WRF Hindcast
The WRF Hindcast Project generates the data used in the Grow Degree Calculator and the Soil Moisture Estimator projects. WRF stands for Weather, Research, and Forecasting and is a program made available by UCAR/NCAR and many other research participants.
WRF is normally used to forecast weather into the future, but for our purposes we use it to simulate weather in the past for better accuracy; in effect simulating a weather station every 3.3 kilometers.
Contents
Sectors
The area modeled by the WRF program is called a "domain", but since this implementation uses three domains (at 30km, 10km, and 3.3km resolution), the area of interest, the third domain, is called a "sector". Each sector is made up of 171x171 "pixels", with each pixel 3.3km x 3.3km in size. The pixel's data is accessible by client programs indicating latitude and longitude coordinates.
The image to the right shows sectors defined, and those currently active are shown in green.
Procedure
Input Files
GFS
Our implementation of the WRF program uses the Global Forecast System (GFS) as input forcing files. These are files generated by NOAA (NCEP) which are used to force data interpolations to defined values at certain times, projected into the future at six hour intervals. Once those projected times are reached, the forcing file is regenerated using real data instead of projected data and a new set of projected files are then generated, etc. This project uses the re-analyzed files at six-hour intervals for historical evaluation.
WRF Output
variables
