Modulation of snow on the daily evolution of surface heating over the
Tibetan Plateau during winter: Observational analyses
Abstract
Studying the daily evolution of turbulent fluxes modulated by snowfall
over the Tibetan Plateau (TP) is of importance to understand the
features of the change in the TP heat source/sink. Based on observations
from 4 sites of the Third TP Atmospheric Scientific Experiment, the
process of surface energy balance impacted by snow is investigated. The
results show that the surface albedo increases on the first day of snow
and then slowly decreases. Correspondingly, the sensible heat (H) flux
sharply decreases after snow and then recovers to the original level
during the following approximately 10 days. The latent heat (LE) flux
becomes more active and stronger after snowfall and persists for a
longer period than H, since the soil moisture may still contribute to a
high LE after snowmelt. As the synergistic result of H and LE modulated
by snow, the surface turbulent heating (i.e., the sum H and LE) of the
TP decreases at the early period of snow events and then even enhances
to a higher level after the snowmelt than before snow. Comparison
analyses reveal that the impact of snow on the H and LE over the TP is
much stronger than over similar latitude low-altitude regions in North
America and Europe, which may be partly attributed to the larger and
more drastic change of the surface net solar radiation associated with
snow processes in the TP. This study may help further understand the
detailed physical processes of modulation of snow events on Asian
weather processes during winter.