Fig. 1. Schematic diagram representing the (a) ALEXI and (b) DisALEXI modeling schemes, coupling atmospheric boundary layer (ABL) and two-source surface energy balance (TSEB) submodels. The models compute fluxes of sensible heat (H) from the soil and canopy (subscripts c and s) along gradients in temperature (T), and regulated by transport resistances R_A (aerodynamic), R_X (bulk leaf boundary layer) and R_S (soil surface boundary layer). DisALEXI uses the air temperature predicted by ALEXI near the blending height (T_A) to disaggregate 5-km ALEXI fluxes, given vegetation cover [f(_i)] and directional surface radiometric temperature [T_RAD(_i)] information derived from high-resolution remote-sensing imagery at look angles _i. See Norman et al. (2003) for further details.