Evaluating land use change impacts on rainfall in various categories using the Weather Research and Forecasting‐mosaic approach

Abstract

To evaluate land use change impacts on rainfall in various categories, satellite‐based images representing land use change between 1980 and 2010 were adopted to perform numerical experiments using the Weather Research and Forecasting regional climate model. The mosaic approach, rather than the dominant approach, was employed to describe the land surface characteristics and their corresponding changes, for which the changes in the land surface physical parameters were closer to the actual values. Changes in rainfall displayed marked subregional characteristics, which could be interpreted by changes in local upward and large‐scale moisture fluxes. Meanwhile, changes in the total rainfall (RCN) in various categories displayed remarkably different characteristics. Among these characteristics, storm and heavy storm rain expressed larger changes (relative values) and displayed stronger sensitivities over semi‐arid subregions. Storm and heavy storm rainfall increased up to 10.5% in the eastern part of northwestern China (NWE) and 13.6% over northeastern China and decreased up to 6.5% over the Tibetan Plateau and 11.9% over NWE. According to changes in the convective (RC) and non‐convective (RN) rainfall, the RCN for both storm and heavy storm rain were influenced by changes not only in the RC, RN, and RCN intensities, but also in the rain areas and number of rain days. The impacts of land use change on the summed RC, RN, and RCN for various categories might be less, whereas changes in the RC, RN, and RCN for individual various categories could be much larger. The rainfall impacts in various categories were higher over the subregions of China compared to China overall or the East Asian land areas, and those impacts demonstrated smaller influences at the regional scale (country‐wide, China) compared to the local scale (subregions of China). Therefore, the impacts of land use change on rainfall in various categories are important for climatic change studies.