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

GPM Ground Validation Dual Polarized C-Band Doppler Radar King City GCPEx

Table of Contents

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

Introduction

The GPM Ground Validation Dual Polarized C-Band Doppler Radar King City GCPEx dataset includes special RHI and sector scans of several dual polarization parameters created by the C-Band radar during the GPM Cold-season Precipitation Experiment (GCPEx) in Ontario, Canada. Standard WKR IRIS volume and PPI scans, along with corresponding standard PPI imagery, are included. Additionally, specially configured CARE-centric composite images were also generated. Data was collected from January 15, 2012 through March 3, 2012.

Citation

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.

Hudak, D. 2013. GPM Ground Validation Dual Polarized C-Band Doppler Radar King City GCPEx [indicate subset used]. Dataset 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/GPMGV/GCPEX/MUTIPLE/DATA201

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.

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 Environment Canada C-band dual polarization Doppler radar is located in King City, Canada. The location of the King City radar is:

Lat: 43°57'50.15" N; Lon: 79°34'25.97"W

The radar has the following characteristics:

Characteristic Specification
Frequency 5.625 GHz
Antenna Diameter 6.1 m
Beamwidth 0.62°
Minimum Detectable Signal -40 dBZ at 1 km
Polarization H/V or H
Scan Speed 36° s-1
PRF 400 Hz
Pulse Width 1.64 μs
Elevation Angles 24

More information on the WKR radar task configurations can be found in the GCPEx Task Configuration document.

Investigators

David Hudak
Research Scientist, Cloud Physics and Severe Weather Research Section
Environment Canada
King City, Ontario

File Naming Convention

The GPM Ground Validation Dual Polarized C-Band Doppler Radar King City GCPEx data files are named with the following convention:

gcpex_wkr_YYYYMMDDHHMM_polppi_.iri
gcpex_wkr_YYYYMMDDHHMM_dopvol2_.iri
gcpex_wkr_YYYYMMDDHHMM_convol_.iri
gcpex_wkr_YYYYMMDD_HHMMSS_ rhi_care.iri
gcpex_wkr_YYYYMMDD_HHMMSS_ rhi_sat.iri
gcpex_wkr_YYYYMMDD_HHMMSS_ sector.iri

where,

gcpex = GPM Cold-season Precipitation Experiment
wkr = King City radar
YYYYMMDDHHMM = the year, month, day, hour, and minute of the data
YYYYMMDD_HHMMSS = the year, month, day, hour, minute, and second of the data
polppi = high resolution plan position indicator scan
dopvol2 = long range Doppler volume scan
convol = 24-elevation non-Doppler conventional volume scan
rhi = range height indicator
care = the main GCPEx ground site at the Centre for Atmospheric Research Experiments (CARE)
sat = the four other GCPEx ground sites (Bob Morton, Steamshow, Huronia, Skydive)
sector = sector scans
iri = a binary file extension for Vaisala's Interactive Radar Information System (IRIS)

Data Format

The GPM Ground Validation Dual Polarized C-Band Doppler Radar King City GCPEx dataset consists of binary files in the .iri format. The .iri format is a file extension of Vaisala's Interactive Radar Information System (IRIS). More information on IRIS can be found at Vaisala's IRIS web page.

Browse files are also available in .gif format. The browse files also include specially configured CARE-centric composite images of both Z and ZDR products.

Product Descriptions

RHI Scans

The RHI scan files (gcpex_YYYYMMDD_HHMMSS_rhi_care.iri and gcpex_YYYYMMDD_HHMMSS_rhi_sat.iri) were created for each GCPEx ground site and include the following parameters: T, Z, ZDR, RHOV, PHIDP, KDP, SQI, WID, and VEL. The azimuth angle for each site is listed in the table below:

GCPEx Ground Site Azimuth Angle
CARE
331°
Bob Morton
311°
Steamshow
334°
Huronia
341°
Skydive
350°

Browse images for the Z, ZDR, RHOHV, and PHIDP parameters of the RHI scan files were also created.

Sector Scans

The sector scans (gcpex_wkr_YYYYMMDD_HHMMSS_sector.iri) include the following parameters: T, Z, ZDR, RHOV, PHIDP, KDP, SQI, WID, and VEL at azimuth angles ranging from 290 - 359°. The angle numbers and elevation angles are listed in the table below:

Angle Number Elevation Angle
11
0.2°
10
0.4°
9
0.6°
8
0.8°
7
1.1°
6
1.7°
5
2.6°
4
3.8°
3
5.3°
2
7.4°
1
10.1°
0
13.8°

Z products were created for the 12 elevations and ZDR, RHOHV, and PHIDP for the lowest angle only. At times on February 29, 2012, only the lowest 2 angles were scanned.

Browse images are available for Z, ZDR, RHOHV, and PHIDP for certain elevation angles.
*Note: The sector scan images do no have any lookup tables included. The color lookup tables are the same tables that are used in the RHI images.

CONVOL Volume Scans

The CONVOL volume scans (gcpex_wkr_YYYYMMDDHHMM_convol_.iri) include the following parameters: T, Z, ZDR, RHOV, PHIDP, KDP, SQI, WID, and VEL. The angle numbers and elevation angles are listed in the table below:

Angle Number Elevation Angle Angle Number Elevation Angle
0
0.0°
12
4.5°
1
0.2°
13
5.3°
2
0.°4
14
6.3°
3
0.6°
15
7.4°
4
0.8°
16
8.7°
5
1.1°
17
10.1°
6
1.4°
18
11.8°
7
1.7°
19
13.8°
8
2.°1
20
16°
9
2.6°
21
18.4°
10
3.1°
22
21.2°
11
3.8°
23
24.3°

Browse images are available for the CONVOL volume scans at the chosen elevation angle of 0.2°.

DOPVOL2 Long Range Doppler Scans

The DOPVOL2 long range Doppler scans (gcpex_wkr_YYYYMMDDHHMM_dopvol2_.iri) include the following variables: Z, T, VEL, and WID and were scanned at a PPI angle of 0.0°. Browse images are also available for these scans.

POLPPI High Resolution PPI Scans

The POLPPI high resolution PPI scans (gcpex_wkr_YYYYMMDDHHMM_polppi_.iri) include the following parameters: T, Z, ZDR, RHOV, PHIDP, KDP, SQI, WID, and VEL at a single PPI scan angle of 0.3°. Browse images are also available for these scans.

References

Boodoo, S., D. Hudak, N. Donaldson, and M. Leduc. 2010. "Application of Dual-Polarization Radar Melting-Layer Detection Algorithm." Journal Of Applied Meteorology & Climatology 49, no. 8: 1779-1793.

Hudak, D., P. Rodriguez, G. Lee, A. Ryzhkov, F. Fabry, and N. Donaldson. 2006. "Winter Precipitation Studies with a Dual Polarized C-band Radar."4th European Conference on Radar in Meteorology and Hydrology. Barcelona, Spain, 18-22 Sep, 2006.

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/