洞庭湖流域极端降水变化特征分析

随着极端降水事件变率增强,洞庭湖流域频繁的极端洪旱事件严重威胁了地区人水和谐。基于洞庭湖流域28个国家气象站1961-2015年的逐日降水资料,采用RClim Dex模型定义阈值来识别极端降水事件,利用线性倾向估计法和集合经验模态分解(EEMD)组合的方法进一步分析了洞庭湖流域极端降水变化特征,由EEMD方法分解得到的各类极端降水指数的3个固有模态函数分量分别表现出3~6a、8~15a和21~27a的准周期。结果表明:洞庭湖流域极端降水频次峰值出现在6月,4-10月份极端降水频次之和占全年的82.7%,南岳和安化为极端降水高发带。洞庭湖流域除持续湿润日数CWD略有减小外,各项极端降水指数均表现出小幅上升趋势。在空间分布上,该流域东南部受山区地形地貌的影响,极端降水呈明显上升趋势。洞庭湖流域极端降水时空格局变化特征分析对流域水资源开发利用和水安全预警具有重要参考价值。     

黄河流域植被水分利用效率对干旱的时空累积响应EI北大核心CSCD

Using gross primary productivity (GPP) of vegetation and evapotranspiration (ET) data, combined with standardized precipitation evapotranspiration index (SPEI) data, the variation characteristics of vegetation water use efficiency (WUE) in the Yellow River Basin from 1982 to 2018 were revealed, and the cumulative effect of drought on vegetation WUE were quantified. The results indicate that the cumulative impact of drought on WUE can be measured by the months with the most significant correlation between multi-scale SPEI and WUE. The annual average WUE shows a distribution pattern of low in the north and high in the south, showing a certain similarity to the spatial distribution of annual average GPP. The WUE shows an upward trend, mainly because the GPP growth rate is greater than the ET growth rate. Drought has a cumulative effect on 58. 48% area of vegetation WUE in the Yellow River Basin, with cumulative time scales of 1 ~2 months, 6 ~8 months, and 19 ~ 24 months accounting for 43. 58%, 23. 10%, and 16. 96%, respectively. The cumulative time scale of drought on WUE varies depending on vegetation types and hydrological and climatic conditions. The cumulative impact of drought on grasslands and farmland near desert areas in the north is long-term (> 18 months), while the cumulative impact on grasslands and forests in humid and semi humid areas is short-term (≤4 months). The average cumulative time scale decreases with the increase of annual average SPEI, and the larger the SPEI, the shorter the cumulative time scale of drought on vegetation WUE. © 2023, Editorial Board of Water Resources Protection. All rights reserved.     

人类活动影响下塔里木河流域气象干旱向水文干旱传播的规律

为了解人类活动影响下塔里木河流域气象干旱向水文干旱传播的规律,基于标准化降水指数(SPI)和径流干旱指数(SDI)分析了气象、水文干旱的变化特征,探讨了人类活动对气象干旱向水文干旱传播规律的影响。研究结果表明：源流区气象、水文干旱均呈减弱趋势,干流气象干旱呈减弱趋势,水文干旱与之相反;随时间尺度增大,干旱历时延长;源流区气象、水文干旱以及干流气象干旱的发生频率受人类活动影响后(1993年后)均降低,仅干流水文干旱的发生频率升高;受人类活动影响后,源流区不同季节气象干旱向水文干旱的传播时间均变长,干流干旱传播时间除春季外均缩短;源流区干旱传播时间延长与气候变化有关,而干流干旱传播时间缩短主要是受人类活动的影响。     

基于量子行为粒子群优化算法的河道糙率反演

糙率是河道水动力模型的重要参数,在模型中敏感性高,但其在实际工作中难以准确测定。量子行为粒子群算法(QPSO)是粒子群算法的发展,相对于粒子群算法,在全局收敛和收敛率上有很大提高。将量子行为粒子群优化算法与一维河道水动力模型耦合,建立河道糙率反演模型,并在淮河干流蚌埠到花园咀河段进行了模拟,取得了较好的效果。与其他糙率反演算法相比,该算法具有理论简单、参数少、易于编程实现、通用性强等优点。     

基于地表径流量预测的玛纳斯河流域绿洲适宜规模计算

基于神经网络算法和水热平衡原理,结合水文、气象数据,构建了玛纳斯河绿洲适宜规模模型,分析计算了1990-2020年绿洲适宜规模与现状规模,预测了2021-2030年流域地表径流量和绿洲适宜规模.结果表明:1990-2000年、2001-2010年、2011-2020年绿洲适宜规模分别为11003.3 km2、9902....