R adar Analysis
APPLICATION TO THE OHIO POWER SITING BOARD FOR A
CERTIFICATE OF ENVIRONMENTAL COMPATIBILITY AND PUBLIC NEED FOR THE GRANGE
SOLAR GRAZING CENTER
Case No. 24-0801-EL -BGN
Westslope Consulting, LLC
3940 West Tecumseh Road, Suite 200
Norman, Oklahoma 73072
(405) 310-6058
OCTOBER 3, 2024
INTRODUCTION
The study area for the Grange Solar Grazing Center Project consists of approximately 3,000 acres of land in Logan County, Ohio. 1 This report provides the results of a radar line-of-sight study conducted by Westslope Consulting, LLC (Westslope) for the study area using a maximum solar panel height of 15 feet above ground level (AGL).
This study includes the following:
• Research into radar sites near the study area.
• An Air Route Surveillance Radar (ARSR) and Airport Surveillance Radar (ASR) line-of-sight analysis.
• A Terminal Doppler Weather Radar (TDWR) line-of-sight analysis.
• A Weather Surveillance Radar-1988 Doppler (WSR-88D) line-of-sight analysis
RESEARCH
ARSR and ASR Sites
Primary Surveillance Radar
Westslope’s research identified the following seven ARSR and ASR sites near the study area:
• Columbus Airport Surveillance Radar-9 (ASR-9)
• Dayton ASR-9
• Fort Wayne ASR-9
• London Common Air Route Surveillance Radar (CARSR)
• Mansfield Airport Surveillance Radar-8 (ASR-8)
• Toledo ASR-9
• Wilmington ASR-9
The Department of Defense (DoD) uses these radar sites for air defense at the North American Aerospace Defense Command, and the Department of Homeland Security uses these radar sites for homeland security at the Air and Marine Operations Center. In addition, the Federal Aviation Administration (FAA) uses these radar sites for air traffic control at multiple facilities, including the Columbus Terminal Radar Approach Control (TRACON), the Fort Wayne TRACON, the Indianapolis Air Route Traffic Control Center, the Cleveland TRACON, and the Toledo TRACON
1 Grange_BuildableArea_083024.shp, Grange_SubSwitchArea_083024.shp, and Grange_Study_Area.shp
Co-Located Secondary Surveillance Radar
Westslope’s research identified the following secondary surveillance radar systems co-located with the ARSR and ASR systems:
• A Mode S is co-located with the Columbus ASR-9, the Dayton ASR-9, the Toledo ASR-9, and the Wilmington ASR-9.
• An Air Traffic Control Beacon Interrogator-5 is co-located with the Fort Wayne ASR-9 and the Mansfield ASR-8.
• An Air Traffic Control Beacon Interrogator-6 is co-located with the London CARSR.
TDWR Sites
Westslope’s research identified the following two TDWR sites near the study area:
• Columbus TDWR
• Dayton TDWR
The FAA uses these radar sites for air traffic control at the Columbus TRACON. In addition, the National Weather Service (NWS), part of the National Oceanic and Atmospheric Administration, uses these radar sites for weather operations at the Wilmington, Ohio Weather Forecast Office (WFO). These radar sites scan at the lowest elevation angles of 0.1 degrees and 0.3 degrees, respectively
WSR-88D Sites
Westslope’s research identified the Cincinnati WSR-88D Next Generation Radar (NEXRAD) site near the study area.
The NWS uses this radar site for weather operations at the Wilmington, Ohio WFO. In addition, the DoD may use this radar site for weather operations.
The NWS, and possibly the DoD, use data from the lowest elevation angle scanned by this radar site to monitor hazardous weather conditions. This radar site scans at the NWS’s standard lowest elevation angle of 0.5 degrees.
ANALYSIS
ARSR and ASR Line-of-Sight Analysis
Westslope conducted an ARSR and ASR line-of-sight analysis using the 4/3rd Effective Earth’s Radius Model and United States Geological Survey (USGS) 1/3rd arc-second 3-Dimensional Elevation Program (3DEP) bare-earth data. 2 The 4/3rd Effective Earth’s Radius Model accounts for the refraction of radio waves as these waves propagate through the lowest layer of the atmosphere under standard atmospheric conditions. Westslope’s analysis shows whether solar panels in the study area at a maximum height of 15 feet AGL will be within line-of-sight of and will interfere with ARSR or ASR sites.
Westslope conducted the line-of-sight analysis for the following seven ARSR and ASR sites:
• Columbus ASR-9
• Dayton ASR-9
• Fort Wayne ASR-9
• London CARSR
• Mansfield ASR-8
• Toledo ASR-9
• Wilmington ASR-9
The study area is beyond the instrumented range of the Fort Wayne ASR-9, the Mansfield ASR-8, the Toledo ASR-9, and the Wilmington ASR-9. As such, Westslope did not consider any additional analysis necessary for these radar sites.
The line-of-sight analysis results show that solar panels located in the study area will not be within lineof-sight of and will not interfere with the Columbus ASR-9, the Dayton ASR-9, or the London CARSR at a maximum height of 15 feet AGL. As a result, Westslope does not expect any effects to these radar sites at or below this panel height
2 The USGS 1/3rd arc-second 3DEP bare-earth data has a vertical accuracy of approximately 2.7 feet root mean square error. [1]
TDWR Line-of-Sight Analysis
Westslope conducted a TDWR line-of-sight analysis using the 4/3rd Effective Earth’s Radius Model and USGS 1/3rd arc-second 3DEP bare-earth data. Westslope’s analysis shows whether solar panels in the study area at a maximum height of 15 feet AGL will be within line-of-sight of a TDWR site at the lowest elevation angle scanned by the radar site.
Westslope conducted the TDWR line-of-sight analysis for the following two radar sites:
• Columbus TDWR
• Dayton TDWR
These radar sites scan at the lowest elevation angles of 0.1 degrees and 0.3 degrees, respectively
The study area is beyond the instrumented range of the Columbus TDWR. As such, Westslope did not consider any additional analysis necessary for this radar site.
Dayton TDWR
The line-of-sight analysis results show that, at a maximum height of 15 feet AGL, solar panels located in the study area will not be within line-of-sight of the Dayton TDWR at the lowest elevation angle scanned by this radar site. As a result, Westslope does not expect any impacts to Dayton TDWR operations at or below this panel height.
WSR-88D Line-of-Sight Analysis
Westslope conducted a WSR-88D line-of-sight analysis using a 1.21 effective earth’s radius model and USGS 1/3rd arc-second 3DEP bare-earth data. Westslope’s analysis shows whether solar panels in the study area at a maximum height of 15 feet AGL will be within line-of-sight of a WSR-88D site at the lowest elevation angle scanned by the radar site
Westslope conducted the WSR-88D line-of-sight analysis for the Cincinnati WSR-88D NEXRAD site. This radar site scans at the NWS’s standard lowest elevation angle of 0.5 degrees.
Cincinnati WSR-88D
The line-of-sight analysis results show that, at a maximum height of 15 feet AGL, solar panels located in the study area will not be within line-of-sight of the Cincinnati WSR-88D at the lowest elevation angle scanned by this radar site. As a result, Westslope does not expect any impacts to Cincinnati WSR-88D operations at or below this panel height.
CONCLUSIONS
ARSR and ASR Line-of-Sight Analysis
Westslope conducted an ARSR and ASR line-of-sight analysis for the following seven radar sites:
• Columbus ASR-9
• Dayton ASR-9
• Fort Wayne ASR-9
• London CARSR
• Mansfield ASR-8
• Toledo ASR-9
• Wilmington ASR-9
The study area is beyond the instrumented range of the Fort Wayne ASR-9, the Mansfield ASR-8, the Toledo ASR-9, and the Wilmington ASR-9. As such, Westslope did not consider any additional analysis necessary for these radar sites.
Westslope’s ARSR and ASR line-of-sight analyses for the Columbus ASR-9, the Dayton ASR-9, and the London CARSR show that solar panels located in the study area will not be within line-of-sight of and will not interfere with these radar sites at a maximum height of 15 feet AGL As a result, Westslope does not expect any effects to these radar sites at or below this panel height.
TDWR Line-of-Sight Analysis
Westslope conducted a TDWR line-of-sight analysis for the following two radar sites:
• Columbus TDWR
• Dayton TDWR
The study area is beyond the instrumented range of the Columbus TDWR. As such, Westslope did not consider any additional analysis necessary for this radar site.
Westslope’s TDWR line-of-sight analysis for the Dayton TDWR shows that, at a maximum height of 15 feet AGL, solar panels located in the study area will not be within line-of-sight of this radar site at the lowest elevation angle scanned by this radar site. As a result, Westslope does not expect any impacts to Dayton TDWR operations at or below this panel height
WSR-88D Line-of-Sight Analysis
Westslope’s WSR-88D line-of-sight analysis for the Cincinnati WSR-88D shows that, at a maximum height of 15 feet AGL, solar panels located in the study area will not be within line-of-sight of this radar site at the lowest elevation angle scanned by this radar site. As a result, Westslope does not expect any impacts to NWS WFO operations or to DoD weather operations at or below this panel height.
Contact Information
If you have any questions regarding this analysis, please contact Geoff Blackman at (405) 816 -2604 or via email at gnblackman@westslopeconsulting.com.
REFERENCES
[1] USGS, “What is the vertical accuracy of the 3D Elevation Program (3DEP) DEMs?,” 2022. (https://www.usgs.gov/faqs/what-vertical-accuracy-3d-elevation-program-3dep-dems). Last accessed October 3, 2024.