Table of Contents - The Atmospheric Studies Group at TRC

Section 7: Prognostic Meteorological Interfaces
7.3 CALRUC Preprocessor
CALRUC operates on the output from the National Centers for Environmental Prediction (NCEP)
operational Rapid Update Cycle (RUC) model. Gridded model output is stored in GRIB format, and
consists of analysis and forecast fields for multiple parameters and levels. CALRUC extracts and
reformats a subset of these fields, and creates a 3D.DAT file for CALMET (see section 7.5).
RUC datasets are available at 20km and 40km resolution, covering the same domain. A map of the
domain is reproduced in Figure 7-7. The NOAA/Earth System Research Laboratory RUC development
group report that the key features of RUC include:
high-frequency (every hour) short-range weather model forecasts (out to 12+ hours)
high-frequency (every hour) 3-D objective analyses over the contiguous United States,
assimilating the following types of observations:
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commercial aircraft
wind profilers
rawinsondes and special dropwinsondes
surface reporting stations and buoys (including cloud, visibility, current weather)
GPS total precipitable water estimates
VAD (velocity-azimuth display) winds from NWS WSR-88D radars
RASS (Radio Acoustic Sounding System) - experimental
GOES total precipitable water estimates
SSM/I total precipitable water estimates
GOES high-density visible and IR cloud drift winds
hybrid isentropic-sigma vertical coordinate system.
The run frequency is hourly, with hourly analysis fields. Forecast fields are produced for the subsequent
3 hours. Additional forecasts for +6, +9, and +12 hours are made every 3 hours starting at 00 UTC.
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