气候变化领域集成服务门户(CCPortal): Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau

CCPortal

DOI	10.1016/j.jhydrol.2020.124668
	Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau
	Wang, Junbo; Huang, Lei; Ju, Jianting; Daut, Gerhard; Ma, Qingfeng; Zhu, Liping; Haberzettl, Torsten; Baade, Jussi; Maeusbacher, Roland; Hamilton, Andrew; Graves, Kelly; Olsthoorn, Jason; Laval, Bernard E.
通讯作者	Wang, JB (通讯作者)
发表日期	2020
ISSN	0022-1694
EISSN	1879-2707
卷号	584
英文摘要	We investigate the seasonal evolution of stratification in a deep (100 m), high-altitude (4,730 m a.s.l.) dimictic lake on the Tibetan Plateau using three years of observation of Nam Co. The lake is situated at relatively low latitude (30 degrees N) where it receives high solar radiative forcing (observed maximum daily average 400 W m(-2)), yet the annual average air temperature is close to 0 degrees C at this high altitude. These features make Nam Co distinct from most well-documented dimictic lakes, which are usually located at higher latitude and lower altitude. We classify seasonal stratification into six phases based on strength of stratification, surface temperature relative to the temperature of maximum density, ice-cover, and heat and mixing dynamics, which we use to compare Nam Co with better-documented, higher-latitude dimictic lakes. While the three warm stratification phases (i.e. when water is warmer than the temperature of maximum density) in Nam Co are relatively cold, they are otherwise similar to that observed in high-latitude dimictic lakes. Conversely, two of Nam Co's cold stratification phases are distinct from that reported in high-latitude lakes. These two phases are characterized by the interplay between the relatively strong radiative forcing and surface heat flux, and include the following: 1) during fall turnover, persistent winds aided by radiatively driven convection prolong vertical mixing (i.e. turnover) and surface heat loss such that the entire water column cools well below the temperature of maximum density (as low as 1 degrees C); and 2) in contrast, under ice-cover with relatively little snow, the entire water column of the lake warms continuously due to through-ice solar radiative flux. The intense cooling and heating during these two phases counteract each other such that hypolimnetic temperature at spring turnover is similar to that observed in high latitude lakes. Our observations highlight the relative importance of radiatively driven convection on the seasonal stratification dynamics of Nam Co, and underscore that these dynamics must be considered when attempting to predict climate change impacts on high-altitude, low-latitude lakes, including the > 1100, largely unstudied, lakes on the Tibetan Plateau.
关键词	ICE PHENOLOGY WATER TEMPERATURE CLASSIFICATION VARIABILITY BALANCE CHINA HEAT
英文关键词	Nam Co; The Tibetan Plateau; Radiatively driven convection; Winter stratification; Dimictic; Thermal fluxes
语种	英语
WOS研究方向	Engineering ; Geology ; Water Resources
WOS类目	Engineering, Civil ; Geosciences, Multidisciplinary ; Water Resources
WOS记录号	WOS:000527390200080
来源期刊	JOURNAL OF HYDROLOGY
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/259932
推荐引用方式 GB/T 7714	Wang, Junbo,Huang, Lei,Ju, Jianting,et al. Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau[J]. 中国科学院青藏高原研究所,2020,584.
APA	Wang, Junbo.,Huang, Lei.,Ju, Jianting.,Daut, Gerhard.,Ma, Qingfeng.,...&Laval, Bernard E..(2020).Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau.JOURNAL OF HYDROLOGY,584.
MLA	Wang, Junbo,et al."Seasonal stratification of a deep, high-altitude, dimictic lake: Nam Co, Tibetan Plateau".JOURNAL OF HYDROLOGY 584(2020).