雅鲁藏布大峡谷地区降水时空变化特征分析

Analysis of Spatiotemporal Variation Characteristics of Precipitation in the Yarlung Zangbo Grand Canyon Region

摘要: 研究雅鲁藏布大峡谷地区降水变化规律，有助于加深对雅鲁藏布大峡谷地区降水变化特征的理解。本文使用了欧洲气象资料中心的全球再分析气象数据ERA-interim，分析了1979~2018年雅鲁藏布大峡谷地区降水的气候特征，并结合趋势分析、Mann-Kendall突变检验、滑动T检验、小波分析和EOF分析等方法分析了大峡谷地区降水的时空变化特征。结果表明：1) 雅鲁藏布大峡谷地区年平均降水量自西南部向东北部逐渐减少。4个季节中，夏季平均降水量最多、春秋两季适中、冬季平均降水量偏少。降水量变化趋势的空间分布中，大峡谷大部分地区年平均降水量呈下降趋势，西南部地区下降趋势最明显。各季节平均降水量均趋于减少，其中夏季平均降水量的减少趋势最明显。2) EOF分析中年平均降水量的第一、二模态共同解释了大峡谷地区40.3%的降水量变化，第一模态中大部分地区呈一致的降水量增多或减少的分布型式。第二模态年平均降水量呈中部与四周相反的分布型式。3) 通过小波分析得到大峡谷地区年平均降水量存在2~3年的显著周期。4) 年平均降水量在2005年前后发生了由增多到减少的气候突变过程。

Abstract: The study of the variations of precipitation in Yarlung Zangbo Grand Canyon region will help deepen the understanding of the characteristics of precipitation change in the Yarlung Zangbo Grand Canyon Region. This article uses the global reanalysis meteorological data ERA-interimfrom European Center for Mediumrange Weather Forecasts to analyze the climate characteristics of precipitation in the Yarlung Zangbo Grand Canyon region from 1979 to 2018. It combines trend analysis, Mann-Kendall mutation test, sliding T-test, wavelet analysis, EOF analysis, and other methods to analyze the spatiotemporal variation characteristics of precipitation in the Grand Canyon region. The results indicate that: 1) The annual average precipitation in the Yarlung Zangbo Grand Canyon region gradually decreases from the southwest to the northeast. Among the four seasons, the average precipitation in summer is the highest, the spring and autumn seasons are moderate, and the average precipitation in winter is relatively low. In the spatial distribution of precipitation variation trend, the annual average precipitation in most areas of the Grand Canyon shows a downward trend, with the southwest region showing the most obvious downward trend. The average precipitation in all seasons tends to decrease, with the summer average precipitation showing the most significant decrease. 2) The first and second modes of average precipitation in EOF analysis jointly explain the precipitation change of 40.3% in the Grand Canyon area. In the first mode, most areas show a consistent pattern of precipitation increase or decrease. The annual average precipitation of the second mode is in the opposite distribution pattern in the middle and around. 3) Through wavelet analysis, it is found that there is a significant period of 2~3 years in the annual average precipitation of the Grand Canyon region. 4) The annual average precipitation experienced a sudden climate change from increasing to decreasing around 2005.