HR: 10:20h
AN: U51C-01 INVITED     [PDF]
TI: Framework for Inclusion of Urbanized Landscapes in a Climate Model.
AU: * Dickinson, R E
EM: robted@eas.gatech.edu
AF: Georgia Institute of Technology, 311 Ferst Drive, Atlanta, Ga 30332-0340 United States
AB: Because of concentrated human populations, it becomes necessary to examine the consequences of urban areas for global climate. Urbanization changes the landscape by modifying the natural energy and water cycling processes and may introduce significant additional energy sources. Urban areas can either be considered from the viewpoint as to how their local climates are modified by their specifiic micrometeorological characteristics, or how there effects can be scaled up to the scales addressed by global regional climate models. We address the latter question. The land surfaces under a single atmospheric column of the model is partitioned into tiles with distinct micrometerological properties. However, the model resolution may restrict them to all interacting with the same atmospheric properties. The urban properities that cover the widest areas need to be considered first. These are evidently forests, grass, and pavements. Of these, the forests and grass might be combined with those outside the urban area to populatethe model's gridsquare forest and grass tile. However, urban/suburban lawns may be are sufficiently different from natural grasslands to merit a separte tile, and posibly be represented as irrigated where lawn watering prevails. Pavements are drastically different in their physical properties than natural surfaces, and typicaly cover a few tens of percent of an urban area (road densities of order of 10 km/ km2). Largely asphalt, they have very low albedo,and are imperious to infiltration of precipitation. Hence, their characterization may be the most important issue for inclusion of urban effects in a global model. The minimum requirements for their inclusion are : a) global data sets of their relative areas, and b) average properties (e.g. albedo. emissivity, capacity for water storage, roughness, ...) How might these be obtained or what these might be are discussed.
DE: 1620 Climate dynamics (3309)
SC: U
MN: 2003 Fall Meeting