黑河流域大气资料尺度转换的对比分析

Comparison of Atmospheric Data Scaling Transfer Scheme in Heihe River Basin

尺度转换是解决尺度差异问题的有效方法之一。尺度转换统计模式的可靠性和正确性如何,在很大程度上取决于建立统计模式时所用的实际气象资料的处理,尤其在下垫面分布极不均匀地区。本文研究了黑河流域这一复杂下垫面条件下的大气资料的尺度转换问题,对比分析了由NCEP再分析资料直接内插到较小尺度而得到的局地气候变化与由尺度转换统计模式,经过客观分析所得到的局地气候变化。结果表明,直接插值所得的细网格值只能用于对平坦地区的温、湿状况的描述,而对较高山区的区域特征描述不够;进行观测资料的客观分析可以更准确地反映黑河流域复杂下垫面背景下近地层大气要素场的变化。研究表明,客观分析过程是尺度转换过程的重要环节。

Scaling transfer is one of the available approaches in solving scale issues. In a large extended area, the reliability and validity of a statistic scaling model depend on dealing with of the observed data,especially in the area with inhomogeneous highland. Here, downscaling of the meteorological data in Heihe River Basin was studied, where the topography and underlying are extremely complex and heterogeneous.Results of interpolating from the global climate model output and statistical downscaling model, including objective analysis, were compared. The following conclusions were obtained： The finer grid atmospheric data by interpolating from coarse resolution global climate model output could get the local temperature and humidity characteristics of the plat area, while it could not be used in the high mountain area. Wind near surface did not match with the observation also. The 1 km resolution atmospheric grid data by statistical downscaling model through the objective analysis could well present the atmosphere elements condition in Heihe River Basin. It is proved that the objective analysis plays an important role in the scaling transfer process.