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Readme Contents Data Set Overview Sponsor The Data Characteristics The Files Format Naming Convention Companion Software Data Access & Contacts FTP Site Points of Contact The Science Instrument Algorithm References

Data Set Overview

The Millimeter-wave Imaging Radiometer (MIR)data sets of Texas & Florida Underflights field experiments (TEFLUN A & B) are part of the aircraft based measurements collected in support of the TRMM ground validation efforts.

MIR instrument was flown on the NASA ER-2 aircraft over Texas from April 9 through May 6, 1998 for the TEFLUN-A experiment and over Florida from August5 through September 27, 1998 for the TEFLUN-B & CAMEX-3 field campaigns. MIR is an airborne cross-track-scanning radiometer that provides calibrated brightness temperatures at nine different channels in the band 85-340 GHz. It is being used aboard NASA's high-altitude (21 km) ER-2 to study atmospheric water vapor, clouds, rain, and other forms of precipitation. The MIR measurements were made under the direction of the NASA/GSFC scientists Dr. James Wang (Principal Investigator) and Dr. Paul Racett (co-investigator)and the data sets are archived at the Goddard Data and Information Services Center (DISC).

Sponsor

The distribution of these data sets is funded by NASA's Earth Science Enterprise. The data are not copyrighted; however, we request that when you publish data or results using these data, please acknowledge as follows:

The authors wish to thank NASA scientists James Wang and Paul Racette (Goddard Space Flight Center) for the production of this MIR data set. They also thank the Data and Information Services Center (Code 610.2) at the Goddard Space Flight Center, Greenbelt, MD, 20771, for making it available to the scientific community. Goddard's contribution to the distribution and archive of this data set was sponsored by NASA's Earth Science Enterprise.

The Data

Characteristics

The MIR data consist of calibrated brightness temperatures in degrees Kelvin at nine channels (89, 150, 183.3 +/-1, 183.3 +/-3, 183.3 +/-7 , 220, 325  +/- 1, 325  +/- 3, and 325  +/- 8 GHz).

The data is very preliminary, before using this data in your publication, please contact the Principal Investigator Dr. James Wang (wang@sensor.gsfc.nasa.gov).

The Files

Files Format

MIR data for each flight is contained in one file. The data are in four-byte IEEE floating point words.

Each logical record of size 2316 bytes( 4 x 579)contains one calibrated MIR scan comprising temporal, spatial and aircraft attitude information for the nadir position (beam position 29) of the scan followed by a brightness temperature value for each of 57 beam positions at all 9 MIR frequencies.

Logical Record Format
word	Parameter	Source/Units	GHz
1	Record Number
2	Month	Real time clock (RTC)
3	Day	Real time clock (RTC)
4	Hour	IRIG
5	Minute	IRIG
6	Second	IRIG
7	Julian Day	Navigation
8	Hour	Navigation
9	Minute	Navigation
10	Second	Navigation
11	Latitude	Degrees
12	Longitude	Degrees (-West, +East)
13	Air Temperature	Degrees celsius
14	Altitude	Feet
15	Pitch	Degrees (+ for nose down)
16	Roll	Degrees (+ for roll right)
17	Heading	Degrees
18- 26	HouseKeeping Temperatures
27	Hot average temperature for this scan
28	Cold average temperature for this scan
29	Hot temperature, 8-scan moving average
30	Cold temperature, 8-scan moving average
31- 39	Hot average counts for this scan
40- 48	Cold average counts for this scan
49- 57	Hot counts, 8-scan moving average
58- 66	Cold counts, 8-scan moving average
67- 123	57 brightness temperatures	degrees Kelvin	89
124-180			150
181-237			183.3 +/-1
238-294			183.3 +/-3
295-351			183.3 +/-7
352-408			220
295-351			325 +/-1
295-351			325 +/-3
295-351			325 +/-8

File Naming Convention

The file naming convention for MIR data (adopted by DISC)is:

                tefluna_mir.yymmdd.jjj.ssssss.bin
 where:
          yymmdd = year, month & day
             jjj = Julian day 
          ssssss = Aircraft sortie number
             bin = file type designation, binary

Example: File for 21 April, 98              
                tefluna_mir.980421.111.98-048.bin

Companion Software

The MIR dataset was generated using PC computer, in order to read the data on UNIX, the data would need byte swapping (see the attached sample read program)

cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
! This program reads a few records of 1998 MIR data in SGI computer
! !!!!!!!!!!!!!!!!!!!!!***  last 3 channels have zero brightness temp.

      structure /OutStruct/
      real*4   		RecNumber
      real*4   		RTCmonth, RTCDayOfMonth
      real*4   		IrigHour, IrigMin, IrigSec
      real*4   		NavJulian, NavHour,  NavMin,  NavSec
      real*4		latitude, longitude
      real*4		AirTemp, altitude, pitch, roll, heading
      real*4            HouskptTmp(9)
      real*4            HotTemp,CldTemp,HotTemp8a,CldTemp8a
      real*4            HotCnt(9) ,CldCnt(9) ,HotCnt8a(9),CldCnt8a(9)
      real*4   		BrightTemps(9,57)
      end structure

      record/OutStruct/ i
      record/OutStruct/ j

      integer   m, k
       ib=    1
       ie=11111

      open(8, file='/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
     $ access='DIRECT', status='OLD', err=1999, recl=579*4)
c!!! use f77 -bytereclen !!!!

CCC   do m=   1, 11111
      do m=1,2
         read(8, rec=m, end=500, err=400) j
          call FLIP(j,i,579*4)


ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
       if( m.ge.ib.and.m.le.ie) then
       write(*,1)i.RecNumber,i.RTCmonth,i.RTCDayOfMonth
     @,i.IrigHour, i.IrigMin,i.IrigSec
     @  ,i.latitude,i.longitude,i.altitude ,i.pitch,i.roll,
     @i.heading,(i.BrightTemps(k,29)   ,k= 1,6)     


       endif
ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc
      end do
      stop 'Done!'
 400  call perror('Error reading record')
      stop 3
 500  call perror('Hit EOF reading record')
      stop 4
 1999 call perror('Error opening input file!')
      stop 5
  1    format( f6.0,1x,2f3.0,f3.0,f4.0,f4.0,2f6.1,f7.0,12f6.1)
  4    format( 3x ,2f6.1,f9.0,9f6.1)
  2    format(   (10f6.1))                         
  3    format(1x,'NavJulian, hr,min,sec' ,8x,4f5.1)
      end
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
      subroutine flip(ib,jb,n)
      character*1 ib(n),jb(n)
       do k=1,n-3,4
        jb(k  )=ib(k+3)
        jb(k+1)=ib(k+2)
        jb(k+2)=ib(k+1)
        jb(k+3)=ib(k  )
       end do
      return
      end
ccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

Data Access and Contacts

Data Access

FTP Site

The TEFLUN aircraft data resides on DISC anonymous FTP. You may access the files from this document,

MIR Calibrated Brightness Temperatures(Binary files)

MIR Browse Images

or directly via FTP at

ftp disc2.nascom.nasa.gov

login: anonymous

password: < your internet address >

cd data/TEFLUNA/aircraft/nasa_er2/mir/

Points of Contact

For Information about TEFLUN data at Goddard DISC, please contact

Hydrology Data Support Team
Goddard DISC, Code 610.2
NASA Goddard Space Flight Center
Greenbelt, MD 20771 email: hydrology-disc@listserv.gsfc.nasa.gov

Technical Inquiries about this Data should be addressed to:

MIR Data Investigators:

For detailed information about the sensor or data,

Principal Investigator:

Dr. James R. Wang

Code 975

NASA Goddard Space Flight Center

Greenbelt, MD 20771

Internet: wang@sensor.gsfc.nasa.gov

(301) 614-5655 (voice)

(301) 614-5558 (fax)

The Science

The instrument was first flown in May, 1992, and has accumulated more than 400 flight hours since. It has been involved in a number of field experiments e,g, TOGA/COARE - Tropical ocean Global Atmosphere/Coupled Ocean Atmosphere Response Experiment; CAMEX - Convection and Atmospheric Moisture Experiment, SUCCESS - Subsonic aircraft: Contrail and Cloud Effect Special Studies, WINCE - WINter Cloud Experiment, as well as the calibration/validation work for the SSM/T-2 - Special Sensor Microwave/Temperature-2 aboard the Defense Meterological Satellite Project DMSP, F11 and F12 satellites. Excellent data sets were acquired in all of these flights.

Instrument Characteristics

MIR is a total power cross-track scanning radiometer that measures millimeter-wave radiation at 9 channels: 89, 150, 183.3+/-3, 183.3+/-7, 220, 325+/-1, 325+/-3, 325+/-8ghz. It utilizes the strong water vapor lines at 183.3 and 325 Ghz to provide estimation of atmospheric water vapor profiles. As radiation in this frequency range also responds strongly to absorption and scattering by clouds and hydrometeors, the instrument could provide a measure of cloud and rain-associated parameters.

The MIR is nadir-oriented in the forward compartment of the right wing pod of the ER-2 aircraft. It scans in a plane perpendicular to the direction of flight with a swath of +/- 50 degrees from nadir. At the ER-2 aircraft cruising altitude of about 20 km, the footprint at nadir is about 1km. The speed of aircraft is about 200 m/sec. With a scanning cycle of about 3 seconds, MIR produces continuos images at all nine channels with a ground swath of about 42 km. Each scan takes 3 seconds and produces 57 brightness temperature values for all nine channels.

              
                      
                    Accuracy   : +/-2 Kelvin
                                      
                    Precision  : 0.5 Kelvin
                                      
               Angular Swath   : +/-50 
                                      
                   Beamwidth   : ~ 3 dB (independent of frequencies)
                                      
               Response Time   :  ~40 msec
                                     
                      Weight   : ~180 lbs
                                      
                       Power   : ~400 watts
                                      
                     Platform  : ER-2 aircraft (at ~20 km altitude)
                                      
                     Location  : Right front wing pod
                                      

Algorithm

Data Quality Assessment

The data are geo-referenced based on the ER-2's Inertial Navigation System (INS). Absolute calibration is performed every scan cycle by consecutively pointing the scan mirror at the hot (at 330 K) and cold (at ambient air cooled) external calibration targets which are closely monitored to within +/- 0.1 K.

References

Racette, P., R.F. Adler, A.J. Gasiewski, D.M. Jackson, J.R. Wang and D.S. Zacharias; An airborne millimeter-wave imaging radiometer for cloud, precipitation and water vapor studies, J. Atmos.Ocean.Tech., 13(3), 610-619, 1996.

Wang, J.R., S.H. Melfi, P. Racette, D.N. Whitemen, L.A. Chang, R.A. Ferrare, K.D. Evans and F.J. Schmidlin; Simultaneous measurements of atmosperic water vapor with MIR, Raman lidar and rawinsondes., J.Appl.Meteor., 34(7) 1595-1607, 1995.

Wang, J. R., S. H. Melfi, P. Racette, D. N. Whiteman, R. A. Kakar, R. A. Ferrare, K. D. Evans and F. J. Schmidlin, 1993: Simultaneous measurements of atmospheric water vapor with MIR, Raman Lidar and rawinsondes. IGARSS'93.

Falcone, V. J., K. Griffin, R. G. Isaacs, J. D. Pickle, J. F. Morrissey, A. J. Jackson, A. Bussey, R. Kakar, J. Wang, P. Racette, D. J. Boucher, B. H. Thomas, and A. M. Kishi, 1993: SSM/T-2 calibration and validation data analysis. Environ. Res. Papers, No. 1111, PL-TR-92-2293, Phillips Laboratory, Hanscom Air Force Base, MA 01731-5000.

Racette, P., L. R. Dod, J. C. Shiue, R. F. Adler, D. M. Jackson, A. J. Gasiewski, and D. S. Zacharias, 1992: Millimeter-wave imaging radiometer for cloud, precipitation, and atmospheric water vapor studies. IGARSS'92, Houston, Texas, 1426-1428.

Wang, J. R. and L. A. Chang, 1990: Retrieval of water vapor profiles from microwave radiometric measurements near 90 and 183 GHz. J. Appl. Meteor., 29(10), 1005-1013.