850 hPa relative vorticity in two 50-km aquaplanet integrations
From Burnett et al. (2021), animations of 850-hPa relative vorticity in the northern hemisphere during year 1 of the 5-year model run with SST maximum at 10°N and 45°N. The shaded area is the intertropical convergence zone (ITCZ). The center of the ITCZ is identified as a maximum in the zonally and temporally averaged precipitation, and its extent is defined here as the region where the zonally and temporally averaged precipitation value is at least half of the value at the ITCZ center. Disturbances can be seen forming near the poleward edge of the ITCZ and propagating northward. Some of these disturbances register as TCs, as indicated by the black circles tracking them, and by the instantaneous TC count in the lower right corner of the video frame.
2009 stratospheric sudden warming
Evolution of PV on the 850 K surface over the 2009 stratospheric sudden warming event (vortex split)
Evolution of PV on the 850 K surface over the Antarctic from September 1 - October 31, 2013.
The seasonal breakdown of the vortex (the final warming) is evident.
Leading tropospheric and stratospheric modes for an SH-like winter integration
Leading tropospheric and stratospheric modes for an unforced integration of an idealized model in perpetual winter conditions, with EP flux anomalies superimposed. (Left) A fast mode capturing poleward propagation of zonal flow anomalies in the troposphere, with a strong stratospheric response at a certain phase of the signal. The location of the anomalous upward EP fluxes migrates with the wind anomalies. (Right) a slower stratospheric mode capturing latitudinal shifts of the stratospheric jet. While the EP fluxes switch from being anomalously upward to downward, there is little downward extension into the troposphere (similar to the observed SH in which stratosphere-troposphere coupling is not thought to be strong in midwinter).
Leading tropospheric and stratospheric modes for an NH-like winter integration
Leading tropospheric and stratospheric modes for an integration of an idealized model in perpetual winter conditions, with diabatic heating in the troposphere providing a source of planetary scale waves (as in Lindgren et al. 2018). (Left) the leading tropospheric mode captures poleward propagation of zonal flow anomalies, with the strong stratospheric response at a certain phase. (Right) The leading stratospheric mode capturing vortex pulsing, in which both anomalously strong and weak vortex events are followed by like-signed tropospheric anomalies in the mode, all the way to the surface. Increased EP flux anomalies, indicating a period of increased wave propagation into the stratosphere (and anomalously weak stratospheric winds) are followed by anomalously low wave activity as the vortex recovers.