GRIP High Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP)

Table of Contents

Introduction

The High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) is a dual-frequency (Ka- and Ku-band) conical scan system, configured with a nadir viewing antenna on the Global Hawk aircraft. It provides calibrated reflectivity and unfolded Doppler velocity. These dual-frequency radar measurements have similar frequencies to the GPM. These data are from the Genesis and Rapid Intensification Processes (GRIP) experiment which took place in August and September 2010. HIWRAP flew on the Global Hawk aircraft over the Pacific Ocean.

The Genesis and Rapid Intensification Processes (GRIP) experiment was a NASA Earth science field experiment conducted August 5 to September 30, 2010. The major goal was to better understand how tropical storms form and develop into major hurricanes. NASA used the DC-8 aircraft, the WB-57 aircraft and the Global Hawk Unmanned Airborne System (UAS), configured with a suite of in situ and remote sensing instruments that were used to observe and characterize the lifecycle of hurricanes. This campaign also capitalized on a number of ground networks and space-based assets, in addition to the instruments deployed on aircraft from Ft. Lauderdale, Florida ( DC-8), Houston, Texas (WB-57), and NASA Dryden Flight Research Center, California (Global Hawk). More information about this Campaign can be found on the GRIP web site:https://ghrc.nsstc.nasa.gov/home/field-campaigns/grip

On Global Hawk, HIWRAP utilizes a dual-look angle antenna (30 & 40 degree incidence angle) with a dual-frequency (Ku- and Ka-band) feed at each angle. Each of the solid based transceivers (Ku and Ka-band) uses a single up-converter to generate an upper and a lower sideband signals, which are sent to the inner feed (30 degree) and the outer feed (40 degree), respectively. Therefore HIWRAP is able to transmit and receive four RF beams simultaneously. In addition, the use of a direct digital synthesizer (DDS) for transmit waveform generation and FPGA based digital receiver for data acquisition enable HIWRAP to transmit and receive a versatile waveform within each RF beam, including fully programmable FM chirps and conventional pulses. Each of the chirps or pulses has a slightly different center frequency so that they can be separated by the digital receiver. During GRIP, a waveform consists of a 20 microsecond linear FM chirp and a 2 microsecond conventional pulse was used for each RF beam. The 20 microsecond chirp pulse is the main return of interest. The conventional pulse is used to obtain returns near the radar in the "blind" zone of the chirp pulse. The reflectivity from the chirp channel has about 7 to 9 dB higher sensitivity than that of short pulses. Further details on the HIWRAP instrument are found in the document HIWRAP_data_grip_v0.docx.

Gerald Heymsfield
NASA/Goddard Space Flight Center
Mesoscale Atmospheric Process Branch
Greenbelt, MD 20771

Lin Tian
NASA/Goddard Space Flight Center
Mesoscale Atmospheric Process Branch
Greenbelt, MD 20771

Lihua Li
NASA/Goddard Space Flight Center
Mesoscale Atmospheric Process Branch
Greenbelt, MD 20771

James Carswell
Remote Sensing Solutions, Inc.
3179 Main Street
Unit #3
POB 1092
Barnstable, MA 02630

Data and browse files are of the form:

grip_hiwrap_KKWchirp_yyyymmdd_hhmmss-hhmmss.nc
grip_hiwrap_KKWchirp_yyyymmdd_hhmmss-hhmmss.gif

where

grip = Genesis and Rapid Intensification Processes
hiwrap = High Altitude Imaging Wind and Rain Airborne Profiler
KK = ka or ku-band
W = inner or outer beam
yyyymmdd = year, month and day
hhmmss = hour, minutes and seconds (15 seconds earlier than the data due to the GPS system)
nc = network Common Data Form
gif = Graphics Interchange Format

The GRIP High Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP) dataset consists of netCDF (.nc) files and images (.gif). Measurements included within the data files are chirp radar reflectivity and Doppler velocity profiles for given radar frequency and antenna pointing angle (inner or outer beam). Additional details on the file naming convention and data format are found in the document HIWRAP_data_grip_v0.docx.

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

References

G.M. Heymsfield, J. Carswell, High Altitude Imaging Wind and Rain Radar (HIWRAP). , NASA Science Technology Conference 2008 (NSTC2008).

Lihua Li; Heymsfield, G.; Carswell, J.; Schaubert, D.; McLinden, M.; Vega, M.; Perrine, M.; "Development of the NASA High-Altitude Imaging Wind and Rain Airborne Profiler," 2011 IEEE Aerospace Conference, pp. 1 - 8.

Lihua Li; Heymsfield, G.; Carswell, J.; Schaubert, D.; Creticos, J.; Vega, M.; "High-Altitude Imaging Wind and Rain Airborne Radar (HIWRAP)," IEEE International Geoscience and Remote Sensing Symposium, 2008. IGARSS 2008. Vol. 3, pp. III - 354 to III - 357.

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/