A Microwave Wetland Surface Emissivity Calibration Scheme Using SCE-UA Algorithm and AMSR-E Brightness Temperature Data

Abstract

Abstract Determination of land surface emissivity is important for land surface characterization, satellite data assimilation and retrievals of geophysical parameters from satellite observations. However, it is a very complex problem to calculate the microwave wetland surface emissivity, and there has not been a land radiative transfer model (RTM) for calculating it. This study presents a microwave wetland surface emissivity calibration scheme based on the National Center for Atmosphere Research (NCAR) Community Land Model version 2.0 (CLM2.0), microwave land emissivity model (LandEM), Shuffled Complex Evolution algorithm (SCE-UA) and gridded Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) satellite brightness temperature (BT) data, which considers the influences of the land surface sub-grid scale heterogeneity. It used the outputs of the CLM2.0 as the inputs of the LandEM to simulate the AMSR-E BT, SCE-UA algorithm to calibrate the microwave wetland surface emissivity with the AMSR-E BT observation data. The experimental results indicate that the SCE-UA algorithm can effectively calibrate the microwave wetland surface emissivity and the calibrated microwave wetland surface emissivity possesses excellent transportability. Although the calibration scheme presented in this study lacks the physical mechanism, this study provides a promising solution to obtain the microwave wetland surface emissivity through parameter calibration method, which will greatly improve land data assimilation study.