一种气象干旱综合指数的过程事件研究

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  • 1. 中国气象局气候资源经济转化重点开放实验室,重庆市气候中心,重庆 401147
    2. 贵州省气象台,贵州 贵阳 550002

网络出版日期: 2024-09-12

基金资助

中国气象局创新发展专项(CXFZ2022J031);重庆市自然科学基金面上项目(CSTB2022NSCQ-MSX0558);重庆市气象部门
业务技术攻关项目(
YWJSGG-202125

Study on Process Event of a Meteorological Drought Comprehensive Index

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  • 1. China Meteorological Administration Key Open Laboratory of Transforming Climate Resources to EconomyChongqing Climate CenterChongqing 401147China
    2. Guizhou Meteorological ObservatoryGuiyang 550002GuizhouChina

Online published: 2024-09-12

摘要

为掌握重庆气象干旱长时间序列演变规律,利用重庆 1960-2022 34 个国家站的本地化改进型气象干旱综合指数(RMCI)结合区域性气象干旱过程评估地方标准做气象干旱综合指数(MCI1981-2020 年同期对比,进而解析 RMCI 历史 63 a 数据结构及其时空分布特征。研究表明:(1)重庆40 a RMCI单站过程累计频次较MCI偏多4. 2%,二者频次-强度拟合都呈显著的指数型分布,两者所有单站过程开始时间的差异率仅为 8. 1%;重庆东北部为 RMCIMCI单站过程各级旱情的一致高发区,而中心城区、西南部及中部地区发生频率相对较低。(2)重庆63 a RMCI日数据总体呈正态分布,全市及各分区轻旱、中旱、重旱(特旱)日数据分布差异较小(较大),中心城区重旱、特旱日数据较其他分区分别一致性偏大、偏小;RMCI单站、区域过程的频次与强弱都呈显著反相关,其中重庆西部发生轻旱、中旱、特旱单站过程的站均频次最多,而区域过程中特旱的极差绝对值最大、中旱次之。(363 a 间重庆RMCI单站和区域气象干旱过程强度趋势都不显著,但1962-2013年却均为显著减小趋势,2013年后重庆过程强度的总体减弱与21世纪以来高温日数的年代际减少有所关联,气象干旱过程事件具有复杂的年际和年代际信号。RMCI单站过程事件主要存在 2~6 a和准 20 a的周期振荡,发生在重庆东北部偏东和东南部偏北地区的单站过程事件变干尤为显著;RMCI区域过程事件则存在 2~3 a4~6 a8~12 a的周期振荡,开始于伏旱期及7月的区域过程事件频次最多、强度最强,而秋旱期和12月的频次相对最少、强度最弱。

本文引用格式

张 驰, 何慧根, 谢清霞, 唐红玉, 廖代强 . 一种气象干旱综合指数的过程事件研究[J]. 高原气象, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2024.00017

Abstract

In order to understand the long-term evolution of meteorological drought in Chongqingthe localized revised meteorological drought comprehensive indexRMCIof 34 national stations in Chongqing from 1960 to 2022 was used in conjunction with local standard for regional meteorological drought process evaluation to synchronously compare with the meteorological drought comprehensive indexMCIprocess data from 1981 to 2020then analysed the data structure and spatiotemporal distribution characteristics of the historical 63 a RMCI. The conclusion was as follows:(1The cumulative frequency of the 40a RMCI single station process in Chongqing was 4. 2% higher than that of MCIand the frequency-intensity fitting of both showed a significant exponential distribution. The difference rate in the start time between RMCI and MCI single station processes was only 8. 1%. The northeast of Chongqing was a consistently high incidence district of drought at all levels for RMCI and MCI single station processeswhile the frequencies were relatively low in the central urban areasouthwestand middle districts.2The daily data of Chongqing's 63 a RMCI showed a normal distribution overallwith smallsignificantdifferences in the distribution of mildmoderateand severe droughtextreme droughtdaily data across whole region and various districts. The daily data of RMCI severe and extreme drought in the central urban area was consistently relatively high and low compared to other districtsrespectively. The frequency-in‐ tensity of RMCI single station process and regional process data were significantly inversely correlatedwith the station-averaged frequency of mildmoderateand extreme droughts for single station processes occurring in the western district of Chongqing being the highestand the absolute range of extreme drought in regional process data was the highestfollowed by moderate drought.3The intensity trends of RMCI single station and region‐ al meteorological drought processes in Chongqing during the 63 a were not significantbut both showed a significant decreasing trend from 1962 to 2013. The overall weakening of both processes intensity in Chongqing after 2013 was related to the interdecadal decrease in high-temperature days since the 21st century. It could be considered that meteorological drought process events had complex interannual and interdecadal signals. The RMCI single station process events mainly exhibited periodic oscillations of 2~6 a and quasi-20 awith the "drying out" of single station process events occurring in parts of Chongqing northeastern and southeastern districts being particularly significant. The RMCI regional process events exhibited periodic oscillations of 2~3 a4~6 aand 8~12 awith the highest frequency and strongest intensity of regional process events starting during the hot summer drought period and Julywhile the frequency and intensity of autumn drought period and December was relatively lowest and weakestrespectively.

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