1961-2010年青藏高原降水时空变化特征分析

Analysis of the spatial-temporal variation characteristics of precipitation over the Tibetan Plateau from 1961 through 2010

利用青藏高原69个气象台站的降水量资料,采用旋转经验正交函数分析(REOF)、线性趋势分析和累积距平法,系统地研究了1961-2010年青藏高原降水的时空变化规律,揭示了青藏高原不同区域降水变化的差异性.研究表明:近50 a来青藏高原降水量总体呈现增加趋势,增长率为6.7 mm·(10a)-1;青藏高原降水季节分配极不均匀,雨季和旱季非常明显,雨季降水占有主导作用;青藏高原降水由东南向西北递减,而且年际变化具有一定的多元化特征;青藏高原降水量变化空间分布差异显著,采用REOF法将整个高原划分为10个小区,每个小区降水变化都具有不同的特征,除了青海东北部区和青海东南部-川北区降水呈减少趋势外,其他8个小区降水均呈增加趋势.

The precipitation data from 69 meteorological stations over the Tibetan Plateau from 1961 to 2010 are analyzed by using REOF （Rotated Empirical Orthogonal Function）, linear trend analysis and cumulative anoma- ly methods. The spatial-temporal variability characteristics of the precipitation during last five decades are also analyzed, and the differences in precipitation change over the Tibetan Plateau are revealed as well. The results show that： 1 ） from 1961 through 2010, the annual precipitation in the plateau had been increasing with an increasing rate of 6.7 mm · （10a） ^-1 2） The seasonal distribution of precipitation is uneven over the plateau. Wet and dry seasons are obvious and precipitation mainly concentrates in rainy season. 3 ） Spatially, precipitation decreases from southeast to northwest with altitude increasing and topography changing, and inter-annual variability has diversified characteristics with diversification in interannual variation. 4 ） The entire plateau can be divided into ten zones of different features by REOF method. Among them, there are eight zones have increasing precipitation tendency, but decreasing precipitation tendency takes place in northeastern Qinghai Province and southeastern Qinghai Province-northern Sichuan Province.