Customizing Global/Theater Weather Analysis and Prediction System Data Sets

The Global/Theater Weather Analysis and Prediction System (GTWAPS) provides model output data for a number of regions covering most of the Earth's land surface with horizontal resolutions ranging from 45 to 5 kilometers. The raw model output data is post-processed to produce over 1400 two-dimensional fields per output time. In GRIB format, this data can exceed 2.5 Gigabytes for some GTWAPS theaters. This data is produced for more than 2 dozen theaters and nests. Each theater or nest is produced at least twice per day and some are produced 4 times per day. Network bandwidth, storage, and processing limitations at the customer sites required that the data be transferred more efficiently. The GTWAPS program is pursuing multiple strategies to make the data available to customers more efficiently. One such strategy is a generic post-processing program (GENPOST) that will produce only selected outputs. A graphical user interface (GUI) is provided which allows the user to create a data profile that controls the operation of GENPOST. The GUI allows the user to select the input data, the output data file names, and to select what data elements are output. Another strategy is combining government-developed programs that create subsets of GRIB data into an operational system called trimGRIB. One of the programs selects specified GRIB elements from a file containing many elements. Another program creates geographical subsets of GRIB data given the latitude and longitude of the corners of the desired area. GTWAPS is integrating these programs into production and developing a GUI to control it. The GUI will allow users to select input data, draw the geographical subsets, and select the GRIB elements to be output. The GUI will also allow the user to thin the data by processing fewer output times. A key advantage of this tool is the selection of specific level types. The MM5 model as used in GTWAPS creates outputs on over 40 sigma levels. The data is then interpolated to isobaric and altitude levels. If the vertical resolution provided by the original sigma data is not needed the data set can be greatly reduced by selecting a set of pressure or altitude levels. In the future GTWAPS plans to create a standalone version of the trimGRIB system. GTWAPS customers would use this to create a subset of the data they receive and pass it on to their customers. We will investigate allowing remote users to access the trimGRIB GUI and select the parameter set they need. The result of this selection could be immediately transferred to the customer or serve as a subscription to that set of data. GTWAPS will also work to integrate these capabilities into the Air Force Weather architecture that is being developed by other programs. These programs are developing standard communication and database structures, which will enhance GTWAPS ability to server, its customers.