Work

Role of Nighttime Precipitation in Mitigating Land Surface Warming on the Tibetan Plateau

Year: 2025

Type: article

Abstract: The Tibetan Plateau has warmed markedly alongside increased nighttime precipitation, yet the mechanisms remain poorly understood. Using CLM5.0 sensitivity experiments with 50% nighttime precipitation perturbations (HALF and PLUS50) and fixed precipitation variability (FIX1979), we show that nighttime precipitation anomalies modulate soil moisture, repartition turbulent and ground heat fluxes and, during daytime, alter surface albedo. HALF and FIX1979 amplify land surface temperature (LST) warming by 0.07°C decade −1 and 0.17°C decade −1 , respectively; PLUS50 reduces it by 0.06°C decade −1 . LST warming sensitivity peaks over arid/semi‐arid regions and is offset responses in semi‐humid regions. The response is diurnally asymmetric: daytime LST is jointly controlled by evapotranspiration and albedo anomalies, whereas nighttime LST is dominated by changes in turbulent and ground heat fluxes. These results establish nighttime precipitation and its variability as key regulators of high terrain surface warming and demonstrate that hourly‐resolved diagnostics are essential for evaluating diurnally varying land‐atmosphere coupling.

Source: Geophysical Research Letters

DOI: 10.1029/2025gl116428