Numerical study on the response of the largest lake in China to climate change
<p>Lakes are sensitive indicators of climate change. There are thousands of lakes on the Tibetan Plateau (TP), and more than 1200 of them have an area larger than 1 km<span class="inline-formula"><sup>2</sup></span>; they respond quickly to climate...
Main Authors: | , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2019-04-01
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Series: | Hydrology and Earth System Sciences |
Online Access: | https://www.hydrol-earth-syst-sci.net/23/2093/2019/hess-23-2093-2019.pdf |
Summary: | <p>Lakes are sensitive indicators of climate change. There are thousands of
lakes on the Tibetan Plateau (TP), and more than 1200 of them have an area
larger than 1 km<span class="inline-formula"><sup>2</sup></span>; they respond quickly to climate change, but few
observation data of lakes are available. Therefore, the thermal condition of
the plateau lakes under the background of climate warming remains poorly
understood. In this study, the China regional surface meteorological feature dataset developed
by the Institute of Tibetan Plateau Research, Chinese Academy of Sciences
(ITPCAS), MODIS lake surface temperature (LST) data and buoy observation data
were used to evaluate the performance of lake model FLake, extended by simple
parameterizations of the salinity effect, for brackish lake and to reveal the
response of thermal conditions, radiation and heat balance of Qinghai Lake to
the recent climate change. The results demonstrated that the FLake has good
ability in capturing the seasonal variations in the lake surface temperature
and the internal thermal structure of Qinghai Lake. The simulated lake
surface temperature showed an increasing trend from 1979 to 2012, positively
correlated with the air temperature and the downward longwave radiation
while negatively correlated with the wind speed and downward shortwave
radiation. The simulated internal thermodynamic structure revealed that
Qinghai Lake is a dimictic lake with two overturn periods occurring in late
spring and late autumn. The surface and mean water temperatures of the lake
significantly increased from 1979 to 2012, while the bottom temperatures
showed no significant trend, even decreasing slightly from 1989 to 2012. The
warming was the strongest in winter for both the lake surface and air
temperature. With the warming of the climate, the later ice-on and earlier
ice-off trend was simulated in the lake, significantly influencing the
interannual and seasonal variability in radiation and heat flux. The annual
average net shortwave radiation and latent heat flux (LH) both increase
obviously while the net longwave radiation and sensible heat flux (SH)
decrease slightly. Earlier ice-off leads to more energy absorption mainly
in the form of shortwave radiation during the thawing period, and later ice-on
leads to more energy release in the form of longwave radiation, SH and LH
during the ice formation period. Meanwhile, the lake–air temperature difference
increased in both periods due to shortening ice duration.</p> |
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ISSN: | 1027-5606 1607-7938 |