咸阳地区参考蒸散量变化特征及敏感性分析

为了研究咸阳地区作物参考蒸散量变化特征及其影响因素,利用1981—2012年咸阳地区的气象资料,根据Penman-Monteith公式计算参考蒸散量(ET_0),分析咸阳地区的ET_0及主要气象因子的变化趋势,并通过响应曲线和敏感矩阵分析咸阳地区ET_0对气温、日照时数、风速、相对湿度等的敏感性。结果表明:(1)咸阳地区年平均日ET_0整体上处于基本稳定状态,在以2.37 mm/d为平均值、±0.3 mm/d的范围内波动;(2)咸阳地区的年平均气温、最高气温及最低气温均呈显著增长趋势,平均风速与平均相对湿度呈下降趋势;(3)咸阳地区多年日平均参考蒸散量年际变化以及四季变化趋势不明显;(4)气温、日照时数、平均风速的变化与日ET_0呈正比关系,而平均气压和平均相对湿度与日ET_0呈显著负相关,并且平均相对湿度对日ET_0的影响最为明显。该结果对确定咸阳地区的作物需水量有重要指导意义。

Reference Evapotranspiration: Variation Characteristics and Sensitivity in Xianyang

The paper aims to study the variation characteristics and influence factors of reference evapotranspiration in Xianyang. Daily reference evapotranspiration (ET0) during 1981-2012 was calculated by using Penman-Monteith equation, based on daily meteorological data of Xianyang, the variation of ET0 and main meteorological factors were analyzed, the sensitivity of daily ET0 to main climate factors, such as temperature, sunshine hours, average wind speed and average relative humidity was analyzed by using the methods of response curves and sensitivity matrix. The results showed that: (1) the annual average daily ET0 in Xianyang was steady as a whole which was 2.37 mm/d, fluctuations were in a range of 0.3 mm/d; (2) the annual average temperature, the maximum temperature and the minimum temperature in Xianyang generally showed asignificant increasing trend, while the average wind speed and average relative humidity decreased; (3) the inter-annual and seasonal variation of average daily ET0 during 1981-2012 in Xianyang was not obvious; (4) the daily ET0 was in positive relation with temperature, sunshine hours and average wind speed and in negative relation with average air pressure and average relative humanity, and average relative humidity was the most sensitive to ET0 in Xianyang. The results can provide certain guidance for determining local crop water requirement.