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| Titel |
Spatial and seasonal variability of thermal stratification in Lake Nam Co, central Tibetan Plateau |
| VerfasserIn |
Junbo Wang, Jianting Ju, Gerhard Daut, Lei Huang, Yong Wang, Qingfeng Ma, Torsten Haberzettl, Jussi Baade, Roland Mäusbacher, Liping Zhu |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094730
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| Publikation (Nr.) |
 EGU/EGU2014-10161.pdf |
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| Zusammenfassung |
| As a big and deep lake in high altitude environment, Lake Nam Co, located in central Tibetan
Plateau with an altitude of 4730m and a maximum depth of ~98m, has played an important
role in the past decade concerning paleoenvironmental change studies. However, some
aspects related to the lake itself remained still unclear, for example, how the water
quality of lake water varies in different seasons and how the thermal stratification
develops within a year. As basic and important limnological issues, such kinds of
questions need to be addressed to better understand modern process within the lake.
Based on in situ monitoring by using a multi-probe water quality sonde (Hydrolab
DS5, Hach, USA) and deployed water temperature data logger (VEMCO Minilog,
Canada), we present preliminary results focusing on the seasonal variations of thermal
stratification in Nam Co and their different temporal behaviors at different monitoring
stations.
The regular water quality profiling was conducted at two stations located in two
sub-basins of the lake, one in the eastern area (T1, ~57m depth) and the other in the main
western basin (T2, ~93m depth), respectively. The monitoring campaigns were carried out
from mid-May to late November, covering almost the whole open lake period, and the data
logger were deployed throughout the whole year.
Nam Co usually has a frozen season from late January to mid-May, during which the
water body shows isothermal status vertically. After that, the increasing air temperature
causes a rapid lake ice melt and a short spring overturn of the lake’s water body. Then the
water temperature begins to rise from lake surface and thermal stratification forms gradually
and enhances until late October (T1 station) and late November (T2 station). This thermal
stratification will be destroyed then and autumn overturn occurs, after mixing the lake
enters a winter stagnation period. Based on the annual circulation pattern, Nam
Co can be classified as a dimictic lake which is typically distributed in temperate
zones.
Although the thermal stratification patterns are rather consistent throughout the year at
both T1 and T2 stations, they still show remarkable variations concerning the timing,
intensity and disappearance of thermocline as well as the absolute temperature in
different periods. In late May, only T1 station show obvious temperature rising (~8° at
surface and |
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