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 | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.77 #392 Over-estimation |
| Bethune, SK | XBE | WWG | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 720-hr:1.44 #54 Under-estimation |
| Bismarck, ND | BIS | BIS | 06 Nov 2009 21:00 | Z=200R1.6 | 7.87 | Marshall/Palmer Stratiform Z/R | 168-hr:1.36 #54 Under-estimation |
| Chicago, IL | LOT | LOT | 06 Nov 2009 21:00 | Z=200R1.6 | 3.44 | Marshall/Palmer Stratiform Z/R | 168-hr:1.12 #1090 Under-estimation |
| Des Moines, IA | DMX | DMX | 06 Nov 2009 21:00 | Z=250R1.2 | 5.91 | Rosenfeld Tropical Z/R | 168-hr:1.24 #1429 Under-estimation |
| Detroit, MI | DTX | DTX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.53 | Marshall/Palmer Stratiform Z/R | 168-hr:0.97 #279 No Bias |
| Dryden, ON | XDR | WTO | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:5.23 #67 Under-estimation |
| Duluth, MN | DLH | DLH | 06 Nov 2009 21:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 168-hr:0.98 #878 No Bias |
| Exeter, ON | WSO | WTO | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.32 #74 Under-estimation |
| Foxwarren, MB | XFW | WWG | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 720-hr:1.57 #59 Under-estimation |
| Gaylord/NC Lwr MI | APX | APX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.03 #295 No Bias |
| Grand Rapids, MI | GRR | GRR | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.00 #694 No Bias |
| Green Bay, WI | GRB | GRB | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.12 #576 Under-estimation |
| Indianapolis, IN | IND | IND | 06 Nov 2009 21:00 | Z=200R1.6 | 4.92 | Marshall/Palmer Stratiform Z/R | 168-hr:0.98 #417 No Bias |
| La Crosse, WI | ARX | ARX | 06 Nov 2009 21:00 | Z=200R1.6 | 3.00 | Marshall/Palmer Stratiform Z/R | 168-hr:0.94 #1044 Over-estimation |
| Lasseteer Lake, ON | XNI | WTO | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:2.98 #63 Under-estimation |
| Lincoln/Ctl Illinois | ILX | ILX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.09 #1725 Under-estimation |
| Marquette, MI | MQT | MQT | 06 Nov 2009 21:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 168-hr:1.02 #292 No Bias |
| Mayville/Grand Forks | MVX | FGF | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.26 #350 Under-estimation |
| Milwaukee, WI | MKX | MKX | 06 Nov 2009 21:00 | Z=200R1.6 | 1.97 | Marshall/Palmer Stratiform Z/R | 168-hr:1.29 #1042 Under-estimation |
| Minneapolis, MN | MPX | MPX | 06 Nov 2009 21:00 | Z=130R2 | 2.78 | Cool Season (East) Stratiform Z/R | 168-hr:0.95 #943 No Bias |
| Minot AFB, ND | MBX | BIS | 06 Nov 2009 21:00 | Z=200R1.6 | 7.87 | Marshall/Palmer Stratiform Z/R | 168-hr:0.98 #52 No Bias |
| Montreal River, ON | WGJ | WTO | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:2.13 #145 Under-estimation |
| North Webster/Nrn IN | IWX | IWX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.87 #708 Over-estimation |
| Omaha/Valley, NE | OAX | OAX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.70 #439 Under-estimation |
| Owensville, IN | VWX | PAH | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.11 #734 Under-estimation |
| Paducah, KY | PAH | PAH | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.99 #796 No Bias |
| Pleasant Hill, MO | EAX | EAX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.96 #349 No Bias |
| Quad Cities, IA/IL | DVN | DVN | 06 Nov 2009 21:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 168-hr:0.93 #1665 Over-estimation |
| Sioux Falls, SD | FSD | FSD | 06 Nov 2009 21:00 | Z=130R2 | 4.09 | Cool Season (East) Stratiform Z/R | 168-hr:1.19 #569 Under-estimation |
| Springfield, MO | SGF | SGF | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:1.54 #345 Under-estimation |
| St. Louis, MO | LSX | LSX | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:0.97 #1776 No Bias |
| Woodlands, MB | XWL | WWG | 06 Nov 2009 21:00 | Z=200R1.6 | 4.09 | Marshall/Palmer Stratiform Z/R | 168-hr:3.42 #51 Under-estimation |