Using antarctic Dome C site and simultaneous nadir overpass observations for monitoring radiometric performance of NPP VIIRS instrument

Abstract

In this study, two methods were used to evaluate radiometric calibration of the VIIRS sensor data records: (1) imaging of radiometrically stable Earth's surfaces and (2) SNO (Simultaneous Nadir Overpass) observations by VIIRS and other satellite instruments. Measurements acquired by VIIRS at the stable Dome C calibration site in Antarctica confirm that a faster-than-expected degradation of the radiometric response occurs for selected spectral bands in the visible and near-infrared region, with other bands remaining stable. SNO comparisons with MODIS show that the implemented regular updates of the radiometric calibration coefficients have stabilized the calibration and that the VIIRS and MODIS measurements are in agreement.

Stability Monitoring of the VIIRS Day/Night Band over Dome C with a Lunar Irradiance Model and BRDF Correction

“…The site of interest is Antarctic Dome C. It is located at −75.1 degrees latitude and 123.35 degrees longitude in the Southern Hemisphere with a mean elevation of 3.2 km above sea level. The site surface is covered with uniformly-distributed permanent snow, the atmospheric absorption is low, and skies are generally clear, with more than 75% of days each year being cloud-free [26,32,33]. Due to these advantages, Dome C is one of the Committee on Earth Observation Satellites (CEOS)-endorsed vicarious calibration sites.…”

“…Due to these advantages, Dome C is one of the Committee on Earth Observation Satellites (CEOS)-endorsed vicarious calibration sites. On the other hand, the Dome C site shows significant BRDF effect at high solar/lunar zenith angles [26,29,32]. In this study, a circular area with a 10-km radius centered at 75.1 • S, 123.35 • E is selected as the region of interest (ROI) and the average radiance over the ROI is calculated to characterize the measurement of Dome C made by VIIRS DNB.…”

“…Wu et al [29] compared the Warren model with the TOA reflectance factor over Dome C observed by MODIS during the daytime and found that the Warren model matches the TOA reflectance factor by better than 5%. According to the radiative transfer simulations by moderate resolution atmospheric transmission (MODTRAN), the dominant atmospheric effects at the Dome C site are Rayleigh scattering and ozone absorption, which can have strong effects only upon short wavelengths, especially below 500 nm [30,32,42].…”

Suomi NPP VIIRS sensor data record verification, validation, and long‐term performance monitoring

“…VIIRS radiometric performance for imaging (I1 and I2) and moderate‐resolution (M1 through M8) bands have been continuously evaluated since early launch using the SNOs [ Blonski et al ., ]. VIIRS band M6 often becomes saturated over snow and thus only a few SNO events have been analyzed.…”

“…[32] VIIRS radiometric performance for imaging (I1 and I2) and moderate-resolution (M1 through M8) bands have been continuously evaluated since early launch using the SNOs [Blonski et al, 2012] saturated over snow and thus only a few SNO events have been analyzed. The major difference between the SNO at polar region and the SNO in the low latitudes is that, in the polar area, VIIRS and MODIS are compared at the exact orbital intersection rather than at the orbital overlapping areas.…”