Atmospheric Radiation Measurement Climate Research Facility US Department of Energy




15 July 2022 - 30 August 2022

Lead Scientist: Stephen Munchak

Observatory: amf, osc

NOTE: NPOL did not participate in this campaign.

This activity concerns the deployment of the NASA POLarization (NPOL) S-Band dual-polarization Doppler radar for the DOE Atmospheric Radiation Measurement Tracking Aerosol Convection Interactions ExpeRiment (TRACER). NPOL will be deployed by NASA’s Global Precipitation Measurement Ground Validation (GPM-GV) program in a coordinated scanning configuration with the ARM CSAPR-2 radar near Iowa Colony, Texas.

The scientific purpose of this deployment is to significantly enhance TRACER radar observations to (1) enable improved microphysical retrievals to better meet TRACER scientific objectives, and (2) provide resilience and redundancy to the TRACER radar deployment during the TRACER intensive operational period (IOP). For (1), NPOL would add an additional frequency and multiple Doppler capability at S-band, which would enable dual-frequency, dual-polarization retrievals for reduction of uncertainty in microphysical processes in deep convective cores related to thermodynamic, kinematic, and aerosol processes, which are major objectives of the TRACER scientific deployment.  S-band observations in convective precipitation will experience less attenuation and differential attenuation than C-band and thus will enhance scanning radar retrievals in heavy precipitation and mixed-phase regions (hail, graupel, melting band) where C-band attenuation, differential attenuation, and non-Rayleigh resonance effects can be significant. For (2), NPOL will provide a redundant measurement that can meet TRACER scientific objectives should there be any down time with CSAPR-2.  NPOL, at the direction of the TRACER science team, can be operated in an adaptive scanning mode closely matching CSAPR-2’s operations and can collect data with identical range and azimuth resolution if desired.

The radars will be arranged on the site to minimize beam blockage in the CSAPR-2 sector scans at low levels by the larger NPOL system within the TRACER observational domain.  NPOL will be deployed to be operational at minimum for the entire TRACER IOP (15 June−1 August), with possibility for extension on either end.


V. Chandrasekar
Toshihisa Matsui
Steve Nesbitt
David Wolff


  • Parent Campaign
  • Sibling Campaign


Sullivan JT, LW Twigg, TH Nguyen, and M Roots. 2022. TRACER NASA Goddard Space Flight Center TOLNet Field Campaign Report. Ed. by Robert Stafford, ARM user facility. DOE/SC-ARM-22-004. 10.2172/1894663.

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