WMOD00309

• Title: Applications of the Clark Model to Winter Storms Over the Wasatch Plateau
• Prepared For: Utah Department of Natural Resources Division of Water Resources
• Prepared By: James A. Heimbach, Jr.
• Date: 7/1/1993
• State: UT
• Weather Modification - Doc Type: Report

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

c. ~~~MnifGro~~Prod~~
A brief description of the graphics produced by the analysis portion of the model is given below to help
the reader's interpretation. Only the graphics of innermost domain (1 kIn resolution) are presented in this report.
For example, Fig. 6 is a surface plot of the modeled W-E (u) wind component In this figure, the 1 km intervals
are shown by the ticks on the margins. The numbers on the margins refer to distarIce (km) from the soothwest
corner of the outermost domain. The west and east flight tracks are drawn, as well as the positions of the High
Altitude Site (HAS) and the Department of Transportation (DOT) site (n+n). On surface plots only, the positions
of the eight valley sites and any release points being modeled are indicated by a n+" as well. The surface plots also
have a coarse topography entered which is the 1.6 km or 5.2 kft and 2.4 kIn or 7.9 kft contours. Several 1.6 kIn
contours are on the NW edges of the map (not labeled).
The analysis produced N-S, W-E and A-B vertical cross sections, the last enabling a cross section in any
direction. Only W-E cross sections are presented in this report. For example, Fig. 7 shows a vertical cross section
of vertical speed (w). The terrain is drawn below which there are no contours. This cross section was taken through
the 85 kIn N-S point of the model, and as with the x-y plot, horizontal distarIce tick marks indicate 1 kIn grid points.
The horizontal limits of Fig. 7 are not exactly those of Fig. 8 because of the interpolation scheme applied to the
latter. The tick marks on the ordinate represent the stretched vertical coordinate system. The surface ~z is 100 m,
stretching to 1 kIn maximum. This is somewhat misleading because the ordinate's ticks start at 0 MSL, whereas
in the model they start at terrain elevation.
Assigning an average elevation to an analyzed horizontal level is complicated by converting the terrain-
following coordinates to MSL. This is somewhat ambiguous in areas having large terrain relief as in central Utah.
Also, there remain uncertainties as to the programming techniques best for this task. For example, an x-y plot
labeled 2.53 km should be 2.85 km over the Wasatch Plateau, but over the Sanpete Valley this error is less. For
this reason, the headers put on the graphics by the analysis portion of the model through NCARGraphics have been
clipped and relevant information has been entered in the titles of applicable figures in this report.
Only a limited number of contours have been labeled by the current analysis portion of the model. In
general, the minimum contour is equal to the contour interval which is part of the clipped header. The contour
interval is also included in the figure title. The analyses of liquid water content (LW) (Figs. 26 and 44) have a
minimum contour of 0.01 gm kg-1 with the remainder of the contours being an integer times the contour interval.
d. Logistics of Running Model
All model runs for this report have been done on the NCAR CRA Y YMP located in Boulder, CO. The
model has run parameters input by making changes to the FORTRAN code stored on the CRA Y, then compiling
the program. The changes are made by submission of JCL (job control language) which is used by the CRA Y
system to make insertions, substitutions and deletions to the code in a temporary file. The JCL is submitted from
the Mesoscale and Microscale Meteorology Division of NCAR (hereafter MMM) operating under the VMS operating
system. The CRA Y automatically vectors mail messages describing the status of the job.

-3-