Evaluation of the Satellite-based Air Temperature for All Sky Conditions Using the Automated Mountain Meteorology Station (AMOS) Records: Gangwon Province Case Study

Abstract

Surface air temperature (T air ) is a key variable for the meteorology and climatology, and is a fundamental factor of the terrestrial ecosystem functions. Satellite remote sensing from the Moderate Resolution Imaging Spectroradiometer (MODIS) provides an opportunity to monitor the T air . However, the several problems such as frequent cloud cover and mountainous region can result in substantial retrieval error and signal loss in MODIS T air . In this study, satellite-based T air was estimated under both clear and cloudy sky conditions in Gangwon Province using Aqua MODIS07 temperature profile product (MYD07_L2) and GCOM-W1 Advanced Microwave Scanning Radiometer 2 (AMSR2) brightness temperature (T b ) at 37 GHz frequency, and was compared with the measurements from the Automated Mountain Meteorology Stations (AMOS). The application of ambient temperature lapse rate was performed to improve the retrieval accuracy in mountainous region, which showed the improvement of estimation accuracy approximately 4% of RMSE. A simple pixel-wise regression method combining synergetic information from MYD07_L2 T air and AMSR2 T b was applied to estimate surface T air for all sky conditions. The T air retrievals showed favorable agreement in comparison with AMOS data (r=0.80, RMSE=7.9K), though the underestimation was appeared in winter season. Substantial T air retrievals were estimated 61.4% (n=2,657) for cloudy sky conditions. The results presented in this study indicate that the satellite remote sensing can produce the surface T air at the complex mountainous region for all sky conditions.