WMOD00283

• Sponsor Name: USBR, Technical Service Center, River Systems 7 Meteorology Group
• Project Name: Use of NEXRAD WSR-88D Radar Snow Accumulations Algorith in the GCIP LSA-NC
• Title: Use of NEXRAD WSR-88D Radar Snow Accumulations Algorith in the GCIP LSA-NC
• Prepared For: USBR Technical Service Center
• Prepared By: Arlin B. Super
• Date: 1/1/1998
• State: MN
• Weather Modification - Doc Type: Report

REPORT DOCUMENTATION PAGE Form Approved
OMS No. 0704-0188
Public reporting burden for this colleclion of infonnation is estimated to average 1 hour per response, including the tine for reviewing instru<:tions, _rching existing data sources. gathering and mainta~ing
the data needed, and completing and reviewing the collection of infonnation. Send comments regarding this burden es1imate or any other aspect of this collection of information. including suggestions
for reducing this burden, to Washington Headquarters Services. Directorate for Infonnation Operations and Reports. 1215 Jefferson Davis Highway, sune 1204, Arlington VA 22202-4302. and to the
Office of Manacement and Budael. Paaerworl< Reduction Renart 10704-01881. Washinalon DC 20503.
1. AGENCY USE ONLY (Leave Blank) 12. REPORT DATE 13. REPORT TYPE AND DATES COVERED
January 1998 Annual
4. TITLE AND SUBTITLE 5. F-UNDING NUMBERS
Use of the Reclamation WSR-88D Radar Snow
Accumulation Algorithm in the GCIP LSA - NC PR
6. AUTHOR(S)
Arlin B. SUDer
7, PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION
Bureau of Reclamation REPORT NUMBER
Technical Service Center R-98-01
Denver CO 80225
9. SPONSORINGlMONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORINGlMONITORING
Bureau of Reclamation AGENCY REPORT NUMBER
Denver Federal Center DffiR
PO Box 25007
Denver CO 80225-0007
11. SUPPLEMENTARY NOTES
Hard copy available at the Technical Service Center, Denver, Colorado
128. DISTRIBUTION/AVAILABilITY STATEMENT 12b. DISTRIBUTION CODE
Available from the National Technical Information Service,
Operations Division, 5285 Port Royal Road, Springfield, Virginia 22161
13. ABSTRACT (Maximum 200 words)
The Bureau of Reclamation accomplished two tasks related to estimating snowfall with NEXRAD radar measurements and
Reclamation's Snow Accumulation Algorithm (SAA). The fIrst task pursued development of a range correction scheme based on
the vertical profile of reflectivity.
The vertical profile of reflectivity was converted to the vertical profile of radar estimated snow water equivalent (VPS). Equations
fIt to storm. averaged VPS indicated the VPS is linear. Although slopes varied, the seasonal median VPS provided useful range
corrections. These results justify continued pursuit of a range correction scheme based on radar observed vertical profile of
reflectivity.
The second task involved the use of "degraded" Level ill reflectivity data instead of high resolution Level II data. Use of Level ill
reflectivities with the SAA would allow radar estimation of snow water equivalent (SWE) with Level ill data being archived for
the GCIP LSA-NC.
Parallel runs of the SAA, using Level II and Level ill reflectivities as input, were made for fIve Minnesota snow storms. Use of
archived Level ill data provided reasonable SWE estimates using Level II estimates as the standard.
.
14. SUBJECT TERMS- -radar! NEXRAD! WSR-88D! snow! snowfall! precipitation 15. NUMBER OF PAGES
24
16. PRICE CODE
17. SECURITY CLASSIFICATION 18. SECURITY CLASSIACATION 19. SECURITY CLASSIACATION 20. LIMITATION OF ABSTRACT
OF REPORT OF THIS PAGE OF ABSTRACT
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I NSN 7540-01-280-5500

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Standard Fonn 298 (Rev. 2-89)
Prncrlbed by ANSI SId. 239-18
298-102