Duan Zexia, Fan Sihui, Zhang Yichi, Ji Tianbo
School of Electrical Engineering and Automation, Nantong University, Nantong 226019, China.
China Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory, Hebei 071700, China.
iScience. 2026 Feb 4;29(3):114892. doi: 10.1016/j.isci.2026.114892. eCollection 2026 Mar 20.
Heatwaves over the Yangtze River Delta (YRD) have intensified in frequency and diversity amid rapid urbanization and climate change, yet their underlying boundary-layer processes remain insufficiently understood. This study examines boundary-layer energy budgets of three heatwave types across the YRD using observations from 186 meteorological stations and reanalysis data covering 2002-2022. Daytime-only heatwaves exhibited reduced cloudiness (-37%), enhancing shortwave radiation (+201 W/m), while efficient nocturnal cooling limited nighttime warming. Nighttime-only events were characterized by greater cloudiness (+6%) and humidity, increasing longwave radiation and suppressing cooling, with rice paddies buffering daytime temperature extremes more effectively than forests. Compound heatwaves combined both mechanisms-enhanced daytime solar heating and inhibited nocturnal cooling-producing the most intense temperature anomalies (>10 °C) concentrated in coastal-urban areas. Enhanced thermal turbulence deepened the boundary layer during daytime and compound events, whereas mechanical turbulence weakened under subsidence. These findings clarify heatwave boundary-layer processes and support region-specific climate adaptation strategies.
在快速城市化和气候变化的背景下，长江三角洲地区（YRD）热浪的频率和多样性不断增加，但其潜在的边界层过程仍未得到充分理解。本研究利用186个气象站的观测数据和2002 - 2022年的再分析数据，研究了长江三角洲地区三种热浪类型的边界层能量收支。仅白天的热浪表现出云量减少（-37%），增强了短波辐射（+201 W/m），而有效的夜间冷却限制了夜间变暖。仅夜间的事件特点是云量增加（+6%）和湿度增加，增加了长波辐射并抑制了冷却，稻田比森林更有效地缓冲了白天的极端温度。复合型热浪结合了两种机制——增强白天太阳加热和抑制夜间冷却——产生了最强烈的温度异常（>10°C），集中在沿海城市地区。增强的热湍流在白天和复合型事件期间加深了边界层，而在下沉作用下机械湍流减弱。这些发现阐明了热浪边界层过程，并支持了针对特定区域的气候适应策略。
