Cross-calibration of MODIS and VIIRS long near infrared bands for ocean color science and applications

Abstract Generation of consistent multi-sensor datasets is critical to the assessment long-term global changes using satellite-borne instruments. Recent research suggests, however, that a fundamental assumption in satellite ocean color data processing concerning calibration long near infrared band (i.e., 865 nm for MODIS) may introduce sensor-specific biases space and/or time, which also contribute cross-sensor inconsistency derived reflectance products. As such, it necessary assess this across sensors – performed here MODIS/Aqua and VIIRS/SNPP ‘simultaneous same view’ matchups (SSV; similar simultaneous nadir overpass, but allowing non-nadir measurements). Towards end, we geometric, temporal, spatial homogeneity metrics identify SSVs, develop band-shifting approach applicable within standard routines resolve expected spectral differences radiometry. We find top-of-atmosphere (TOA) radiance from be approximately 3% higher than corresponding MODIS/A data. With expectation cross-calibrating NIRL should improve continuity downstream geophysical products (e.g., chlorophyll-a), reprocessed VIIRS updated coefficients. While noticed many minor improvements such products, large-scale geographic temporal between these two still remain. These discontinuities result disparate errors polarization correction or atmospheric correction, both are modulated by radiant path geometry.