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Cloud‐Radiative Feedback Intensified Yunnan's Record‐Breaking 2023 Spring Drought‐Heatwave.

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Title:	Cloud‐Radiative Feedback Intensified Yunnan's Record‐Breaking 2023 Spring Drought‐Heatwave.
Authors:	Zhou, Xinqiang¹ (AUTHOR), Li, Jiandong² (AUTHOR), Chen, Bing¹ (AUTHOR) chenbing@ynu.edu.cn, Lin, Guo³ (AUTHOR), Wu, Xue⁴ (AUTHOR), Luo, Tao⁵ (AUTHOR), Chen, Liangfu⁶ (AUTHOR), Shi, Guangyu² (AUTHOR)
Source:	Journal of Geophysical Research. Atmospheres. May2026, Vol. 131 Issue 10, p1-17. 17p.
Subject Terms:	Climate feedbacks, Heat waves (Meteorology), Atmospheric pressure, Solar radiation, Extreme weather, Droughts, Land-atmosphere interactions, Cloudiness
Geographic Terms:	China, Yunnan Sheng (China)
Abstract:	In 2023, Yunnan in southwestern China experienced the most severe compound drought–heatwave (CDHW) event on record. To effectively address these extremes, it is crucial to understand the atmospheric physical processes that initiate and sustain them. This study provides a comprehensive diagnosis of the formation and amplification mechanisms of this event. The results indicate that the CDHW in MAM 2023 was exceptionally intense. An anomalously westward‐extending subtropical high placed Yunnan under persistent high‐pressure anticyclonic conditions that suppressed cloud development. As a result, there were marked reductions in cloud cover and cloud thickness, which weakened shortwave reflection and enhanced surface solar absorption. This led to positive anomalies in surface shortwave cloud radiative forcing (SWCF; +15.12 W m−2) and surface net cloud radiative forcing (NCF; +11.86 W m−2), while surface longwave cloud radiative forcing (LWCF) exhibited a negative anomaly (−3.26 W m−2). In MAM 2023, the SWCF value (−55.98 W m−2) accounted for 27% of the net surface shortwave radiation (NSW; 209.08 W m−2), whereas the LWCF value (25.31 W m−2) contributed 32% of the net longwave radiation (NLW; −77.80 W m−2). Meanwhile, strengthened sensible heat flux (SHF) and reduced latent heat flux (LHF) indicate a transition from a "moist evaporative" to a "dry sensible‐heating" surface regime. These processes together established a positive cloud–radiation–land–atmosphere feedback in which reduced cloudiness enhanced radiative warming, thereby suppressing evaporation and strengthening sensible heating, and further favored cloud reduction, thus sustaining and intensifying the CDHW. Plain Language Summary: In 2023, Yunnan province in southwestern China experienced its most severe recorded compound drought‐heatwave event. To elucidate the mechanisms driving such extreme weather, this study investigated the atmospheric processes that initiated and sustained the disaster. During spring 2023, an anomalously westward‐extending subtropical high‐pressure system dominated the region, suppressing cloud formation. Reduced cloud cover enhanced surface solar absorption, while diminished cloud thickness weakened nocturnal longwave radiation trapping, collectively amplifying daytime warming. Results revealed that these cloud changes significantly altered the land‐atmosphere energy balance. The reduction in shortwave cloud radiative forcing (SWCF) increased surface solar absorption (+15.12 W m−2 on average), whereas the decrease in longwave cloud radiative forcing (LWCF) enhanced nighttime cooling. Concurrently, dry conditions suppressed latent heat flux from soil and vegetation, shifting surface energy partitioning from evaporative cooling to sensible heating. These processes established a positive feedback loop in which reduced cloudiness enhanced surface heating, decreased soil moisture, further suppressed cloud development, and intensified warming. This study demonstrates how coupled cloud‐radiation‐land‐atmosphere interactions can synergistically amplify extreme climate events, providing critical insights for improving predictive models and disaster preparedness strategies. Key Points: Spring (MAM) compound drought–heatwave (CDHW) events over Yunnan exhibit a pronounced long‐term intensification trendCloud radiative forcing (CRF) plays a significant role in promoting the occurrence and development of Yunnan 2023 spring CDHW eventsReduced cloud cover leads to surface warming, enhanced sensible heating, and limited latent heat flux, strengthening the CDHW further [ABSTRACT FROM AUTHOR]
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Database:	GreenFILE

Description
Abstract:	In 2023, Yunnan in southwestern China experienced the most severe compound drought–heatwave (CDHW) event on record. To effectively address these extremes, it is crucial to understand the atmospheric physical processes that initiate and sustain them. This study provides a comprehensive diagnosis of the formation and amplification mechanisms of this event. The results indicate that the CDHW in MAM 2023 was exceptionally intense. An anomalously westward‐extending subtropical high placed Yunnan under persistent high‐pressure anticyclonic conditions that suppressed cloud development. As a result, there were marked reductions in cloud cover and cloud thickness, which weakened shortwave reflection and enhanced surface solar absorption. This led to positive anomalies in surface shortwave cloud radiative forcing (SWCF; +15.12 W m−2) and surface net cloud radiative forcing (NCF; +11.86 W m−2), while surface longwave cloud radiative forcing (LWCF) exhibited a negative anomaly (−3.26 W m−2). In MAM 2023, the SWCF value (−55.98 W m−2) accounted for 27% of the net surface shortwave radiation (NSW; 209.08 W m−2), whereas the LWCF value (25.31 W m−2) contributed 32% of the net longwave radiation (NLW; −77.80 W m−2). Meanwhile, strengthened sensible heat flux (SHF) and reduced latent heat flux (LHF) indicate a transition from a "moist evaporative" to a "dry sensible‐heating" surface regime. These processes together established a positive cloud–radiation–land–atmosphere feedback in which reduced cloudiness enhanced radiative warming, thereby suppressing evaporation and strengthening sensible heating, and further favored cloud reduction, thus sustaining and intensifying the CDHW. Plain Language Summary: In 2023, Yunnan province in southwestern China experienced its most severe recorded compound drought‐heatwave event. To elucidate the mechanisms driving such extreme weather, this study investigated the atmospheric processes that initiated and sustained the disaster. During spring 2023, an anomalously westward‐extending subtropical high‐pressure system dominated the region, suppressing cloud formation. Reduced cloud cover enhanced surface solar absorption, while diminished cloud thickness weakened nocturnal longwave radiation trapping, collectively amplifying daytime warming. Results revealed that these cloud changes significantly altered the land‐atmosphere energy balance. The reduction in shortwave cloud radiative forcing (SWCF) increased surface solar absorption (+15.12 W m−2 on average), whereas the decrease in longwave cloud radiative forcing (LWCF) enhanced nighttime cooling. Concurrently, dry conditions suppressed latent heat flux from soil and vegetation, shifting surface energy partitioning from evaporative cooling to sensible heating. These processes established a positive feedback loop in which reduced cloudiness enhanced surface heating, decreased soil moisture, further suppressed cloud development, and intensified warming. This study demonstrates how coupled cloud‐radiation‐land‐atmosphere interactions can synergistically amplify extreme climate events, providing critical insights for improving predictive models and disaster preparedness strategies. Key Points: Spring (MAM) compound drought–heatwave (CDHW) events over Yunnan exhibit a pronounced long‐term intensification trendCloud radiative forcing (CRF) plays a significant role in promoting the occurrence and development of Yunnan 2023 spring CDHW eventsReduced cloud cover leads to surface warming, enhanced sensible heating, and limited latent heat flux, strengthening the CDHW further [ABSTRACT FROM AUTHOR]
ISSN:	2169897X
DOI:	10.1029/2025JD046196