山西省不同地貌类型的极端降水时空分布变化特征

Characteristics of temporal and spatial distribution changes of extreme rainfall in different geomorphic types in Shanxi Province

摘要

【目的】研究全球气候变化背景下极端降水规律，有助于生态保护、气候变化应对、水资源管理和环境影响评估。【方法】根据1975—2020年山西省27个气象站的日降水数据，对山西省46 a极端降水事件进行筛选，计算出ETCCDMI推荐的10个极端降水指标，采用显著性水平(P_value)、趋势斜率(Slope)、平均值(Mean_value)及中位数(Median_value)等11个特征指标来分析数据的趋势和分布情况，叠加地貌类型计算出相应的极端降水指数特征，分析不同地貌类型下极端降雨事件的强度、分布及趋势变化规律，探讨极端降雨与地貌类型的相关关系，揭示极端降雨在各种地貌类型的分布特征。【结果】山西省站点CDD全部呈现降低趋势，达到显著性的站点占比为81%;除CWD以外，其余8个极端降水指标都以正相关站点数较多，PRCPTOT、R10mm、Rx1day与Rx5day正相关站点比例分别达到了74%、74%、69%与67%,但整体显著低；山西省CDD空间分布上表现为自南向北，自西向东减少趋势增加，CDD的平均值等6个指标具有相似的空间分布特征，表现为自北向南梯度式逐渐减少。CV等三个指标具有相似的空间分布特征，都以东南部阳泉与忻州交界处自北向南辐射减少，山西省北部的干旱情况较南部缓解快；山西省海拔与CDD、CWD、PRCPTOT、R10mm及Rx5day指数存在一定的显著相关性，与CDD的Slope、CWD的Median、Ave_Year_Change、Q50值，及RX5day的Min值都呈现显著的负相关关系(-0.44、-0.41、-0.42、-0.41、-0.45),与PRCPTOT及R10mm的Slope值呈现显著的正相关关系(0.46,0.45),与SDII的6项指标都呈现显著的负相关关系，对SDII的影响整体较为显著。【结论】山西省的地形起伏度与极端气候指标的特征值无显著相关性；山西省不同地貌类型区极端降水指数特征指标分布特征不同，低海拔丘陵台地区、小起伏中山、中海拔丘陵台地的各项指标都较为分散，该地貌区内的极端气候指标需要考虑空间变异。

Abstract

[Objective] Investigating extreme rainfall patterns in the context of global climate change can aid in ecological protection, climate change response, water resource management, and environmental impact assessment. [Methods] Utilizing daily precipitation data from 27 meteorological stations in Shanxi Province from 1975 to 2020, extreme precipitation events over a span of 46 years were selected. Ten extreme precipitation indices recommended by ETCCDMI were calculated. Eleven characteristic indicators, including significance level(P_value), trend Slope(Slope), Mean value(Mean_value), and Median value(Median_value), were used to analyze the trends and distribution of the data. The corresponding extreme precipitation index characteristics were calculated by superimposing landform types, analyzing the intensity, distribution, and trend changes of extreme rainfall events across different landform types, exploring the correlation between extreme rainfall and landform types, and revealing the distribution characteristics of extreme rainfall in various landform types. [Results] All sites in Shanxi Province showed a decreasing trend in CDD, with 81% of the sites reaching significance. Except for CWD, the other eight extreme precipitation indices had more sites with positive correlations, with the proportions of sites positively correlated with PRCPTOT, R10mm, Rx1day, and Rx5day reaching 74%, 74%, 69%, and 67%, respectively, although the overall significance was low. The spatial distribution of CDD in Shanxi Province exhibited an increasing trend of reduction from south to north and west to east. Six indices, including the Mean value of CDD, showed similar spatial distribution characteristics, gradually decreasing in a gradient from north to south. Three indices, including CV, shared similar spatial distribution characteristics, with a radiating decrease from north to south at the junction of Yangquan and Xinzhou in the southeast. The drought situation in the northern part of Shanxi Province alleviated faster than in the southern part. There was a significant correlation between elevation in Shanxi Province and the indices CDD, CWD, PRCPTOT, R10mm, and Rx5day. CDDSlope, the Median of CWD, Ave_Year_Change, Q50 value, and the Minimum value of Rx5day all showed significant negative correlations(-0.44,-0.41,-0.42,-0.41,-0.45), while the Slope values of PRCPTOT and R10mm showed significant positive correlations(0.46, 0.45). All six indicators of SDII showed significant negative correlations, indicating a significant overall impact on SDII. [Conclusion] The relief amplitude of Shanxi Province had no significant correlation with the characteristic values of extreme climate indices. The distribution characteristics of extreme precipitation index characteristic indicators varied across different landform types in Shanxi Province. Indicators were more scattered in low-altitude hilly terraces, small undulating middle mountains, and mid-altitude hilly terraces, requiring consideration of spatial variation within these landform types regarding extreme climate indices.

关键词

极端降水 / 特征指标 / 地貌类型 / 山西省 / 气候变化 / 生态保护 / 水资源 / 降雨

Key words

extreme rainfall / characteristic index / geomorphic type / Shanxi Province / climate change / ecological protection / water resources / rainfall

基金资助

国家自然科学基金青年基金项目“极端降雨工况下黄土梁峁采空区入渗产流规律与机理”(42307261)

江西省教育厅科学技术研究项目“气候变化对江西省主汛期降雨极值分布影响研究”(GJJ211945)