GPM Ground Validation Environment Canada (EC) Wind Profiler GCPEx

Table of Contents

Introduction

The GPM Ground Validation Environment Canada (EC) Wind Profiler GCPEx data set provides post-processed consensus winds and daily quick look plots from the Vaisala Wind Profiler LAP 3000. The LAP 3000 is a pulsed Doppler radar that operates in clean air, reporting data from the atmosphere 3 kilometers or more above ground level. The Wind Profiler data was collected from January 15, 2012 to March 1, 2012 for the GPM Cold-season Precipitation Experiment (GCPEx) at the CARE site in Ontario, Canada. The Wind Profiler data is available as ASCII text files (.cns format). The browse images (daily plots) are available in the .gif format and depict wind information from both the profiler and the Global Environmental Multiscale (GEM) model.

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, a Wind Profiler was located at the CARE site in Ontario, Canada. The location of the CARE site is:

Lat: 44 degrees 13'59.45"N; Lon: 79 degrees 46'50.11"W

Data was collected from January 15, 2012 to 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.

The Vaisala Wind Profiler LAP 3000 (915 GHz) is a pulsed Doppler radar that operates in clean air and reports data from the atmosphere 3 kilometers or more above ground level. The name "profiler" comes from the radar's ability to show data for many heights of the atmosphere at the same time, thus giving a profile of the atmosphere. The profiler uses the Doppler beam swinging (DBS) method to provide continuous and real-time vertical profiles of horizontal wind speed and direction and also radial velocity up to three kilometers above ground level.

More information on the LAP3000 can be found in the Vaisala Lower Troposphere Wind Profiler LAP-3000 presentation and in the Vaisala Wind Profiler LAP-3000 brochure.

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

Norman Donaldson
Research Scientist, Cloud Physics and Severe Weather Research Section
Environment Canada
King City, Ontario

File Naming Convention

The GPM Ground Validation Environment Canada (EC) Wind Profiler GCPEx data and browse files are named with the following convention:

gcpex_windprofiler_YYYYJJJ-std_EC_CARE.cns
gcpex_windprofiler_YYYYJJJ-daily_EC_CARE.gif

where,

gcpex = GPM Cold-season Precipitation Experiment
windprofiler = Vaisala LAP 3000 Wind Profiler
YYYYJJJ = year and Julian day number of the data
std = standard format
daily = daily quick look plots
EC = Environment Canada
CARE = site location
.cns = type of ASCII format that originates from Vaisala's software
.gif = a type of graphics file

The GPM Ground Validation Environment Canada (EC) Wind Profiler GCPEx data set consists of ASCII text files in the .cns format. The .cns file format originates from Vaisala's software. These files contain the consensus winds for 30 minute intervals which is why the extension is named .cns (CoNsenSus).

The Wind Profiler data is presented in table format. For each 30 minute interval, there will be two consensus wind tables. Each table is preceded by a 9 line header. The following lines are important for most users:

Line 3 contains the location (latitude and longitude) of the instrument
Line 4 contains the start time of the consensus period (YYMMDDHHMMSS = year, month, day, hours, minutes, and seconds of the data)
Line 7 contains sampling parameters. Entries 5 and 6 list the pulse lengths of the profiler (708 or 2833 microseconds)
Line 9 contains beam directions

The table columns are labelled as follows:

HT = height (km)
SPD = wind speed (999999 if consensus is not achieved)
DIR = wind direction (meteorological degrees) (999999 if consensus is not achieved)
RAD = radial velocity for each beam (same order as in header). A positive value is towards the radar.
CNT= the count of samples used for consensus
SNR = signal to noise for each beam

The GPM Ground Validation Environment Canada (EC) Wind Profiler GCPEx browse files are .gif graphics files. These daily quick look plots depict wind information from the profiler (marked in black) and from the GEM model (marked in pink).

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

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/