1960～2009年民勤地区气候变化特征分析

Analysis on Climate Changes in the Minqin Region from 1960-2009

利用民勤气象站1960～2009年逐日平均气温、平均最高气温、平均最低气温、平均风速、平均相对湿度、日照时数和降水量的观测数据,结合P-M模型所提供的最大可能蒸散量计算方法,运用一元线性回归分析了民勤地区气温、降水、最大可能蒸散量及湿润度的变化特征。结果表明,近50年来,民勤地区年平均气温以0.397℃/10 a的速率呈极显著上升趋势,和同时期西北干旱区年平均气温升温速率相当;各季节平均气温亦极显著上升,且以冬季上升幅度最为突出;年降水量以2.508 mm/10 a的速率呈不显著增加趋势,各季节降水量变化趋势亦不明显,但均略有增加;年最大可能蒸散量以-7.233 mm/10 a呈不显著减小趋势,各季节最大可能蒸散量均呈减小趋势,但均不显著;年湿润度以0.005/10 a的速率略增大趋势,各季节湿润度亦均呈增大趋势,但均不显著。

Based on the climate data observed from Minqin meteorological station including the daily mean temperature,mean maximum temperature,mean minimum temperature,mean wind speed,mean relative humidity and precipitation from 1960-2009,the fundamental changes characteristics of annual and seasonal mean temperature,precipitation,potential evapotranspiration and wetness degree were analyzed by the linear regression analysis method and the maximum potential evaporation flux provided by P-M model.The result showed that the annual mean temperature increased significantly in recent 50 years at a rate of 0.397 ℃/10 a,which was equal to the speed of annual average temperature increasing in northwest dry area in the same period.The average temperature in each season increased significantly and the increasing span in winter was most outstanding.Annual precipitation in the past 50 years increased slightly at a rate of 2.508 mm/10 a but not significant.The seasonal variation of precipitation was not obvious but all increased.Annual potential evapotranspiration decreased not significantly with a rate of-7.233 mm/10 a and all seasonal potential evapotranspiration also decreased not obviously.Annual wetness degree increased at a rate of 0.005/10 a but was not significant.Seasonal wetness degree increased too in the past 50 years and the change trend of winter was the highest.