My WebLink
|
Help
|
About
|
Sign Out
Home
Browse
Search
WMOD00290
CWCB
>
Weather Modification
>
DayForward
>
WMOD00290
Metadata
Thumbnails
Annotations
Entry Properties
Last modified
7/28/2009 2:33:47 PM
Creation date
3/5/2008 10:45:43 AM
Metadata
Fields
Template:
Weather Modification
Title
1994 Field Operation Plan
Date
1/1/1994
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.
/
31
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 />publications based on observations in Utah and nearby States have shown that SLW is found during portions <br />of most winter storms. Estimates have been made of the seasonal SLW flux passing over the Tushar <br />Mountains and Wasatch Plateau of Utah, and over mountain barriers in neighboring States. These estimates <br />indicate that considerable SLW is transported over mountains without being converted to snowfall. <br />Beneficial streamflow enhancement should result is even a fraction of the excess SLW flux can be converted <br />to snow. <br /> <br />1.2 T &D Studies <br /> <br />Some work has been done on scientific objective b., the T &D of IN, especially during the past two field <br />seasons (1990 and 1991). Now that the availability of SLW has been well documented and related to the <br />meteorological conditions involved in its production and depletion, it is reasonable to devote more attention <br />to the crucial processes of the seeding agent T&D. <br /> <br />The delivery of appropriate concentrations of IN to supercooled cloud regions is probably the most difficult <br />problem currently facing winter orographic cloud seeding. Investigation of the T&D of ground-released <br />seeding material will receive emphasis in the 1994 field program. <br /> <br />A limited number of 1991 studies documented trapping of high concentrations of valley-released AgI in a <br />shallow layer along the valley floor. However, several case studies demonstrated vertical mixing of the AgI <br />to aircraft sampling levels about 600 m above the Plateau. The latter cases generally had embedded <br />convection present within the storm clouds. Few cases were obtained to examine the hypothesis that the <br />frontal passage during stable storms will "sweep out" high concentrations of previously trapped AgI, often <br />when abundant SL W is being produced. More observations of stable and neutral stability storm phases are <br />needed because few such phases passed the experimental area in 1991. <br /> <br />Even when valley-released AgI was transported to aircraft levels in 1991, the concentrations of effective IN <br />appeared to be limited. Estimates of effective AgI IN at typical SLW temperatures have often been less than <br />a few per liter. However, these estimates depend upon cloud simulation laboratory calibrations of AgI <br />generators. It is still uncertain how appropriate these calibrations are for winter orographic clouds. <br />Therefore, the estimates of effective AgI should be considered tentative until more observations of resulting <br />ice crystal concentrations are obtained. One of the goals of the 1994 field program is to obtain such <br />observations. <br /> <br />1.3 Detection of Seeding Effects <br /> <br />Relatively little research has been done concerning scientific objectives c. and d. because it was reasonable to <br />first document that objectives a. and b. were being satisfied. Observations of ice particle production by <br />seeding were accomplished by aircraft sampling of AgI plumes released from a high-altitude site during the <br />1991 field program. Tracer gas was co-released with the AgI to help identify the seeded cloud volumes. <br />Obvious increases in IPC (ice particle concentration) were observed in two of these cases which had <br />sufficiently cold temperatures. <br /> <br />"Direct detection" physical seeding experiments are planned for 1994, as discussed in the next section. These <br />experiments will attempt to monitor the key links in the chain of physical processes from release of seeding <br />agents to associated modifications in snowfall. The direct detection experiments will allow more serious <br />examination of scientific objectives c. and d. <br /> <br />2 <br />
The URL can be used to link to this page
Your browser does not support the video tag.