中国天山山区降水空间分布模拟及成因分析
Spatial distribution of rainfall simulation and the cause analysis in China's Tianshan Mountains area
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摘要: 为了研究中国天山山区降水空间分布规律及其形成机理,基于研究区DEM及气象站点数据资料,运用偏最小二乘法和GIS技术建立了山区降水估算模型,并分析其降水成因。结果表明:天山山区年降水具有明显的经度和纬度地带性,西段多于东段,北坡(迎风坡)多于南坡(背风坡);研究区降水在海拔4 000 m以下呈线性增加特征,随后显著减少,在5 500 m左右出现第二极大值带;坡度小于50°时降水与坡度呈显著正相关。在地形抬升条件下,随气温下降和相对湿度上升使降水增加,这也是山区降水形成的必要条件。总体来看,偏最小二乘法可以有效解决降水及各因子间多重相关性问题,模型回归效果较显著,在模拟山区降水方面具有一定适用性。Abstract: To study the rainfall spatial distribution laws as well as the formation mechanism in China's Tianshan Mountains area, this thesis built the mountain area rainfall estimation model and analyzed the rainfall causes with the partial least squares(PLS) and GIS technology, based on the DEM in the research areas as well as the data information from the meteorological stations. The result shows that the rainfall in the Tianshan Mountain area is showing an obvious longitudinal and latitudinal zonality, with more rainfall in the west section than that in the east, and more in the north slope (windward slope) than that in the south slope (leeward slope). We can find a linear increase of the rainfall in the research areas with an altitude of 4 000 m below, and then a rapid decrease, with the second maximum belt at around 5 500 m. The rainfall and the slope are positively associated when the slope is less than 50°. When the topography lifts, the rainfall will increase with the drops of temperature and the rise of humidity, which is the requirement for the rainfall formation in the mountain areas. Generally, the method of PLS can effectively solve the multiple correlation issues between the rainfall and various factors, the regression effect of the model being obvious. This model has certain adaptability for the mountain area rainfall simulation.