Year to Year Variations of Horizontal Eddy Flux of Momentum in the Winter Stratosphere

[摘要] Year to year variations of horizontal flux of momentum due to the planetary-scale disturbances in the winter stratosphere are studied based on the 3-month mean statistics throughout five winters from 1963 to 1967 by the use of the gridpoint data of 30mb isobaric heights over the Northern Hemisphere. Computations are made to separate the total momentum transport into the standing eddy flux and the transient eddy flux, as well as into the zonal wave numbers, for the purpose of clarifying the nature of planetary waves.It is likely that the poleward flux of momentum observed in the lower latitudes is caused by the penetration of planetary waves from the middle latitudes into the low-latitude stratosphere. It is also found that, in contrast to Wallace and Newell (1966), the year to year variation of total momentum transport does not necessarily show a direct relation to the quasi-biennial oscillation of the zonal wind in the equatorial lower stratosphere, but that planetary wave activity in the winter stratospheric circulation has, in a broad sense, a close relation to the zonal wind in the tropics.

[学科分类] 大气科学