Quantifying the spatial extent and attenuation of lake thermal regulation at diurnal scales under extreme heat

Lakes worldwide are experiencing intensifying extreme heat, with escalating ecological impacts. Despite lakes' role as thermal buffers to modulate air temperature is well-documented, the spatial propagation dynamics of lake effects remain poorly understood due to complex interactions of lake-atmosphere. This study proposes a synergistic WRF modeling and directional buffer analysis framework to investigate the spatial propagation dynamics and underlying physical mechanisms of lake-induced thermal regulation during extreme heat, focusing on Poyang Lake, China's largest freshwater lake. The results demonstrate a pronounced diurnal asymmetry in lake-induced thermal effects, with distinct spatial propagation characteristics between daytime and nighttime periods. Daytime cooling exhibits an intensity of −1.16 °C, with its influence confined within a 40 km radius, showing a relatively rapid attenuation rate of 0.28 °C per 10 km. In contrast, nighttime warming (+0.97 °C) propagates 1.75 times farther than its daytime counterpart, extending up to 70 km downwind while maintaining a slower attenuation rate of 0.13 °C per 10 km. Directional analysis reveals north-oriented propagation of lake thermal effects, influenced by prevailing southerly winds and lake-land breeze. ... mehrVertical profile analysis reveals distinct altitudinal penetration of lake-induced thermal effects, with daytime influences confined below 900 hPa while nighttime impacts extend up to 700 hPa. Daytime cooling extent is limited by turbulent mixing, whereas nighttime warming is enhanced by stable air conditioning and advective transport. The study underscores the role of lake-atmosphere interactions in mitigating regional climate extremes, providing critical insights for nature-based heat adaptation strategies in lake-rich regions. These findings advance the understanding of inland water bodies as active climate regulators under anthropogenic warming.