期刊名称:Tellus A: Dynamic Meteorology and Oceanography
电子版ISSN:1600-0870
出版年度:2004
卷号:56
期号:4
页码:278-286
DOI:10.3402/tellusa.v56i4.14423
摘要:In the extratropics the analysis of the time–space structure of the dynamical tropopause shows a marked signature of nonpropagating, low-frequency (time-scale >10 d), ultra-long (zonal wavenumber <5) waves. This suggests the extension of theories relating the tropopause height to the baroclinic adjustment to the orographic-baroclinic disturbances, generally operating in the low-frequency domain. Such an extension is here proposed. By analysing Eady modes in a Boussinesq atmosphere, it has been found that the form-drag instability must be accounted for in an extended theory of baroclinic neutralization. The produced unstable standing waves carry a poleward large amount of heat at planetary scale for most of the external parameter settings and their spatial structure strongly resembles the observed winter mid-latitude eddy fields. Furthermore, we show how a simple representation of the stratosphere affects the tropopause neutralization requirements.