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 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 10-hr:0.71 #31 Over-estimation |
| Bethune, SK | XBE | WWG | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 720-hr:2.23 #66 Under-estimation |
| Bismarck, ND | BIS | BIS | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 10-hr:1.03 #27 No Bias |
| Britt, ON | WBI | WTO | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 0-hr:1.00 #0 No Bias |
| Chicago, IL | LOT | LOT | 23 Sep 2008 06:00 | Z=300R1.4 | 3.44 | Summer Deep Convection Z/R | 168-hr:0.86 #1068 Over-estimation |
| Des Moines, IA | DMX | DMX | 23 Sep 2008 06:00 | Z=300R1.4 | 5.91 | Summer Deep Convection Z/R | 10-hr:0.59 #51 Over-estimation |
| Detroit, MI | DTX | DTX | 23 Sep 2008 06:00 | Z=200R1.6 | 4.53 | Marshall/Palmer Stratiform Z/R | 168-hr:1.24 #356 Under-estimation |
| Dryden, ON | XDR | WTO | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.16 #74 Under-estimation |
| Duluth, MN | DLH | DLH | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:1.60 #251 Under-estimation |
| Exeter, ON | WSO | WTO | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.61 #82 Under-estimation |
| Foxwarren, MB | XFW | WWG | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.48 #21 Under-estimation |
| Gaylord/NC Lwr MI | APX | APX | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:1.06 #177 Under-estimation |
| Grand Rapids, MI | GRR | GRR | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.92 #700 Over-estimation |
| Green Bay, WI | GRB | GRB | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:1.18 #308 Under-estimation |
| Indianapolis, IN | IND | IND | 23 Sep 2008 06:00 | Z=200R1.6 | 4.92 | Marshall/Palmer Stratiform Z/R | 168-hr:1.06 #302 Under-estimation |
| La Crosse, WI | ARX | ARX | 23 Sep 2008 06:00 | Z=300R1.4 | 3.00 | Summer Deep Convection Z/R | 168-hr:0.96 #420 No Bias |
| Lasseteer Lake, ON | XNI | WTO | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.35 #33 Under-estimation |
| Lincoln/Ctl Illinois | ILX | ILX | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.98 #1394 No Bias |
| Marquette, MI | MQT | MQT | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.61 #68 Under-estimation |
| Mayville/Grand Forks | MVX | FGF | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 3-hr:0.65 #20 Over-estimation |
| Milwaukee, WI | MKX | MKX | 23 Sep 2008 06:00 | Z=300R1.4 | 3.94 | Summer Deep Convection Z/R | 168-hr:1.09 #908 Under-estimation |
| Minneapolis, MN | MPX | MPX | 23 Sep 2008 06:00 | Z=300R1.4 | 2.78 | Summer Deep Convection Z/R | 168-hr:1.39 #271 Under-estimation |
| Minot AFB, ND | MBX | BIS | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 5-hr:0.63 #23 Over-estimation |
| Montreal River, ON | WGJ | WTO | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:15.43 #35 Under-estimation |
| North Webster/Nrn IN | IWX | IWX | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.08 #724 Under-estimation |
| Omaha/Valley, NE | OAX | OAX | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 10-hr:0.56 #43 Over-estimation |
| Owensville, IN | VWX | PAH | 16 Sep 2008 12:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:1.89 #450 Under-estimation |
| Paducah, KY | PAH | PAH | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.96 #383 No Bias |
| Pleasant Hill, MO | EAX | EAX | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.97 #451 No Bias |
| Quad Cities, IA/IL | DVN | DVN | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:0.70 #1563 Over-estimation |
| Sioux Falls, SD | FSD | FSD | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 10-hr:0.64 #33 Over-estimation |
| Springfield, MO | SGF | SGF | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:1.10 #264 Under-estimation |
| St. Louis, MO | LSX | LSX | 23 Sep 2008 06:00 | Z=300R1.4 | 4.09 | Summer Deep Convection Z/R | 168-hr:1.06 #1126 Under-estimation |
| Woodlands, MB | XWL | WWG | 23 Sep 2008 06:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 10-hr:0.90 #24 Over-estimation |