黑龙江省参考作物蒸散量变化及气象因子分析

为研究中纬度寒区参考作物蒸散量时空变化及影响因子变化，揭示参考作物蒸散量与各气象因子间响应关系，基于黑龙江省34个标准气象站点数据资料，运用Penman-Monteith公式方法计算逐日参考作物蒸散量。利用累积距平、气候倾向率、趋势分析和突变检验、Hurst指数方法，分析了黑龙江省参考作物蒸散量时空变化特征及气象因子间响应关系，明确了产生差异性的主要原因。结果表明:整体上，黑龙江省1990—2019多年平均参考作物蒸散量呈下降趋势；春季相对湿度是影响参考作物蒸散量变化的主要气象因子，而冬季影响参考作物蒸散量较大的气象因子是平均气温；全省高蒸散区集中在以泰来为中心的西南部，低蒸散区集中在以呼中为中心的西北部；风速和气温是影响黑龙江省南部地区参考作物蒸散量变化的主要气象因素，相对湿度是影响北部地区参考作物蒸散量变化的主要气象因素；对未来变化趋势预测表明，黑龙江省Hurst指数为0.60~0.69，说明未来参考作物蒸散量变化呈与现在相同的下降趋势且具有一定持续性。

Analysis of reference crop evapotranspiration changes and meteorological factors in Heilongjiang Province

To explore the temporal and spatial variation of reference crop evapotranspiration and the change of influencing factors in mid-latitude cold regions, the response relationship between reference crop evapotranspiration and various meteorological factors was revealed. Based on the data of 34 standard meteorological stations in Heilongjiang Province, daily reference crop evapotranspiration was calculated by the Penman-Monteith formula. Using the methods of cumulative departure curve, climate tendency rate, trend analysis and mutation test (Mann-Kendall test), and Hurst exponent, the spatial and temporal variation characteristics of reference crop evapotranspiration in Heilongjiang Province and the response relationship between diversified key meteorologic factors were analyzed, and the leading causes for the dissimilitude identified. The results show that the average reference crop evapotranspiration in Heilongjiang Province from 1990 to 2019 exhibited a moderating trend as a whole; the relative humidity was the main meteorological factor affecting evapotranspiration of reference crops in spring, while the average temperature in winter was that leading to the variation of reference crop evapotranspiration. In the entire province, the high evapotranspiration areas are concentrated in the southwest, with Tailai as the center, while the low evapotranspiration areas are concentrated in the northwest, with Huzhong as the center. The main meteorological factors that affect reference crop evapotranspiration changes in the southern region of Heilongjiang Province are mean wind speed, maximum air temperature, and minimum air temperature. The main meteorological factor that affects the change of reference crop evapotranspiration in the northern region is relative humidity, which refers to the ratio of the vapor pressure of water in the air to the saturated vapor pressure of water at the same temperature and pressure. The prediction of a future variation trend proves that the Hurst exponent in Heilongjiang Province is between 0.60 and 0.69, indicating that the future change of reference crop evapotranspiration will be similar to the same present downward trend as well as a certain degree of sustainability.