For help with NASA TOGA COARE data residing at the DAAC contact Pat Hrubiak at hrubiak@daac.gsfc.nasa.gov.
... BACKGROUND TOGA COARE was a multidisciplinary, international research effort that investigated the scientific phenomena associated with the interaction between the atmosphere and the ocean in the warm pool region of the western Pacific. The field experiment phase of the program took place from 1 November 1992 through 28 February 1993 and involved the deployment of oceanographic ships and buoys, several ship and land based Doppler radars, multiple low and high level aircraft equipped with Doppler radar and other airborne sensors, as well as a variety of surface based instruments for in situ observations.
The NASA component of TOGA COARE, while contributing directly to overall COARE objectives, emphasized scientific objectives associated with the Tropical Rainfall Measuring Mission (TRMM) and NASA's cloud and radiation program.
AIRCRAFT
The NASA ER-2 is a high altitude, single pilot aircraft based at Ames Research Center, Moffett Field, CA, and deployed globally in support of a variety of atmospheric research projects. It has a maximum altitude of 70,000 feet (21 km), a range of 3000 nautical miles, a maximum flight duration of 8 hours (nominal 6.5 hours) and a top speed of 410 knots true air speed. The aircraft accommodates about 2700 pounds (1200 kg) of payload. For the TOGA COARE campaign, the ER-2 payload consisted of a variety of radiometers, a lidar, a conductivity probe and a camera.
INSTRUMENT INFORMATION
The Advanced Microwave Precipitation Radiometer (AMPR) remotely senses passive microwave signatures of geophysical parameters from an airborne platform. The instrument is a low noise system which can provide multifrequency microwave imagery with high spatial and temporal resolution. AMPR data are collected at a combination of frequencies unique to current NASA aircraft instrumentation. These frequencies are well suited to the study of rain cloud systems, but are also useful to studies of various ocean and land surface processes.
The AMPR is a cross-track scanning total power microwave radiometer with four channels centered at 10.7, 19.35, 37.1 and 85.5 GHz. It has a dual lens antenna to accommodate two separate feedhorns. One horn that feeds the three higher frequency channels is a copy of the Special Sensor Microwave/Imager (SSM/I) spaceborne multifrequency feedhorn currently flying aboard the Defense Meteorological Satellite Program (DMSP) F8 and F10 satellites. The other AMPR feedhorn accommodates the 10.7 GHz frequency.
The following table lists several of the AMPR performance characteristics:
The AMPR radiometer is designed to fly in the Q-bay of a NASA ER-2, a compartment in the belly of the aircraft directly behind the pilot's cockpit. The dual antenna and scanning mirror extend below the aircraft body into a hatch opening. The instrument has a 90 degree total scan centered at nadir. The data footprints are contiguous at 85.5 GHz and coincident at all four channels leading to oversampling at the lower frequencies. Rotating polarization for all four channels is currently used during scanning. The polarization varies from vertical at 45 degrees to the left of nadir. At the nadir position, the polarizations are equally mixed. This scanning geometry allows dual-polarized information to be collected at the extreme scan angles with opposite aircraft passes over a given target.
DATA
The total volume of the AMPR dataset, including browse products, is 111 MB. There are 12 AMPR data files, each containing data from one mission flight of the NASA ER-2. These files total 85 MB in volume and have a typical file size of approximately 7.5 MB. The files are named
amprtb93.XXX_toga_v023.dat
where XXX is the Julian day on which the flight took off.
The following table relates AMPR data file names to ER-2 and DC-8 flight numbers and to the dates of the 13 mission flights of the NASA/TOGA COARE campaign. The objectives column is included for the convenience of the user; the mission objective was convection when it was forecast in the target area and radiation when it was not. Because of the length of the AMPR file names, only the unique portion of each file name (the Julian day) is listed in the table.
Jan 11-12 93-053 93-01-06 011 Radiation Jan 17-18 93-054 93-01-07 017 Convection Jan 18-19 93-055 93-01-08 019 Convection Jan 25-26 93-056 93-01-09 025 Radiation Jan 31-Feb 1 93-057 93-01-10 031 Radiation Feb 4 93-060 93-01-11 035 Convection Feb 6 93-01-12 Convection Feb 7 93-061 039 Feb 8-9 93-062 93-01-13 040 Convection Feb 10-11 93-063 93-01-14 041 Convection Feb 17-18 93-01-15 Convection Feb 20-21 93-065 93-01-16 051 Convection Feb 22-23 93-066 93-01-17 053 Convection Feb 23-24 93-067 93-01-18 054 Radiation
Data Format: The AMPR data is in a binary native format. The "fixed INS" AMPR dataset structure (version 1; v1) is detailed in document "amprdata.format.v1" which resides in directory ampr.
Software: Fortran 77 program ampr_read.f was provided by the data producer to read a binary AMPR data file.
Browse Products: The AMPR dataset includes two types of browse products: a) calibrated brightness temperatures in GIF format and b) flight tracks for the NASA-ER2 mission flights in GIF format. The browse files total approximately 26 MB in volume and may be displayed with any GIF viewer.
a) Calibrated Brightness Temperature Images: Browse images in GIF format were generated from data segments that were deemed noteworthy by the AMPR instrument team. A group was created for each mission flight of the ER-2 and they range in number from 22 to 27 per flight. The naming convention for these image files is:
amprbr93.XXX_toga_tb_brwsYY.gif
where XXX is the Julian day on which the flight took off and YY is the sequence number of the image within that flight group.
b) NASA ER-2 Mission Flight Track Images: Each image consists of an ER-2 mission flight track geo-located on a 2 degree x 2 degree grid.
The naming convention for these image files is:
amprft93.XXX_toga_track.gif
where XXX is the Julian day on which the flight took off.
Description:
Access the TOGA COARE ER-2 AMPR Data.
Geographic Coverage
(Click for Interactive Map)
Spatial coordinates
N: 10.0
S: -20.0
E: 180.0
W: 140.0
Data Set Citation
Dataset Originator/Creator:
TOGA COARE
Dataset Title:
Advanced Microwave Precipitation Radiometer (AMPR) Measurements Taken Onboard the NASA ER-2 During the TOGA COARE Intensive Observing Period
Aircraft Data Facility, 1993: ER-2 Flight Summary Report, NASA ER-2 Deployment, Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment. NASA Ames Research Center, Moffett Field, CA 94035.
Marzano, F.S., A. Mugnai, E.A. Smith, X. Xiang, J. Turk, and J. Vivekanandan, 1994: Active and passive remote sensing of precipitating storms ... during CaPE. Part II: Intercomparison of precipitation retrievals over land from AMPR radiometer and CP-2 radar. Meteorology and Atmospheric Physics, Special Issue on Physical Retrievals of Hydrological Variables from Space-Based Microwave Instruments, in press.
NASA TOGA COARE Project Office, 1993: Mission Summary Reports, TOGA COARE. NASA Langley Research Center, Mail Stop 483, Hampton, VA 23666.
NASA TOGA COARE Project Office, 1994: NASA/TOGA COARE Science Data Workshop II Proceedings, Albuquerque, New Mexico, March 15-17, 1994, NASA Langley Research Center, Mail Stop 483, Hampton, VA 23666, 4 pp.
Spencer, R.W., R.E. Hood, F.J. LaFontaine, E.A. Smith, R.Platt, J. Galliano, V.L. Griffin and E. Lobl, 1993: High resolution imaging of rain systems with the Advanced Microwave Precipitation Radiometer. J. Atmos. Oceanic Technol., 11, 849-857.
TOGA COARE International Project Office (TCIPO), 1992: TOGA COARE Operations Plan, Working Version September 1992. University Corporation for Atmospheric Research, Boulder, CO 80307, 138 pp.
TOGA COARE International Project Office (TCIPO), 1993: TOGA COARE Intensive Observing Period Operations Summary. University Corporation for Atmospheric Research, Boulder, CO 80307, 505 pp.
TOGA COARE International Project Office (TCIPO), 1994: Summary Report of the TOGA COARE International Data Workshop, Toulouse, France, 2 - 11 August 1994, University Corporation for Atmospheric Research, Boulder, CO 80307, 170 pp.
Turk, J., J. Vivekanandan, F.S. Marzano, R.E. Hood, R.W. Spencer, and F.J. LaFontaine, 1994: Active and passive microwave remote sensing of precipitating storms during CaPE. Part I: Advanced Microwave Precipitation Radiometer and polarimetric radar measurements and models. Meteorology and Atmospheric Physics, Special Issue on Physical Retrievals of Hydrological Variables from Space-Based Microwave Instruments, in press.
Vivekanandan, J., J. Turk, and V.N. Bringi, 1993: Comparisons of precipitation measurements by the Advanced Microwave Precipitation Radiometer and multiparameter radar. IEEE Trans. on Geosci. and Remote Sens., 31, No. 4, 800-870.
Webster, P.J., and R. Lukas, 1992: TOGA COARE: The Coupled Ocean- Atmosphere Response Experiment. Bull. Am. Meteorol. Soc. 73, 1377-1416.
World Climate Research Programme (WCRP), 1985: Scientific Plan for the TOGA Coupled Ocean-Atmosphere Response Experiment. WCRP Publications Series, No. 3 Addendum, World Meteorological Organization, Geneva, 96 pp.
