WRF - Developmental Testbed Center

Description of GEOGRID.TBL OptionsThe GEOGRID.TBL file is a text file that defines parameters of each of the data sets tobe interpolated by geogrid. Each data set is defined in a separate section, with sectionsbeing delimited by a line of equality symbols (e.g., ‘==============’). Within eachsection, there are specifications, each of which has the form of keyword=value. Somekeywords are required in each data set section, while others are optional; some keywordsare mutually exclusive with other keywords. Below, the possible keywords and theirexpected range of values are described.1. NAME : A character string specifying the name that will be assigned to theinterpolated field upon output. No default value.2. PRIORITY : An integer specifying the priority that the data source identified in thetable section takes with respect to other sources of data for the same field. If a field has nsources of data, then there must be n separate table entries for the field, each of whichmust be given a unique value for priority in the range [1, n]. No default value.3. DEST_TYPE : A character string, either categorical or continuous, that tellswhether the interpolated field from the data source given in the table section is to betreated as a continuous or a categorical field. No default value.4. INTERP_OPTION : A sequence of one or more character strings, which are the namesof interpolation methods to be used when horizontally interpolating the field. Availableinterpolation methods are: average_4pt, average_16pt, wt_average_4pt,wt_average_16pt, nearest_neighbor, four_pt, sixteen_pt, search,average_gcell(r); for the grid cell average method (average_gcell), the optionalargument r specifies the minimum ratio of source data resolution to simulation gridresolution at which the method will be applied; unless specified, r = 0.0, and the option isused for any ratio. When a sequence of two or more methods are given, the methodsshould be separated by a + sign. No default value.5. SMOOTH_OPTION : A character string giving the name of a smoothing method to beapplied to the field after interpolation. Available smoothing options are: 1-2-1, smthdesmth,and smth-desmth_special (ARW only). Default value is null (i.e., nosmoothing is applied).6. SMOOTH_PASSES : If smoothing is to be performed on the interpolated field,smooth_passes specifies an integer number of passes of the smoothing method to applyto the field. Default value is 1.7. REL_PATH : A character string specifying the path relative to the path given in thenamelist variable geog_data_path. A specification is of the general formRES_STRING:REL_PATH, where RES_STRING is a character string identifying thesource or resolution of the data in some unique way and may be specified in the namelistvariable geog_data_res, and REL_PATH is a path relative to geog_data_path whereWRF-NMM V3: User’s Guide 3-38