On the influence of surface heterogeneity on latent heat fluxes and stratus properties

A mesoscale atmospheric model is used to examine the three-dimensional structure and evolution of low extended stratus over various synthetic landscapes of different heterogeneity in mid-latitudes in spring. The simulation results substantiate that surface heterogeneity nonlinearly influences the distributions of latent heat fluxes, vertical motions, and cloud-water presupposed the length of the patches of equal surface type is about 10 km or larger than that. For low degrees of heterogeneity (large patch sizes), a great coverage by lowly evapotranspiring, but strongly heating patches may enhance vertical motion. Moreover, this constellation may increase the cloud-water amount of low extended stratus as compared to that of the other heterogeneous landscapes or that with the highest domain-averaged daily sum of latent heat fluxes. Although there exists a relationship between the degree of heterogeneity and the modulation of latent heat fluxes as well as cloud-water amount, the kind of surface characteristics is also important for the modulation of the properties of low extended stratus.