The influence of ice thermodynamic characteristics on the lake-atmosphere interaction process over a large high-altitude dimictic lake, Nam Co
- 1Lanzhou University, Lanzhou, China, (shixd@itpcas.ac.cn)
- 2Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China, (shixd@itpcas.ac.cn)
- 3Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China, (wangbinbin@itpcas.ac.cn; ymma@itpcas.ac.cn; sunlijun@itpcas.ac.cn)
The lakes’ frozen and melting process is largely determined by the ice thermodynamic characteristics, i.e. the momentum roughness length, the surface albedo etc, which can impact on the lake-atmosphere interaction process, and finally affect the local hydrological cycle and the water resources. However, because of the data scarcity during frozen period of the lakes, there are relatively few studies and less clarity on the lakes’ thermodynamic characteristics, especially over the harsh environment of the Tibetan Plateau. In this study, based on meteorological forcing, eddy covariance measurements and remote sensing products, we explored,the effects of ice surface momentum roughness length (z0m) and snowfall on ice-frozen processes in Nam Co by using WRF-Lake model. The simulation results show that the WRF-Lake model can reproduce the mixing and stratification pattern, but with an over-early ice break up date and an overestimated sublimation. Based on eddy covariance measurements, the typical z0m value of ice surface Nam Co is approximately one magnitude lower than the default value in WRF-Lake (3.04×10-4 m vs 1×10-3 m), Numerical simulations indicate that the decrease of the ice surface will contribute to a warmer lake surface, an increase of the sensible heat flux, a decrease of the sublimation and a shorten ice-covered duration. Moreover, snowfall events can cool the lake significantly, then delay the lake ice break up date and reduce the sublimation significantly. After considering the two factors the WRF-Lake model can improve the simulated over-early ice break up date and the overestimated sublimation significantly. Therefore, this study provides valuable in situ measurements of the ice-atmosphere interaction process and shows significance for quantifying lake’ water resouces and climate effects.
Keywords: ice phenology, roughness length, lake-atmosphere interaction
How to cite: Shi, X., Wang, B., Ma, Y., and Sun, L.: The influence of ice thermodynamic characteristics on the lake-atmosphere interaction process over a large high-altitude dimictic lake, Nam Co, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10143, https://doi.org/10.5194/egusphere-egu24-10143, 2024.
