Study on Process Event of a Meteorological Drought Comprehensive Index

Expand
  • 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

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.

Cite this article

ZHANG Chi, HE Huigen, XIE Qingxia, TANG Hongyu, LIAO Daiqiang . Study on Process Event of a Meteorological Drought Comprehensive Index[J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2024.00017

Outlines

/