Geoscience Reference
In-Depth Information
SEASONAL VARIATION IN THE STRUCTURE OF QTP
ATMOSPHERIC HEAT SOURCE IN 1961-2001
ZHONG SHANSHAN, HE JINHAI, GUAN ZHAOYONG
and LIU XUANFEI
Key Laboratory of Meteorological Disasters of Jiangsu,
Nanjing University of Information Science and Technology,
Nanjing, China 210044
ECMWF daily reanalysis is applied to investigate 1961-2001 heat source/sink
and the climate features in relation to the atmospheric heat distribution over
the QTP (Qinghai-Tibetan Plateau) by means of the “inverse algorithm.”
Results suggest that (1) in March-September (October-February), the QTP
acts as a heat (cold) source, the strongest being in June (December). The
heating effects of the QTP are asymmetric in the seasons; (2) as shown in
the heating vertical profile, the maximum heat source layer occurs dominantly
between 500 and 600 hPa, but with the season-dependent heating strength and
depth, and, in contrast, the cold source has its maximum layer and intensity
varying as a function of time; (3) the horizontal distribution of the heat sources
throughout the troposphere
(from surface to 100 hPa) is complicated,
displaying noticeable regionality; (4) since 1979 the seasonal variability of the
heat source has shown climate transition signals, as clearly seen in 1990/1991.
Q
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1. Introduction
The QTP is a region higher in elevation and more complicated in surface
feature than any other area in the world, called a “third pole” next to the
Arctic and Antarctic in climate. The tremendous prominence of the QTP
has changed the pattern of Asian climate, exerting pronounced effects on
atmospheric circulations and climate worldwide.
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Abnormal change in the QTP thermal condition in the atmosphere
bears a close relation to East-Asian circulations,
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acting as an indicator of
summer precipitation over the Jiang-Huai valley, South China and North
China.
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,
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When the QTP heat source is strengthened, the rainfall increases
in the upper Yangtze and Huaihe valleys as opposed to Southeast and North
China. Around seasonal transition, the differences in the source/sink over
the QTP with its vicinity are one of the causes of heavy flood/drought
happening in the Jiang-Huai valley.
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,
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