WMOD00425

• Title: Demonstration of Improved Operational Water Resources Management Through Use of Better Snow Water Equivalent Information
• Date: 9/1/2002
• Weather Modification - Doc Type: Report

Standard Fon" 298 (Rev. 2-89)
Prescribed by ANSI Std. 239- 18
298- 1 O~~

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REPORT DOCUMENTATION PAGE Form Approv.~d
OMB No. 0704-0188
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1. AGENCY USE ONLY (Leave B/ank) 12. REPORT DATE 13. REPORT TYPE AND DATES COVERED
Julv 2002 Suoo I em ental
4. TITLE AND SUBTInE 5. FUNDING NUMBERS
Demonstration of Improved Operational Water Resources Management Through
Use of Better Snow Water Equivalent Information
6. AUTHOR(S)
Steven M. Hunter and Edmond W. Holroyd, III
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS{ES) 8. PERFORMING ORGANlZAll0N
REPORT NUMBER
Bureau of Reclamation
Technical Service Center R-02-02
River Systems and Meteorology Group
Water Resources Division
Denver, Colorado
9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING
AGENCY REPORT NUMBER
Same
11. SUPPLEMENTARY NOTES
12.. DISTRIBUTION/AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE
13. ABSTRACT (Maximum 200 words)
This research is designed to aid Reclamation's water managers by providing them with decision assistance in the i
form of enhanced precipitation estimation over watersheds affecting the reservoir system. The overall gClal is more
efficient use of water. To achieve this goal, the following project objectives were defined: (1) to demonstrate a
significant improvement in the technology used to estimate snow water equivalent (SWE) distributions and (2) to
demonstrate benefits to Reclamation from improved streamflow forecasting resulting from better SWE information
and emerging new NOAA hydrologic prediction schemes.
Reclamation's Snow Accumulation Algorithm (SAA) was deployed in the north-central United States during cool
seasons from 1998-2001, providing near-real-time graphical distributions of snow water equivalent (SWE) and
snow depth (SD) estimates on the Internet. The SAA has undergone several major modifications in the last year
that extend its accuracy and applicability. The SAA now accommodates several more precipitation types, and
accordingly, the algorithm is now called the Precipitation Accumulation Algorithm (PAA). The SAA correction for
range degradation was replaced by a fixed adjustment for the vertical profile of reflectivity (VPR), and the new PAA
uses temperature and relative humidity from numerical (Eta) model soundings and temperature altitude tl1resholds
to classify precipitation type.
14. SUBJECT TERMS 15. NUMBER OIF PAGES
weather radar, NEXRAD, WSR-88D, Snow Accumulation Algorithm, Precipitation
Accumulation Algorithm, quantitative precipitation estimation, snow water equivalent, snow 16. PRICE CO[IE
depth, snowfall, virga, precipitation type
17. SECURITY CLASSIFICATION OF 18. SECURITY CLASSIFICATION OF 19. SECURITY CLASSIFICATION OF 20. UMITATIOIl OF
REPORT THIS PAGE ABSTRACT ABSTRACT
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NSN 7540-01 -280-5500