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 NEXRAD GCPEx (KAPX, KBOX, KBUF, KCBW, KCXX, KGYX, KTYX)

Table of Contents

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

Introduction

The GPM Ground Validation NEXRAD GCPEx datasets were collected from seven radar sites from January 2012 through March 2012 for the GPM Cold-season Precipitation Experiment (GCPEx) which took place in Ontario, Canada. Radar sites include: KAPX, KBOX, KBUF, KCBW, KCXX, KGYX, and KTYX. The Next Generation Weather Radar (NEXRAD) system comprises 160 Weather Surveillance Radar-1988 Doppler (WSR-88D) sites throughout the United States and select overseas locations. The resulting data includes the base data, called Level-II, and the derived products, called Level-III. This dataset includes Level-II data which contains three meteorological base data quantities: reflectivity, mean radial velocity, and spectrum width. The GPM Ground Validation NEXRAD GCPEx data files are available as level 2 binary files and level 3 compressed binary files.

Citation

The following examples show how to cite the use of these datasets in a publication. For more information, please see our Citing GHRC DAAC and Data page.

GPM Ground Validation NEXRAD KAPX GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD/KAPX/] from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA201

GPM Ground Validation NEXRAD KBOX GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD/KBOX/] from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA202

GPM Ground Validation NEXRAD KBUF GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD//KBUF/] from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA203

GPM Ground Validation NEXRAD KCBW GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD/KCBW/] from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA204

GPM Ground Validation NEXRAD KCXX GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD/KCXX/] from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA205

GPM Ground Validation NEXRAD KGYX GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD/KGYX/] from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA206

GPM Ground Validation NEXRAD KTYX GCPEx [indicate subset used]. Data set available online [ftp://gpm.nsstc.nasa.gov/gpm_validation/gcpex/NEXRAD/KTYX/} from the NASA EOSDIS Global Hydrology Resource Center DAAC Huntsville, Alabama, U.S.A. doi: http://dx.doi.org/10.5067/GCPEX/NEXRAD/DATA207

Campaign

The Global Precipitation Measurement (GPM) mission Ground Validation (GV) campaign used a variety of methods for validation of GPM satellite constellation measurements prior to launch of the GPM Core Satellite, which launched on February 27th, 2014. The validation effort included numerous GPM-specific and joint-agency/international external field campaigns, using state of the art cloud and precipitation observational infrastructure (polarimetric radars, profilers, rain gauges, disdrometers). Surface rainfall was measured by very dense rain gauge and disdrometer networks at various field campaign sites. These field campaigns accounted for the majority of the effort and resources expended by Global Precipitation Measurement (GPM) mission Ground Validation (GV). More information about the GPM mission is available here http://pmm.nasa.gov/GPM.

The GPM Cold-season Precipitation Experiment (GCPEx) occurred in Ontario, Canada during the winter season (Jan 15- Feb 26) of 2011-2012. GCPEx addressed shortcomings in GPM snowfall retrieval algorithm by collecting microphysical properties, associated remote sensing observations, and coordinated model simulations of precipitating snow. These data sets were collected toward achieving the overarching goal of GCPEx which is to characterize the ability of multi-frequency active and passive microwave sensors to detect and estimate falling snow. Additional information can be found at http://gpm.nsstc.nasa.gov/gcpex/.

Data from seven NEXRAD locations are included in the datasets:

KAPX - Gaylord, Michigan
LATITUDE: 44.907, LONGITUDE: -84.72
Bounding Box Coordinates:
N: 49.043889, S: 40.77, E: -78.889167, W: -90.550833

KBOX - Boston, Massachusetts
LATITUDE: 41.956, LONGITUDE: -71.137
Bounding Box Coordinates:
N: 46.092778, S: 37.819167, E: -65.581944, W: -76.692222

KBUF - Buffalo, New York
LATITUDE: 42.949, LONGITUDE: -78.737
Bounding Box Coordinates:
N: 47.085833, S: 38.812222, E: -73.093611, W: -84.380278

KCBW - Houlton, Maine
LATITUDE: 46.039, LONGITUDE: -67.806
Bounding Box Coordinates:
N: 50.175833, S: 41.902222, E: -61.8575, W: -73.754444

KCXX - Burlington, Vermont
LATITUDE: 44.511, LONGITUDE: -73.167
Bounding Box Coordinates:
N: 48.647778, S: 40.374167, E: -67.375556, W: -78.958333

KGYX - Portland, Maine
LATITUDE: 43.891, LONGITUDE: -70.256
Bounding Box Coordinates:
N: 48.027778, S: 39.754167, E: -64.524722, W: -75.987222

KTYX - Fort Drum, New York
LATITUDE: 43.756, LONGITUDE: -75.68
Bounding Box Coordinates:
N: 47.892778, S: 39.619167, E: -69.961667, W: -81.398333

Instrument Description

The Next Generation Radar (NEXRAD) is a pulsed Doppler weather radar used to detect and indirectly measure meteorological and hydrological phenomena. There are currently 160 radars positioned throughout the United States and in selected regions around the world. The radars are constantly scanning a few hundred kilometers around each site. The main purpose of NEXRAD is to provide real-time measurements of winds and precipitation, thus improving weather forecasting, specifically the prediction of severe weather events. The transmitter, receiver, and antenna are contained within the radar data acquisition (RDA) component of the system. The RDA derives three parameters, reflectivity, radial velocity, and Doppler spectrum width. Range resolution of the WSR-88D is 1 km for reflectivity and .25 km for velocity and spectrum width; azimuthal resolution is 1 degree for reflectivity, velocity and spectrum width.

More information about NEXRAD II is available on the NOAA website https://www.ncdc.noaa.gov/data-access/radar-data/nexrad and in a journal article at http://web.ics.purdue.edu/~huberm/huber+trapp.pdf.

File Naming Convention

Data files are named with the following convention:

gcpex_<site>_YYYYMMDDHHMMSS.bz2
gcpex_<site>_YYYYMMDDHHMMSS.raw

Browse files are named with the following convention:

YYYY-MM-DD_HH-MM-SS_<site>_ELEV_##.png
YYYY-MM-DD_HH-MM-SS_<site>_ttag.png

Where,

gcpex = GPM Cold-season Precipitation Experiment
<site> = NEXRAD radar site
YYYYMMDDHHMMSS = year, month, day, hour, minute, and seconds of data
YYYY-MM-DD_HH-MM-SS = year, month, day, hour, minute, and seconds of data
ELEV_## = elevation of data
ttag = time tag
.bz2 = binary file format (cmp)
.raw = binary file format (raw)

Data Format

The GPM Ground Validation NEXRAD GCPEx datasets include data files and browse image files. Data files are available as level 2 binary files and level 3 compressed binary files; browse images are in PNG file format.

References

Huber, M., and Trapp, J, 2009: A Review of NEXRAD Level II: Data, Distribution, and Applications. Journal of Terrestrial Observation, 1, 5 - 15.

NEXRAD. NOAA website. https://www.ncdc.noaa.gov/data-access/radar-data/nexrad.

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