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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.
Zhou et al. (Sat,) studied this question.