Instrument : X-Band Scanning ARM Cloud Radar (XSACR)
Beneficiary of Recovery Act funding.
Instrument Categories
Cloud Properties
Note: All the Scanning ARM Cloud Radars have been technically accepted by ARM as meeting specification and each radar’s first data are available at this URL: http://www.archive.arm.gov/sacr/.
ARM's scanning cloud radars are fully coherent dual-frequency, dual-polarization Doppler radars mounted on a common scanning pedestal. Each pedestal includes a Ka-band radar (2kW peak power) and the deployment location determines whether the second radar is a W-band (1.7 kW peak power) or X-band (20 kW peak power). At ARM's tropical sites, X-band radars are paired with the Ka-band because they are better suited for the atmospheric attenuation in this region.
Beamwidth for the X-band is approximately 1 degree, and the Ka-band beamwidth is roughly 0.3 degrees. Due to the narrow antenna beamwidth, ARM’s scanning cloud radars utilize scanning strategies that are unlike typical weather radars. Rather than focusing on plan position indicator, or PPI, scans, the X-SACR will utilize range height indicator, or RHI, scans at numerous azimuths to obtain cloud volume data. For the second ARM Mobile Facility (AMF2), the X-SACR can be dismounted from the pedestal it shares with the Ka-SACR and mounted on a separate pedestal. This will allow the X-SACR to operate more like a weather (precipitation) radar in deployments where local weather radar coverage is lacking.
Measurements collected with the X-SACR are copolar and cross-polar radar reflectivity, Doppler velocity, spectra width and spectra when not scanning, differential Reflectivity (Zdr), correlation coefficient (rho-hv), and specific differential phase (phi-dp).
This represents a new capability for the ARM Facility.
Output Datastreams
- xsacrawrhi : X-Band Scanning ARM Cloud Radar (XSACR) Along-Wind RHI Scan
- xsacrblrhi : X-Band Scanning ARM Cloud Radar (XSACR) Boundary Layer RHI Scan
- xsacrcwrhi : X-Band Scanning ARM Cloud Radar (XSACR) Cross-Wind RHI Scan
- xsacrhsrhi : X-Band Scanning ARM Cloud Radar (XSACR) Hemispherical Sky RHI Scans (6 horizon-to-horizon scans at 30-degree azimuth intervals)
- xsacrppi : X-Band Scanning ARM Cloud Radar (XSACR) PPI Scan
- xsacrrhi : X-Band Scanning ARM Cloud Radar (XSACR) RHI Scans, which can vary in elevation range and azimuth
- xsacrspeccmaskcopol : X-Band Scanning ARM Cloud Radar, filtered spectral data, co-polarized mode
- xsacrspeccmaskxpol : X-Band Scanning ARM Cloud Radar, filtered spectral data, cross-polarized mode
- xsacrvpt : X-Band Scanning ARM Cloud Radar (XSACR) Vertically Pointing Scan
Primary Measurements
The following measurements are those considered scientifically relevant.
Locations
- Tropical Western Pacific (TWP)
- Central Facility, Darwin, Australia (C3)
- ARM Mobile Facility (GAN)
- Wharf site, Gan Island, Maldives (S1)
Contact(s)
Nitin Bharadwaj
(509) 372-4267
nitin@pnnl.gov
Kevin Widener
(509) 528-9565
kevin.widener@pnnl.gov
