鄱阳湖流域气象干旱的区域性特征及干旱过程演变

Regional Characteristics and Evolution of Meteorological Droughtsin Poyang Lake Basin

基于1960—2020年鄱阳湖流域及周边29个国家气象站的连续观测资料,通过计算标准化降水蒸发指数(SPEI)并结合游程理论,研究分析了气象干旱的区域性特征及干旱过程演变。结果表明:①鄱阳湖流域月尺度气象干旱的发生频率为31.7%~34.8%,不同等级干旱发生频率的空间格局差异明显;②春、秋季节流域尺度SPEI呈现微弱下降趋势,干旱影响范围呈不显著的增加趋势,夏、冬季节情况与此相反;③就干旱区域性特征而言,鄱阳湖流域季节性气象干旱以全流域性干旱和局域性干旱为主(发生频率分别为29.5%和23.4%),区域性干旱和部分区域性干旱的发生频率(分别为10.7%和5.7%)相对较低;④游程理论揭示在过去的61 a间共发生50次流域尺度气象干旱事件,干旱事件的发生频次随干旱历时的增加显著减少,其中干旱历时最长的可达49个月;⑤流域尺度气象干旱事件的历时、峰值烈度以及总烈度的演变呈现较强的年代际波动特征;⑥干旱历时与总烈度之间存在显著的线性关系,与峰值烈度之间存在显著的幂函数关系,与平均烈度之间的相关关系不明显。这些研究结果明晰了鄱阳湖流域气象干旱的区域性特征与干旱过程演变,为合理开展流域气象干旱影响评估和制定防范策略提供科学依据。

Based on observation data from 29 national meteorological stations within and surrounding Poyang Lake basin from 1960 to 2020,we investigated the regional characteristics and evolution of meteorological droughts in the basin by calculating the Standardized Precipitation Evapotranspiration Index(SPEI)in association with the run theory.The findings indicate that the frequency of monthly meteorological droughts in the Poyang Lake basin ranged from 31.7%to 34.8%.Moreover,the spatial patterns of drought frequency varied significantly across different drought levels.SPEI of the Poyang Lake basin exhibited a slight downward trend in spring and autumn,with the affected area showing a marginal increase.Conversely,opposite trend was observed in summer and winter.Regarding regional characteristics,basin-wide(29.5%occurrence)and local droughts(23.4%occurrence)were predominant seasonal droughts in the Poyang Lake basin,whereas regional(10.7%occurrence)and partial regional droughts(5.7%occurrence)occured less frequently.The run theory revealed that 50 meteorological drought events have occurred in the past 61 years.The frequency of these events decreased notably with increasing drought duration,with the longest drought lasting up to 49 months.The duration,peak intensity,and total intensity of drought events exhibited pronounced inter-decadal fluctuations.A significant linear correlation existed between drought duration and total intensity,while a notable power function relationship was observed between drought duration and peak intensity.However,no significant correlation was found between drought duration and average intensity.These findings have clarified the regional characteristics and evolutionary processes of meteorological droughts in the Poyang Lake basin,thereby providing a scientific basis for assessing drought impacts and formulating effective prevention strategies.