A method for monitoring the on-orbit performance of a satellite sensor infrared window band using oceanic drifters

摘要

In this study, we propose a method to monitor the on-orbit performance of a satellite sensor thermal emissive band (TEB) using oceanic drifters and National Centers for Environmental Prediction (NCEP) data. Based on the radiance simulated using oceanic drifter data, NCEP data, and a radiative transfer model, we primarily aim to develop a method for the real-time monitoring of the on-orbit performance of a satellite sensor thermal emissive band. One month of Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) L1b radiance data from Channels 31 and 32 are used as proxy data to test this method. In this paper, we propose some improvements to the cloud test algorithm for this monitoring method, thereby significantly enhancing the quality of this method. We describe the sensitivity tests conducted to identify the important sources of errors. Our improvements eliminate the cases contaminated by clouds and influenced by non-uniform distribution of seawater temperature. Comparisons with Aqua MODIS data reveal systematic underestimations (0.48 ± 0.97 K for Channel 31, 0.36 ± 1.05 K for Channel 32) of this method. Our sensitivity analysis also reveals that surface emissivity and drifter temperature are likely to make the greatest contributions to the total uncertainty of this method. We should therefore correct systematical errors in the real-time monitoring algorithm for other satellite TEB sensors.