Abstract

Hydrological models serve as valuable instruments for assessing the impact of climate change on water resources and agriculture as well as for developing adaptation measures. In Yemen, climate change and variability are imposing a significant impact on the most important sectors such as agriculture and economy. The current study evaluates the influence of future climate on hydrology and water balance components in Yemen’s highlands using a semi-distributed physical-based hydrologic model Soil Water Assessment Tool (SWAT) and employing high-resolution climate projections. The SWAT was calibrated and verified using observed streamflow data from 1982 to 2000 in three large catchments. Ground data from 24 stations and statistically downscaled future climate data for the period 2010–2100 under RCP2.6 and RCP8.5 are used. SWAT performance was assessed using multiple statistical methods, which revealed the commendable performance of SWAT during the calibration (average NSE = 0.80) and validation (NSE = 0.72) periods. The outcome indicates an increase in future seasonal and annual rainfall, maximum temperature, and minimum temperature in the 2020s and the 2080s under both RCP2.6 and RCP8.5 scenarios. This projected increase in the rainfall and the local temperature will result in increased averages of surface runoff, evapotranspiration, soil water, and groundwater recharge in the representative three catchments up to 6.5%, 21.1%, 7.6%, and 6.4%, respectively. Although, the projected increase in the water balance components will benefit the agriculture and water sector, specific adaptation measures will be crucial to mitigate potential flood impacts arising from the increased precipitations as well as to minimize the consequences of the increased temperature. Likewise, demand for supplementary irrigation is expected to increase to offset the higher evapotranspiration rates in the future.

中文翻译：

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气候变化对也门高原农业梯田流域水平衡组成影响的水文调查

摘要

水文模型是评估气候变化对水资源和农业影响以及制定适应措施的宝贵工具。在也门，气候变化和变异正在对农业和经济等最重要的部门产生重大影响。目前的研究使用半分布式物理水文模型土壤水评估工具（SWAT）并采用高分辨率气候预测来评估未来气候对也门高地水文和水平衡组成部分的影响。SWAT 使用 1982 年至 2000 年在三个大型流域观测到的水流数据进行了校准和验证。使用来自 24 个站点的地面数据以及 RCP2.6 和 RCP8.5 下 2010-2100 年期间统计缩小的未来气候数据。使用多种统计方法评估 SWAT 性能，揭示了 SWAT 在校准（平均 NSE = 0.80）和验证（NSE = 0.72）期间的值得称赞的性能。结果表明，在 RCP2.6 和 RCP8.5 情景下，2020 年代和 2080 年代未来季节性和年降雨量、最高气温和最低气温都会增加。预计降雨量和当地气温的增加将导致代表性三个流域的地表径流、蒸散量、土壤水和地下水补给量平均分别增加6.5%、21.1%、7.6%和6.4%。尽管预计水平衡部分的增加将有利于农业和水务部门，但具体的适应措施对于减轻降水增加造成的潜在洪水影响以及最大限度地减少气温升高的影响至关重要。同样，补充灌溉的需求预计也会增加，以抵消未来较高的蒸散率。