Microscale Modeling Needs for Digitized Surface Feature Morphology—Urban and Rural

The most recent report (July, 2005) on the effort to define and consolidate the needs of all agencies for digitized morphological data sets as required by meteorological and diffusion modelers and users reflects a very strong emphasis on meso-scale and CFD model requirements. The development of a plan for this ‘standardized National Data Base (of Morphology)' as currently described may not include data types required as inputs to micro-scale models and similar analyses that numerous federal agencies, military entities, academia, and private industry so desperately need. Organizations and agencies that focus on micro-scale modeling and analyses include US Department of Agriculture, US Forest Service (USDA), Urban Forest Centers, US Army small area field operations, city planers of new urban development, energy and nuclear facilities, HAZMAT responders, and more generally speaking, Homeland Security entities. If a National Plan is to be achieved, then it must satisfy at the very least all federal groups: civilian and military. The characteristics, properties, and format of digitized surface feature morphology for micro-scale usage differ from the coarse grid size and limited morphology types of the meso-scale as well as the ultra-high resolution of the CFD one-for-one dimensions/footprint and the disregard for morphology other than just buildings. Presently, micro-scale modelers have 17 urban morphology types and some 20 non-building morphology types, whereas meso-scale usually account for seven or eight very generic land use/'morphology' types, and most CFD users seem to be limited to just buildings dimensions and footprints within a CDB area. Data resolution of all types of micro-scale morphology tends to be on the order of 100m, 50m or so grid cells. Meso-scale grids tend to be 36km, 12km, 4km, 1.3km, and some say 1km. Even at the highest resolution, the meso-scale at 1km can not definitively discern morphology for the 100 x 100 data point array that micro-scale models require for computations on the 100m grid spacing. As for morphology data for CFD purposes, one could consolidate data points to a somewhat coarser resolution (~100m or so), but then the undefined areas of non-buildings would be missing within such a reverse engineered data set. It is clear that one cannot go top down from meso-scale to satisfy the mirco-scale need, nor can one go bottom up from CDB-centric CFD data (from building only data and considerable areas of undefined cells) to satisfy the micro-scale needs. The scope of this National Data Base must include the meso-scale and the micro-scale domains and the three sub-division of motion (alpha, beta, and gamma) such as was proposed by Orlanski some years ago. Within this scheme, the micro-gamma scale can be equated to the CFD scale. Examples of micro-scale morphology data characteristics, properties, and formats as well as comparable data sets will be presented