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NDFDClimate: A Computer Application for the National Digital Forecast Database. Christopher Mello WFO Cleveland. NDFDClimate. NDFDClimate is a computer application that creates images of forecast and climatological parameters for the U.S. from two different digital data sets.
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NDFDClimate: A Computer Application for theNational Digital Forecast Database Christopher Mello WFO Cleveland
NDFDClimate • NDFDClimate is a computer application that creates images of forecast and climatological parameters for the U.S. from two different digital data sets. • NDFD (National Digital Forecast Database) weather forecast grids produced by the NWS and PRISM data (Parameter-elevation Regressions on Independent Slopes Model), an expert system that uses point climatological temperature data and a digital elevation model (DEM) to generate gridded estimates of climate parameters.
PRISM DataParameter-elevation Regressions on Independent Slopes Model • PRISM system determines climate elements (temp, or rainfall) values at grid cells by calculating linear regression relationships between the climate element and elevation • Each grid cell estimate is determined from a separate multiple linear regression using data from nearby climate stations • Each station in the regression is weighted based on five factors: distance, elevation, vertical layer (helps identify temp inversions in high mountain valleys), topographic orientation, coastal proximity
PRISM DataParameter-elevation Regressions on Independent Slopes Model • Temperature data from PRISM consist of daily maximum and minimum temp fields for 1971 – 2000 at 5 km resolution • PRISM derived daily normal max & min temperature grids were compared to official data from the NCDC for CLE, TOL, ERI, YNG, SYR, RIC, & GSP • Each site had a MAE near 0.25° F for both max and min temp with the highest daily error < 1° F
NDFD DataNational Digital Forecast Database • NDFD consists of digital forecast data that are produced by the WFOs across the U.S. and merged into a single image or file for each parameter and projection. • Forecast grids are produced for Days 1-7 with 5 km resolution • NDFD grids include max and min temp, POP, temp, water equivalent, snow amount
NDFDClimate • NDFDClimate uses the GRADS software to create images that utilize information from both the NDFD and PRISM data • GRADS has the ability to add, subtract, or manipulate fields using many formulas. Users can specify the domain and contour interval of images.
NDFDClimate • NDFDClimate produces temperature anomaly grids by subtracting NDFD grids from PRISM derived daily climate grids • NDFDClimate combines some NDFD fields to generate 5 day totals of heating and cooling degree days and 60 hour QPF
NDFDClimate Uses • Processes NDFD data for users with 5 day HDD & CDD totals temp changes • Educate users on current temperatures anomalies where point data may be inadequate
NDFDClimate • References Berman, F., A. Chien, K. Cooper, J. Dogarra, I. Foster, D. Gannon, L. Johnson, K. Kennedy, C. Kesselman, J. Mellor-Crummey, D. Reed, L. Torczon, and R. Wolski., 2002. The GRADS Project: Software Support for High-Level Grid Application Development. International Journal of High Performance Computing Applications, 15 327-344. Daly, C., R.P. Neilson, and D. L. Phillips, 1994. A Statistical-Topographic Model for Mapping Climatological Precipitation over Mountainous Terrain. J. Appl. Meteor., 33, 140-158