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Chinese Journal of Ecology ›› 2026, Vol. 45 ›› Issue (7): 2447-2457.doi: 10.13292/j.1000-4890.202607.003

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Evolution characteristics of compound heat and drought events for single-season rice in Southwest China based on Copula function.

LEI Zhiwen1, CHEN Dongdong2,3*, LI Xiaowei4, ZHANG Yi5   

  1. (1Sichuan Climate Center, Chengdu 610072, China; 2The Agrometeorological Center of Sichuan Province/Environment-Friendly and Efficient Water-Saving Technology and Equipment for Hilly Agriculture Key Laboratory of Sichuan Province, Chengdu 610072, China; 3Joint Laboratory of Agriculture Coping with Climate Change of China Meteorological Administration and China Agricultural University, Beijing 100193, China; 4Chongqing University of Education, Chongqing 400065, China; 5Chinese Academy of Meteorological Sciences, Beijing 100081, China).

  • Online:2026-07-10 Published:2026-07-17

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Abstract: Based on daily meteorological data from 351 stations in single-season rice planting areas of Southwest China and the data of critical phenological stages of single-season rice during 1980-2022, we examined the spatiotemporal variations of compound events of heat and drought events during critical phenological stages of single-season rice in subregions (by dividing the region according to the phenological stages). The Copula function was employed to construct two-dimensional joint cumulative probability distributions of high-temperature intensity and drought intensity for each subregion, and the recurrence intervals and occurrence patterns of compound events were analyzed. The results showed that the frequency of compound events during both the heading-filling and filling-maturity stages followed a pattern of “lower in west, higher in east” and “lower in south, higher in north”. High-frequency areas during the heading-filling stage were concentrated in Chongqing, northern and eastern Guizhou, and parts of Panxi in Sichuan, while those during the filling-maturity stage slightly shifted southward and become less extensive. From 1980 to 2022, the frequency of compound events during both stages increased, with a more significant increase in moderate-to-severe events during heading-filling stage starting from 1990 and a larger increase in severe compound events during filling-maturity stage. Student’s t Copula function optimally fitted the joint distribution of heat intensity and drought intensity in most subregions, followed by Frank and Gumbel Copula functions. The recurrence intervals of compound events increased with intensified heat and drought intensities, with drought intensity exerting a stronger influence. Compound events occurred more frequently during the heading-filling stage, while higher-intensity events predominated during the filling-maturity stage. This study clarified the evolutionary characteristics of compound heat and drought events during the critical phenological stages of single-season rice, providing a scientific basis for disaster prevention and mitigation in rice production.


Key words: Southwest China, single-season rice, compound event of heat and drought, Copula function