辽西地区潜在蒸散发敏感性分析及变化成因研究

Sensitivity and Attribution of Potential Evapotranspiration in Western Liaoning

【目的】了解辽西地区潜在蒸散发敏感性及蒸散发变化成因。【方法】基于辽西地区13个气象台站1965—2015年的基础气象资料,依据FAO-56 Penman-Monteith法估算了辽西地区近50 a的蒸散发(ET_0),采用Mann-Kendall检验法对ET_0及各气象要素的变化趋势进行了检验,同时基于敏感性系数法探讨了ET_0对各气象要素的敏感性,并定量揭示了引发ET_0变化的主导因子。【结果】1965—2015年,辽西地区年均ET_0以12.5 mm/10 a的速率显著降低,均值为1 007.6 mm/a,空间上由西南向东北呈低—高—低的分布格局;最低温度和最高温度表现为极显著升高趋势,风速和太阳辐射表现为极显著降低趋势,相对湿度未发生明显变化;辽西地区ET_0对各气象要素的敏感性依次为:相对湿度>最高温度>风速>太阳辐射>最低温度,且ET_0与相对湿度变化呈负相关,而与其他要素变化均为正相关;最低温度、最高温度的升高和相对湿度的降低引发区域ET_0变动为正贡献,而太阳辐射和风速的降低则为负贡献,且贡献率最大的为风速,最小的为相对湿度。【结论】风速的降低是引发辽西地区ET_0降低的主导因子。

【Objective】Study the relationship between ET_0 and meteorological factors in a region with specific climate.【Method】Based on the meteorological dataset during 1965 to 2015 from the thirteen selected meteorological stations of the western Liaoning,the FAO-56 Penman-Monteith method was used to estimate the reference evapotranspiration（ET_0）.The variation trend of meteorological variables and ET_0 were examined with the MannKendall trend test.Besides,according to sensitivity coefficient,sensitivity of ET_0 to meteorological variables and the dominate factor which affects the variation of ET_0 were analyzed.【Result】The results showed the average ET_0 in western Liaoning was 1 007.6 mm/a,decreased at the rate of 12.5 mm/10 a in 1965—2015 and observed a low-high-low distribution pattern from the southwest to northeast.Daily maximum and minimum temperature were significantly increased.Wind speed and solar radiation were significantly decreased and relative humidity didn＇t significantly change.Sensitivity of ET_0 to meteorological variables were ranked as： relative humiditymaximum air temperaturewind speedsolar radiationminimum air temperature.And ET_0 was negatively correlation with relative humidity,while other meteorological variables showed positive correlation.Contribution rate analysis showed the increased minimum,maximum temperature and decreased relative humidity impacted positively to ET_0 variation,and the decreased wind speed and solar radiation impacted negatively.The largest contribution rate to ET_0 variation was wind speed,while the relative humidity was lowest.【Conclusion】In general,the decreased wind speed was the dominant factor to the ET_0 variation in western Liaoning.