Journal of Earth system science | |
Equatorial modes observed in atmospheric variables | |
G S Bhat11  L Kiranmayi11  | |
[1] Center for Atmospheric and Oceanic Sciences, Indian Institute of Science, Bangalore 560 012, India.$$ | |
关键词: Tropical intraseasonal oscillation; equatorial modes; MJO; equatorial wave theory.; | |
DOI : | |
学科分类:天文学(综合) | |
来源: Indian Academy of Sciences | |
【 摘 要 】
Wavenumber –frequency spectral analysis of different atmospheric variables has been carried out using 25 years of data.The area considered is the tropical belt 25°S –25°N. A combined FFT- wavelet analysis method has been used for this purpose.Variables considered are outgoing long- wave radiation (OLR),850 hPa divergence,zonal and meridional winds at 850,500 and 200 hPa levels,sea level pressure and 850 hPa geopotential height.It is shown that the spectra of different variables have some common properties,but each variable also has few features different from the rest. While Kelvin mode is prominent in OLR and zonal winds,it is not clearly observed in pressure and geopotential height ï¬elds;the latter two have a dominant wavenumber zero mode not seen in other variables except in meridional wind at 200 hPa and 850 hPa divergences.Different dominant modes in the tropics show signiï¬cant variations on sub-seasonal time scales.
【 授权许可】
Unknown
【 预 览 】
Files | Size | Format | View |
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RO201912040492080ZK.pdf | 432KB | download |