气候变化对澜湄流域气象水文干旱时空特性的影响

Impact of climate change on the spatio-temporal characteristics of meteorological and hydrological drought over the Lancang-Mekong River basin

  • 摘要: 受全球气候变化影响,澜沧江-湄公河流域气象水文干旱发生了较大变化,预测未来流域干旱的时空变化与传播特征是应对气候变化、开展澜湄水资源合作的基础。利用SWAT模型通过气陆耦合方式模拟了澜沧江-湄公河流域历史(1960—2005年)和未来时期(2022—2050年,2051—2080年)的水文过程,采用标准化降水指数和标准化径流指数预估并分析了流域未来气象水文干旱时空变化趋势。结果表明:①澜沧江-湄公河流域未来降水呈增长趋势,气象干旱将有所缓解,但降水年内分配不均与流域蒸发的增加,将导致水文干旱更为严峻,干旱从气象到水文的传播过程加剧;②水文干旱具有明显的空间异质性,允景洪和清盛站的水文干旱最为严重,琅勃拉邦、穆达汉和巴色站次之,万象站最弱;③未来流域水文干旱事件发生频次略有减少,但其中重旱、特旱事件占比增加,极端干旱将趋多趋强,且空间变化更加显著。

     

    Abstract: Affected by global climate change, the status of meteorological and hydrological drought in the Lancang-Mekong River basin (LMRB) has witnessed great changes. Therefore, predicting the temporal and spatial variations of future drought as well as its propagation characteristics has become the basis for tackling climate changes and conducting cooperation on the water resources of the Mekong River. By applying the SWAT model and the method of atmosphere-land coupling, both the history (1960-2005) and the future (2022-2050 and 2051-2080) hydrological processes of the LMRB were simulated. Moreover, the future temporal and spatial variation trends of meteorological and hydrological drought were also predicted and analyzed by using the Standardized Precipitation Index and Standardized Runoff Index. The research results indicated that: ① In the future, the amount of precipitation will be increased. Thus, the meteorological drought will be alleviated to some extent, but at the same time, the inhomogeneous distribution of intra-annual precipitation and increased evaporation from the river basin together will cause a severer hydrological drought and an intense propagation process. ② Hydrological drought will have significant spatial heterogeneity. Specifically, the hydrological drought will be the most intense in Jinghong and Chiang Saen stations, followed by Luang Prabang, Mukdahan, and Pakse stations, and be the weakest in Vientiane station. ③ Over time, the frequency of hydrological drought in the river basin will be slightly decreased, but the proportion of heavy drought and severe drought will be increased, and the extreme drought will be enhanced both in amount and strength. Furthermore, the features of spatial variation will be more significant and noticeable.

     

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