My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
WMOD00309
CWCB
>
Weather Modification
>
DayForward
>
WMOD00309
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/28/2009 2:35:12 PM
Creation date
3/11/2008 11:22:28 AM
Metadata
Fields
Template:
Weather Modification
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
There are no annotations on this page.
Document management portal powered by Laserfiche WebLink 9 © 1998-2015
Laserfiche.
All rights reserved.
/
72
PDF
Print
Pages to print
Enter page numbers and/or page ranges separated by commas. For example, 1,3,5-12.
After downloading, print the document using a PDF reader (e.g. Adobe Reader).
Show annotations
View images
View plain text
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />t <br />I <br /> <br />degrees true prior to 1200, to 245 degrees at 1430, and thereafter was between 210-240 degrees. The wind speed <br />ranged from 10-15 m S-1 at the head of the north fork of Birch Creek Canyon, consistently from the west Winds <br />on the valley floor were between 205-240 degrees near 5 m S-1 until after 1500 when they began to decrease. Winds <br />in the lower portion of Fairview Canyon were consistently up-canyon with speeds of 14 m S-I. <br />Until 1540 the vertically-integrated SLW varied markedly, typical of embedded convection The peak hourly <br />average was 0.3 rom in the hour ending 0700. Between 0200 and 1600, the hourly LW averages were at least 0.12. <br />The SLW after 1600 was negligible as skies cleared with the end of the storm. <br />b. Simulated Flow Patterns for 2 March 1991 <br />Most of the discussion for flow of the 2 March case will center on the 2.5 hr point of the model integration. <br />This is near the center of the maXimum run made and is far enough into the modeling to insure the run had properly <br />stabilized. Figure 6 shows the surface W-E wind component (u) for this time. In general, there is a westerly <br />component, but some valley areas show the reverse. This variability is only for a very shallow surface layer. This <br />trend is also shown for the S-N component (v) of wind (not shown). From this directional shear, one would <br />anticipate some releases of tracer material to show a rapid lateral spread. <br />The vertical velocity above 5 km shows poor organization (see Fig. 6 for W-E vertical cross section). This <br />is due to the lack of a stable layer which is required for the formation of gravity waves. There is some terrain-forced <br />vertical motion in the lower 2 km which gives positive w upwind of the crests and negative w downwind of the <br />crests. Figure 8 shows the surface patterns of w. The band of negative w on the lee of the San Pitch Mountains <br />makes seeding from that crest a poor option for this date. The entire length of the Wasatch Plateau shows positive <br />w at and west of the western flight track, but negative w east of the track, except for the vicinity of the DOT site. <br />This suggests good targeting potential for seeding material released from the windward foothills and canyons. Some <br />of the valley seeding sites lie in an area of weak negative w for this simulation <br />c. Comparing Airborne Plwne Tracing to Model Simulations: Birch Creek Release of2 March 1991. <br />On 2 March SF6 was released from the mouth of the Birch Creek Canyon for two periods, 1000 to 1110 <br />and 1230 to 1410, at the rate of 3.42X1<f gm lIT1. The latitude, longitude and elevation of the release site was 39" <br />35.7' and 1963 m, respectively. The SF6 plume encounters of the morning and afternoon flights are depicted in Figs. <br />9 and 10. Both flights were terminated prematurely due to icing, which restricted flow through the intake manifold <br />for the AM flight and possibly the PM flight. There was only one plume encounter in the AM, probably because <br />of the late start of the SF6 arid early termination of the flight. The peak SF6 concentrations from each pass ranged <br />from 46 to 202 ppt. If a Skyfire-type generator was dispensing 30 gm hr-1 at this release point, then the <br />concentration of AgI inferred by Eq. 3 would be 1.7XlO-4 to 7.0XlO-4 pgm m-3. The largest concentration was from <br />the single morning SF6 penetration. Estimates of maximum effective IN concentrations can be inferred using the <br />Skyfire natural draft calibration described by Super and Heimbach (1983, p 1993). The temperatures recOlded at <br />the times of peak SF6 encounters in each plume ranged from -12.6 to -10.0 oC. The estimated concentrations of IN <br />rarIged from 15 to 153 IN L-1. These concentrations are suitable for cloud seeding operations. <br /> <br />-13- <br /> <br />
The URL can be used to link to this page
Your browser does not support the video tag.