热处理对沙漠边缘土壤腐殖酸荧光性质及其与Cu(Ⅱ)络合作用的影响

利用Penman-Monteith公式和常规气象资料计算和分析中国北方半干旱典型沙区(科尔沁沙地、浑善达克沙地和毛乌素沙地)50多年来主要气象要素和潜在蒸散量的变化趋势及其原因。 结果表明,自20世纪50年代以来,北方半干旱典型沙区年平均气温均呈上升趋势,年降水量均呈波动变化特征,但年平均风速呈明显下降的趋势。浑善达克沙地年潜在蒸散量随时间呈现显著增加趋势,科尔沁沙地年潜在蒸散量随时间呈现小幅的增加趋势,但毛乌素沙地年潜在蒸散量随时间呈现微弱的下降趋势。偏相关分析显示,毛乌素沙地潜在蒸散量与日照时数和风速呈显著的正相关,与平均温度呈显著的负相关;浑善达克沙地和科尔沁沙地潜在蒸散量与年平均温度显著正相关,但与日照时数无显著相关性。因此,毛乌素沙地日照时数减少和风速降低有可能是区域潜在蒸散量近几十年呈现减少的主要原因,科尔沁沙地和浑善达克沙地潜在蒸散量变化可能主要受温度的影响。

Changes of Main Climatic Parameters and Potential Evapotransipiration in Typical Semi-arid Sandy Lands of Northern China during 1951--2005

The changes of main climatic parameters and potential evapotranspiration were calculated and analyzed by using the Penman-Monteith model and observation data in typical semi-arid sandy lands(Horqin Sandy Land,Hunshadake Sandy Land and Mu Us Sandy Land) of Northern China during 1950-2005.During this period,annual mean temperature significantly increased;annual precipitation fluctuated,and annual mean wind speed decreased significantly in these sandy lands.Potential evapotranspiration increased significantly in the Hunshandake Sandy Land,increased slightly in the Horqin Sandy Land,but slightly decreased in the Mu Us Sandy Land.Partial correlation analysis showed that the annual potential evapotranspiration in Mu Us Sandy Land was significantly positively correlated with the annual sunshine hours and the annual mean wind speed,and was significantly negatively correlated with the annual mean temperature.However,the annual potential evapotranspiration in Horqin Sandy Land and Hanshandake Sandy Land was significantly positively correlated with the annual mean temperature,but it was irrelevant with the sunshine hours.Therefore,it can be concluded that decreasing of annual sunshine hours and annual mean wind speed may cause the decreasing of annual potential evapotranspiration in the Mu Us Sandy Land,and variations of annual potential evapotranspiration in the Horqin Sandy Land and the Hunshandake Sandy Land may be affected by annual mean temperature.