J. Song et al., INFLUENCE OF HETEROGENEOUS LAND SURFACES ON SURFACE-ENERGY AND MASS FLUXES, Theoretical and applied climatology, 58(3-4), 1997, pp. 175-188
Land-surface heterogeneity affects surface energy fluxes. The magnitud
es of selected land-surface influences are quantified by comparing obs
ervations with model simulations of the FIFE (First ISLSCP Field Exper
iment) domain. Several plausible heterogeneous and homogeneous initial
and boundary conditions are examined, although soil-moisture variabil
ity is emphasized. It turns out that simple spatial averages of surfac
e variation produced biased flux values. Simulated maximum latent-heat
fluxes were approximately 30 to 40 W m(-2) higher, and air temperatur
es similar or equal to 0.4 degrees C lower (at noon), when computation
s were initialized with spatially averaged soil-moisture and leaf-area
-index fields. The planetary boundary layer (PBL) height and turbulent
exchanges were lower as well. It additionally was observed that (larg
ely due to the nonlinear relationship between initial soil-moisture av
ailability and the evapotranspiration rate), ''real'' latent-heat flux
can be substantially less than simulated latent-heat flux using model
s initialized with spatially averaged soil-moisture fields. Difference
s between ''real'' and simulated fluxes also vary with the resolution
at which ''real'' soil-moisture heterogeneity is discretized.