Cross calibration of SeaWiFS and MODIS using on-orbit observations of the Moon

Abstract

Observations of the Moon provide a primary technique for the on-orbit cross calibration of Earth remote sensing instruments. Monthly lunar observations are major components of the on-orbit calibration strategies of SeaWiFS and MODIS. SeaWiFS has collected more than 132 low phase angle and 59 high phase angle lunar observations over 12 years, Terra MODIS has collected more than 82 scheduled and 297 unscheduled lunar observations over nine years, and Aqua MODIS has collected more than 61 scheduled and 171 unscheduled lunar observations over seven years. The NASA Ocean Biology Processing Group Calibration and Validation Team and the NASA MODIS Characterization Support Team use the USGS RObotic Lunar Observatory (ROLO) photometric model of the Moon to compare these time series of lunar observations over time and varying observing geometries. The cross-calibration results show that Terra MODIS and Aqua MODIS agree, band to band, at the 1%-3% level, while SeaWiFS and either MODIS instrument agree at the 3%-8% level. The combined uncertainties of these comparisons are 1.3% for Terra and Aqua MODIS, 1.4% for SeaWiFS and Terra MODIS, and 1.3% for SeaWiFS and Aqua MODIS. Any residual phase dependence in the ROLO model, based on these observations, is less than 1.7% over the phase angle range of -80° to -6° and +5° to +82°. The lunar cross calibration of SeaWiFS, Terra MODIS, and Aqua MODIS is consistent with the vicarious calibration of ocean color products for these instruments, with the vicarious gains mitigating the calibration biases for the ocean color bands.

Validation, Stability, and Consistency of MODIS Collection 6.1 and VIIRS Version 1 Deep Blue Aerosol Data Over Land

“…The effects of sensor-specific differences are difficult to reduce, and impossible to entirely remove, from such attempts to create a long-term aerosol data record. Sensor absolute calibration is typically determined prelaunch via laboratory measurements, while on-orbit calibration is focused on stability and degradation via internal checks and/or observations of the Earth (Uprety et al, 2014) or Moon (Sun et al, 2007;Eplee et al, 2011). To bring separate sensors into absolute calibration alignment is complicated by the lack of a spaceborne on-orbit absolute calibration reference.…”

Known and unknown unknowns: uncertainty estimation in satellite remote sensing

“…Slater et al, 1996;Fougnie et al, 2007;Powell et al, 2009;Kuze et al, 2014). For example, radiometers have been calibrated by observing an area of the Libyan desert known to have a very stable surface reflectance over time (Smith et al, 2002) or the Moon (Eplee et al, 2011). This can complement pre-launch calibration or may be the only direct calibration possible (Heidinger et al, 2003).…”

Satellite Climate Data Records: Development, Applications, and Societal Benefits

“…Both artificial and natural sites, such as the under-orbit airplanes, deserts, ice domes, deep convective clouds (DCC), and the Moon [9][10][11][12][13][14][15] have been used for the post-launch vicarious calibration of satellite sensors. This vicarious calibration and on-board calibration strive to match the satellite radiometric measurements to the international standards (SI) [16][17][18].…”