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 XSACR uses range height indicator, or RHI, scans at numerous azimuths to obtain cloud volume data.

For the second ARM Mobile Facility (AMF2), the XSACR can be dismounted from the pedestal it shares with the KASACR and mounted on a separate pedestal. This allows the XSACR to operate more like a weather (precipitation) radar in deployments where such local coverage is lacking.

Measurements collected with the XSACR 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).

XSACR data from the 2018–2019 Cloud, Aerosol, and Complex Terrain Interactions (CACTI) field campaign in Argentina are now available as b1-level products. Building on the original CACTI operational data, the b1-level products feature improved data quality resulting from extensive analyses and corrections. The data are cross-calibrated to a common point, datastreams are corrected for operational issues that occurred during the campaign, and several data quality masks and basic derived products are incorporated. For more information, read the CACTI radar b1-level processing report.



  • Fixed
  • AMF1
  • AMF2
  • AMF3

Active Instrument Locations

Facility Name Instrument Start Date
MOSAIC (Drifting Obs - Study of Arctic Climate); AMF2 2019-03-04


Hunzinger A, J Hardin, N Bharadwaj, A Varble, and A Matthews. 2020. "An extended radar relative calibration adjustment (eRCA) technique for higher-frequency radars and range–height indicator (RHI) scans." Atmospheric Measurement Techniques, 13(6), 10.5194/amt-13-3147-2020.

Hardin JC, A Hunzinger, E Schuman, A Matthews, N Bharadwaj, K Johnson, and S Giangrande. 2020. CACTI Radar b1 Processing: Corrections, Calibrations, and Processing Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-244.

Matsui T, B Dolan, T Iguchi, S Rutledge, W Tao, and S Lang. 2020. "Polarimetric Radar Characteristics of Simulated and Observed Intense Convective Cores for a Midlatitude Continental and Tropical Maritime Environment." Journal of Hydrometeorology, 21(3), 10.1175/JHM-D-19-0185.1.
Research Highlight

Lubin D, D Zhang, I Silber, R Scott, P Kalogeras, A Battaglia, D Bromwich, M Cadeddu, E Eloranta, A Fridlind, A Frossard, K Hines, S Kneifel, W Leaitch, W Lin, J Nicolas, H Powers, P Quinn, P Rowe, L Russell, S Sharma, J Verlinde, and A Vogelmann. 2020. "AWARE: The Atmospheric Radiation Measurement (ARM) West Antarctic Radiation Experiment." Bulletin of the American Meteorological Society, 101(7), 10.1175/BAMS-D-18-0278.1.


Tyynelä J and A von Lerber. 2019. "Validation of Microphysical Snow Models Using in situ, Multifrequency, and Dual‐Polarization Radar Measurements in Finland." Journal of Geophysical Research: Atmospheres, 124(23), 10.1029/2019JD030721.

Kollias P, N Bharadwaj, E Clothiaux, K Lamer, M Oue, J Hardin, B Isom, I Lindenmaier, A Matthews, E Luke, S Giangrande, K Johnson, S Collis, J Comstock, and J Mather. 2019. "The ARM Radar Network: At the Leading-edge of Cloud and Precipitation Observations." Bulletin of the American Meteorological Society, 101(5), 10.1175/BAMS-D-18-0288.1.

Varble A, S Nesbitt, P Salio, E Avila, P Borque, P DeMott, G McFarquhar, S van den Heever, E Zipser, D Gochis, R Houze, M Jensen, P Kollias, S Kreidenweis, R Leung, K Rasmussen, D Romps, and C Williams. 2019. Cloud, Aerosol, and Complex Terrain Interactions (CACTI) Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-19-028.

Mason S, R Hogan, C Westbrook, S Kneifel, D Moisseev, and L von Terzi. 2019. "The importance of particle size distribution and internal structure for triple-frequency radar retrievals of the morphology of snow." Atmospheric Measurement Techniques, 12(9), 10.5194/amt-12-4993-2019.

Li H and D Moisseev. 2019. "Melting layer attenuation at Ka‐ and W‐bands as derived from multi‐frequency radar Doppler spectra observations." Journal of Geophysical Research: Atmospheres, , 10.1029/2019JD030316. ONLINE.
Research Highlight

Kalesse H, T Vogl, C Paduraru, and E Luke. 2019. "Development and validation of a supervised machine learning radar Doppler spectra peak-finding algorithm." Atmospheric Measurement Techniques, 12(8), 10.5194/amt-12-4591-2019.

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