不同升温阈值下塔里木河源区径流组成的预估及不确定性研究

Stream flow of headwater catchment plays a crucial role in social economic sustainable development of inland arid region. Aksu catchment of the Tarim river basin is selected as a target area in the current project to improve the hydrological models (HBV, SWIM, WASA), therein, process of glacier shrinkage, snow cover changes and frozen soil mechanics are included. Sensitivity tests will be conducted to analyze the composition and evolution characteristics of stream flow in the headwater catchment during the last half century. Climate condition in the 21st century in the Tarim River Basin will be projected based on bias corrected five GCMs (GFDL, Had, IPSL, MIROC and Nor) and two RCMs (RegCM4.0 and CCLM) under RCP scenarios (RCP2.6, RCP4.5, RCP8.5). Composition of stream flow from headwater catchment will be projected under different warming thresholds (1.5℃, 2.0℃, 3.0℃ warming relative to average temperature between 1850-1900) based on combination of climate scenarios (RCPs), climate models (GCMs and RCMs) and hydrological models (HBV,SWIM,WASA) to reveal the hydrological response of the cryosphere to climate change. Uncertainty sources of the projection will be assessed by a mean of ANOVA. Research results can provide a theoretical basis for development of adaptive water resource management strategy for arid inland river basins.

干旱区出山口径流是维持区域社会经济可持续发展的重要水资源。项目以塔里木河源阿克苏流域为研究对象，构建包含冰川变化、积雪消融、冻土冻融过程的水文评估模型，开展多组敏感性试验，揭示径流的组成。RCP2.6, RCP4.5, RCP8.5情景下，采用CMIP5输出资料最为详尽的5个全球气候模式（GFDL, Had, IPSL, MIROC、Nor）及2个区域气候模式（RegCM4.0, CCLM）的订正数据，分析流域21世纪气候变化趋势。基于多情景（RCPs）多模式（GCMs, RCMs）多模型（HBV, SWIM, WASA），预估不同升温阈值（相对1850-1900年升温 1.5℃, 2.0℃, 3.0℃）下河源区径流组成，探讨冰冻圈变化的水文效应。运用方差贡献率法（ANOVA）辨识预估结果的不确定性来源，为干旱区内陆河流域应对气候变化的水资源管理提供理论依据。

根据1961年以来的地面气象观测数据和塔里木河流域水文观测数据，结合数字高程模型、土地利用土地覆盖、土壤类型、冰川分布等地理信息资料，率定具有冰川积雪模块的WASA和HBV-Light水文模型；设计敏感性试验解析了径流组成，定量评估降雨径流、积雪融水和冰川融水对塔里木源区出山口径流的贡献。基于耦合模式比较计划（CMIP5/6）的多个全球气候模式，经降尺度和偏差订正处理，预估了RCPs / SSP-RCPs情景下21世纪塔里木河流域气温、降水、蒸散发、积雪的演变趋势；以降尺度全球气候模式驱动水文模型，预估了相对于工业化革命前全球升温1.5℃与2.0℃时塔里木河流域未来径流组成的变化。并考虑到水资源变化的社会经济影响，基于标准化降水蒸散发指数，开展了干旱事件演变趋势预估，定量评估了区域干旱缺水的可能影响。