近56年来新疆策勒县潜在蒸散量变化及影响因子分析

Analysis of Variation Characteristics and Influence Factors of Potential Evapotranspiration in Cele County of Xinjiang in Recent 56 Years

【目的】对策勒县潜在蒸散量变化特征进行分析,近而为评价该区域气候干湿状况提供一定的参考依据。【方法】基于策勒县近56年气象数据,依据Penman-Monteith模型计算得出该区1960-2015年逐日潜在蒸散量值(ET_0),并利用一元线性回归、Mann-Kendall检验及小波分析法分析ET_0的变化趋势、突变年份及周期性特征,最后结合主成分分析法探讨影响研究区潜在蒸散量变化的主要气象因子。【结果】①策勒县年均潜在蒸散量为784.23 mm,且以-4.83 mm/年趋势减小;②四季潜在蒸散量的变化一致,均呈减小趋势,其中春季ET_0的年际变化率为-1.60 mm/年,减少最为明显;③潜在蒸散量在1986年出现了一次明显的减小突变,小波分析发现年ET_0存在9、21、29年的变化周期,第一主周期为29年,其次为21年;④研究区潜在蒸散量的减少主要受平均风速的影响。【结论】近56年来策勒县ET_0的变化整体为波动下降的趋势,而除风速外降水的增加也是其ET_0减小的原因之一。

【Objective】The change characteristics of potential evapotranspiration in Cele county are analyzed,which provides a reference for evaluating the dry and wet climate in the region.【Method】Based on the meteorological data of Cele County in recent 56 years,the daily potential evapotranspiration(ET0)of the area was calculated according to the Penman-Monteith model,and the variation trend,the mutation year and the periodic characteristics of the ET0 were analyzed by the linear regression,the Mann-Kendall test and the wavelet analysis.Finally the main influencing of potential evapotranspiration was discussed by principal component analysis.【Result】(i)The average annual potential evapotranspiration was 784.23 mm and the variation showed a significant declining tendency with a changing rate varied at-4.83 mm/a;(ii)The changes of ET0 during the four seasons were consistent and all showed a decreasing trend.Among them the inter-annual variation rate of ET0 in spring was-1.6 mm a^-1,which was the most obvious;(iii)The potential evapotranspiration experienced a significant reduction in 1986.Wavelet analysis revealed that there was a oscillation cycle of 9,21 and 29 years.(iv)The first main period was 29 years,and the second one was 21 years in the study area;(v)The reduction of potential evapotranspiration in the study area was mainly affected by the average wind speed.【Conclusion】In the past 56 years,the change of ET0 in Cele county has been a trend of volatility decline,in addition to the wind speed,the increase of precipitation is also one of the reasons for the decrease of ET0.