Changing Stability » Advection Differential Advection
Differential advection is less obvious than uniform advection and also more difficult to evaluate on synoptic charts. Differential geostrophic temperature advection is simply advection of different stability into the sounding from an upwind (geostrophic) source, but ageostrophic advections can be very important, as well. Since observed or model-derived wind trajectories contain the ageostrophic wind component, we may use them to estimate temperature advection, rather than geostrophic winds computed from height fields. By examining the temperature advection at multiple levels, we can assess the effects of differential advection on the local lapse rate.