Electronically Scanned Microwave Radiometer (ESMR) Measurements Taken Onboard the NASA DC-8 During the TOGA COARE Intensive Observing PeriodEntry ID: COARE_cm_dc8.esmr
Abstract: DATA ACCESS
The NASA/TOGA COARE Data Archive
The ESMR data are available from the NASA GSFC DAAC via ftp from
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.
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
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
Then execute the following calculations:
sinBP = (sin(50/57.2)*(BP-20)/19)
ofsBP = 0.1 * (sinBP/sqrt(1-sinBP*sinBP))
latBP = lat - ofsBP*sin(hdg)*alt/36000
lonBP = lon + ofsBP*cos(hdg)*alt/(cos(lat)*36000)
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
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
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.
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.
Data Set Citation
Dataset Originator/Creator: TOGA COARE
Dataset Title: Electronically Scanned Microwave Radiometer (ESMR) Measurements Taken Onboard the NASA DC-8 During the TOGA COARE Intensive Observing PeriodOnline Resource: http://daac.gsfc.nasa.gov/fieldexp/TOGA/
Start Date: 1993-01-01Stop Date: 1993-02-28
ATMOSPHERE > PRECIPITATION > PRECIPITATION AMOUNT
ATMOSPHERE > ATMOSPHERIC RADIATION > SOLAR IRRADIANCE
ATMOSPHERE > ATMOSPHERIC RADIATION > SOLAR RADIATION
SPECTRAL/ENGINEERING > MICROWAVE > BRIGHTNESS TEMPERATURE
SPECTRAL/ENGINEERING > MICROWAVE > MICROWAVE IMAGERY
SPECTRAL/ENGINEERING > PLATFORM CHARACTERISTICS > ATTITUDE CHARACTERISTICS
ISO Topic Category
Distribution Media: On-line
Role: TECHNICAL CONTACT
Phone: (409) 845-7671
Fax: (409) 845-6331
Email: rick-russell at tamu.edu
Department of Meteorology Texas A&M University
City: College Station
Province or State: TX
Postal Code: 77843-3150
Phone: +1 (979) 845-0176
Fax: +1 (979) 862-4466
Email: wilheit at tamu.edu
Department of Atmospheric Sciences Texas A&M University 3150 TAMU
City: College Station
Province or State: TX
Postal Code: 77843-3150
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
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
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.
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