全球气候变化下黄土高原泾河流域近40年的气候变化特征分析

全球气候变化对于农业生产活动和生态环境保护有着深刻的影响。本文用时间序列分析中的距平曲线和短期预测方法分析了泾河流域内14个气象站点1960~1999(1971-2000)年气温和降水量的变化趋势,并用简单气候偏差指数计算了逐年的降水量变差;同时用变异系数计算了14个站点1960~1999(1971-2000)年的降水量年际变差。结果表明:近40年来14个站点的年均温度呈现明显的上升趋势,平均增温0.7℃略高,年平均增温率为0.0225℃/a;年降水量呈现微弱的减少趋势,但是波动幅度和变异系数都在增加,降水量年际间偏差呈现先减少后又增加的趋势。年内气候变化的趋势变化表现为:冬季温度升高;春季、夏季降水量占全年的百分比有显著增加趋势,而秋季降水所占的百分比显著减少。最后分析了全球变化背景下泾河流域近40年来气候出现的这种暖干化趋势对流域农业生产和生态环境的可能影响,可为相关部门调整农业结构、种植结构,优化种植模式等决策提供指导。

Variations of the Climatic Characteristics in the Past 40 Years of Jinghe River Basin,Loess Plateau of China

Under the background of global climate change,there are even greater uncertainties of the climatic characteristics changing trend and regional differences.Fluctuations and trends in temperature and precipitation for the fourteen meteorological stations in Jinghe River Basin during the periods of 1960-1999(1971-2000) were calculated to analyze the climate variation in short term scale.Moreover,two methods of simple climate departure index and variation coefficient(CV%) were used to analyze inter-annual variation of precipitation for this area.The results showed that annual mean temperature has increased by 0.732 C during the last 40 years,and the annual mean temperature was mainly ascended in winter of Jinghe River Basin.The trend of temperature rising in the whole region was not only agreed with the global warming,but also the warming extent was more obvious.There was a lightly downward tendency of annual mean precipitation in the last 40 years.The extents of fluctuation and variation coefficient were both increased,and simple climate departure index of precipitation was decreased firstly then increased.Distribution of seasonally precipitation were plotted and compared in order to determine moisture deficit periods in this area.The precipitation data was analyzed according to the proportion of four seasons,which showed that the percentage of precipitation in summer and spring were increased dramatically,and percentage of precipitation was decreased.Temperature and precipitation were the two major climatic factors affecting agricultural production and ecological protection.The variation trend of these climatic factors had both advantages and disadvantages to the agricultural production.Rain-fed agriculture is very risky.Rainfall inclusion in irrigation scheduling causes difficulties.To improve agricultural economic benefits,agricultural administrative departments should adjust and optimize the agricultural structure and planting structure of the crops in time,and pay attention to the protection of agricultural resources and the improvement of the ecological environment to realize the sustainable development of agriculture.