Generic Guidance and Optimum Model Settings for the CALPUFF ...

2.3.1 No-Observations Approach
When run this way, CALMET uses gridded wind fields generated by a numerical prognostic
model such as MM5, WRF, RUC, RAMS, Eta and TAPM in the form of a three dimensional data
file, known as a 3D.DAT file. The procedure permits the prognostic model to be run with a
significantly larger horizontal grid spacing and different vertical grid resolution than that used in
the diagnostic model. This option allows certain features of the flow field such as the sea breeze
circulation with return flow aloft, which may not be captured in the surface observational data, to
be introduced into the diagnostic wind field results.
Existing 3D.DAT files are available (see below) or can be obtained by running one of the
prognostic models. Existing 3D.DAT files can be used directly in CALMET. If new prognostic
modeling is used, the CALMET-compatible 3D.DAT file is created by running independent
modules, CALMM5, CALWRF, CALRUC, CALRAMS, CALETA or CALTAPM on the
numerical model output in their individual model data format. The 3D.DAT file contains data of
horizontal and vertical velocity components, pressure, temperature, relative humidity, vapor,
cloud, rain, snow, ice and graupel mixing ratios. Depending on the base model used and also the
configuration switch settings within that model, the output may also contain solar and long wave
radiation, sea surface temperature, 2m air temperature, precipitation amount and other variables.
There are many important significant advantages in running the model in No-Observations mode
using gridded prognostic data. These are listed and described briefly below;
Spatial Variability in the Horizontal and Vertical. The three-dimensional wind field reflects local
terrain and mesoscale winds, temperature and stability variations and offer advantages in terms of
representing horizontal and vertical spatial variability over point (observation) measurements.
Simplicity of No-Obs Run. It is easy to load a 3D.DAT file into CALMET and execute. The
only other input file required is the geophysical (terrain and land use) file and the control file with
user switch settings. Three-dimensional MM5 (Fifth Generation NCAR/PENN State Mesoscale
Model) data are currently available for all of New South Wales for three years (2006-2008) at 12km
horizontal resolution for 40 vertical levels at the official CALPUFF web site (www.src.com)
or data can be generated with customized runs of any of the readily available prognostic models
(MM5, WRF, TAPM, RAMS). Using existing data is generally much easier than running the
prognostic models, which depending on the model may require significant effort.
Fast and Efficient – By using an already prepared 3D.DAT file, no additional effort is required to
prepare other observational data files or deal with missing data.
No Additional Data Required – A big advantage of No-Obs mode is that no additional data files
other than a geophysical data file is required. The 3D.DAT file contains three-dimensional
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