秦巴谷地夏季降水的时空特征分析

利用安康和汉中地区21个测站1963—2012年逐日降水和气温资料以及统计诊断方法,分析了秦巴谷地年均气温和降水以及季节降水的时空变化特征,结果表明:秦巴谷地的年均气温呈明显线性增暖趋势,而年降水量的线性变化趋势不明显;在降水量较为集中的春夏秋3季中,春秋季降水量呈减小的趋势,而夏季的降水量却呈增多的趋势,尤其是近10年来降水量增多趋势明显。利用REOF方法将秦巴谷地夏季降水量分解为3个主要空间模态,即西部、东部和中部型,其中西部型和东部型是秦巴谷地夏季降水分布最敏感的区域类型。对秦巴山区2010年7月17—18日一次典型强降水天气过程的分析表明,西部型和东部型可能是秦巴地区的主要典型降雨型,对于秦巴地区降水规律认识和天气预报及防灾减灾有着重要意义。

Spatial and Temporal Distribution Characteristics of Summer Precipitation in Qinling and Daba Valley

On the basis of the statistical diagnostic analysis method and the daily mean temperature and precipitation of 21 meteorological observation stations in the Ankang and Hanzhong from 1963 to 2012, a series of analysis is made of the spatial and temporal distribution characteristics of the annual mean temperature and precipitation, as well as seasonal mean rainfall in the Qinling and Daba valley. Results indicate that the annual mean temperature of the Qinling Daba valley significantly increased, and the change trend of the annual total precipitation of the Qinling Daba valley was not obvious; the precipitation in spring and autumn decreased, but the precipitation in summer showed an increasing trend. At the same time, using the REOF method, the summer precipitation in the Qinling Daba valley is divided into three main mode (rainfall pattern): western, eastern, and central, and the western, and the eastern types of summer precipitation were more sensitive. The analysis of a typical strong precipitation processes shows that the western and the eastern types of summer precipitation are the typical rainfall patterns and have great significance to precipitation forecasting and disaster prevention service.