基于植被蒸散发法的孔雀河流域天然植被生态需水估算

.Estimation of Ecological Water Requirement for the Natural Vegetation in the Kongque River Basin based on Vegetation Evapotranspiration

【目的】定量天然植被生态需水,为流域有限水资源的合理分配和使用供科学依据和决策参考。【方法】采用FAO56Penman-Monteith公式,结合干旱强度指数DSI,分析新疆孔雀河流域2000-2016年天然植被生态需水时空变化特征,幵计算了丌同干、湿状况下天然植被的生态需水。【结果】①研究区内天然植被生长季多年平均生态需水量为7.575 7×10^8 m^3,天然草地需水量大于天然林地需水量。②从时间上看,2000-2016年天然植被生长季生态需水总量以2006年为分界点整体上呈现出上升-下降波动趋势;在生长季内变化特征上,天然植被的生态需水主要集中在6-8月,占植被主要生长季全部需水量的69.64%;从空间上看,天然植被生态需水主要集中在绿洲区的农区外围及河流中、上游两侧。③丌同干、湿状况下,天然林、草地单位面积生态需水量均表现为:正常年>湿润年>轻度干旱年>极度干旱年,天然植被生态需水总量呈现:极度干旱年>正常年>轻度干旱年>湿润年。【结论】丌同干湿条件下天然植被生态需水存在差异,气候因子和天然植被面积的变化是导致生态需水差异的主要因素。

【Objective】 Quantitative ecological water requirement of natural vegetation provides scientific basis and reference for rational allocation and use of limited water resources in basin.【Method】Using FAO56 Penman-Monteith formula and the drought intensity index(DSI), the spatio-temporal variation characteristics of ecological water requirement of natural vegetation in Kongque River basin, Xinjiang from 2000 to 2016 were analyzed and the ecological water requirement of natural vegetation under different dry and wet conditions was calculated.【Result】①The average annual ecological water requirement of the natural vegetation growing season in the study area is 7.575 7× 10^8 m^3, and the water demand of natural grassland exceeds that of natural forest land.②From the perspective of time, the total ecological water requirement in the natural vegetation growing season in the last 17 years shows a rising-falling trend as a whole and the demarcation point occurs in 2006. As for the variation characteristics of the growing season, the ecological water requirement of the natural vegetation in the study area is mainly concentrated in June-August, accounting for 69.64% of the total water requirement in the main growing season of the vegetation. From the From the perspective of space, the ecological water requirement of the natural vegetation in the Kongque River Basin is mainly concentrated in the periphery of the agricultural area in the oasis and on both sides of the middle and upper reaches of the river. ③Under different dry and wet conditions, the average ecological water requirement per unit area of natural forest land and grassland shows the following rules: normal year > wet year > mild dry drought year > extreme drought year. The total amount of natural vegetation ecological water requirement shows: extreme drought years>normal years> mild drought years> wet years.【Conclusion】There are differences in the ecological water requirement of natural vegetation under different dry and wet conditions, and the change of climate factors and natural vegetation area is the main factor leading to the difference of ecological water requirement.