A Study On The Distribution And Characteristics Of The Low-frequency Oscillation Of The Atmospheric Heat Source Over The Eastern Tibetan Plateau And Surrounding Areas

There has been a lot of discussion about the effect of the atmospheric heating source over the Tibetan Plateau and the low-frequency oscillation of atmospheric circulation. However, the research on low-frequency oscillation of heat source over Plateau and its impact on atmospheric circulation are not fully carried out. By using the whole layer atmospheric heat source which is calculated by the derivation method, main oscillation period and propagation features of the atmospheric heat source over the eastern Tibetan Plateau (Q1ETP) is diagnosed and analyzed in summer, and a more detailed analysis on this four years (1985.1989,1992,1998) is carried out. Finally, through the method EOF, the climate state distribution and change of Q1ETP is analyzed. The results show that:(1)Q1ETP in summer has two significant oscillation periods:The previous one is 10-20 d(BWO, Quasi-Biweekly Oscillation), the other is 30-60 d(LFO, Low Frequency Oscillation). During the above-mentioned 20 years, the BWO of QETP exceeds 90% confidence level every year (The average period of oscillation is 14 days), but LFO just 9 years does (The average period of oscillation is 49 days).(2)A remarkable positive correlation is found between Q1ETP and rainfall over the eastern Tibetan Plateau in above-mentioned years. So it can be considered that the low-frequency oscillation of heat source is likely to be stimulated by oscillation of latent heat. And this also proves the reliability of this heat source data.(3)There are three climate heat source centers over the Tibetan Plateau and its vicinity region from 1981 to 2000:the south of Tibetan Plateau, the north of Bay of Bengal and the Arabian Sea eastern region. The negative correlation between the Bay of Bengal and the Arabian Sea can be founded in the space of the first characteristic vector of and, and the time factor has certain negative tendency. Oscillation of over the Tibetan Plateau is weak, mainly activities in the Bay of Bengal.(4) The oscillation of heat source on the plateau mainly generates in the local, occasionally originates from other place. The BWO of Q1ETP mainly appears standing wave, sometimes moves out (mainly eastward), and it has a close relationship with the BWO from the Bay of Bengal. Same as BWO, the LFO mainly appears local oscillation, occasionally propagates (mainly westward) out, and it has a connection with the LFO from East China. In meridionally, there is high value center on Bay of Bengal and northern and southern slope of the plateau. In zonally, the oscillation center mainly located at eastern and western slope of the plateau and Western Pacific.In summary, more attention should be paid to the study on BWO of Q1ETP and the negative correlation between the Bay of Bengal and the Arabian Sea.