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 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.78 #65 Over-estimation |
| Bethune, SK | XBE | WWG | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 720-hr:1.44 #31 Under-estimation |
| Bismarck, ND | BIS | BIS | 23 Nov 2009 03:00 | Z=200R1.6 | 7.87 | Marshall/Palmer Stratiform Z/R | 720-hr:1.21 #239 Under-estimation |
| Chicago, IL | LOT | LOT | 23 Nov 2009 10:00 | Z=200R1.6 | 3.44 | Marshall/Palmer Stratiform Z/R | 168-hr:0.91 #704 Over-estimation |
| Des Moines, IA | DMX | DMX | 23 Nov 2009 10:00 | Z=200R1.6 | 5.91 | Marshall/Palmer Stratiform Z/R | 2-hr:0.37 #32 Over-estimation |
| Detroit, MI | DTX | DTX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.53 | Marshall/Palmer Stratiform Z/R | 168-hr:0.91 #125 Over-estimation |
| Duluth, MN | DLH | DLH | 23 Nov 2009 10:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 0-hr:0.72 #21 Over-estimation |
| Exeter, ON | WSO | WTO | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.34 #30 Under-estimation |
| Foxwarren, MB | XFW | WWG | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 720-hr:1.57 #34 Under-estimation |
| Gaylord/NC Lwr MI | APX | APX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.05 #70 No Bias |
| Grand Rapids, MI | GRR | GRR | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.94 #295 Over-estimation |
| Green Bay, WI | GRB | GRB | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.92 #221 Over-estimation |
| Indianapolis, IN | IND | IND | 23 Nov 2009 10:00 | Z=200R1.6 | 4.92 | Marshall/Palmer Stratiform Z/R | 168-hr:1.06 #362 Under-estimation |
| La Crosse, WI | ARX | ARX | 23 Nov 2009 10:00 | Z=200R1.6 | 3.00 | Marshall/Palmer Stratiform Z/R | 2-hr:0.45 #28 Over-estimation |
| Lasseteer Lake, ON | XNI | WTO | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:2.38 #47 Under-estimation |
| Lincoln/Ctl Illinois | ILX | ILX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.01 #1544 No Bias |
| Marquette, MI | MQT | MQT | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.17 #75 Under-estimation |
| Mayville/Grand Forks | MVX | FGF | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.11 #85 Under-estimation |
| Milwaukee, WI | MKX | MKX | 23 Nov 2009 10:00 | Z=200R1.6 | 1.97 | Marshall/Palmer Stratiform Z/R | 168-hr:1.16 #405 Under-estimation |
| Minneapolis, MN | MPX | MPX | 23 Nov 2009 10:00 | Z=130R2 | 2.78 | Cool Season (East) Stratiform Z/R | 2-hr:0.57 #23 Over-estimation |
| Minot AFB, ND | MBX | BIS | 23 Nov 2009 10:00 | Z=200R1.6 | 7.87 | Marshall/Palmer Stratiform Z/R | 720-hr:0.90 #232 Over-estimation |
| Montreal River, ON | WGJ | WTO | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.90 #20 Under-estimation |
| North Webster/Nrn IN | IWX | IWX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.72 #426 Over-estimation |
| Omaha/Valley, NE | OAX | OAX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.59 #104 Under-estimation |
| Owensville, IN | VWX | PAH | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.31 #480 Under-estimation |
| Paducah, KY | PAH | PAH | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.12 #422 Under-estimation |
| Pleasant Hill, MO | EAX | EAX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.02 #405 No Bias |
| Quad Cities, IA/IL | DVN | DVN | 23 Nov 2009 10:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 2-hr:0.41 #26 Over-estimation |
| Sioux Falls, SD | FSD | FSD | 23 Nov 2009 10:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 168-hr:1.11 #87 Under-estimation |
| Springfield, MO | SGF | SGF | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.57 #221 Under-estimation |
| St. Louis, MO | LSX | LSX | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.96 #1584 No Bias |
| Woodlands, MB | XWL | WWG | 23 Nov 2009 10:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 720-hr:1.76 #184 Under-estimation |