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| Titel |
Towards the water level fluctuations of Lake Nam Co with a lumped watershed-lake model |
| VerfasserIn |
Binquan Li, Li Chen, Zhongmin Liang, Zhongbo Yu |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104317
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| Publikation (Nr.) |
 EGU/EGU2015-3739.pdf |
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| Zusammenfassung |
| Hydrologic cycles of most inland lake watersheds on the Tibetan Plateau are not
closely monitored due to lack of observation abilities in the harsh environment.
Understanding the hydrologic processes of lake watersheds in the Tibetan Plateau could
provide insights into the responses of Tibetan lake dynamics to climate change. An
efficient approach for this purpose is to represent complex hydrologic behaviors
of such Tibetan lake watersheds with simple and plausible hydrologic models. In
this study, water level fluctuations of an inland saline lake in the central Tibetan
Plateau, Nam Co, were investigated using a lumped watershed-lake model. This
terminal lake is fed by both precipitation and glacier melt water from west slopes of
Nyainqentanglha Ranges. The degree-day factor method was introduced to improve the
model applicability in the glacier-covered basins. The model simulated the hydrologic
processes as well as lake water budget of the Nam Co watershed. Remote sensing
images (Landsat MSS, TM and ETM) from 1972 to 2008 were used to identify
the boundaries of glacier and lake. Multi-source climate data (e.g., ground point
observation, 0.25o gridded APHRODITE and TRMM 3B42 v7) were used to drive the
hydrologic model at a monthly time step. It was found that both precipitation and
air temperature experienced increasing trends with rates of 2.2 mm/year and 0.04
oC/year, respectively, for the period of 1963-2012. As a response to climate change, in
the study basin, glaciers decreased by 51 km2 (-23%) while lakes expanded by
98 km2 (+5%) from 1972 to 2007. Results also showed that, during the period
of 1961-2013, precipitation on lake, surface and subsurface runoff productions
contributed 33%, 39% and 28%, respectively, to the total water mass gain of Lake
Nam Co. As for its water sinks, lake water evaporation and groundwater outflow
contributions were 63% and 23%, respectively. Consequently, a 14% of incoming
water remained in the lake, producing an increase of the lake level. The hydrologic
analysis of this study echoes the point that there exists groundwater outflow in the
Lake Nam Co, which has been deemed to be a closed inland lake for a long time. |
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