关键词: 青藏高原, 降水, 集中度, 集中期

Abstract:

Based on the daily precipitation data in the Tibetan Plateau (TP) from 1979 to 2016, the spatial and temporal characteristics of precipitation, precipitation concentration degree (PCD) and precipitation concentration period (PCP) were analyzed with statistical methods. The results showed that precipitation decreased from southeast to northwest in the TP. The PCD ranged from 0.61 to 0.71, and PCP ranged from 38 to 41 pentad in the TP. The precipitation was unevenly distributed in each area, and it was the most concentrated and PCP was the latest in southern of the TP, while it was relatively even in northeastern of the TP. The PCD and PCP had the largest interannual fluctuations in northwestern of the TP. There was the most positive correlation between precipitation and PCD in Ali, but it was negative in Nielamu. The correlation between precipitation and PCP was positive in east part of 90°E and negative in west part. The high pressure ridges over Urals and lower reaches of Mongolia strengthened in summer in more precipitation years, while the East Asian trough enhanced in less precipitation years. There were convergences in lower troposphere and divergence in upper troposphere in summer of more precipitation years.

Key words:  Tibet Plateau, precipitation, precipitation concentration degree, precipitation concentration period