Instrument : C-Band ARM Precipitation Radar (CSAPR)

Instrument Categories
Cloud Properties

General Overview

The C-SAPR is a C-band dual-polarization Doppler weather radar manufactured by ARC, Inc. The C-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 C-SAPR also has the ability to transmit on a single polarization (either horizontal or vertical) and measure linear depolarization ratio (LDR). The C-SAPR transmitter is a 250 kW (peak power) magnetron. The receiver is based upon the NCAR Hi-Q digital receiver and runs NCAR’s TITAN software. In addition to the first three Doppler moments (reflectivity, radial velocity, and spectra width), the C-SAPR also provides differential reflectivity, correlation coefficient, and specific differential phase. The dual-polarization variables will allow the provision to provide estimates of rainfall rates and identification of precipitation types.

The C-SAPR represents a new measurement capability for ARM.

Suggested software for converting C-SAPR data to netCDF: Radx

Output Datastreams

  • csaprrhi : C-SAPR Range Height Indicator scan
  • csaprsec : C Scanning ARM Precipitation Radar (CSAPR), SEC ???
  • csaprsur : C-SAPR Surveillance scan
  • csaprvert : C Scanning ARM Precipitation Radar (CSAPR), vertical scan

Primary Measurements

The following measurements are those considered scientifically relevant.


Southern Great Plains
SGPI7 Browse DataNardin, OK (C-band radar site, Intermediate / Auxiliary)
Tropical Western Pacific
TWPI1 Browse DataLombrum Navy Base, Los Negros I., PNG retired
TWPI10 Browse DataLombrum Navy Base, Los Negros I., PNG retired
 retired = Originating instrument has been retired at this location


Nitin Bharadwaj
Pacific Northwest National Laboratory
(509) 372-4267

Dan Nelson
Pacific Northwest National Laboratory
(509) 375-6895

Iosif (Andrei) Lindenmaier
Pacific Northwest National Laboratory
(509) 375--6802

Scott Collis
Argonne National Laboratory
data analysis