Global Hydrology Resource Center (GHRC) is one of NASA's Earth Science Data Centers and is a collaboration between MSFC and the University of Alabama in Huntsville.

GPM Ground Validation Dual Polarization Radiometer GCPEx

Table of Contents

Introduction
Citation
Campaign
Instrument Description
Investigators
File Naming Convention
Data Format
References
Contact Information

Introduction

The GPM Ground Validation Dual Polarization Radiometer GCPEx data set was collected using a dual polarized radiometer (DPR) at the Centre for Atmospheric Research Experiments in Ontario, Canada for the GPM Cold-season Precipitation Experiment (GCPEx) during the period from November 23, 2011 to March 1, 2012. The data set contains brightness temperature observations at 90 GHz (non polarized) and 150 GHz (HV-polarized) and is available in .nc netCDF format.

Citation

The following example shows how to cite the use of this data set in a publication. For more information, please see our Citing GHRC DAAC and Data page.

Löhnert, U. and M. Maahan. 2014. GPM Ground Validation Dual Polarization Radiometer GCPEx [indicate subset used]. Data set available online [http://ghrc.nsstc.nasa.gov/] from the NASA EOSDIS Global Hydrology Resource Center Distributed Active Archive Center, Huntsville, Alabama, U.S.A. doi: 10.5067/GPMGV/GCPEX/RADIOMETER/DATA102

Campaign

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, the Dual Polarization Radiometer was located at the CARE site in Ontario, Canada. The coordinates of the CARE site are: Lat: 44°13'59.45"N, Lon: 79°46'50.11"W.

Data was collected from November 23, 2011 through March 1, 2012. Further details on GCPEx are available at http://gpm.nsstc.nasa.gov/gcpex. Information on the Global Precipitation Measurement (GPM) mission is available at http://pmm.nasa.gov/GPM.

Instrument Description

The RPG-DP-90-150 Dual Polarization Radiometer (DPR), manufactured by Radiometer Physics GmbH, measures brightness temperatures at the frequencies of 90 and 150 GHz. The DPR is sensitive to particle orientation since it observes the brightness temperature difference between the vertical and horizontal polarization channels at 150 GHz, which is important for the retrieval of particle shape and orientation with polarization observations. Due to high-frequency window channels, the DPR also has a high sensitivity to the supercooled liquid water in clouds. Ancillary data is captured for the internal calibration of the instrument.

More detailed information on the RPG-DP-90-150 Dual Polarization Radiometer is available in the reference manual at
http://www.radiometer-physics.de/rpg/html/docs/RPG_MWR_POL_TN.pdf

Investigators

Ulrich Löhnert
Institute for Geophysics and Meteorology
University of Cologne
Pohligstr. 3, room 3.122
50969 Köln
Germany

Maximillian Maahan
Institute for Geophysics and Meteorology
University of Cologne
Albertus-Magnus-Platz
50923 Köln
Germany

File Naming Convention

The GPM Ground Validation Dual Polarization Radiometer GCPEx data set consists of .nc netCDF files. The files are named with the following convention:

gcpex_dpr_YYYYMMDD_L1b.nc

where,

gcpex = GPM Cold-season Precipitation Experiment
dpr = Dual Polarization Radiometer
YYYYMMDD = the year, month, and day of the data
L1b = NASA processing level "L1b"; information about NASA processing levels may be found at http://science.nasa.gov/earth-science/earth-science-data/data-processing-levels-for-eosdis-data-products/
nc = netCDF file

These files contain daily brightness temperature measurements at 90 GHz (not polarized) and 150 GHz (HV-polarized).

Data Format

The GPM Ground Validation Dual Polarization Radiometer GCPEx data set is in netCDF format.

References

Xie, X., U. Löhnert, S. Kneifel, and S. Crewell, 2012: Snow particle orientation observed by ground-based microwave radiometry. Journal of Geophysical Research: Atmospheres, 117, D02206, 12 pp., doi: 10.1029/2011JD016369.

Contact Information

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/