1995 Waugh 1996), which is capsulized as the “downward control” principle ( Haynes et al. Wave dissipation in the stratosphere drives the poleward transport and forces mean downwelling at high latitudes ( McIntyre and Palmer 1983, 1984 Haynes and McIntyre 1987 McIntyre 1990, 1999 Haynes et al.
The extratropical part of the BDC is relatively better understood than tropical upwelling (i.e., the tropical part of the BDC). 2001), and the age of stratospheric air ( Hall and Plumb 1994 Waugh and Hall 2002 Austin and Li 2006 Austin et al. Variations of the BDC have important implications for stratospheric ozone and its recovery ( WMO/UNEP 2011, and references therein), water vapor concentrations and other chemical species ( Ko et al. 1994 Salby and Callaghan 2002 Ueyama and Wallace 2010). 7, but for the high-pass filtered and deseasonalized T* at the 70-hPa level and the corresponding adjusted wave forcing.Īdiabatic cooling in the upwelling branch of the BDC leads to the “tropical cold point” while adiabatic warming in the downwelling branch keeps temperatures above radiative equilibrium over the winter polar region ( Andrews et al. 7, but for the high-pass filtered and deseasonalized T* at the 70-hPa level and the corresponding wave forcing.Īs in Fig. 1, but for the high-pass filtered and deseasonalized T* at the 70-hPa level.Īs in Fig. 7, but for the low-pass filtered and deseasonalized T* at the 70-hPa level and the corresponding wave forcing.Īs in Fig. (b) The corresponding first principal component (solid line) and the vertical shear of the zonal mean equatorial zonal wind at the 70-hPa level represented by (dotted line).Īs in Fig. (a) The first leading EOF of the low-pass filtered and deseasonalized T* at the 70-hPa level from 1980 to 2001. Dotted lines denote the 95% confidence limits as a function of latitude.
#Brewer high s annual 1980 Pc#
1a.Ĭontemporary correlation coefficients (solid line) between PC 1 of the deseasonalized T* at the 70-hPa level and the deseasonalized wave forcings from 1980 to 2001 derived from (a) the 6-hourly ERA-40 data and (b) the monthly mean ERA-40 data. The horizontal scale in (a) is as in Fig. (a) The first leading EOF of the deseasonalized T* at the 70-hPa level from 1980 to 2001 and (b) the corresponding first principal component time series.
#Brewer high s annual 1980 series#
(b) The corresponding second principal component time series (black line), the vertical shear of the zonal mean equatorial zonal wind at the 30-hPa level represented by (red line), and the zonal mean equatorial zonal wind at the 50-hPa level (blue line). (a) The second leading EOF of T* at the 30-hPa level from 1980 to 2001. 1, but for T* at the 30-hPa level from 1980 to 2001. 1, but for T* at the 150-hPa level from 1980 to 2001.Īs in Fig.
1, but for T* at the 70-hPa level from 1980 to 2001.Īs in Fig. The horizontal scale in (a) is such that the spacing between latitudes is proportional to the area of the earth’s surface between them (i.e., is linear in the sine of the latitude) ( Gill 1982).Īs in Fig. (a) The first leading EOF of from 1980 to 2001 and (b) the corresponding first principal component time series.