Subjects: Other Disciplines >> Synthetic discipline submitted time 2023-03-28 Cooperative journals: 《中国科学院院刊》
Abstract： The Tibetan Plateau is the source zone of major rivers, which provide water resources for more than 2 billion people downstream. Compared with runoff, riverine sediment load is considered as a more sensitive variable in response to climate and land surface process changes, and also as an important index to quantify regional land degradation and soil resource changes. In this study, 8 major rivers originated in the Tibetan Plateau, including Yerqiang River, Shule River, Heihe River, Yarlung Tsangpo River, Nujiang River, Yellow River, Yangtze River, and Lancang River, were selected to study the variation of sediment load in the source zone or upper reaches. Firstly, the general amount and spatial variation of runoff and sediment load of these rivers were explored. Secondly, the changes of riverine sediment load in recent decades (1960–2017) were analyzed, with the spatial and temporal variations of sediment load compared to climate (temperature, precipitation) and land surface process (glacier, frozen soil, vegetation cover) factors. Thirdly, the uncertainty of sediment load variation associated with interaction of multi-factors was discussed. Finally, the significant impacts of sediment load variation on the ecological environment and the safety of hydropower projects was pointed out with typical cases. Nowadays, the scarcity of hydrometeorological data is a major challenge to understand the variation of riverine sediment load from the Tibetan Plateau and assess the impacts. It is urgent to strengthen observation and modeling studies to reveal the complex mechanism of sediment transport changes, so as to provide scientific basis for the sustainable utilization of water and soil resources on the Tibetan Plateau and the downstream water resources management, so as to serve the national ecological security.
Subjects: Geosciences >> Geography submitted time 2022-03-28 Cooperative journals: 《干旱区研究》
Abstract：在西营河九条岭站以上流域内，利用20112018年格点降水和气温数据集的逐日资料，通过降水径流成因关系探索出格点降水异常点修正方法，并将融雪模块与三水源新安江模型耦合，研究流域日径流模拟过程。采用确定性系数和相对误差两个评估准则进行模拟效果的评价，将降水修正后以及融雪耦合后的模拟效果与未改进的模型模拟效果进行比较，分析融雪模块耦合后的新安江模型在西营河流域的适用性。结果表明：参照降水径流成因关系进行的格点降水修正提高了径流模拟的精度，75%的年份模拟径流的确定性系数有所提高。耦合融雪的新安江模型在研究区模拟较好，75%以上年份的模拟比未改进时模拟效果好，87%以上年份的模拟确定性系数达0.6以上。耦合融雪的新安江模型为西营河流域融雪径流的预报预警提供决策参考。
Subjects: Geosciences >> Geography submitted time 2022-03-28 Cooperative journals: 《干旱区研究》
Abstract：TIGGE降水产品作为目前中短期集合预报最权威的数据集合的重要组成部分，其在中国干旱半干旱地区的适用性如何，还需要进一步探讨。基于中国干旱半干旱地区20152017年实测降水数据，采用平均绝对偏差、均方根误差、TS评分等指标，从降水量预报、降水分级预报、降水探测能力和空间预报精度等多角度出发，综合评估了TIGGE数据中心的ECMWF、JMA、KMA和UKMO 4种模式在研究区的预报效果。结果表明：（1）4种模式对小雨的预报效果均较好，在进行不同降水量级预报时，JMA对于小雨的降水预报效果最佳，而对于其他降水量级的降水预报，4种模式无明显差别；（2）针对日降水量预报，KMA效果最差，而ECMWF最精确；（3）在不同降水阈值下对降水的探测能力评估结果显示，ECMWF更具优势，尤其在以25 mmd-1为阈值时优势明显；（4）空间预报精度检验结果显示，各模式在80~100E，35~45N范围表现最佳，主要是新疆中部以及新疆、甘肃和青海三省交界处，对比各模式之间，ECMWF表现更稳定，KMA则表现较差。
Subjects: Geosciences >> Geography submitted time 2022-01-26 Cooperative journals: 《干旱区研究》
Abstract：在无资料地区，降水、气温等观测资料缺乏，影响洪水预报的准确性，进而影响防汛抗旱、水资源规划等工作的开展。因此，研究无资料地区已有降水、气温数据的适用性分析十分必要。应用包含融雪径流模拟的HBV模型，在呼图壁河流域石门水文站以上区域，基于模拟出的融雪洪水径流与实测径流对比，分别对中国地面降水与气温日值0.50.5格点数据集和气象站观测数据集进行了对比分析及其融雪型径流模拟的适用性分析。结果表明：格点数据驱动下水文模型的融雪径流模拟效果总体优于利用站点观测数据驱动的水文模型。格点数据驱动下水文模型模拟融雪径流的Nash系数在验证期为0.792，站点数据驱动下水文模型模拟融雪径流的Nash系数在验证期为0.433。同时分析了呼图壁河流域融雪洪水的一些特征，并结合驱动数据的不同，分析了模拟融雪径流出现误差的可能原因，为如何提高具有融雪特征的无资料地区融雪型洪水预报准确性提供支撑。
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