A Feasibility Study of Cloud Base Height Remote Sensing by Simulating Ground‐Based Thermal Infrared Brightness Temperature Measurements

Abstract

AbstractThis paper attempts to study the feasibility of cloud base height (cloud base height–CBH) remote sensing by ground‐based sky thermal infrared brightness temperature (thermal infrared brightness temperature‐Tb) observation and the quantitative effects of aerosol layer on it. Using MODTRAN4.0 model simulation, the variations of Tb with zenith angle of observation for different types of aerosol and different visibilities (visibility‐VIS) under clear and cloudy sky conditions were systematically investigated. Based on the simulated results, the statistic equations for clear and cloudy sky Tb calculation were obtained respectively, and then a preliminary method of CBH estimation was developed. The results of simulation and preliminary experiments show that for low and middle clouds, the sky Tb observed on the ground is very sensitive to the change of CBH, therefore it can be used to estimate CBH. The influence of aerosol (VIS and aerosol types) above the ground on the sky Tb cannot be neglected, it must be corrected. Because the regularity of aerosol's influence on Tb at different zenith angles is fairly clear, it can be corrected well.