基于MOD16产品的沂沭泗河流域蒸散量时空变化特征

Temporal and Spatial Variation of Evapotranspiration in Yishusi River Basin Based on MOD16

【目的】蒸散量是陆面水循环和地表能量平衡的重要组成。沂沭泗河流域位于淮河流域东北部,研究其蒸散量时空变化有利于研究区域水循环及流域对气候变化的响应。【方法】基于MOD16数据分析2005年—2014年沂沭泗河流域蒸散发时空分布与变化特征。【结果】2005年─2014年沂沭泗河流域蒸散量年均蒸散为514.59 mm,呈现出蒸散量下降的趋势,91.19%的面积呈蒸散量减少趋势,流域分区下降趋势由强到弱为日赣区、南四湖西区、南四湖东区、中运河区以及沂沭河区。年内蒸散量总体上先升后降,有5月、7月—9月两个峰值,8月蒸散量最大,各土地类型年内蒸散量变化情况与沂沭泗河流域年内变化基本一致。季节蒸散量大小为:夏季>春季>秋季>冬季。蒸散量多年均值空间异质性较强,总体上南高北低,北部丘陵地区蒸散数值偏低,平均值为465 mm/a,平原地区平均值为529.08 mm/a。【结论】流域分区蒸散量大小排序为:中运河区>沂沭河区>南四湖西区>南四湖东区>日赣区。不同土地利用类型年际、年内蒸散量排序均为:农田>林地>湿地>聚居地>草地>其它土地。

【Objective】Evapotranspiration is an important component of surface water cycle and surface energy balance.Yishusi River Basin is located in the northeast of Huaihe River Basin.【Method】The study of its evapotranspiration is conducive to the study of regional water cycle and the basin's response to climate change.【Result】Based on MOD16 data,the temporal and spatial distribution and variation characteristics of evapotranspiration in Yishusi River Basin from 2005 to 2014 were analyzed.The results showed that the average annual evapotranspiration volume in Yishusi River Basin was 514.59 mm from 2005 to 2014,showing a decreasing trend of evapotranspiration volume.The area of 91.19%showed a decreasing trend of evapotranspiration volume,and the downward trend of the river basin regions was from strong to weak,including rigan district,nansihu west district,nansihu east district,zhongyun river district and yishu river district.In general,the evapotranspiration in the year increased first and then decreased,with two peaks in May and July to September.The evapotranspiration in August is the largest.The change of evapotranspiration in each land type year is basically the same as that in Yishusi River Basin.The evapotranspiration of the season is:summer>spring>autumn>winter.The multi-year mean value of evapotranspiration has a strong spatial heterogeneity.On the whole,the value of evapotranspiration is high in the south and low in the north,and the value of evapotranspiration in the northern hilly region is low,with an average value of 465 mm/a and 529.08 mm/a in the plain region.【Conclusion】The order of evapotranspiration is:zhongyunhe district>yishuhe district>nansihu west district>nansihu east district>rigan district.The order of annual and annual evapotranspiration of different land use types was:farmland>woodland>wetland>settlement>grassland>other land.