基于GIS的中国西南地区覆冰气象条件评估

采用中国西南地区(95°~110° E、 25°~35° N) 96个常规气象观测站1961年1月1日至2009年12月31日逐日气象要素资料提取覆冰相关要素, 利用1 km×1 km DEM资料通过GIS技术建立经度、 纬度、 海拔高度3个宏观地形因子以及坡度、 坡向和开放度3个微观地形因子的数据库, 通过三维二次趋势面的逐步回归方法, 在ArcMap/Info中进行与覆冰有关的气象要素栅格空间化, 在此基础上按照轻、 中、 重三个级别建立了各级覆冰模型并划分了覆冰风险分布. 结果表明: 满足覆冰条件日数序列在2000年以来呈显著上升趋势, 覆冰灾害发生的可能性增大. 一般来说, 宏观地形因子对气象要素的分布影响较大, 相对湿度模型和日照时数模型通过微观地形因子订正后, 精度有所提高. 通过模型得到的西南地区覆冰风险分布图能够较为精确的模拟出西南地区覆冰的风险分布, 与实际情况相符.

Assessing Meteorological Conditions Concerning Icing in Southwest China Based on GIS

The main meteorological elements based on daily meteorological records for the period of 1960-2009 from 96 stations in Southwest China is used for picking the factors involving icing conditions. A database of geographical factors, including longitude, latitude, slope, aspect and sky-view factors is set up by using 1 km?1 km digital elevation model (DEM) and GIS. Based on the mathematical theorem of tendency simulation and stepwise regression, a grid of icing meteorological element and icing comprehensive evaluation index is established by ArcMap/Info. From this index, Southwest China can be zoned for 3 ranks of icing intensity. It is found that the trend of the series of days with icing conditions has increased significantly since 2000. The risk of the icing would be increasing. Icing conditions and icing intensity (risk) models are developed and all pass the significant level 0.05. Generally, the effect of macro-topographic factors is greater. The accuracy of relative humidity model and sunshine duration model will be improved by micro-topographic factors corrected. A map based on icing intensity (risk) model in Southwest China is presented, which shows the distribution of icing risk clearly and agrees with the actual situation vary well.