摘要
青藏高原的大气热源及其影响以及环流的低频振荡已有很多探讨,但有关高原大气热源低频振荡及其对环流影响的研究目前尚未充分开展。利用倒算法计算得到的大气热源总量(Q1),诊断和分析1981—2000年夏季青藏高原东部逐日大气热源(Q1ETP,Q1 of the eastern Tibetan Plateau)的主要振荡周期及其对应的传播特征,并取其中1985、1992年进行更详细的分析。结果表明:(1)夏季高原东部大气热源存在两种低频振荡,主要为10～20 d振荡(BWO,Quasi-Biweekly Oscillation),其次为30～60 d振荡(LFO,Low Frequency Oscillation)。(2)在1985、1992年中,高原热源低频振荡与当地降水低频振荡有很好的同位相谱相关,表明热源低频振荡很可能由凝结潜热的振荡激发的,这证明了本文热源数据的可靠性。(3)高原在夏季主要是振荡源地,但也接受外来影响。高原热源BWO生成后主要在原地维持振荡,并受来自孟加拉湾的热源BWO影响,有时部分振荡向外(主要向东)传播;热源LFO情况与BWO类似,以本地振荡为主但也受来自东部大陆LFO的影响,外传时则主要向西。所以研究高原热源低频振荡需要特别注意热源BWO。
There has been a lot of discussion about the effect of atmospheric heating sources over the Tibetan Plateau and the low-frequency oscillation of the atmospheric circulation. However, the research on the low-frequency oscillation of heat sources over Plateau and its impact on the atmospheric circulation are not fully carried out. By using whole-layer atmospheric heat sources, calculated by derivation methods, the main oscillation periods and propagation features of the atmospheric heat sources over the eastern Tibetan Plateau （Q1ETP） are diagnosed and analyzed for the summer. The results are as follows： （1） Q1ETP in summer has two significant oscillation periods： The first one is 10 ~ 20 d （BWO, Quasi-Biweekly Oscillation）, the other is 30- 60 d （LFO, Low-Frequency Oscillation）. （2） A remarkable correlation is found between Q1ETP and rainfall over the eastern Tibetan Plateau in 1985 and 1992. So it can be suggested that the low-frequency oscillation of heat sources is likely to be stimulated by oscillation of latent heat. （3） The oscillation of heat sources over the plateau mainly generates locally while occasionally originating from other places. The BWO of Q 1ETP mainly appears to be a stationary wave, sometimes moves out （mainly eastward）, and has a close relationship with the BWO from the Bay of Bengal. Same as BWO, the LFO is mainly of local oscillation, occasionally propagates out （mainly westward）, and has a connection with the LFO from East China. In summary, more attention should be paid to the study on BWO of Q1ETP.
出处
《热带气象学报》
CSCD
北大核心
2012年第3期330-338,共9页
Journal of Tropical Meteorology
基金
国家自然科学基金面上项目(40475029)
国家自然科学基金重点项目(40633018
90711003)共同资助
关键词
青藏高原
大气热源
低频振荡
小波分析
交叉谱
Qinghai-Tibet Plateau
atmospheric heat sources
low-frequency oscillations
wavelet analysis
cross spectra
