Page 15 - 《高原气象》2021年第5期

高 原 气 象 40 卷
976

Study on the Warming Characteristics during the Ice-covered Period

of Ngoring Lake in the Qinghai-Xizang Plateau

WANG Mengxiao ，WEN Lijuan ，LI Zhaoguo ，SU Dongsheng 1，2
1，2
1
1
（1. Key Laboratory of Land Surface Process and Climate Change in Cold and Arid Regions，Northwest Institute of Eco-Environment
and Resources，Lanzhou 730000，Gansu，China；
2. University of Chinese Academy of Sciences，Beijing 100049，China）

Abstract：The water temperature of most of the frozen lakes is stable at a certain value during the ice period.
However，the water temperature of Ngoring Lake，a typical lake in the Qinghai-Xizang Plateau，will continue to
rise during the ice period，and this phenomenon generally exists in the whole water body，but the reason for this
phenomenon is still unclear. Based on station observation and lake temperature observation data in Ngoring
Lake，Enontekiö Kilpisjärvi Kyläkeskus station observation data，MODIS surface temperature data，China Mete‐
orological Administration precipitation data and NCEP-DOE reanalysis data，the applicability of LAKE2. 3 mod‐
el in Ngoring lake was evaluated，and the influence of local climate characteristics and main physical parameters
affecting radiation transmission in water body on the phenomenon is analyzed. The assessment results show that
LAKE2. 3 can well simulate the temperature change and thermal stratification in Ngoring lake，especially during
the ice period，and the simulated and observed lake temperature profiles are relatively consistent. However，the
simulated ice thickness is about 30% smaller than the observed value，which may be due to the limitation of
shore observation and one-dimensional model that can’t simulate the lake ice accumulation phenomenon caused
by three-dimensional dynamic action. The results of sensitivity experiments show that the strong downward short-
wave radiation is the main climate factor that causes the continuous rise of water temperature in Ngoring Lake
during the ice period. The larger wind speed further increases the rising range and speed of water temperature
range and rate of the temperature rise，while the smaller downward long wave radiation shortens the ice duration.
The rising rate and amplitude of lake temperature in ice period decrease when ice albedo and ice extinction coeffi‐
cient increased，while the temperature of deep layer of the lake in ice free period decreases with the increase of
water extinction coefficient.
Key words：Ngoring Lake；thermal condition；ice thickness；the phenomenon of rising lake temperature；
LAKE2. 3 model