WSR-88D Z/R Relationship Table | |||||||
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This table shows WSR-88D Z/R relationships for sites used in the North Central River Forecast Center Multisensor Precipitation radar mosaic. A Z/R relationship is an empirical formula used to estimate rainfall rates from reflectivity signal strength. Parameters that can be varied at each radar site are shown in red. Max Precip Rate is an adjustable parameter which limits overestimation from hail contamination, ground clutter, etc. The Bias Correction Factor shows three elements: the duration (in hours) used to calculate the bias, the bias (in red), and the number of non-zero gage/radar pairs used to calculate the bias for that duration. Most stratiform rain has a reflectivity signal strength of 20-40dBZ with peaks to 45dBZ, but rarely anything higher (that isn't "brightbanding"). For more information, authorization, instructions, and recommendations regarding Z/R relationships, see the Radar Operations Center's page. | |||||||
| Radar Site | Radar Id | WFO Id | Time Reported (UTC) | Z/R Formula | Max Precip Rate(in/hr) | Z/R Type | Bias Correction Factor |
| Aberdeen, SD | ABR | ABR | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 2-hr:0.55 #20 Over-estimation |
| Bethune, SK | XBE | WWG | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 5-hr:4.00 #24 Under-estimation |
| Bismarck, ND | BIS | BIS | 23 May 2012 22:00 | Z=200R1.6 | 7.87 | Marshall/Palmer Stratiform Z/R | 168-hr:0.89 #90 Over-estimation |
| Chicago, IL | LOT | LOT | 23 May 2012 22:00 | Z=300R1.4 | 3.44 | Summer Deep Convection Z/R | 168-hr:0.59 #440 Over-estimation |
| Des Moines, IA | DMX | DMX | 23 May 2012 22:00 | Z=300R1.4 | 5.91 | Summer Deep Convection Z/R | 168-hr:0.52 #299 Over-estimation |
| Detroit, MI | DTX | DTX | 23 May 2012 22:00 | Z=200R1.6 | 4.53 | Marshall/Palmer Stratiform Z/R | 168-hr:0.61 #311 Over-estimation |
| Dryden, ON | XDR | WTO | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 10-hr:0.96 #30 No Bias |
| Duluth, MN | DLH | DLH | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 0-hr:1.08 #29 Under-estimation |
| Exeter, ON | WSO | WTO | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.42 #79 Under-estimation |
| Foxwarren, MB | XFW | WWG | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 1-hr:0.64 #24 Over-estimation |
| Gaylord/NC Lwr MI | APX | APX | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.68 #171 Over-estimation |
| Grand Rapids, MI | GRR | GRR | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.78 #408 Over-estimation |
| Green Bay, WI | GRB | GRB | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.78 #196 Over-estimation |
| Indianapolis, IN | IND | IND | 23 May 2012 22:00 | Z=200R1.6 | 4.92 | Marshall/Palmer Stratiform Z/R | 168-hr:0.65 #156 Over-estimation |
| La Crosse, WI | ARX | ARX | 23 May 2012 22:00 | Z=300R1.4 | 3.00 | Summer Deep Convection Z/R | 168-hr:0.84 #249 Over-estimation |
| Lasseteer Lake, ON | XNI | WTO | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.35 #117 Under-estimation |
| Lincoln/Ctl Illinois | ILX | ILX | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.54 #454 Over-estimation |
| Marquette, MI | MQT | MQT | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.64 #164 Over-estimation |
| Mayville/Grand Forks | MVX | FGF | 23 May 2012 22:00 | Z=200R1.6 | 4.92 | Marshall/Palmer Stratiform Z/R | 1-hr:1.03 #20 No Bias |
| Milwaukee, WI | MKX | MKX | 23 May 2012 22:00 | Z=300R1.4 | 1.97 | Summer Deep Convection Z/R | 168-hr:0.79 #340 Over-estimation |
| Minneapolis, MN | MPX | MPX | 23 May 2012 22:00 | Z=300R1.4 | 3.00 | Summer Deep Convection Z/R | 3-hr:1.33 #30 Under-estimation |
| Minot AFB, ND | MBX | BIS | 23 May 2012 22:00 | Z=200R1.6 | 7.87 | Marshall/Palmer Stratiform Z/R | 10-hr:0.77 #26 Over-estimation |
| Montreal River, ON | WGJ | WTO | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.56 #47 Over-estimation |
| North Webster/Nrn IN | IWX | IWX | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.57 #456 Over-estimation |
| Omaha/Valley, NE | OAX | OAX | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.57 #164 Over-estimation |
| Owensville, IN | VWX | PAH | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.53 #178 Over-estimation |
| Paducah, KY | PAH | PAH | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.52 #169 Over-estimation |
| Pleasant Hill, MO | EAX | EAX | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.72 #61 Over-estimation |
| Quad Cities, IA/IL | DVN | DVN | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.67 #307 Over-estimation |
| Sioux Falls, SD | FSD | FSD | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 5-hr:0.70 #30 Over-estimation |
| Springfield, MO | SGF | SGF | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.55 #45 Over-estimation |
| St. Louis, MO | LSX | LSX | 23 May 2012 22:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.50 #314 Over-estimation |
| Woodlands, MB | XWL | WWG | 23 May 2012 22:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 10-hr:1.23 #59 Under-estimation |