Atmospheric Radiation Measurement Climate Research Facility US Department of Energy

xsapr > X-Band Scanning ARM Precipitation RadarInstrument Type(s) > Baseline • Guest

The X-band Scanning ARM Precipitation Radar (X-SAPR) is an X-band dual-polarization Doppler weather radar. The X-SAPR operates in a simultaneous transmit and receive (STAR) mode, meaning that the transmit signal is split so that power is transmitted on both horizontal and vertical polarizations at the same time. The X-SAPR transmitter is a 200 kW (peak power) magnetron. The receiver is based upon the Vaisala RVP-900 and runs Vaisala’s IRIS software.

In addition to the first three Doppler moments (reflectivity, radial velocity, and spectra width), the X-SAPR also provides differential reflectivity, correlation coefficient, and specific differential phases. The dual-polarization variables enable estimates of rainfall rates and identification of precipitation types. At the Southern Great Plains site, three X-SAPRs surround the Central Facility, allowing the use of multi-Doppler velocity retrievals to estimate wind fields.


  • Fixed
  • AMF1
  • AMF2
  • AMF3

Active Locations

Facility Name Start Date
Central Facility, Barrow AK 2011-06-24


Collis SM, JJ Helmus, ZS Sherman, and RC Jackson. 2022. Corrected Moments in Antenna Coordinates (CMAC) X-SAPR Technical Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-283. 10.2172/1898601.

Skow A, M Poellot, D Delene, M Askelson, K North, and M Oue. 2022. "A Multi-Platform In Situ Kinematic and Microphysical Analysis of a Hybrid Parallel–Trailing Stratiform Mesoscale Convective System." Monthly Weather Review, 150(4), 10.1175/MWR-D-21-0009.1.

Wang J, R Wood, M Jensen, J Chiu, Y Liu, K Lamer, N Desai, S Giangrande, D Knopf, P Kollias, A Laskin, X Liu, C Lu, D Mechem, F Mei, M Starzec, J Tomlinson, Y Wang, S Yum, G Zheng, A Aiken, E Azevedo, Y Blanchard, S China, X Dong, F Gallo, S Gao, V Ghate, S Glienke, L Goldberger, J Hardin, C Kuang, E Luke, A Matthews, M Miller, R Moffet, M Pekour, B Schmid, A Sedlacek, R Shaw, J Shilling, A Sullivan, K Suski, D Veghte, R Weber, M Wyant, J Yeom, M Zawadowicz, and Z Zhang. 2022. "Aerosol and Cloud Experiments in the Eastern North Atlantic (ACE-ENA)." Bulletin of the American Meteorological Society, 103(2), 10.1175/BAMS-D-19-0220.1.


Kedzuf N, J Chiu, V Chandrasekar, S Biswas, S Joshil, Y Lu, P van Leeuwen, C Westbrook, Y Blanchard, and S O'Shea. 2021. "Retrieving microphysical properties of concurrent pristine ice and snow using polarimetric radar observations." Atmospheric Measurement Techniques, 14(10), 10.5194/amt-14-6885-2021.

Theisen A, A Lindenmaier, JH Mather, J Comstock, S Collis, and S Giangrande. 2021. ARM FY2022 Radar Plan. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-TR-273. 10.2172/1826575.

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