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.


 retired = Originating instrument has been retired at this location
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


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