1971-2015年青藏高原东北边坡降水特征及主要影响因子分析

利用1971-2015年青藏高原东北边坡20个站的降水观测资料和美国国家环境预报中心（NCEP）再分析资料，分析了青藏高原东北边坡年、季降水量空间分布和变化趋势，并采用相关系数法分析和讨论其所受的影响因素。结果表明：青藏高原东北边坡地区的年、季平均降水量空间分布极为不均，总体上是从南向北递减，东北部最少；青藏高原东北边坡年、夏、秋季平均降水量北部呈上升趋势，南部呈下降趋势；青藏高原东北边坡地区年平均降水量呈下降趋势，气候倾向率为-3.1 mm·（10a）^-1，其中春、秋、冬季平均降水量呈上升趋势，夏季平均降水量呈明显下降趋势；青藏高原东北边坡地区年、季降水量的显著周期为2～3 a、4～5 a及10～15 a；南亚季风对青藏高原东北边坡地区降水量影响显著，为明显的正相关，西风指数对高原东北边坡地区降水量有一定影响，相关不是很明显，与其北部降水量呈正相关，南部降水量呈负相关。

Precipitation characteristics and its affecting factors on the northeast slopes of Qinghai-Tibet Plateau from 1971 to 2015

Based on the in-situ observation of precipitation at 20 stations in the northeast slopes of the Qinghai-Tibet Plateau and the National Centers for Environmental Prediction (NCEP) reanalysis data from 1971 to 2015, regional changing trend and spatial characteristics of annual and seasonal precipitations have investigated. Furthermore, affecting factors of annual precipitation were also analyzed using the correlationship related to climatic indices. The results showed that:spatial distribution of the annual and seasonal precipitations were extremely uneven in the northeast slopes of the Qinghai-Tibet Plateau, northwards decreasing; the annual precipitation, summer precipitation and autumn precipitation showed an increasing trend in the north and a decreasing trend in the south; the spring precipitation showed an increasing trend and the winter precipitation showed an increasing trend in some stations; the annual and summer precipitation showed a decreasing trend in some stations, autumn precipitation, spring precipitation and winter precipitation showed an increasing trend in some stations. It is also found that the there were vibration periods of 2~3 a, 4~5 a and 10~15 a. The South Asian monsoon mainly influenced the precipitation on the northeast slopes of the plateau; the westerly affected annual precipitation certainly, which was positively related to the precipitation in the north and negatively related to the precipitation in the south.