Geoscience Reference
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1981-1990 (1991-2001), suggesting that the trend of anomalous change in
the heat source occurs over 1990/1991. Prior to 1990 the central-Northeast
QTP is inside the positive anomaly variability center as opposed to the
situation after the year, with an opposite change in the Southeast source.
In summer,
EOF1 shows a see-saw form divided by 32.5
◦
N,
positive in the north and negative values in the south. The maximal
variability center was not over the QTP but to the south, where there were
three cores. The temporal sequence also indicates the climate change of the
anomalous variation in the heat source, with positive (negative) values in
1981-1987 (1994-1998), with 1988-1993 as the transition stage, i.e. south
of 32
◦
N there occurred negative anomaly of variability in summer in the
1980s and positive anomaly was from the end of the 1980s to early 1990s.
The EOF1 Winter/Autumn space patterns are similar to that of Spring
(figure not shown), showing the anti-phase distribution between the central
and Northeast and Southeast QTP, with the 1990/1991 as the climate
transition year.
It follows that the EOF1 — given seasonal
Q
1
indicates the climate
transition, differing in that the variability center is kept over the QTP in
all but summer seasons and it is on the south side of the QTP in Summer,
i.e. over the Indo-China and northern Indian Peninsula. This may be due
to the fact that the summer QTP heat source is not an independent center
but part of the source in the Indo-China and Indian Peninsula as well as
the Bay of Bengal in between.
Q
1
5. Conclusions
The study calculated heat source and heat sink over the Tibetan Plateau
and its vicinity (QTP) during 1961-2001 using the ERA daily reanalysis
and the “inverse algorithm,” and discussed the climate regimes linked to
the thermal source over the QTP.
Some reasonable conclusions are obtained, that is, the region over the
QTP with the height more than 3000 m above the sea level acts as a heat
source, and as a heat sink during October-February. The heat source lasts
for 7 months in the whole atmospheric extent and much stronger than
the sink in the wintertime. Therefore, the heating effects of the QTP are
asymmetric in the seasons. We also discussed the space extent in the vertical
and time variation of the heat source and sink over the QTP. It is found
that during April-August, the heat source is stronger in the west than
in the east. As Spring arrives, the western heat source increases rapidly
