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10/25/2005 ND GIS Users Conference 2005
An Introduction to Basic Concepts of Weather RADAR
for Use Within a GIS
Scott Kroeber
RGIS – Great PlainsRegional Weather Information Center
University of North Dakota
Grand Forks, North Dakota
10/25/2005 ND GIS Users Conference 2005
The National Consortium for RuralGeospatial Innovations in America
(RGIS)
Consists of eight sites across the United States
Chesapeake, Pennsylvania State UniversityChesapeake, Wilkes University
Great Lakes, University of Wisconsin-MadisonGreat Plains, University of North Dakota
Mid-South, University of ArkansasPacific Northwest, Central Washington University
South Georgia, South Georgia Regional Development CenterTribal Technical Center, Southwestern Indian Polytechnic Institute
Web Sitehttp://www.ruralgis.org
RGIS Sites:
Heavy Rain Eventin Eastern ND
NDAWN Automated Station
ARBCON
Wedge Rain Gauge
Tipping bucketTru-Chek by Edwards Mfg, Co
SURFACE STATIONS
10/25/2005 ND GIS Users Conference 2005
Density of Precipitation Recording Stations in North Dakota
(NDAWN, NWS CO-OP)
“NEXRAD” = “WSR-88D”
(NEXRAD) – Next Generation Weather Radar
Is the same thing as…
(WSR-88D) - Weather Surveillance Radars”, which came about in 1988 and were Doppler-ized*
---------------------------
*Doppler effect is the ability of the radar to measure the change in frequency returned and equate that to a speed “towards” or “away” from the radar
Precipitation Estimation using the
Z-R Relationship
R = aZb
where
R = Rain Estimation
a = 300
Z = Radar Reflectivity
b = 1.5
The equation used forthe Z-R relationship can be changed to produce different outputs. Private
companies or researchers may use
a different Z-R relationship for
different geographical regions or climatic
zones
10/25/2005 ND GIS Users Conference 2005
WSR-88D (NEXRAD) Radar Locations
WSR-88D Coverage with124 Nautical Mile Range
Coverage showing maximum distance for a
radar’s “base reflectivity” to display precipitation
Height of Radar Beam
Height formula taken from Radar for Meteorologists by Ronald E. Rinehart
Altitude vs. Range
0
5
10
15
20
25
30
35
40
45
0 10 20 30 40 50 60 70 80 90 100 124
Range (NMi)
MS
L A
ltit
ud
e (
NM
i)
0.5
1.5
2.4
3.4
4.3
5.3
6.2
7.5
8.7
10.0
12.0
14.0
16.7
19.5
Requesting Radar Data From
NCDC
Using The Hierarchical DataStorage System (HDSS)
Level II & III Radar Data Viewing Software
•Skyview 95 and SkyVision – UNISYS (http://www.unisys.com/transportation/solutions/weather__information__services/index.htm)
•WSR-88D Efficient Data Format and Visualization Browser – K2 Tech. L.L.C. (http://www.k2tech.net)
•GRW88Level3 – GibsonRidgeSoftware (http://www.gibsonridgesoftware.com/grw88level3/)
•Interactive Radar Analysis System (IRAS) – Funded by Environmental Services Data and Information Management Program
•WSR-88D Algorithm Testing And Display System (WATADS) – National Severe Storms Laboratory NO LONGER SUPPORTED! (http://www.nssl.noaa.gov/teams/watads/public_html/)
Most Current Viewers Do Not Export a Data Set Which Is
Easily Viewed in a GIS
Radar Grids vs. Geographic Points
Program written to convert level II data to geographic points
Local Applications:Park River Basin
Location of Park River Basin within the Red River of the North Drainage Basin
Park River Basin
Grafton , ND
Park River Basis with Elevation Contours
Sub-basin delineated
Basin Polygon converted to 2km Grid
RADAR Precipitation Estimate June 8 – 11, 2002
2 km Resolution
Precipitation Estimate using (NDAWN)
overlaid onto the RADAR background
Reporting in Real-Time
NDAWN Stations
Precipitation Estimate using (COOP) overlaid
onto the RADAR background
Reporting on a Monthly Basis with some Stations
Polled Within 24 Hours
COOP Stations
Precipitation Estimate using (NDARB)
overlaid onto the RADAR background
Reporting on a
Monthly Basis
NDARB Stations
RADAR Estimated Precipitation NDAWN Interpolated
COOP InterpolatedNDARB Interpolated
Precipitation Volume Estimation Park River Basin, ND
Acre Feet (% difference from radar estimation)
95,838
108,281 (+13%)
135,040 (+ 41%)
181,814 (+ 90%)
-- Different patterns are a result of station location and “NOT” quality of data.
-- Differences in recorded amount verses radar estimates are caused by many factors such as…
Evaporation of Rain below cloud base
Wind speed and direction below cloud base
Radar algorithm used (Z-R Relationship)
Radar beam elevation above surface reporting station
Regional Applications:Central Washington
“Topographic Issues to Consider”
Area of the Naches basin located in Central Washington
Naches
WSR-88D Radar Locations
Spokane Cross-Section
Spokane Cross-Section
Pendleton Cross-Section
Pendleton Cross-Section
Portland Cross-Section
Portland Cross-Section
Seattle Cross-Section
Seattle Cross-Section
Spokane RadarPrecipitation Estimate
Pendleton Radar Precipitation Estimate
Portland RadarPrecipitation Estimate
Seattle RadarPrecipitation Estimate
Regional Applications Pennsylvania
Precipitation greater than 1”
May 1, 2003 (24 hour total)
Precipitation greater than 2”
May 1, 2003 (24 hour total)
Precipitation greater than 3”
May 1, 2003 (24 hour total)
Precipitation greater than 5”
May 1, 2003 (24 hour total)
LAT LON PRCP CU_FT ACRE_FT41.9536 -76.3862 4.51 16181746 37141.9536 -76.3683 4.31 15464152 35541.9356 -76.4761 2.1 7534738 17341.9356 -76.4401 2.53 9077565 20841.9356 -76.4222 1.85 6637745 15241.9356 -76.4042 1.39 4987279 11441.9356 -76.3862 3.72 13347250 30641.9356 -76.3683 4.48 16074107 36941.9356 -76.3503 4.47 16038227 368
……
BASIN TOTAL 10452511092 239986
Upper Susquehanna - Tunkhannock
Volume Estimates
Please Check the RGIS Web Site This Summer For Information on the Education Module’s
http://www.ruralgis.org/
USDA – Cooperative State, Research, Education, and Extension Service (CSREES)
University of North Dakota (Regional Weather Information Center)
Scott Kroeber
scottk@rwic.und.eduRGIS – Great Plains
Regional Weather Information Center
University of North Dakota
Grand Forks, North Dakota
Thank You!
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