NASA GHRC Collaboration between NASA MSFC and The University of Alabama in Huntsville
  • Access Data
    • Dataset List (HyDRO)
      • View a list of all GHRC dataset holdings using our custom search tool, HyDRO.
    • Search (HyDRO)
      • HyDRO is GHRC's custom dataset search and order tool.

        With HyDRO, you can search, discover, and filter GHRC's dataset holdings.

        HyDRO will also help you find information about browse imagery, access restrictions, and dataset guide documents.
    • NASA Earthdata Search
      • Earthdata is NASA's next generation metadata and service discovery tool, providing search and access capabilities for dataset holdings at all of the Distributed Active Archive Centers (DAACs) including the GHRC.
    • Latest Data (HyDRO)
      • View the latest additions to our data holdings using HyDRO.
  • Measurements
  • Field Campaigns
    • Hurricane Science
      • GHRC has worked with NASA's Hurricane Science Research Program (HSRP) since the 1990's. We are the archive and distribution center for data collected during HSRP field campaigns, as well as the recent Hurricane Science and Severe Storm Sentinel (HS3) Earth Venture mission. Field campaigns provide for intensive observation of specific phenomena using a variety of instruments on aircraft, satellites and surface networks.

        GHRC also hosts a database of Atlantic and Pacific tropical storm tracks derived from the storm data published by the National Hurricane Center (NHC).
    • HS3 (2012-14)
      • Hurricane and Severe Storm Sentinel (HS3) is an Earth Ventures – Suborbital 1 mission aimed at better understanding the physical processes that control hurricane intensity change, addressing questions related to the roles of environmental conditions and internal storm structures to storm intensification.

        A variety of in-situ, satellite observations, airborne data, meteorological analyses, and simulation data were collected with missions over the Atlantic in August and September of three observation years (2012, 2013, 2014). These data are available at GHRC beginning in 2015.
    • GRIP (2010)
      • The Genesis and Rapid Intensification Processes (GRIP) experiment was a NASA Earth science field experiment in 2010 that was conducted to better understand how tropical storms form and develop into major hurricanes.

        The GRIP deployment was 15 August – 30 September 2010 with bases in Ft. Lauderdale, FL for the DC-8, at Houston, TX for the WB-57, and at NASA Dryden Flight Research Facility, CA for the Global Hawk.
    • TC4 (2007)
      • The NASA TC4 (Tropical Composition, Cloud and Climate Coupling) mission investigated the structure and properties of the chemical, dynamic, and physical processes in atmosphere of the tropical Eastern Pacific.

        TC4 was based in San Jose, Costa Rica during July 2007.

        The Real Time Mission Monitor provided simultaneous aircraft status for three aircraft during the TC4 experiment. During TC4, the NASA ER-2, WB-57 and DC-8 aircraft flew missions at various times. The science flights were scheduled between 17 July and 8 August 2007.
    • NAMMA (2006)
      • The NASA African Monsoon Multidisciplinary Analyses (NAMMA) campaign was a field research investigation based in the Cape Verde Islands, 350 miles off the coast of Senegal in west Africa.

        Commenced in August 2006, NASA scientists employed surface observation networks and aircraft to characterize the evolution and structure of African Easterly Waves (AEWs) and Mesoscale Convective Systems over continental western Africa, and their associated impacts on regional water and energy budgets.
    • TCSP (2005)
      • The Tropical Cloud Systems and Processes (TCSP) mission was an Earth science field research investigation focused on the study of the dynamics and thermodynamics of precipitating cloud systems and tropical cyclones. TCSP was conducted during the period July 1-27, 2005 out of the Juan Santamaria Airfield in San Jose, Costa Rica.

        The TCSP field experiment flew 12 NASA ER-2 science flights, including missions to Hurricanes Dennis and Emily, Tropical Storm Gert and an eastern Pacific mesoscale complex that may possibly have further developed into Tropical Storm Eugene.
    • ACES (2002)
      • The Altus Cumulus Electrification Study (ACES) was aimed at better understanding the causes and effects of electrical storms.

        Based at the Naval Air Station Key West in Florida, researchers in August 2002 chased down thunderstorms using an uninhabited aerial vehicle, or "UAV", allowing them to achieve dual goals of gathering weather data safely and testing new aircraft technology. This marked the first time a UAV was used to conduct lightning research.
    • CAMEX-4 (2001)
      • The Convection And Moisture EXperiment (CAMEX) was a series of NASA-sponsored hurricane science field research investigations. The fourth field campaign in the CAMEX series (CAMEX-4) was held in 16 August - 24 September, 2001 and was based out of Jacksonville Naval Air Station, Florida.

        CAMEX-4 was focused on the study of tropical cyclone (hurricane) development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.
    • CAMEX-3 (1998)
      • The Convection And Moisture EXperiment (CAMEX) is a series of hurricane science field research investigations sponsored by NASA. The third field campaign in the CAMEX series (CAMEX-3) was based at Patrick Air Force Base, Florida from 6 August - 23 September, 1998.

        CAMEX-3 successfully studied Hurricanes Bonnie, Danielle, Earl and Georges, yielding data on hurricane structure, dynamics, and motion. CAMEX-3 collected data for research in tropical cyclone development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.
    • GPM Ground Validation
      • The NASA Global Precipitation Measurement Mission (GPM) Ground Validation (GV) program includes the following field campaigns:

        a) LPVEx, Gulf of Finland in autumn 2010, to study rainfall in high latitude environments

        b) MC3E, cental Oklahoma spring and early summer 2011, to develop a complete characterization of convective cloud systems, precipitation and the environment

        c) GCPEx, Ontario, Canada winter of 2011-2012, direct and remove sensing observations, and coordinated model simulations of precipitating snow.

        d) IFloodS, Iowa, spring and early summer 2013, to study the relative roles of rainfall quantities and other factors in flood genesis.

        e) IPHEx, N. Carolina Appalachians/Piedmont region May-June 2014, for hydrologic validation over varied topography.

        f) OLYMPEx, Washington's Olympic Peninsula scheduled November 2015-February 2016, for hydrologic validation in extreme coastal and topographic gradients
    • OLYMPEX (Upcoming)
      • The OLYMPEX field campaign is scheduled to take place between November, 2015, and February, 2016, on the Olympic Peninsula in the Pacific Northwest of the United States.

        This field campaign will provide ground-based validation support of the Global Precipitation Measurement (GPM) satellite program that is a joint effort between NASA and JAXA.

        As for all GPM-GV campaigns, the GHRC will provide a collaboration portal to help investigators exchange planning information and to support collection of real-time data as well as mission science, project and instrument status reports during the campaign.
    • IPHEx (2014)
      • The Integrated Precipitation and Hydrology Experiment (IPHEx) was conducted in North Carolina during the months of April-June, 2014.

        IPHEx sought to characterize warm season orographic precipitation regimes, and the relationship between precipitation regimes and hydrologic processes in regions of complex terrain.
    • IFLOODs (2013)
      • The Iowa Flood Studies (IFloodS) experiment was conducted in the central to northeastern part of Iowa in Midwestern United States during the months of April-June, 2013.

        IFloodS' primary goal was to discern the relative roles of rainfall quantities such as rate and accumulation as compared to other factors (e.g. transport of water in the drainage network) in flood genesis.
    • GCPEX (2011-2012)
      • 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. Collectively the GCPEx data set provides a high quality, physically-consistent and coherent data set suited to the development and testing of GPM snowfall retrieval algorithm physics.
    • MC3E (2011)
      • The Mid-latitude Continental Convective Clouds Experiment (MC3E) took place in central Oklahoma during the April–June 2011 period.

        The overarching goal was to provide the most complete characterization of convective cloud systems, precipitation, and the environment that has ever been obtained, providing constraints for model cumulus parameterizations and space-based rainfall retrieval algorithms over land that had never before been available.
    • LPVEx (2010)
      • The Light Precipitation Evaluation Experiment (LPVEx) took place in the Gulf of Finland in September and October, 2010 and collected microphysical properties, associated remote sensing observations, and coordinated model simulations of high latitude precipitation systems to drive the evaluation and development of precipitation algorithms for current and future satellite platforms.

        In doing so, LPVEx sought to address the general lack of dedicated ground-validation datasets from the ongoing development of new or improved algorithms for detecting and quantifying high latitude rainfall
  • Projects
    • HS3 Suborbital Mission
      • Hurricane and Severe Storm Sentinel (HS3) is an Earth Ventures – Suborbital 1 mission aimed at better understanding the physical processes that control hurricane intensity change, addressing questions related to the roles of environmental conditions and internal storm structures to storm intensification.
      • DISCOVER was funded by NASA’s MEaSUREs program to provide highly accurate, multi-decadal geophysical products derived from satellite microwave sensors.
    • LIS Mission
      • Lightning observations from the Lightning Imaging Sensors (LIS) aboard the NASA’s TRMM satellite and International Space Station, as well as airborne observations and ground validation data.
    • SANDS
      • The SANDS project addressed Gulf of Mexico Alliance priority issues by generating enhanced imagery from MODIS and Landsat data to identify suspended sediment resulting from tropical cyclones. These tropical cyclones have significantly altered normal coastal processes and characteristics in the Gulf region through sediment disturbance.
      • The Land, Atmosphere Near real-time Capability for EOS (LANCE) system provides access to near real-time data (less than 3 hours from observation) from AIRS, AMSR2, MLS, MODIS, and OMI instruments. LANCE AMSR2 products are generated by the AMSR Science Investigator-led Processing System at the GHRC.
  • Resources
    • Tools & Technologies
      • A collection of tools & technologies developed and/or used by GHRC.
    • Publications
      • View GHRC & ITSC publications on the ITSC website
    • Innovations Lab
      • The GHRC Innovations Lab is a showcase for emerging geoinformatics technologies resulting from NASA-sponsored research at the University of Alabama in Huntsville.
    • Educational Resources
      • A list of resources from NASA, MSFC, and other sources for teachers and students focused on global change, hydrology, and science education.
    • Referencing our data
      • GHRC dataset citation help and examples.
    • Documents
      • Documentation related to GHRC datasets, software, and other offerings.
    • Glossary
      • Terms and their definitions
    • Featured items
      • The latest tools from GHRC.
  • Multimedia
  • About
    • Welcome
      • Local resources, lodging information, and weather to help you plan your visit to GHRC.
    • GHRC Personnel
      • A list to help you keep in touch with our personnel
    • FAQ
      • Frequently Asked Questions about GHRC data and services, and their answers.
    • Data Citations and Acknowledgements
      • GHRC dataset citation help and examples
  • Cite Us
  • Contact Us


Guide Documents

Dataset PI Documents

Dataset Software

CAMEX-4 Mobile X-band Polarimetric Weather Radar

Table of Contents

Instrument description
Data Extraction
Data Format
Contact Information


The Convection And Moisture EXperiment (CAMEX) is a series of field research investigations sponsored by the Earth Science Enterprise of the National Aeronautics and Space Administration (NASA). The fourth field campaign in the CAMEX series (CAMEX-4) ran from 16 August to 25 September, 2001 and was based out of Jacksonville Naval Air Station, Florida. CAMEX-4 focused on the study of tropical cyclone (hurricane) development, tracking, intensification, and landfalling impacts using NASA-funded aircraft and surface remote sensing instrumentation.

Mobile X-band Polarimetric Weather Radar on Wheels (X-POW) is an X-band Doppler scanning radar operating at 9.3 GHz. with horizontal and vertical polarization. Used for detection and detailing surface rainfall rate and precipitation classification fields, 3D precipitation microphysical retrievals including water/frozen hydrometeor contents and drop size distribution profiles, X-POW was located in the Florida Keys during the CAMEX-4 field experiment.

Instrument Description

The table below shows the X-POW radar specifications:

Platform: Mobile flatbed truck
  Gasoline generator

Transmitter: Frequency 9.3 GHz (3.2 cm)
  Pulse width 1 s (150 m) Peak power 50 kW

Polarization diversity: Simultaneous transmission of horizontal and vertical polarization

Antenna: Gain 44.3 dB Beam width (3 dB) 0.95 degrees
  Azimuthal scan rate 30 degrees per sec
  Maximum sidelobe -20 dB

Recorded variables: Horizontal and vertical reflectivity, velocity, spectrum width, and differential phase shift

Data Extraction

This information is for running on UNIX/LINUX machines. Windows documentation is not provided.

Supplied with the documentation is a file named xpow.tar. This tar file contains a data extraction program, instructions and a sample dataset. The program should be used on data from other days to allow the user to manipulate it into a more useable form. Once this file is 'untarred', there will be created a directory named XPOW_READ. In this directory are the following directory and files:


The XPOW_README.TXT is shown below: This is the README.TXT file for XPOW Version 1.02 *************************************************************************

This file contains information on how to run the C program XPOW, that reads the XPOW data. *************************************************************************

This program has been tested on HP and SGI UNIX and LINUX platforms. You do not need any setup or installation to run it. The main programs are called XPOW_PPI.C (for reading sector scans), XPOW_PPI2.C (for reading full 360 deg PPI scans), and XPOW_RHI.C (for reading RHI scans). These are the programs you need to modify to adjust to the specifics of your application.Before run the program it is important to create five list files that contain the data you would like to read. The data we read are: Horizontal polarization reflectivity (listfile with extention .zh), vertical polarization reflectivity (extention .zv), differential phase shift (expention phd), spectral width (extention sw), and radial velocity (extention vel). Be aware the path of the data (it is hardcoded in the programs).Enjoy!


In the second paragraph above, the instructions require the user to create listfiles. These are already created for use with this example program, and is included with the documentation and software. When using 'real' instead of the data that comes with XPOW.TAR, you need to do that yourself. Here is code that will do that.



# script "xpowlist"
# This script reads the data directory and creates the "list" directories
# required by the freq program and puts them in the /Data directory
# This script must be run in the /Data directory

ls -1 ppi2*.ncp >> list_ppi2_ncp
ls -1 ppi2*.phdp >> list_ppi2_phdp
ls -1 ppi2*.sw >> list_ppi2_sw
ls -1 ppi2*.vdbz >> list_ppi2_vdbz
ls -1 ppi2*.vel >> list_ppi2_vel
ls -1 ppi2*.hdbz >> list_ppi2_hdbz

ls -1 ppi_*.ncp >> list_ppi_ncp
ls -1 ppi_*.phdp >> list_ppi_phdp
ls -1 ppi_*.sw >> list_ppi_sw
ls -1 ppi_*.vdbz >> list_ppi_vdbz
ls -1 ppi_*.vel >> list_ppi_vel
ls -1 ppi_*.hdbz >> list_ppi_hdbz

ls -1 rhi*.ncp >> list_rhi_ncp
ls -1 rhi*.phdp >> list_rhi_phdp
ls -1 rhi*.sw >> list_rhi_sw
ls -1 rhi*.vdbz >> list_rhi_vdbz
ls -1 rhi*.vel >> list_rhi_vel
ls -1 rhi*.hdbz >> list_rhi_hdbz


To prepare the data files for processing, run the above script, and then follow the instructions in paragraph one in the README.TXT file shown above.

If you are running the example file, you'll be able to compare your output to the output file supplied separately with this documentation. (That file is called example_output.dat). Create an output file ('make', then 'freq >output'). Here are the first ten lines of output from the example_output.datfile.

64 0.210000 0.710000
40.796875 40.500000 5.604156 0.500000 5.796875
41.000000 40.593750 5.000000 0.906250 2.703125
41.093750 40.796875 5.197906 0.703125 2.906250
40.406250 40.093750 3.895844 0.406250 5.406250
41.093750 40.593750 2.802094 0.796875 1.203125
40.593750 40.000000 2.802094 0.906250 1.500000
40.093750 39.593750 3.395844 0.703125 2.203125
41.203125 40.593750 7.395844 0.500000 2.406250
40.500000 40.406250 1.197906 0.500000 3.406250

These software and documentation files can be downloaded here:

Data Format

XPOW data are 'tarred' into daily data files of the form:


where c4xpow represents CAMEX4 and the xpow instrument, yyyy.ddd is the four digit year and day of year. When untarred, these data should be put into the /XPOW_READ/Data directory. Once there, run the xpowlist script shown above to create the listfiles. Note, these listfiles have to be in the /Data directory. At this point, run 'make' and 'freq > [output filename]' and the data is ready for use in radar presentation programs.

Note: It is assumed that the user is familiar with radar presentation programs, and as such, they are not provided here.

Contact Information

The data producer is:

Prof. E.N. Anagnostou
University of Connecticut

or, as an alternative:

Marios N. Anagnostou
University of Connecticut

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



RSS feed GHRC Facebook GHRC Twitter

NASA Official:
Manil Maskey

Website maintained by the

If you have trouble viewing or
navigating this page, please contact
GHRC User Services

NASA Web Privacy Policy and Important Notices

    The GHRC is a member of the ICSU World Data System