xsacr: X-Band Scanning ARM Cloud Radar

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 (WSACR; 1.7 kW peak power) or X-band (XSACR; 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 use scanning strategies unlike typical weather radars. Rather than focusing on plan position indicator, or PPI, scans, the X-SACR uses 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 allows the X-SACR to operate more like a weather (precipitation) radar in deployments where such local 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).



  • Fixed
  • AMF1
  • AMF2
  • AMF3

Related Publications


Verlinde J, MJ Bartholomew, J Cherry, and M Ritsche. 2017. North Slope of Alaska Snow Intensive Operational Period Field Campaign Report. Ed. by Robert Stafford, ARM Climate Research Facility. DOE/SC-ARM-17-018.


Helmus JJ and SM Collis. 2016. "The Python ARM Radar Toolkit (Py-ART), a Library for Working with Weather Radar Data in the Python Programming Language." Journal of Open Research Software, 4(1), 10.5334/jors.119.


Oue M, MR Kumjian, Y Lu, Z Jiang, EE Clothiaux, J Verlinde, and K Aydin. 2015. "X-Band Polarimetric and Ka-Band Doppler Spectral Radar Observations of a Graupel-Producing Arctic Mixed-Phase Cloud." Journal of Applied Meteorology and Climatology, 54(6), 10.1175/jamc-d-14-0315.1.

Kneifel S, A von Lerber, J Tiira, D Moisseev, P Kollias, and J Leinonen. 2015. "Observed relations between snowfall microphysics and triple-frequency radar measurements." Journal of Geophysical Research: Atmospheres, 120(12), 10.1002/2015jd023156.

Jundt R. 2015. ARM Mobile Facility Fact Sheet. DOE/SC-ARM-15-022.


Yano J and TP Lane. 2014. "Convectively generated gravity waves simulated by NAM-SCA." Journal of Geophysical Research: Atmospheres, 119(15), 10.1002/2013jd021419.

Kollias P, N Bharadwaj, K Widener, I Jo, and K Johnson. 2014. "Scanning ARM Cloud Radars. Part I: Operational Sampling Strategies." Journal of Atmospheric and Oceanic Technology, 31(3), 10.1175/jtech-d-13-00044.1.

Kollias P, I Jo, P Borque, A Tatarevic, K Lamer, N Bharadwaj, K Widener, K Johnson, and EE Clothiaux. 2014. "Scanning ARM Cloud Radars. Part II: Data Quality Control and Processing." Journal of Atmospheric and Oceanic Technology, 31(3), 10.1175/jtech-d-13-00045.1.


Yoneyama K, C Zhang, and CN Long. 2013. "Tracking Pulses of the Madden–Julian Oscillation." Bulletin of the American Meteorological Society, 94(12), 10.1175/bams-d-12-00157.1.

Mather JH and JW Voyles. 2013. "The Arm Climate Research Facility: A Review of Structure and Capabilities." Bulletin of the American Meteorological Society, 94(3), 10.1175/bams-d-11-00218.1.

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