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.
INSTRUMENT INFORMATION
The ESMR instrument, which was mounted on NASA's DC-8 aircraft for the TOGA COARE Field Experiment, is a 19.35 GHz scanning radiometer that measures brightness temperatures in degrees Kelvin. It was operational during 13 mission flights of the DC-8 between 11 January and 26 February 1993 under the direction of Dr. Thomas Wilheit of Texas A & M University.
The objective for the ESMR instrument in the TOGA COARE Campaign was to provide observations to develop better radiative transfer models for rainfall retrieval algorithms to be used in the development of the TRMM research paradigm.
The ESMR radiometer is nadir-mounted in the aircraft and scans in a plane perpendicular to the direction of flight with a swath of +/-50 degrees from nadir. Beam position (BP) 20 is at nadir during level flight; BP 1 is 50 degrees to the left, and BP 39 is 50 degrees to the right. The beam positions are distributed in equal divisions of the sine of the scan angle.
When the pitch and roll of the plane are negligible, a simple algorithm can be used to obtain the latitude and longitude at each BP.
If we define:
- BP is the beam position (integer, 1-39) - sinBP is the sine of the scan angle of the BP - lat and lon are the aircraft position - ofsBP is the offset angle of the BP - hdg is the aircraft heading - alt is the aircraft altitude - latBP and lonBP are the latitude and longitude of the beam position
One data product consisting of 13 binary files of calibrated brightness temperatures in degrees Kelvin was produced by the ESMR instrument during the TOGA COARE Campaign. Each file contains data from 1 flight. The ESMR data totals appproximately 12 MB in volume and has a typical file size of approximately .8 MB. The naming convention for ESMR files is .tbn.
The TbN data format is as follows
bytes Type variable
1-39 unsign 1 byte Brightness Temp for each BP (add 100.) 40 " Hour 41 " Minute 42 " Seconds (integer part) 43 " Hundredths of seconds 44-45 signed 2-byte Julian Day 46-47 " Latitude(integer part) 48-49 " 1/10000ths of latitude 50-51 " Longitude (integer part) 52-53 " 1/10000ths of longitude 54-55 " Altitude (tens of feet) 56-57 " Heading (tenths of degrees) 58-59 " Roll (tenths of degrees) 60-61 " Pitch (tenths of degrees) 62-64 - Empty
Note that the latitude and longitude fractions share the same sign; to obtain either variable, simply sum the integer and fractional parts without manipulating the signs. All of the integers are standard MS-DOS format.
ESMR Browse Images: A series of GIF images which are 256 color pictures of the data, made from screen shots of the data viewing program. The GIF images are labeled with the Julian Day, hour and minute that the data starts, in the form DDDHHMM.GIF.
The GIFs are 800x600, and can be viewed with any image viewing application, on any platform. If you do transfer the files to another platform, remember to transfer them in binary (8-bit) format.
There are GIF images for all of the high-priority convection legs and days specified by Drs. Ed Zipser, Barry Nolan, and others at the 3-6 August TOGA COARE Conference in San Diego.
SOFTWARE
1) DOS Software: Read software in Turbo Pascal (RDTBNAV) was submitted by the ESMR instrument team. The program reads a specified record from an ESMR binary data file and displays it to the pc screen. Program DISP_TB displays an ESMR image file to the pc screen.
Display software used by the PI in processing the data is also available. It runs in a DOS environment and requires a Super VGA videocard based on the Tseng chipset or a VESA standard compatible videocard with appropriate drivers.
2) UNIX Software: Program esmr_read.c was created by the GSFC DAAC to provide the functionality of the original Pascal read program to UNIX users. Porting the ESMR dataset from a PC to the DAAC's Silicon Graphics machines required a byte swap when loading 2-byte data values into integers, an implementation-dependent feature that may not be required on other systems. The program is self-documenting.
A validation file (ESMR.dat) displaying correct values from the first ten records in data file 011.tbn is offered to assist UNIX users in adapting program esmr_read.c to their environments. It resides with the UNIX software.
Dataset Title:
Electronically Scanned Microwave Radiometer (ESMR) Measurements Taken Onboard the NASA DC-8 During the TOGA COARE Intensive Observing Period
Department of Atmospheric Sciences
Texas A&M University
3150 TAMU
City:
College Station
Province or State:
TX
Postal Code:
77843-3150
Country:
USA
Publications/References
Chang, A.T.C., A. Barnes, M. Glass, R. Kakar, & T.T. Wilheit, 1993: Aircraft observations of the vertical structure of stratiform precipitation relevant to microwave radiative transfer. J. Appl. Meteor. 32, 1083-1091.
FIRE Project Office, 1994: NASA/TOGA COARE Science Data Workshop II, Proceedings of a workshop held in Albuquerque, New Mexico, March ... 15-17, 1994. NASA Langley Research Center, Mail Stop 483, Hampton, VA 23666.
NASA TOGA COARE Project Office, 1993: Mission Summary Reports, TOGA COARE. NASA Langley Research Center, Mail Stop 483, Hampton, VA 23666.
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.
Webster, P.J., and R. Lukas, 1992: TOGA COARE: The Coupled Ocean- Atmosphere Response Experiment. Bull. Am. Meteorol. Soc. 73, 1377-1416.
Wilheit, T.T., A.T.C. Chang and L.S. Chiu, 1991: Retrieval of Monthly rainfall indices from microwave radiometric measurements using probability distribution functions. J. Atmos. Oceanic Tech., 8, 118-136.
Wilheit, T.T., et al., 1994: Algorithms for the retrieval of rainfall from passive microwave measurements. Submitted to Reviews of Remote Sensing.
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.
