Climate characteristics of QTP atmospheric heat source in 1961-2001

摘要

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). For the region as a whole, the heat source feature lasts longer, with its intensity much higher compared to the cold source; 2) as shown in the heating vertical profile, the maximum heat source layer occurs dominantly between 500-600 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 < Q_1 > (from surface to 100 hPa) is complicated, displaying noticeable regionality, I.e., the heat source changes faster in the western than in the eastern QTP, with the western source considerably stronger in April - August, and intensified quickly enough to show a 200 W/m~2 center in May, one month ahead of the eastern source. When July comes the regional heat source begins to weaken towards the south, during which the western source weakens faster, changing to a cold source in October, again one month earlier compared to the eastern counterpart; 4) since 1979 the seasonal variability of the heat source has shown climate transition signals, as clearly seen in 1990/91.