0.09717
aph_giop667661.43855*2.06679*0.00010, 1.144080.00028, 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 BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
adg_giop412640.54221*2.75342*0.00492, 1.990470.00539, 1.23065
adg_giop443640.49526*2.90104*0.00282, 1.139250.00268, 0.77597
adg_giop488640.42602*3.15297*0.00126, 0.506820.00105, 0.40048
adg_giop531640.35003*3.51926*0.00059, 0.233710.00055, 0.22245
adg_giop547640.35889*3.69613*0.00043, 0.175220.00005, 0.16707
adg_giop555640.33423*3.90359*0.00038, 0.151730.00004, 0.15553
adg_giop667640.20556*5.32914*0.00008, 0.020200.00012, 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 BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
bbp_giop412780.93191*1.36138*0.00082, 0.011940.00072, 0.01019
bbp_giop443780.93253*1.34208*0.00071, 0.010940.00067, 0.00928
bbp_giop488780.92903*1.32858*0.00059, 0.009730.00057, 0.00876
bbp_giop531780.92447*1.32353*0.00050, 0.009310.00049, 0.00836
bbp_giop547780.92902*1.32696*0.00047, 0.009190.00045, 0.00818
bbp_giop555780.92400*1.32714*0.00046, 0.009140.00045, 0.00814
bbp_giop667780.91136*1.35350*0.00032, 0.008480.00031, 0.00732
bbp_giop67830.62566*1.59831*0.00030, 0.002950.00058, 0.0048






Photosynthetically Available Radiation (par)

Product
Name
#Mean BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
par2924.783264.7832621.74514, 64.438488.89095, 60.16832

Particulate Inorganic Carbon (pic)

* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product
Name
#Mean BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
pic420.30577*4.00304*0.00001, 0.000320.00002, 0.00065

Particulate Organic Carbon (poc)

* statistical calculations based on log10 (implies ignoring values equal to or less than zero)
Product
Name
#Mean BiasMean Absolute Error (MAE)Aqua RangeIn situ Range
poc2470.87239*1.48592*21.54276, 2394.1052020.68700, 1266.61401