鲁中地区参考作物蒸散量时空变化特征及主要气象因子的贡献分析

基于1980-2014年鲁中地区气象资料，采用Penman-Monteith模型计算该区域近35a的参考作物蒸散量（ET0），分析不同时间尺度ET0及主要气象因子的时空变化规律，并利用基于敏感系数的贡献率法探讨主要气象因子对不同时间尺度ET0变化的贡献。结果表明：鲁中平原地区近35a年ET0平均值为1165.8mm，山区为1144.6mm，均呈减少趋势，且平原减少趋势极显著，其气候倾向率为-22.2mm·10a-1（P＜0.01）；季节ET0平均值由多到少依次为夏季、春季、秋季和冬季，春季呈增加趋势，其它季节呈减少趋势；6月是ET0最大的月份，1月为最小的月份，其年内分布呈抛物线状；各时间尺度ET0变化主要空间分布基本同步。年、季ET0对相对湿度的变化最敏感，且呈增加趋势，月ET0对主要气象因子变化的敏感性随月份呈现不同规律，3-6月、9-10月的最敏感气象因子为相对湿度，1-2月、11-12月为风速，7-8月为日照百分率。从主要贡献率看，年ET0变化的主要贡献因子为风速，各季、月ET0变化的主要贡献因子不一，但平原和山区两种地形同一时段主要贡献因子基本一致，4个主要气象因子的总贡献率基本能解释各时间尺度ET0变化的原因。

Temporal and Spatial Variation of Reference Crop Evapotranspiration and Contribution of Main Factors in the Middle Area of Shandong Province

Based on the meteorological data in the middle areas of Shandong Province from 1980 to 2014, the reference crop evapotranspiration(ET0) was calculated by Penman-Monteith model, the spatial and temporal distribution characteristics of the main meteorological factors and ET0 of different time scales were analyzed, and the contribution to ET0 changes of different time scales made by main meteorological factors was also discussed with a method based on sensitivity coefficient. The results showed that annual average ET0 of the plain was 1165.8mm, and the mountainous area was 1144 6mm in the past 35 years,which had an extremely significant reduction trend in the plain, at the rate of 22.2mm·10y-1(P<0.01).The seasonal average ET0 from high to low was summer, spring, autumn and winter, which had an increasing trend in spring and a reduction trend in other seasons. The maximum monthly average ET0 appeared at June, the minimum value appeared at January, and annual distribution presented parabolic shape.The main space distribution of all time scales was basic synchronization. Annual and seasonal average ET0 was sensitive to the changes of relative humidity and it tended to increase. The sensitivity of monthly average ET0 to main meteorological factors had different changing rules by the month. The most sensitive factor which affected monthly average ET0 was relative humidity from March to June, September and October, wind speed in January, February, November and December, percentage of sunshine in July and August. According to the main contribution rate, wind speed had the largest contribution to the annual average ET0, seasonal and monthly average ET0 was different between main contribution factors while the main contribution factors at the time scale in plain and mountain was basically the same. The total contribution rate of four main meteorological factors could basically explain the reasons of ET0 changing of different scales.