GPM Ground Validation Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR) GCPEx

Table of Contents

Introduction

The Conical Scanning Millimeter-wave Imaging Radiometer (CoSMIR), along with the Second Generation Airborne Precipitation Radar (APR-2), flew aboard NASA'S DC-8 during the Cold-season Precipitation Experiment (GCPEx). Both CoSMIR and APR-2 served as an airborne simulator for the GPM core satellite. The CoSMIR was modified with a new scan mode to acquire both conical and cross-track scan data simultaneously in a given flight, satisfying the requirements of the Precipitation Measurement Mission (PMM) algorithm development team.

The GPM Cold-season Precipitation Experiment (GCPEx) occurred in Ontario, Canada during the winter season of 2011-2012. GCPEx addressed shortcomings in the GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. These data sets were collected to aid in the achievement of the over arching goal of GCPEx which is to characterize the ability of multi-frequency active and passive microwave sensors to detect and estimate falling snow.

During GCPEx, CoSMIR was flown on NASA's DC-8 aircraft. The DC-8 made a total of 14 flights over the period of January 19- February 28, 2012. For GCPEx, CoSMIR was included in the campaign to provide aerial insights into snowfall processes and physics. Further details concerning CoSMIR's use during GCPEx can be found at ftp://ghrc.nsstc.nasa.gov/pub/doc/gpmgv/gcpex/gpmcosmirgcpex/gcpex_cosmir.pdf. Information on the Global Precipitation Measurement (GPM) mission is available at http://pmm.nasa.gov/GPM. Additional campaign collections containing CoSMIR data can be found at http://ghrc.nsstc.nasa.gov.

CoSMIR (Conical Scanning Millimeter-wave Imaging Radiometer) is an airborne total power radiometer that measures radiation at the following nine frequencies: 50.3, 52.8, 89 (dual-polarized), 165 (dual-polarized), 183.3+-1, 183.3+-3, 183.3+-7 GHz. Signals at each frequency are sampled in 10 msec intervals. All channels excluding the 89 and 165 GHz are horizontally polarized. Two close-coupled external calibration targets, one maintained at about 328 K and another at an ambient temperature of about 250 K provide calibration of the radiometric measurements. For the GCPEx campaign, CoSMIR was programmed to operate in hybrid mode with equal weight in conical and across-track scans. Further information on CoSMIR is available at http://atmospheres.gsfc.nasa.gov/meso/index.php?section=121.

Investigators

Gail Skofronick-Jackson
Deputy Project Scientist for GPM
NASA/Goddard Space Flight Center
Greenbelt, MD 20771

Bryan Monosmith
NASA/Goddard Space Flight Center
Greenbelt, MD 20771

James R. Wang
NASA/Goddard Space Flight Center/
SSAI (Science Systems and Applications, Inc.)
Lanham, Maryland 20706

File Naming Convention

The CoSMIR GCPEx data files consist of the following naming convention:

GCPEX_CoSMIR_[yyyymmdd]_[scan_mode].txt

where,

GCPEX = GPM Cold-season Precipitation Experiment
CoSMIR = Conical Scanning Millimeter-wave Imaging Radiometer
yyyymmdd = the year, month and day of the data
scan_mode = conical aft (CONAFT) or cross-track (CROSSTRCK) scanning modes
txt = ASCII text

The CoSMIR GCPEx data set consists of daily ASCII files (.txt) containing 10 second scans in both cross-track and conical scan modes. Each file includes a header to identify the columns of data. More information on the CoSMIR data files can be found at ftp://ghrc.nsstc.nasa.gov/pub/doc/gpmgv/gcpex/gpmcosmirgcpex/gcpex_cosmir.pdf.

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

J.R. Wang, P.E. Racette, J.E. Piepmeier, B. Monosmith, and W. Manning, "Airborne CoSMIR Observations Between 50 and 183 GHz over Snow-Covered Sierra Mountains," IEEE Trans. Geosci. Remote Sens., 45(1), 55-61, 2007.

J.R. Wang, P.E. Racette, and J.R. Piepmeier, "A Comparison of Near Concurrent Measurements from the SSMIS and CoSMIR for some Selected Channels over the Frequency Range of 50-183 GHz," IEEE Trans. Geosci. Remote Sens., 46(4), 923-933, 2008.

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: support-ghrc@earthdata.nasa.gov
Web: http://ghrc.nsstc.nasa.gov/