GPM Ground Validation CHILL Radar MC3E
GPM Ground Validation Pawnee Radar MC3E

Table of Contents

Introduction

The CHILL radar data for MC3E were collected while the NASA ER-2 aircraft conducted a series of four legs along the 090 and 120 degree CHILL azimuths on May 24, 2011. The data set contains dual linear polarization variables as well as Doppler velocity, radial velocity, and normalized coherent power. In an effort to expand the MC3E sampling to a wider geographical area, the NASA ER2 aircraft was directed to Northeastern Colorado while widespread rain was in progress on May 24 2011. The aircraft flew a series of pre-defined ground tracks that coincided with radials from the CSU-CHILL radar. This aided in keeping the aircraft in the plane of a series of RHI scans done by CSU-CHILL.

The Pawnee radar data were collected to support the CHILL radar and the NASA ER-2 instrumentation data. The Pawnee radar maintained volume coverage of the echo system while the radial flight legs were in progress. The Pawnee is a single polarization (V polarization) Doppler radar which was located at approximately azimuth 352 deg / range 48 km with respect to CHILL. The half-power antenna pattern main lobe beamwidth is ~1.8 degrees. During the ER2 flight, the Pawnee conducted a wide azimuth opening PPI sector volume scan oriented towards the east designed to provide general 3D coverage of the ER2 flight area.

When the ER2 reported starting a course reversal, the CHILL and Pawnee radars started volume scans in synchronization to support dual Doppler wind syntheses. CHILL and Pawnee radar data are available as separate datasets.

The Midlatitude Continental Convective Clouds Experiment (MC3E) took place in central Oklahoma during the April-June 2011 period. The experiment was a collaborative effort between the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility and the National Aeronautics and Space Administration's (NASA) Global Precipitation Measurement (GPM) mission Ground Validation (GV) program. The field campaign leveraged the unprecedented observing infrastructure currently available in the central United States, combined with an extensive sounding array, remote sensing and in situ aircraft observations, NASA GPM ground validation remote sensors, and new ARM instrumentation purchased with American Recovery and Reinvestment Act funding. The overarching goal was to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that had never before been available.

Further details on GPM MC3E are available at http://gpm.nsstc.nasa.gov/mc3e/. Information on MC3E ARM is available at http://campaign.arm.gov/mc3e/.

CSU-CHILL is a transportable dual-polarization radar system, with a 9 meter parabolic dual-offset reflector antenna. The radar features dual Klystron transmitters driving each polarization channel. Each transmitter develops approximately 1 MW of power. The transmitters are controlled by a flexible digital waveform generator, which can synthesize a wide variety of polarization states. The low-noise receivers are connected to a customized signal processing system, which can output various polarimetric moments. Moment data, as well as raw time series data can be archived for later study. The facility is connected to the CSU network through a high bandwidth microwave link, which provides up to 30 MBps data rate.¹

The CSU-Pawnee Doppler radar is a single-polarization radar system, with a Klystron transmitter. It is located 48 km NNW of the CSU-CHILL radar. The radar system is used in a dual-doppler configuration along with CSU-CHILL, and can perform synchronized scans. ²

1. CSU-CHILL National Radar Facility website. "Facilities Section 1 CSU-CHILL" May 10, 2013. http://www.chill.colostate.edu/w/Facilities#CSU-CHILL.

2. CSU-CHILL National Radar Facility website. "Facilities Section 2 CSU-Pawnee" May 10, 2013. http://www.chill.colostate.edu/w/Facilities#CSU-Pawnee.

Steven Rutledge, Science Director
CSU-CHILL National Radar Facility
Colorado State University
30750 Weld County Road 45
Greeley, Colorado 80631

Data are Universal format files of the form:

<Doppler radar>yyyymmdd_hhmmss.uf

where

Doppler radar = (CHL = CHILL, PAW = Pawnee)
yyyymmdd = year, month, day
hhmmss = hour, minutes, seconds
uf = Universal format

The GPM Ground Validation CHILL and Pawnee Radar datasets consist of Universal format files. The CHILL dataset contains dual linear polarization variables as well as Doppler velocity, radial velocity, and normalized coherent power. The document https://gpm.nsstc.nasa.gov/gpm_validation/mc3e/radar_UF_CHILL/doc/CHILL_readme.txt provides further details on the CSU-CHILL radar data file format. The Pawnee dataset contains reflectivity, radial velocity, spectral width, normalized coherent power and co-polar V polarization returned power. The document https://gpm.nsstc.nasa.gov/gpm_validation/mc3e/radar_UF_Pawnee/doc/Pawnee_readme.txt provides further details on the CSU-Pawnee radar data file format.

Our data sets are provided through the NASA Earth Science Data and Information System (ESDIS) Project and the Global Hydrology Resource Center (GHRC) Distributed Active Archive Center (DAAC). GHRC DAAC is one of NASA's Earth Observing System Data and Information System (EOSDIS) data centers that are part of the ESDIS project. ESDIS data are not copyrighted; however, in the event that you publish our data or results derived by using our data, we request that you include an acknowledgment within the text of the article and a citation on your reference list. Examples for general acknowledgments, data set citation in a reference listing, and crediting online web images and information can be found at: http://ghrc.nsstc.nasa.gov/uso/citation.html

References

A detailed list of publications is available on the CSU-CHILL website at http://www.chill.colostate.edu/w/Publications.

To order these data or for further information, please contact:

Global Hydrology Resource Center
User Services
320 Sparkman Drive
Huntsville, AL 35805
Phone: 256-961-7932
E-mail: ghrcdaac@itsc.uah.edu
Web: http://ghrc.nsstc.nasa.gov/