Comparative Analysis of Three Near-Surface Air Temperature Reanalysis Datasets in Inner Mongolia Region

Abstract

Near-surface air temperature is important for climate change, agriculture, animal husbandry, and ecosystems undergoing climate warming in Inner Mongolia. Land surface reanalysis products feature finer spatial and temporal resolutions, that can provide important data support for the determination of crop growth limits, grassland biomass growth, and desertification research in Inner Mongolia. In this study, 119 in situ observed sites were collected to compare and evaluate the performance of near-surface air temperature in three reanalysis products from 2018 to 2020 in Inner Mongolia. The three reanalysis products included three widely used products derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) Fifth Generation Land Surface Reanalysis (ERA5-Land), and U.S. Global Land Data Assimilation System (GLDAS), as well as the latest reanalysis product from the High-Resolution Land Data Assimilation System reanalysis product by the China Meteorological Administration (HRCLDAS). Results are as follows: (1) The three reanalysis temperature products all reasonably reflect the characteristics of spatial and temporal changes in surface temperature in Inner Mongolia. Compared with ERA5L and GLDAS, HRCLDAS is more consistent with the observed results. (2) For the evaluation period, HRCLDAS has a certain underestimation of temperature, while ERA5-Land and GLDAS have a significant overestimation of temperature. (3) During high-temperature processes, HRCLDAS is more accurate in simulating higher temperatures than ERA5-LNAD and can demonstrate the changes in high-temperature drop zones. The major conclusion of this study is that the HRCLDAS product demonstrates a relatively high reliability, which is of great significance for the study of climate, ecosystem, and sustainable development.