The monsoon effect on energy and carbon exchange processes over a highland lake in the southwest of China
<p>Erhai Lake is a subtropical highland shallow lake on the southeast margin of the Tibetan Plateau, which is influenced by both South Asian and East Asian summer monsoons. Based on 4 years of continuous eddy covariance (EC) data over Erhai Lake, the monsoon effect on water–atmosphere excha...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-10-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | https://www.atmos-chem-phys.net/18/15087/2018/acp-18-15087-2018.pdf |
| Summary: | <p>Erhai Lake is a subtropical highland shallow lake on the southeast
margin of the Tibetan Plateau, which is influenced by both South Asian and East
Asian summer monsoons. Based on 4 years of continuous eddy covariance (EC)
data over Erhai Lake, the monsoon effect on water–atmosphere exchange
processes is investigated by comparing the energy and CO<sub>2</sub> flux patterns and
their main drivers during pre-monsoon (March–April), monsoon (May–October)
and post-monsoon (November–December) periods. The results show that the
atmospheric properties display a large difference during the three different
periods. There is a negative difference between water surface and air
temperature (<i>T</i>) during the pre-monsoon period, while a positive <i>T</i> during
the post-monsoon period. The diurnal sensible heat flux
(<i>H</i><sub>s</sub>) is larger during
the post-monsoon period, while the latent heat flux (LE) is larger during the monsoon
period. The monthly average <i>H</i><sub>s</sub> and heat storage (<i>Q</i>) in the lake
remain negative during the pre-monsoon period and the early monsoon period, and
they become positive in the middle monsoon period, which indicates that the
lake absorbs heat at first and releases it subsequently. LE plays a
dominating role in the energy partitioning of the lake. The Bowen ratio is
higher during the post-monsoon period. The uptake of CO<sub>2</sub> flux is
observed in the middle of the day during monsoon and post-monsoon periods. The
Δ<i>T</i> is the main driver for <i>H</i><sub>s</sub> and the effect of Δ<i>T</i>
is increased as timescales are extended from half-hourly to monthly. The
wind speed has a weak effect on <i>H</i><sub>s</sub> but a strong effect on LE and
CO<sub>2</sub> fluxes. Similar main drivers for <i>H</i><sub>s</sub> are found
during the pre-monsoon and post-monsoon periods, which is also found for
CO<sub>2</sub> flux, indicating a large impact of the monsoon on the heat and
carbon exchange processes over Erhai Lake.</p> |
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| ISSN: | 1680-7316 1680-7324 |