黄河流域农业灌溉的区域气候水分效应

As the sensitive areas of global climate change, Yellow River basin is situated in arid and semiarid regions and also plays an important role in food production. However, the utilization of water resources in the Yellow River basin is facing an awesome task due to the drought and consumption of water increased. The large-scale agricultural irrigation is an important process in the utilization of water resources in Yellow River basin. How to effectively use such the effects of large-scale irrigation on regional climate change is a scientific problem should be answered for the current utilization of water resources in the Yellow River basin. Based on the existing research, different irrigation schemes will be developed for land surface model, and then coupled the modified land surface model into the Weather Research Forecasting regional climate model (WRF). The long-term changes of regional climate, energy budget and water cycle in Yellow River basin are simulated by using the high resolution regional climate model, and quantitatively evaluated the regional climatic water effects of agricultural irrigation in the Yellow River basin, and investigated the physical mechanism. These studies will provide scientific advice to water use sustainable development in Yellow River basin.

黄河流域地处干旱、半干旱地区，是对全球气侯变化响应的敏感地区,也是我国粮食生产的重要基地之一，然而由于干旱化的加剧和人类用水的增加,黄河流域水资源的利用面临严峻的考验。其中，大范围的农业灌溉是黄河流域水资源利用的一个关键过程，如何有效利用和这种大范围的灌溉对区域气候变化的影响是当前黄河流域水资源利用所亟待解决的科学问题。本研究拟在已有研究的基础上，发展陆面模式中不同灌溉方式的参数化方案，并耦合到WRF（Weather Research Forecasting regional climate model）区域气侯模式中，进一步利用高分辨率耦合区域气候模式WRF模拟黄河流域大范围农业灌溉对区域气候、能量和水分循环的长期变化，定量评估黄河流域大范围农业灌溉的区域气候水文效应，探讨其间的作用过程和机理，为黄河流域水资源可持续利用提供科学依据。

项目通过3年的执行完成了申请书中所设计的研究内容，基本达到了预期的目标。发展了一个适用于黄河流域的农业灌溉参数化方案，并将此灌溉参数化方案耦合到区域气候模式WRF之中。基于引入农业灌溉参数化方案的耦合区域气候模式WRF，对黄河流域进行了长期的（2001-2010年）区域气候模拟。研究结果表明当引入农业灌溉参数化方案后，黄河流域农业灌溉区的地面气温降低约0.1～0.4摄氏度，同时感热通量相应的减小以及潜热通量相应增加，在灌溉面积比例最大的区域，感热（潜热）通量减少（增加）可以达到10 Wm-2以上。农业灌溉所引起的冷却效应与蒸发和能量通量的变化是一致的。另外抬升凝结高度和边界层高度的变化导致云量的增加，从而引起辐射发生变化，进而影响地表通量和土壤湿度的变化，最终影响地面气温和降水的空间分布。通过该项目的执行，我们更加深刻的认识到农业灌溉对区域气候的影响，充分认识到农业灌溉通过改变地表能量水分分配从而影响区域气候。项目共发表论文4篇，其中SCI论文4篇，另有一篇核心期刊论文正在修改。