The Hydrological Cycle of Central Asia under Climate and Land Use Changes assessed by a re-gional climate model with novel schemes for irrigation and inland lakes

中亚分别是干旱和亚热带气候区大规模灌溉的典范。例如，咸海的萎缩是众所周知的。相比之下，我们对灌溉农业对亚洲区域水循环的影响的了解相当有限。可以假设，由于夏季部分低云量和高全球辐射，叙拉里亚河和阿穆达里亚河沿岸低地的开放地下水位和部分茂密植被的蒸发蒸腾是可观的。人们忽略了由此产生的水汽是否在这些河流的集水区内凝结，从而加强了该地区的水文循环和供水，或者更像是中亚山脉上空向其他河流集水区的平流。因此，灌溉也可以在水供应方面发挥积极作用。计划中的HYDRASIA项目通过开发一种复杂的气候模型方法致力于解决这一问题，该方法解释了与中亚灌溉和内陆湖泊有关的水循环的那些组成部分。这主要包括在气候模型中对灌溉农业和内陆湖泊的新颖表现。研究项目主要针对区域气候模式REMO中50 km和10 km水平分辨率驱动的陆面方案进行模式开发。根据可用性，还计划以更高的分辨率使用新的非流体静力版本的REMO。然后，扩展和校准的REMO版本将用于温室气体和土地利用情景的长期模拟，直至2100年。一方面，目标是评估全球气候变化对中亚未来水资源供应和一般灌溉边界条件的影响。另一方面，将量化灌溉对未来区域气候的反馈，即其调节作用。

Central Asia represents a paradigm of large-scale irrigation in arid and subtropical climate zones, respectively. For example, the associated shrinking of the Aral Sea is well known. In contrast, our knowledge of the effect of irrigated agriculture on the regional water cycle in Asia is fairly limited. It can be assumed that evapo-transpiration from open water tables and partly dense vegetation cover in the lowlands along the Syrarya and Amudarya rivers is substantial given partially low cloudiness and high global radiation during summer. It is ignored whether the resulting water vapor is con-densed within the catchments of these rivers, hence intensifying the hydrological cycle and enhanc-ing water supply in the region, or is rather subject of advection over the Central Asian mountain ranges towards other river catchments. As such, irrigation could also play a positive role for water availability. The planned project HYDRASIA is dedicated to this issue by developing a sophisticated climate model approach, which accounts for those components of the water cycle that are relevant to irrigation and inland lakes in Central Asia. This mainly includes a novel representation of irrigated agriculture and inland lakes in the climate model. The research project is mainly focused on model development with respect to the land surface scheme in the regional climate model REMO, driven at a horizontal resolution of 50 km and 10 km. According to availability, it is also planned to use the new non-hydrostatic version of REMO at an even higher resolution. The extended and calibrated REMO version will then be employed for long-term simulations with greenhouse gas and land use scenarios until 2100. On the one hand, the goal is to assess the impact of global climate change on future wa-ter availability and general boundary conditions for irrigation in Central Asia. On the other hand, the feedbacks of irrigation, i.e. its regulative effect, on the future regional climate will be quantified.