COSMIC GPS Observations of Northern Hemisphere winter stratospheric gravity waves and comparisons with an atmospheric general circulation model

1] COSMIC satellite temperature data are used to derive the 2006/07 winter mean stratospheric Northern Hemisphere potential energy E-p from gravity waves with vertical wavelengths less than 7 km in grid cells of size 10 degrees X 5 degrees; and to study longitudinal and latitudinal variability in cells of size 20 degrees X 5 degrees X 7 days. Large E-p at 17 - 23 km is mostly associated with the sub-tropical jet and shows significant longitudinal variability. Some contribution to total Ep from local orographic sources may occur above the Canadian Rockies, Scandinavia and northern Japan, but not above the Himalayas, due to the background wind conditions. Many of the waves are likely to have low ground-based phase speeds, as observed by filtering around the 0 - 10 m s(-1) background zonal wind. COSMIC results are compared with a T106L60 AGCM, confirming sub-tropical jet related generation, upward propagation and low phase speeds of the observed gravity waves.