1961—2009年黄土高原气象要素的时空变化分析

Spatiotemporal Analysis of Meteorological Elements on the Loess Plateau during 1961-2009

基于48个气象站点1961—2009年的监测数据,使用反距离权重插值法和Mann-Kendall法,分析了黄土高原气象要素的空间分布和时间变化特征。结果表明,各气象要素在黄土高原都呈梯度分布,沿东南—西北方向降水和平均温度递减而平均风速和日照时数递增,沿南北方向相对湿度降低而参考作物蒸散增加。各气象要素在各站点基本都具有单调趋势,但趋势显著的站点数存在变异。约98%的站点温度的上升趋势显著,约60%的站点日照时数和风速的下降趋势及参考作物蒸散的上升趋势具有显著性,约40%的站点相对湿度的下降趋势显著,约30%的站点的降水具有显著的下降趋势。各气象变量都存在一定的年代际变化,相对湿度在2004年以来显著降低,降水的显著减少、年均温度和参考作物蒸散的显著上升都在20世纪90年代初以来,而日照时数和平均风速的显著下降都发生在20世纪80年代初以来。黄土高原的气候可能出现了一些新趋势,给未来可持续发展带来了不确定性,需引起足够重视。

Based on meteorological data from 48 monitoring stations during 1961 -2009, the spa- tial distribution and temporal trends of meteorological elements on the Loess Plateau were analyzed with Inverse Distance Weighted Interpolation and Mann-Kendall methods. Results show that the meteorological elements on the Loess Plateau spatially distributed with an obvious gradients. Precipitation and mean temperature decreased while mean wind speed and sunshine hours increased from southeast to northwest, relative humidity decreased while reference evapotranspiration in- creased from south to north. Monotonic trends were detected on most stations for each meteorologi- cal element; however, the numbers of stations with significant trends were different. About 98% of stations had significant upward trends in mean temperature, 60% of stations had significant downward trends in sunshine hours and wind speed and upward trends in reference evapotranspira- tion, 40% of stations had significant downward trends in relative humidity, and 30% of stations had significant downward trends in precipitation. Interdecadal variation existed in each meteoro- logical element. Relative humidity decreased significantly since 2004; precipitation decreased, mean temperature and reference evapotranspiration increased significantly since the 1990s; the significant decrease in sunshine hours and wind speed was from the 1980s. Some new changing trends in climate were detected on the Loess Plateau, which might cause some uncertainties for the sustainable development of this region; therefore, more attention should be paid to this issue.