内陆河干旱区生态需水分析

根据水分驱动生态演变模型 ,以水分运动和补给条件 ,研究了内陆河平原生态系统的需水结构。生态需水分为过渡带生态需水 ,绿洲生态需水 ;绿洲生态需水又进一步分为天然绿洲生态需水和人工绿洲生态需水。通过流域水分平衡和地面观测资料确定了生态圈层结构的水分需求 ,以及降水与径流对水分需求的补给比例。生态需水的分析计算 ,类似于供需平衡分析。从植物生理角度分析生态需水 ,得到天然植被的总腾发量 Et,作为植被生态需水总量。各典型天然植被的 Et通过实验资料获得。将植被和水面的总生态需水量扣除有效降水补充的部分 ,即为径流性生态需水量 GE。另一方面 ,以流域为单元进行降水和径流统一考虑的水分综合平衡 ,进行生态可利用水量分析。得到生态系统可能实际利用的径流性水资源量 GR。　　将生态需水量 GE与生态系统可能实际利用的水资源量 GR进行平衡分析 ,计算实际生态耗水 ,并分析盐碱地无效耗水。根据 2 0 2 0年生态状态情景分析 ,作出了 2 0 2 0年生态需水与生态系统结构演变的预测

Ecological water demand analysis in Arid Region

Based on water-driven ecological evolution model, this paper, started with water movement and supply conditions, researched the plain ecosystem water demand structure of inland rivers. The ecological water demand is divided into transition zone ecological water demand and oasis zone ecological water demand. The oasis zone ecological water demand can be further divided into artificial oasis water demand and natural oasis water demand. According to the basin water quantity balance and the observed information on land surface, the water demand of ring and layer structure ecosystem and the proportion of between precipitation and runoff which contribute to ecological water demand was confirmed. Ecological water demand analysis is similar to the supply-demand balance analysis. The total evapo-transpiration (Et) of natural vegetation is obtained by the analysis of the plant physiological conditions, which is taken as the vegetation ecological water demand. The typical natural plant Et can be obtained by experimental data. The runoff ecological water demand GE can be calculated by deducting the efficient precipitation from the total plant and water surface ecological water demand. On the other hand, the available runoff water quantity for the ecosystem GR can be obtained by water quantity balance analysis based on the comprehensive runoff-precipitation for a certain river basin. By the balancing analysis between the ecological water demand GE and the available water supply GR, we can calculate the actual ecological water consumption and analyze the unavailable water consumption in the saline land. According to the scenario analysis on the ecological state in 2020, the ecological water demand prediction and the ecosystem evolution process in 2020 have been made out.