1960-2017年黄土高原极端降水的时空演化及其对环流变化的响应  

Spatio-temporal evolution of extreme precipitation in Loess Plateau during 1960-2017 and its response to atmospheric circulation changes

作　　者：王国桢 晏宏[1,2,3] 刘成程 韩韬[1] 赵楠钰 杨昊天 WANG Guozhen;YAN Hong;LIU Chengcheng;HAN Tao;ZHAO Nanyu;YANG Haotian(State Key Laboratory of Loess and Quaternary Geology,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,China;CAS Center for Excellence in Quaternary Science and Global Change,Xi’an 710061,China;Institute of Global Environmental Change,Xi’an Jiaotong University,Xi’an 710049,China;Xi’an Institute for Innovative Earth Environment Research,Xi’an 710061,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院地球环境研究所黄土与第四纪地质国家重点实验室,西安710061 [2]中国科学院第四纪科学与全球变化卓越创新中心,西安710061 [3]西安交通大学全球环境变化研究院,西安710049 [4]西安地球环境创新研究院,西安710061 [5]中国科学院大学,北京100049

出　　处：《地球环境学报》2023年第5期588-602,共15页Journal of Earth Environment

基　　金：国家杰出青年科学基金(42025304);中国科学院战略性先导科技专项(XDB40000000)。

摘　　要：基于1960—2017年黄土高原47个气象站逐日降水量数据,对黄土高原极端降水量、极端降水日数和极端降水强度的时空演化特征进行了分析。结果显示:(1)黄土高原极端降水时空分布存在明显异质性。极端降水事件在全年发生频率不高(13.2%—46.1%),但对年降水量贡献突出(50.4%—91.4%)。(2)1960—2017年黄土高原极端降水量和降水日数出现下降,但极端降水强度上升。在黄土高原干旱化的同时,极端降水在全年降水中的占比有升高趋势。作为黄土高原土壤侵蚀的主要驱动力,愈发增强的极端降水将会给该地区水土保持和地质灾害防治工作带来严峻挑战。(3)极端降水特征EOF分解第一模态反映了黄土高原极端降水的一致性变化,其空间分布特征可能受到了当地水汽条件及大气层结稳定度等大气动力效应的影响。第二模态反映了黄土高原极端降水的差异性变化,极端降水量和极端降水日数均大致以临夏—太原一线呈反相位变化,这种分布模式可能和地形因素密切相关。(4)黄土高原极端降水特征的年际变化受厄尔尼诺-南方涛动(ENSO)活动的显著影响,厄尔尼诺年极端降水量偏低、日数偏少,拉尼娜年反之。Background,aim,and scope In addition to the variation in the mean climate state,extreme weather events are also important characteristics of the climate system.These are hard to predict and can have serious impacts on socio-economic conditions.IPCC6 demonstrated that the frequency and intensity of heavy precipitation events have increased in many areas since 1950s,under a global warming patterns.Eco-fragile areas with severe soil and water erosion in the world,such as the Chinese Loess Plateau(LP),are one such situation.Here,we investigated the spatio-temporal evolution of extreme precipitation events in the LP and discuss the main atmospheric circulation factors.Materials and methods Based on the daily precipitation data from 47 meteorological stations during 1960—2017 in the LP,the threshold values of extreme precipitation event were defined.We employ correlation analysis,inverse distance weighted interpolation(IDW),radial basic function interpolation(RBF),empirical orthogonal functions(EOF)and spectral analysis.Results The distribution of extreme precipitation amount and intensity are similar.Seasonally,the amount and intensity are high in the main monsoon season and low in other seasons.Spatially,both of these values are high in the southeast and low in the northwest.However,the distribution of extreme precipitation days across the LP seems to be spatially homogeneous in seasons except winter.The contribution of each season to annual extreme precipitation amount and days has a series with summer>autumn>spring>winter.Annual extreme precipitation amount(−1.6 mm·(10a)−1)and days(−0.12 d·(10a)−1)gently decreased during 1960—2017.Simultaneously,the annual extreme precipitation intensity increased(0.05 mm·d−1·(10a)−1).None of these trends pass the 0.05 significance test.In the LP,51.1%of the stations show a decreasing trend while 48.9%of the stations show an increasing trend in annual extreme precipitation amount.Decrease centers are located in Lintao,Huashan,and Yangcheng,with a rate of−21 mm

关 键 词：黄土高原 极端降水 EOF分解 ENSO 

分 类 号：P426.614[天文地球—大气科学及气象学]