A diagnostic study of monsoon energetics for two contrasting years
In the present study we made an attempt to explain the behavior of the southwest monsoon for two contrasting years, from the view point of energetics. As a test case we selected 2002 and 2003, which were weak and strong monsoon years, respectively, based on rainfall. The energy terms <I>K&l...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2010-12-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/28/2201/2010/angeo-28-2201-2010.pdf |
| Summary: | In the present study we made an attempt to explain the behavior of the
southwest monsoon for two contrasting years, from the view point of
energetics. As a test case we selected 2002 and 2003, which were weak and
strong monsoon years, respectively, based on rainfall. The energy terms <I>K</I>ψ, <I>K</I>χ
and APE and the conversion terms <I>f</I>∇ψ. ∇χ, <span style="border-top: 1px solid #000; color: #000;">−ω'<I>T</I>'</span> are calculated at 850 hPa level and also
vertically integrated from 1000 hPa to 100 hPa. The results indicate that, the
year of high energy (both <I>K</I><sub>Ψ</sub>, <I>K</I><sub>χ</sub>) i.e. 2002, does not give
a good amount of rainfall compared to the good year i.e. 2003. The break
period during the year 2002 has been clearly explained using the block
diagrams. Periods of highest rainfall coincide with the positive conversions
of <I>f</I>∇ψ. ∇χ and <span style="border-top: 1px solid #000; color: #000;">−ω'<I>T</I>'</span>. Vertically
integrated moisture fluxes during the break period of 2002, 2003 are also
analyzed. The main reservoirs (sources and sinks) for the monsoon energy are
also identified using block diagrams. Negative correlation between daily
rainfall and energy terms in the year 2002 indicates its unusual behavior
both in terms of energetics as well as precipitation. Positive correlations
in the year 2003 represent strong monsoonal behavior. We calculated the
climatology of the total kinetic energy at 850 hPa, vertically integrated
(1000–100 hPa) for 30 years (1980–2009) and rainfall for 103 years
(1901–2003) which clearly indicates that the monsoon is indeed a season of
high energy for the South Asian region.
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Also the east- west direct thermal circulations are strongly related to the
good and bad monsoon years. |
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| ISSN: | 0992-7689 1432-0576 |