基于GIS的湖南雨凇分布与地形因子关系分析

利用湖南省97个气象站雨凇观测资料，分析了湖南雨凇地理分布特征. 结果表明：湘南属于湖南雨凇多发区，平均雨凇日数多于湘北；湘南雨凇分布特征与山地走向一致，沿雪峰山脉呈西南-东北走向的迎风坡与沿南岭北侧的迎风坡各有一高值区；湘北平均雨凇日数2 d左右，其中，湖区平原明显多于湘北山区.结合1∶50 000湖南省DEM数据，探讨了地形高程、坡度坡向、纬度等地形因子对湖南雨凇形成的作用.在海拔200 m以下，高程的变化对雨凇影响不明显；在海拔200~1 000 m，雨凇日数随高程上升而增多；海拔高于1 000 m，雨淞日数明显多于低海拔台站. 坡向对湖南平均雨凇日数的变异有一定影响，但是坡度的影响并不显著；随着纬度的变化，湖南平均雨凇日数南北差异明显.

Glaze in Hunan Province: Distribution and relation with topographical factors analyzed with GIS technique

In this paper, the relationship between glaze and topographical factors, such as elevation, terrain aspect and slope, are studied by using observations from 97 weather stations in Hunan Province and the 1:50 000 resolution Digital Elevation Model data of the province. The spatial distribution of annual glaze days shows that glaze days in southern Hunan Province are more than those in northern Hunan Province. One of regional maxima of glaze days in southern Hunan Province is along the windward slopes of the Xuefeng Range, the other one is along the windward slopes of the Nan Mountains. The maximum of glaze days over there is more than six days. Glaze days in lake areas of northern Hunan Province are more than that in mountain areas of northern Hunan Province. Elevation plays an important role but not the only role in the variation of glaze days at places higher than 200 m. However, it is not obvious at places lower than 200 m. Variation of glaze days seems to depend on terrain aspect but not terrain slope. Annual glaze days in the province increases with latitude, especially in those stations south of 28°N.