A statistical description method of global sub-grid topography for numerical models
A statistical description method of global sub-grid topography for numerical models
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DOI：
10.1007/s00382-022-06447-2
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Huaqiong Cheng
中科院分区：
文献类型：
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作者：
Yaqi Wang;Lanning Wang;Juan Feng;Zhenya Song;Qizhong Wu;Huaqiong Cheng
Abstract Slope and aspect are important topographic elements for thermodynamics and dynamics of atmospheric circulation, especially for local radiation and topographic precipitation. We propose a simple realistic statistical method based on trigonometric function transformation to calculate sub-grid slope and aspect for describing the orographic characteristics of complex areas over the globe. It is found that the transformed conditional probability density function conforms to the Gaussian distribution in most of the global areas (~ 98%), and this feature is not eliminated with the increasing of horizontal resolution. The reasonability of this method is tested over the Tibetan Plateau. The results show that the improvement ratio of surface solar radiation downward (SSRD) over the Tibetan Plateau improved significantly compared with the results from the grid average scheme, especially in autumn. The improvement of root mean square error is approximately 18.2 W/m 2 , and the improvement ratio reached 38.4%. The improvements of maximum and regional-averaged SSRD over the whole Tibetan Plateau were ~ 130 W/m 2 and ~ 44.3 W/m 2 respectively. Although we only consider the effect of sub-grid slope and aspect on solar shortwave radiation, which has a certain bias with the observation data, it is sufficient to prove the rationality of the statistical method compared with the unobstructed horizontal surfaces scheme.
