GPM Ground Validation NEXRAD Level II IFloodS (KARX, KDMX, KDVN, KMPX)

Table of Contents

Introduction

The GPM Ground Validation Next Generation Weather Radar (NEXRAD) Level II IFloodS datasets were collected from four sites during March 29, 2013 to June 30, 2013 for the GPM Iowa Flood Studies (IFloodS) which occurred in eastern Iowa. There are currently 160 Weather Surveillance Radar-1988 Doppler (WSR-88D) or NEXRAD 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. Level-II datasets include three meteorological base data quantities: reflectivity, mean radial velocity, and spectrum width. The GPM Ground Validation NEXRAD IFloodS data files are in a custom binary format; the visualization and decoding of the data requires specialized software.

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

GPM Ground Validation NEXRAD Level II KARX IFloodS [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: http://dx.doi.org/10.5067/IFLOODS/NEXRAD/DATA201.

GPM Ground Validation NEXRAD Level II KDMX IFloodS [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: http://dx.doi.org/10.5067/IFLOODS/NEXRAD/DATA202.

GPM Ground Validation NEXRAD Level II KDVN IFloodS [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: http://dx.doi.org/10.5067/IFLOODS/NEXRAD/DATA203.

GPM Ground Validation NEXRAD Level II KMPX IFloodS [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: http://dx.doi.org/10.5067/IFLOODS/NEXRAD/DATA204.

The Iowa Flood Studies (IFloodS) was a ground measurement campaign that took place in eastern Iowa from April to June 2013. The goals of the campaign were to collect detailed measurements of precipitation at the Earth's surface using ground instruments and advanced weather radars and, simultaneously, collect data from satellites passing overhead. The ground instruments characterized precipitation (the size and shape of raindrops, the physics of ice and liquid particles throughout the cloud and below as it falls, temperature, air moisture, and distribution of different size droplets) to improve rainfall estimates from the satellites, and in particular the algorithms that interpret raw data for the Global Precipitation Measurement (GPM) mission's Core Observatory satellite, which was launched in February of 2014.

Data from four NEXRAD locations are included in the dataset:

KARX - La Crosse, Wisconsin
LATITUDE: 43.823, LONGITUDE: -91.191
Bounding Box Coordinates:
N: 47.96, S: 39.686111, E: 85.466389, W: 96.915833

KDMX - Des Moines, Iowa
LATITUDE: 41.731, LONGITUDE: -93.723
Bounding Box Coordinates:
N: 45.867778, S: 37.594167, E: 88.187222, W: 99.258611

KDVN - Davenport, Iowa
LATITUDE: 41.612, LONGITUDE: -90.581
Bounding Box Coordinates:
N: 45.748889, S: 37.475, E: 85.055556, W: 96.106667

KMPX - Minneapolis, Minnesota
LATITUDE: 44.849, LONGITUDE: -93.566
Bounding Box Coordinates:
N: 48.985833, S: 40.712222, E: 87.740833, W: 99.391111

Further details on the IFloodS campaign are available at http://gpm.nsstc.nasa.gov/ifloods. Additional information about the Iowa Flood Center can be found at http://iowafloodcenter.org. Information on the Global Precipitation Measurement (GPM) mission is available at http://pmm.nasa.gov/GPM.

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 data is available on the NOAA website https://www.ncdc.noaa.gov/ and in the journal article A Review of NEXRAD Level II by Huber and Trapp (2009).

The GPM Ground Validation NEXRAD Level II IFloodS datasets are organized by radar name; each dataset contains data files and browse image files with the following naming convention:

Level2_RdNm_YYYYMMDD_HHMM.ar2v
Level2_RdNm_YYYYMMDD_HHMM_RdNm_ELEV_0#.png

where,

Level2 = indicates base data
RdNm = Radar Name (KARX, KDMX, KDVN, or KMPX)
YYYYMMDD = the year, month, and day of the data
HHMM = the hour and minute of the data (UTC)
ELEV_0# = elevation
.ar2v = custom binary file type
.png = image file type

The GPM Ground Validation NEXRAD Level II IFloodS datasets includes data and browse images. Data files include composite files which are available in ASCII and netCDF formats and individual files for each of the four radar instruments in ar2v, a custom binary format. Browse images are in PNG file format. NOAA has developed software, Weather and Climate Toolkit (WCT), to open and display weather and climate data in multiple file formats. The WCT program also allows files to be exported into common formats like KMZ and Shapefile. More information about this software is available on NOAA's website http://www.ncdc.noaa.gov/wct/index.php.

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.

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/