1962—2021年闽江流域干旱时空分布特征及驱动因子分析

Spatiotemporal distribution characteristics and driving factors of drought in Minjiang River Basin from 1962 to 2021

摘要

【目的】全球气候变暖条件下,中国南方地区干旱发生频率呈增加趋势,但有关东南沿海湿润流域干旱的研究不足;研究闽江流域干旱的时空演变特征及驱动因子,对流域干旱风险评估和制定科学的水资源管理策略有重要意义。【方法】基于闽江流域26个气象站点的逐日降水和气温数据,选取标准化降水蒸散指数(Standardized Precipitation Evapotranspiration Index, SPEI)作为干旱指标,结合Mann-Kendall趋势检验方法、交叉小波及相干小波分析等方法,分析不同时间尺度下闽江流域干旱的时空变化特征,探究气候条件和大尺度环流因子对闽江流域干旱特征的影响。【结果】结果显示:1962—2021年期间,流域年尺度SPEI以0.030/10 a的速度上升,春、夏、秋、冬季的SPEI变化率分别为-0.013/10 a、0.051/10 a、-0.016/10 a和-0.003/10 a。空间尺度上,流域年度呈湿润化趋势的站点有19个,占总站点数的73.08%;春、夏、秋、冬季呈干旱化趋势的站点比例分别为65.38%、26.92%、76.92%、69.23%。【结论】近60 a来,闽江流域整体呈现不显著湿润化趋势,但存在季节变化差异,春、秋、冬季均呈干旱化趋势,而夏季则表现为湿润化趋势。流域北部和东南部湿润化趋势较为明显,而中南部则趋于干旱化;流域东北部和西南部干旱发生频次较高,东部地区在春季和秋季干旱易发,南部地区冬季易发生干旱。降水是影响闽江流域不同时间尺度干旱的重要因子,气温与春、秋、冬季干旱均呈显著负相关。闽江流域干旱与厄尔尼诺-南方涛动和北极涛动密切相关, SPEI与厄尔尼诺-南方涛动存在约0~5个月的共振周期,与北极涛动存在约3~6个月的共振周期。

Abstract

[Objective] Under the background of global warming, drought frequency has shown an increasing trend in southern China. However, research on drought in the humid river basins of the southeastern coastal area remains insufficient. Investigating the spatiotemporal evolution characteristics and driving factors of drought in the Minjiang River Basin is of great significance for drought risk assessment and the formulation of scientific water resource management strategies. [Methods] Based on daily precipitation and temperature data from 26 meteorological stations in the Minjiang River Basin, the standardized precipitation evapotranspiration index(SPEI) was calculated as the drought indicator. [Methods] including the Mann-Kendall trend test, cross wavelet analysis, and wavelet coherence analysis were used to analyze the spatiotemporal variation characteristics of drought across different time scales in the river basin. Additionally, the effects of climate conditions and large-scale circulation factors on drought characteristics were explored. [Results] The result showed that from 1962 to 2021, the annual-scale SPEI in the river basin increased at a rate of 0. 030/10 a. The change rates of SPEI in spring, summer, autumn, and winter were-0. 013/10 a, 0. 051/10 a,-0. 016/10 a, and-0. 003/10 a, respectively. Spatially, 19 stations(73. 08% of the total) exhibited a drying trend at the annual scale. The proportions of stations showing drying trends in spring, summer, autumn, and winter were 65. 38%, 26. 92%, 76. 92%, and 69. 23%, respectively. [Conclusion] Over the past 60 years, the Minjiang River Basin has exhibited an insignificant wetting trend, but with seasonal differences. Spring, autumn, and winter exhibit a wetting trend, while a wetting trend is observed in summer. Significant wetting trends are observed in the northern and southeastern parts of the river basin, while drying tendencies are observed in the central and southern regions. The drought frequency is higher in the northeastern and southwestern parts of the river basin, with the eastern region prone to drought in spring and autumn, and the southern region prone to drought in winter. Precipitation is a key factor influencing drought at different time scales in the Minjiang River Basin, and temperature exhibits significantly negative correlations with drought in spring, autumn, and winter. Drought in the Minjiang River Basin is closely related to the El Niño-Southern Oscillation(ENSO) and the Arctic Oscillation(AO). The SPEI shows a resonance period of approximately 0~5 months with ENSO and 3~6 months with AO.

关键词

干旱 / SPEI / 时空分布 / 大尺度环流因子 / 闽江流域 / 影响因素 / 交叉小波 / 相干小波

Key words

drought / SPEI / spatiotemporal distribution / large-scale circulation factors / Minjiang River Basin / influencing factors / cross wavelet analysis / wavelet coherence analysis

基金资助

国家自然科学联合基金项目(U22A20554)

福建省公益类科研院所专项(2024R1002003)