Periodic variations in stratospheric meridional wind from 20 to 65km: 80°N to 70°S

✍ Scribed by G. D. Nastrom; A. D. Belmont; D. G. Dartt

• Publisher: John Wiley and Sons
• Year: 1975
• Tongue: English
• Weight: 665 KB
• Volume: 101
• Category: Article
• ISSN: 0035-9009
• DOI: 10.1002/qj.49710142914

✦ Synopsis

Abstract

Height‐latitude sections for January along 70°E and 90°W in the northern hemisphere show a divergence zone above 50km near 60°N 70°E, and an intense, persistent (October–April) convergence zone above 40km near 50°N 90°W. Tidal meridional winds dominate circulation features in summer at all latitudes, and throughout the year at low latitudes. As most rocket data are taken in late morning and as there is an appreciable diurnal tide at rocket levels, all results given here apply only to late morning.

Long‐term periodic features in the meridional wind are analysed. No appreciable periodic waves are found in the tropics. The quasi‐biennial oscillation, annual wave, and four‐month wave have maximum amplitudes of about 10, 20, and 10m/s respectively in the arctic near 45km. The phase of the annual wave changes by nearly 180° in a narrow zone near 45°N. The semiannual wave has an amplitude of 10m/s near 50°N above 50km with equinoctial phase dates in the region of maximum amplitude. The location of this polar semiannual wave corresponds closely to that previously found in the zonal wind.