Relation between Quasi-Decadal and Quasi-Biennial Oscillations of Solar Activity and the Equatorial Stratospheric Wind

摘要

We have established that quasi-decadal and quasi-biennial oscillations of zonal wind velocity in the equatorial stratosphere are coherent with similar oscillations of the solar activity (SA). The time lag of wind velocity oscillations at the isobaric surface 15 hPa (～28 km) relative to SA index F10.7 is approximately equal to 1 yr at both periods. During the period of SA maximum in the 1990s, coherent behavior of the equatorial stratospheric wind (ESW) and the SA was observed at all time scales from 1 to 10 yr. After a distortion in the coherency in 1994, a high coherency was observed again in 2001-2005, but with a simultaneous change of its sign at the scales of the periods of the solar cycle and quasi-biennial oscillation (QBO). The amplitudes of variations in the ESW velocity are maximal at the 15 hPa level. Quasi-decadal variations in the ESW above and below the 20-30 hPa layer are generally in opposite phase to each other. At the boundary of the 50-15 hPa layer, they are exactly in opposite phase to each other.