Interaction between the Land Surface and Atmosphere

New insight is obtained into the structure of theconvective atmospheric boundary layer(CBL) over surface heat flux variation on a scale ofthe order of 10 km. Aircraft data collected duringthe International H2O Project (IHOP_2002) and largeeddy simulation (LES) are used. The new insight includes the followings: First, the CBL changes from a quasi-stationarystate to a non-stationary state when forced by ahigh-amplitude surface heat flux variation. Second, the structure of the CBL in anon-stationary state cannot be described with themixed-layer similarity. Third, moisture advection by thesurface-heterogeneity-induced mesoscale horizontalflows plays a significant role in initiating moistconvection.