词条 | Joint Polarization Experiment |
释义 |
| name = Joint Polarization Experiment | image = NWS Office Slidell LA NEXRAD.JPG | caption = A WSR-88D, the subject of JPOLE | country = USA | manufacturer = | introdate = 1988 | number = 160[1] | type = Weather radar | frequency = 2900 MHz (S-band) | PRF = 300 - 1200 Hz | beamwidth = 0.95°[2] | range = 460km | altitude = | diameter = 8.51 m | azimuth = 0-360° | elevation = -1°— 20° | precision = | power = 750 kW | other names = }} The Joint Polarization Experiment (JPOLE) was a test for evaluating the performance of the WSR-88D in order to modify it to include dual polarization. This program was a joint project of the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the US Air Force Meteorological Agency (AFWA), which took place from 2000-2004. It has resulted in the upgrading of the entire meteorological radar network in the United States by adding dual polarization to better determine the type of hydrometeor, and quantities that have fallen.[3] HistoryDuring the years preceding JPOLE, NCAR was among the first centers in the field to utilize dual polarization for a weather radar, with staff Dusan S. Zrnic and Alexander V. Ryzhkov. In July 2000, the first planning meeting for JPOLE was held at the NSSL, and it was determined that the project would take place in two stages:
DescriptionJPOLE was introduced using a testbed NEXRAD weather radar mounted in Norman, Oklahoma, on the grounds of the National Severe Storms Laboratory (NSSL). The signal from its transmitter was split in two to obtain a conventional horizontal polarization and a vertical polarization.[4] The signals were sent to the antenna by two waveguides and could simultaneously transmit the two signals and furthermore receive the echoes returned by the precipitation in the emitted or orthogonal planes.[5] In general, most hydrometeors have a larger axis in the horizontal (for example, drops of rain become oblates when falling because of the resistance of the air). Because of this, the dipolar axis of the water molecules therefore tends to align in the horizontal and, as such, the radar beam will generally be horizontally polarized to take advantage of maximum return properties. If we send at the same time a pulse with vertical polarization and another with horizontal polarization, we can note a difference of several characteristics between these returns:[6] Differential Reflectivity ()
Correlation Coefficient ()
Differential Phase Shift ()
References1. ^{{cite web|url=https://catalog.data.gov/dataset/noaa-next-generation-radar-nexrad-products|title=NOAA NEXt-Generation RADar (NEXRAD) Products - Data.gov|website=catalog.data.gov}} 2. ^{{cite journal|url=https://www.nap.edu/read/10394/chapter/11|title=Weather Radar Technology Beyond NEXRAD|date=31 July 2002|publisher=|doi=10.17226/10394|isbn=978-0-309-08466-6}} 3. ^{{cite journal|title=The Joint Polarization Experiment: Polarimetric Radar in Forecasting and Warning Decision Making|first1=Kevin A.|last1=Scharfenberg|first2=Daniel J.|last2=Miller|first3=Terry J.|last3=Schuur|first4=Paul T.|last4=Schlatter|first5=Scott E.|last5=Giangrande|first6=Valery M.|last6=Melnikov|first7=Donald W.|last7=Burgess|first8=David L.|last8=Andra|first9=Michael P.|last9=Foster|first10=John M.|last10=Krause|date=1 October 2005|journal=Weather and Forecasting|volume=20|issue=5|pages=775–788|doi=10.1175/waf881.1|bibcode = 2005WtFor..20..775S}} 4. ^{{cite web|url=https://www.weather.gov/contact/weatherreadynation/news/130425_dualpol.html|title=Contact Us|first=US Department of Commerce, NOAA, National Weather|last=Service|website=www.weather.gov}} 5. ^{{cite journal|title=The Joint Polarization Experiment: Polarimetric Rainfall Measurements and Hydrometeor Classification|first1=Alexander V.|last1=Ryzhkov|first2=Terry J.|last2=Schuur|first3=Donald W.|last3=Burgess|first4=Pamela L.|last4=Heinselman|first5=Scott E.|last5=Giangrande|first6=Dusan S.|last6=Zrnic|date=1 June 2005|journal=Bulletin of the American Meteorological Society|volume=86|issue=6|pages=809–824|doi=10.1175/bams-86-6-809|bibcode = 2005BAMS...86..809R}} 6. ^http://cimms.ou.edu/~schuur/jpole/JPOLE_Overview_Report.pdf 7. ^{{cite web|url=http://www.cimms.ou.edu/~schuur/radar.html#Q8|title=Polarimetric Radar Page|website=www.cimms.ou.edu}} 6 : National Weather Service|Federal Aviation Administration|Projects established in 2000|Projects disestablished in 2004|Projects in North America|Weather radars |
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