海南岛参考作物蒸散量时空变化特征及成因分析

摘要

根据海南岛18个气象站1971–2010年逐日气象资料和Penman–Monteith模型计算各站ET0,利用线性回归和ArcGIS空间插值技术分析年和四季ET0的时空变化特征,并采用敏感系数和气象因子的相对变化率相结合的方法对年和四季ET0变化成因进行分析.结果表明:海南岛18个市(县)年ET0均值为1191.4mm,其空间分布,除夏季外,年和其余各季ET0大致呈由东北向西南递增的趋势.近40a海南岛18个市(县)年ET0的气候倾向率均值为-5.0mm?10a-1,其中13市(县)为负值,5市(县)为正值.春、夏、秋、冬四季ET0的气候倾向率分别为-3.1、1.8、-0.7和-2.8mm?10a-1.总体来看,年ET0减少的区域主要是由于春季ET0减少所致,年ET0增加的区域主要是因夏季ET0增加之故.引起海南岛大部分地区年和春、夏、秋季ET0减少的主要原因是平均风速减小和日照时数的减少,冬季ET0减少除与平均风速减小、日照时数减少有关外,水汽压增加也是主要成因之一.年和四季ET0增加的区域主要是平均最高和平均最低气温升高.%Based on the daily data of 18 meteorological stations in Hainan Island from 1971 to 2010, spatiotemporal change characteristics of ET0 of year and the four seasons were analyzed with linear regression and ArcGIS spatial interpolation techniques after calculation with the Penman-Monteith model. Then the sensitivity coefficients were combined with the relative changes of meteorological factors to study the causes of change of ET0 of year and the four seasons. The results showed that the average annual ET0 of 18 stations was 1191.4mm, and except for summer, ET0 of year and the other 3 seasons increased from the northeast to southwest approximately. The average climate change rate of annual ET0 of 18 stations was-5.0mm?10y-1 in recent 40 years, among which 13 stations' climate change rates were negative and 5 stations' were positive. The average climate change rate of four seasons' ET0 were-3.1, 1.8,-0.7 and-2.8mm?10y-1, respectively. Overall, 13 stations' annual ET0 decreased mainly due to the decrease of ET0 of spring, and the rest 5 stations' increase was mainly due to the increase of ET0 of summer. The attribution analysis showed that mean wind speed' decrease and sunshine hours' reduction was by and large the main reason for the decrease of ET0 of year, spring, summer, and autumn in most areas of Hainan Island. Besides the reason above, the decrease of vapor pressure was also one of the major causes for the decrease of winter's ET0. On the other hand, the major reason for the increase of annual and four seasons' ET0 was the rise of the average maximum and minimum temperature.