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High‐Resolution Regional Reanalysis in China: Evaluation of 1 Year Period Experiments
Author(s) -
Zhang Qi,
Pan Yig,
Wang Shuyu,
Xu Jianjun,
Tang Jianping
Publication year - 2017
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2017jd027476
Subject(s) - downscaling , climatology , mesoscale meteorology , data assimilation , environmental science , meteorology , climate model , atmospheric model , precipitation , climate change , geology , geography , oceanography
Abstract Globally, reanalysis data sets are widely used in assessing climate change, validating numerical models, and understanding the interactions between the components of a climate system. However, due to the relatively coarse resolution, most global reanalysis data sets are not suitable to apply at the local and regional scales directly with the inadequate descriptions of mesoscale systems and climatic extreme incidents such as mesoscale convective systems, squall lines, tropical cyclones, regional droughts, and heat waves. In this study, by using a data assimilation system of Gridpoint Statistical Interpolation, and a mesoscale atmospheric model of Weather Research and Forecast model, we build a regional reanalysis system. This is preliminary and the first experimental attempt to construct a high‐resolution reanalysis for China main land. Four regional test bed data sets are generated for year 2013 via three widely used methods (classical dynamical downscaling, spectral nudging, and data assimilation) and a hybrid method with data assimilation coupled with spectral nudging. Temperature at 2 m, precipitation, and upper level atmospheric variables are evaluated by comparing against observations for one‐year‐long tests. It can be concluded that the regional reanalysis with assimilation and nudging methods can better produce the atmospheric variables from surface to upper levels, and regional extreme events such as heat waves, than the classical dynamical downscaling. Compared to the ERA‐Interim global reanalysis, the hybrid nudging method performs slightly better in reproducing upper level temperature and low‐level moisture over China, which improves regional reanalysis data quality.