MLS GW Variances due to Tropospheric
Deep Convection
During December-February MLS GW variances show strong wave
activities over the tropospheric deep convection zones in the subtropics
of the southern hemisphere. These activities are centered
at southern Africa, northern Australia, and souther America.
In previous analyses with MLS data, the variances were smoothed over
a large area to improve GW signal-to-noise ratios. As a result, only planetary-scale
features were able to visualize.
With the recently improved 4-point variances,
we do not need to smooth the maps so that many details on convection-induced
GWs can be investigated. In these color maps, the variances are averaged
into 4deg x 10 deg latitutde-longtitude bins. Note that these convection-related GW
activities tight closely to the topography, including small islands in the south Pacific.
The storm systems over oceans generally produce weaker GW variances compared to those
hitting the east side of land masses. Stratospheric wind profiles are important
for these GWs to propagate into the upper atmosphere.
Plotted in dotted lines are the UKMO total wind, sqrt(U^2+V^2)
averaged between 34-44km and sampled at the same localations as with MLS.
Previous results by McLandress, et al., [2000]
