WMOD00563

• Title: Snow Accumulation Algorithm for the WSR-80D Radar: Final Report
• Date: 7/1/1998
• Weather Modification - Doc Type: Report

REPORT DOCUMENTATION PAGE I Form ApprOvl1d
OM8 No. 0704.0188
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1. AGENCY USE ONLY (b.... 81.nk, 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED
J''''' 1998 Final
4. mu AND SUalrrLE 5. FUNDING NUMBERS
Snow Accumulation AI......,.;lhm lor \he WSR-880 RADAR: Final Rennrt
6. AUTHOR(S)
Arlin B. SIJDPf and Edmond W. Holrovd, II!
7. PERFORMING ORGANIZATION NAME(S) AND ADDRESSeES) 8. PERFORMING ORGANlZAnON
REPORT NUMBER
Bureau of ReclamaliOn
Water Resources Research Labomtory A.98.05
Ted'mlcaJ Service Center
Denver, Colorado
9. SPONSORINGlMONrroR'NG AGENCY NAME(S) AND ADORESS(ES) 10, SPONSORINGlMONITORJNG
AGENCY REPORT NUMBER
S.me
11. SUPPLEMENTARY NOnS
Hard conv available at the technical Sel'Vlce Cenler, Denver, Colorado
12.. DISTRIBUnoH/AVAllABlllTY STATEMENT 12b. DlSTRIBUTlON CODE
Available from the NallOnal techmcal Information service. OperallOns Division,
5285 Po" Roval Rood. -S-~;eId, VirQinia 22162
13. ABSTRACT (M&nmum 2O(J words)
This !loal report mostly descnbes ttl8 final of three years 01 SM (Snow Accumulation Algorithm) development for NEXAAO
WSA-88D radars. An optimization technique applied to special snow/all observallons and Levell! reflectivtty rrn!8Surements
oelermined Z.-S (reflectivity.snowfall) r~hon&hips for radars in SfIveral climatic zones. These relationships were Similar for
most sites WI!h standard power law coeffICients near 150 and exponents near 2.0. Signiflcanl underestimation at longer ranqes
was evidenl at aR raaars, particularly WIth shallow stonns_ The SM now has a flInge correcliOn schernG and SUQgesbOllS are
gIVen lor determining appropriate coefficients lor 'I.
The SM was successfully field tested in real-time in Ohio, Minnesota, and New York. The SM produced reasonably accurate
estimates of storm-total snow water equivalent for all test areas, well correlated wrth surface observations. Customizad hybrid
scans W9fe requirlld in order 10 use the lowesf practical beam tilL The vertical profile of Z.changes the Z..S relationship WIth
higher elevation scamng.
The SM is operationally ready for use at those lew radars With suitable hardware. However, more powerful computers will be
needed belore SAA availability on all NEXRAD units.
Aecommendad SAA improvements include identificaoon 01 bright band contaminatIOn, handling far range virga, and adjusting for
longer range undefes1lmatton of snowfall.
14. SUBJECT TERMS 15. NUMBER OF PAGES
7'
'5. PRICE CODE
17. SECURITY ClASSIFICATION 18. SECUArTY ClASSIFICATION 19. SECURTTY CLASSIFICATION 20. LIMITATION OF
OF REPORT OF THIS PAGE OF ABSTRACT ABSTRACT
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