吉林省参考作物蒸散量的时空变化特征及影响因素

Temporal-Spatial Variation Characteristics of Reference Crop Evapotranspiration and Its Influence Factors in Jilin Province

基于吉林省50个气象站1960—2014年逐日最高气温、最低气温、日照时数、风速数据,采用Penman-Monteith算法,计算各站逐日参考作物蒸散量,进而计算各站及全省四季和年平均参考作物蒸散量,利用数理统计方法,结合地理信息系统软件,分析参考作物蒸散量的时空变化特征及主要气候影响因子。结果表明:近55 a,吉林省年平均参考作物蒸散量为876 mm,年参考作物蒸散量呈显著下降趋势(p <0. 01);空间分布差异显著,由东南向西北逐级递增,56%的站点呈显著下降趋势(p <0. 05)。参考作物蒸散量夏季最大、春季次之、冬季最小,且均呈下降趋势,但只有春季的下降趋势显著(p <0. 01);春、夏、秋、冬季与年平均参考作物蒸散量在空间分布上基本一致,但气候倾向率为负值以及通过显著性检验的站点数依次减少。全省四季和年参考作物蒸散量均与降水呈显著负相关,与日照时数、风速、最高气温呈显著正相关;其中年、春、夏、秋季与气温日较差以及春、夏、秋季与平均气温也呈显著正相关;冬季与最低气温、平均气温呈显著正相关;而典型站点参考作物蒸散量各季节影响因素及影响大小略有差异,各气象因子的共同作用导致了参考作物蒸散量的变化。

The daily reference crop evapotranspiration was calculated based on daily maximum temperature,minimum temperature,sunshine duration and wind speed from 50 meteorological stations in Jilin Province during 1960-2014 by using Penman-Monteith algorithm,then the seasonal and annual average reference evapotranspiration were calculated in the whole province and each station.Spatiotemporal variation characteristics of reference crop evapotranspiration and main influential factors of climate were analyzed according to mathematical statistics method together with the geographic information system.The results show that in recent 55 years,the annual average evapotranspiration was 876 mm in Jilin Province,it showed a significant downward trend(p<0.01),and the spatial distribution difference of it was significant,which showed a gradual increase from southeast to northwest.For climate trend rate,56%stations showed a significant downward trend(p<0.05).In four seasons,reference crop evapotranspiration in summer was the largest,in spring it was the second,in winter it was the smallest,and that all showed a downward trend,but only in spring downward trend was significant(p<0.01).The average reference evapotranspiration in spring,summer,autumn and winter had basically the same spatial distribution patterns with annual average value,but its climate trend rate was negative and the number of sites passing significance test decreased in sequence.The seasonal and annual reference crop evapotranspiration showed significant negative correlation with precipitation,and significant positive correlation with sunshine duration,wind speed and maximum temperature.The average reference crop evapotranspiration in spring,summer,autumn and the whole year showed significant positive correlation with diurnal temperature range,and it in spring,summer,autumn correlated positively with average temperature,and that in winter had a significant positive correlation with the minimum temperature and average temperature.However,the seasonal influencing factors and the extent of influence on the crop reference evapotranspiration in typical stations were slightly different.Reference crop evapotranspiration varied under the influence of these meteorology factors.