Modeling the surface radiation and energy budget inside Arizona's meteor crater

The components of the radiation and surface energy budget have been modeled over the complex terrain of Arizona's Meteor Crater using terrain parameters derivable from a DEM as well as radiation and surface conditions observed at a central location within the terrain. The incoming shortwave radiation was modeled using direct observations taken within the crater at the central observation station and projected onto the variable terrain. When terrain shading made this approach unfeasible, knowledge of the solar radiation distribution was applied. The other radiation components were modeled using physical theory, direct observations, and relevant measured variables. The modeled radiation components are summed to form the modeled net radiation. The sensible heat flux is then modeled assuming a similarity between the ratio of net radiation on an unobstructed inclined surface to that on an unobstructed horizontal surface and the ratio of sensible heat flux on an unobstructed inclined surface to that on an unobstructed horizontal surface. Latent and ground heat fluxes are modeled by the extension of their direct measurements to all points within the domain. All radiation and energy balance components are adjusted for terrain shading, when appropriate. The resulting model was compared against observations taken during the METCRAX field campaign during October 2006. The radiation component found to have the most influence on the values of the net radiation is the incoming shortwave radiation. Accurately representing this component is the first step in a reliable model of the net radiation and therefore the sensible heat flux. The model produced errors within measurement accuracy for incoming short and longwave radiation and outgoing shortwave radiation. The errors produced by the models of the energy budget components are also small enough for the model to be considered useful to the research community. All of the modeled components vary temporally and the majority of the components vary spatially, reflecting the dependency of the energy budget on terrain features.