| NSF Org: |
AGS Division of Atmospheric and Geospace Sciences |
| Recipient: |
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| Initial Amendment Date: | June 28, 2017 |
| Latest Amendment Date: | May 3, 2019 |
| Award Number: | 1655693 |
| Award Instrument: | Continuing Grant |
| Program Manager: |
Nicholas Anderson
nanderso@nsf.gov (703)292-4715 AGS Division of Atmospheric and Geospace Sciences GEO Directorate for Geosciences |
| Start Date: | July 1, 2017 |
| End Date: | June 30, 2021 (Estimated) |
| Total Intended Award Amount: | $650,000.00 |
| Total Awarded Amount to Date: | $650,000.00 |
| Funds Obligated to Date: |
FY 2018 = $184,423.00 FY 2019 = $178,206.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
101 COMMONWEALTH AVE AMHERST MA US 01003-9252 (413)545-0698 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
MA US 01003-9284 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | Physical & Dynamic Meteorology |
| Primary Program Source: |
01001819DB NSF RESEARCH & RELATED ACTIVIT 01001920DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): | |
| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Phased-array radar is a mature technology that has recently been applied to remote sensing of clouds and precipitation. These radar systems have several advantages over current weather radars, however there are biases introduced when dealing with polarimetric variables that help to discriminate between precipitation types. This award will allow researchers to conduct experiments with the goal of providing a clearer picture of the capabilities and limitations of phased-array technology for weather polarimetry. The broader societal impacts of the award are related to improving technology that could eventually be used to study and forecast severe weather. Students would be directly involved in the project, giving them valuable training experience. The radar testbed will be made available to other researchers and it could potentially be used as a gap-filling radar for the local region.
Phased-array radar has a long history of use for point measurements, but making polarimetric measurements using phased-array is more complicated than for a traditional antenna design. The PI will perform engineering and observational experiments with the Raytheon Low Power Radar (LPR) to study the polarization performance, biases, and other measurement uncertainties particular to phased-array weather radar antennas, as well as to explore new capabilities including rapid scanning, polarization correction, and alternate polarization bases. The LPR would be co-located with a mechanically-scanned radar for comparison purposes.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
In this project we investigated how phased-array radars measure precipitation (rain) and how their measurements differ from conventional weather radars that use parabolic "dish" antennas. Phased-array radars scan their beams electronically without physically moving the antenna, whereas conventional radars rotate their antennas mechanically. There is interest in the use of phased-array technology in that it allows for more flexible and arbitrary scanning of weather (and other) targets. A side-effect of electronic scanning is that the amplitude and the polarization (orientation) of the radar beam varies with the scan angle. This variation results in measurements of precipitation that can differ from those that would be measured by a conventional radar, and it is important to understand these differences so they can be corrected.
For this project, we operated and compared measurements made by two co-located radars. One was a phased-array radar developed by Raytheon and on long-term loan to the University of Massachusetts (UMass). The other was a conventional radar built by our research group at UMass. The two radars were of very similar size, power, and frequency, so the main difference is their scanning method.
We deployed both radars on a tower on the UMass campus and operated them observing weather events of opportunity during the Summer-Fall of 2018 and 2019. A photo of the installation of the phased array and mechanical antenna is attached. We compared observations by the phased array radar to theoretical predictions of its response based upon prior published work. We found that variations due to electronic scanning could be corrected adequately over most of the scanning range of the phased array. Our results were published in referreed journals and conferences.
Last Modified: 07/30/2021
Modified by: Stephen J Frasier
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