CCSD1Z00000100000052CCSD1R00000300000032
DELIMITER=EOF;
TYPE=CCSD1F000001;
CCSD1C00000400000026
ADI=NURSML02;
SUD=NURSML01;
CCSD1R00000300000032
DELIMITER=EOF;
TYPE=CCSD1D000002;







                    UPPER ATMOSPHERE RESEARCH SATELLITE
                                     
                                     
                          MICROWAVE LIMB SOUNDER
                                     
                                     
                                     
                       Standard Formatted Data Units
                                     
                          Whole Data Set Document
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                                     
                              June 1996
                                     
                                     
                                     
                                     
                        J. R. Burke and T. A. Lungu
                                     
                         Jet Propulsion Laboratory
                    California Institute of Technology,
                            Pasadena, California
                                   
                                       
                                     
                                     
                                     
                                     
          
          
          
          
          UPPER ATMOSPHERE RESEARCH SATELLITE
          
          MICROWAVE LIMB SOUNDER
          
          
          
          
          Standard Formatted Data Units Document List:
          
          
          NURS1I00ML02   **   Whole Data Set
          
          NURS1I00ML01        File Class:  Level 2 Data
          
          NURS1I00ML03        File Class:  Level 3AT Data
          
          NURS1I00ML04        File Class:  Level 3TP Parameter
          
          NURS1I00ML05        File Class:  Level 3AL Data
          
          NURS1I00ML06        File Class:  Level 3LP Parameter
          
          
                        (**   this document)
          
          
          
          
          
          


          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
          
UARS MLS SFDU DOCUMENT FOR:
===========================

WHOLE DATA SET
--------------


Introduction

The Upper  Atmosphere Research  Satellite (UARS)  project has  an open data
processing and  archiving system  in which  retrieved geophysical data from
any  UARS  investigation is  made  available  to  the  general   scientific 
community. In order to minimize ambiguity and  errors in  interpretation of 
the data the  UARS Science  Team accepted  a recommendation  from the  UARS 
Data   Systems  Working  Group  that all  UARS  data products adhere to the
Standard Formatted Data Units  (SFDU) structure and construction  rules  as 
defined in Reference 1.   The implementation for UARS data is described  in 
Reference 2, and this documentation for  the  Microwave  Limb  Sounder (MLS)  
follows  the  Data Documentation Standard for UARS.

The organization  of SFDU documentation is hierarchical, with the top level
describing the entire data set, and the bottom level describing a data item
within a  record.   The hierarchy  levels are:  Whole Data Set, File Class,
Record, and  Field.  A separate document is required for the Whole Data Set
and for  each File Class.  For MLS there exist five SFDU File Classes:  the
Level 2 Data Set, the Level 3AT Data Set, the Level 3AL Data Set, the Level
3TP Parameter  File and  the Level  3LP Parameter  File.  MLS Level 0 Files
contain raw instrument data;  Level 1 Files contain calibrated measurements
of radiance,  derived diagnostics and supplemental data;  Level 2 Files are
retrieved geophysical  data;  and Level 3 Files contain geophysical data on
common UARS grids.  At each of these levels, the files contain data for one
complete day.   The SFDU documentation standards are only applicable to the
Level 2 and Level 3 Data Sets.

At the  Whole Data  Set level,  the description  of the  data set  gives an
overall understanding of all MLS data products.  A File Class is a group of
files related  by a  common format.   Files  are constructed  from elements
called Records,  which are  constructed from  elements called Fields.  Each
file belonging  to a  particular File  Class is constructed from records of
identical form  in a defined order.  Documentation of the data sets in each
File Class describes how the data in each file was created, how the file is
organized, and how the records within it are related.

This is  the Whole  Data Set  Documentation for  the  UARS  Microwave  Limb
Sounder (MLS)  Output Data  Files Version 4 produced  with MLS   Production
Processing Software Version 4.22, also valid for Output Data  Files Version
3 produced  with  MLS  Production  Processing  Software  Version  4.11/4.12,
unless otherwise specified.   


Data_Set_Name:           UARS MLS Data Set.


Data_Source:             The MLS experiment on the UARS spacecraft.



Scientific_Contact:      ALL INITIAL ENQUIRIES SHOULD BE
                         MADE TO THE MLS DATA MANAGER:
                         
                         MLS Data Manager
                         Jet Propulsion Laboratory
                         Mail Code 183-701
                         4800 Oak Grove Drive
                         Pasadena, Ca. 91109-8099
                         
                         Internet:  mlsdaac@jplrac.jpl.nasa.gov
                         Phone: 818 354-6849
                         Fax:   818 393-5065


                         Evan F. Fishbein
                           Temperature analysis
                         Jet Propulsion Laboratory
                         Mail Code 183-701
                         4800 Oak Grove Drive
                         Pasadena, Ca. 91109-8099
                         
                         Internet:  eff@tugh.jpl.nasa.gov
                         Phone: 818 354-2250
                         Fax:   818 393-5065
                         
                         
                         Lucien Froidevaux
                           Ozone analysis
                         Jet Propulsion Laboratory
                         Mail Code 183-701
                         4800 Oak Grove Drive
                         Pasadena, Ca. 91109-8099
                         
                         Internet:  lucien@wilga.jpl.nasa.gov
                         Phone: 818 354-8301
                         Fax:   818 393-5065
                         
                         
                         William G. Read
                           "Forward Model" analysis
                         Jet Propulsion Laboratory
                         Mail Code 183-701
                         4800 Oak Grove Drive
                         Pasadena, Ca. 91109-8099
                         
                         Internet:  bill@poobah.jpl.nasa.gov
                         Phone: 818 354-6773
                         Fax:   818 393-5065
                         
                         
                         Hugh C. Pumphrey
                           Water vapor analysis
                         Department of Meteorology
                         University of Edinburgh
                         Mayfield Road, Edinburgh, 
                         Scotland, UK
                         
                         Internet:  hcp@met.ed.ac.uk
                         Phone: (UK)  031 650-6026
                         Fax:   (UK)  031 662-4269
                         
                         Michelle  L. Santee
                           Nitric Acid analysis
                         Mail Code 183-701
                         4800 Oak Grove Drive
                         Pasadena, Ca. 91109-8099

                         Internet:  mls@praxis.jpl.nasa.gov
                         Phone: 818 354-9424
                         Fax:   818 393-5065


                         Joe W. Waters
                           Chlorine monoxide analysis
                         Jet Propulsion Laboratory
                         Mail Code 183-701
                         4800 Oak Grove Drive
                         Pasadena, Ca. 91109-8099
                         
                         Internet:  joe@jedediah.jpl.nasa.gov
                         Phone: 818 354-3025
                         Fax:   818 393-5065
                         
                         
Source_Characteristics:  

The UARS  satellite orbit  is inclined at 57 degrees, precessing daily with
respect to  the sun  by about  -4 degrees.  For one day's data, the sampled
local solar  zenith angle varies by less than 10 degrees at a given tangent
latitude  on  either the "day" or  "night" side  of  the orbit. The  entire  
diurnal cycle  is  sampled  in about  36 days.   The  satellite  is   yawed 
through  180 degrees  approximately every  36 days, and this  ensures  that 
one  side of  the satellite  is never  illuminated  by the Sun, as required 
by MLS and other UARS instruments.

The MLS  is a  limb sounder,  viewing perpendicular to the orbital velocity
vector from  the anti-sun  side.   It scans only in elevation and, from the
satellite altitude  of about  580 km,  MLS views  the atmosphere at tangent
points about  22 to 24 degrees below the orbital track.  When the satellite
flies in the forward direction, viewing to the anti-sun side gives latitude
coverage from  34N to  80S, and  when the  satellite flies  in the backward
direction, coverage  is from  80N to  34S.   References 3  and 4  contain a
synopsis of  the UARS  mission and  its goals,  and  Reference  5  gives  a
description of the MLS Instrument.


Investigation_Objectives:

The UARS MLS experiment is designed to investigate the chemical composition
of the  Earth's upper atmosphere (upper troposphere, stratosphere and meso-
sphere) on  a global scale, day and night, over several years.  A climatol-
ogy of  chemical species  will be  obtained, which,  with observations from
other UARS  experiments, will  provide a  large data  base  of  information
regarding ozone  chemistry and  couplings between  dynamical, chemical, and
radiative processes.   The  MLS experiment is unique among UARS instruments
in measuring  chlorine monoxide  (ClO),  the  predominant  form of reactive
chlorine that destroys ozone.  SO2  injected  into  the  upper   atmosphere 
by the Mount Pinatubo  volcanic  eruption in June 1991 has been detected by 
UARS MLS (Reference 10). Additional new  products  from  MLS  include  HNO3
(Reference 11), first  available in  MLS Version 4 data and  upper
tropospheric H2O (Reference 12) which is planned for version 5.

Instrument_Attributes:

UARS MLS measures microwave thermal emission from atmospheric molecules, in
particular  O3,  H2O, ClO, HNO3 and SO2; O2 emission is also measured,  and 
provides information on  tangent pressure  and temperature. There are three 
radiometers (63,  183, and  205 GHz),  providing measurements in a total of
six 510 MHz  wide spectral bands.   (The MLS 183 GHz  radiometer ceased  to 
work on April 16 1993, after which there are no stratospheric H2O  measure-
ments for  MLS; tropospheric  H2O, however  is  obtained from  the 205  GHz 
radiometer which continues to operate as of April 1996). The signals  from  
each  band  are detected in identical spectrometers having 15  contiguous 
channels  with bandwidths ranging from  2 to  128 MHz.  Vertical resolution 
is  about 5 km for species profiles, and horizontal (along-track) resolution 
is 10 to 30 km. MLS views the limb of the Earth perpendicular to the UARS  
orbital velocity  vector, and  typically scans  in  discrete  steps  from  
about 5 km to 90 km every MLS major frame (MMAF) of 65.536  seconds. Within 
each MMAF, measurements are made in 32 minor frames (MMIF, each 2.048 seconds) 
with some of these periods   reserved for  radiometric  calibration.    See 
Reference 5 for more information  on the UARS MLS Instrument, Reference  15 
for Instrument Calibration and Reference 13 for further information  on the 
technique.


Measured_Parameters:

The MLS  Level 2  program has  the flexibility  to retrieve,  constrain, or
ignore a  variety of  parameters.   The measured parameters for the Level 2
Data Set  are specified by the structure SV_INFO (state vector information)
contained in  the  header  record.    The  parameters  that  are  routinely
retrieved are  tangent pressure,  temperature, and  volume mixing ratios of
ozone, water  vapor, chlorine monoxide, nitric acid and sulfur dioxide. For 
ozone,  there are  two  independent retrievals, one  from the  205 GHz band 
(profile name O3_205) and one from the 183 GHz band  (profile name  O3_183).  
See References 16 trough 19 for details on Calibration of the most important 
measured parameters. 

Retrieved atmospheric profiles in the Level 2 data records are in the array
PROFILE.   Their   estimated   1-sigma  uncertainties   (expected  standard
deviations) are  in the  array PROFILE_SDEV.  State vector components which
are normally  constrained include  O3_18_A (asymmetric ozone  18  isotope), 
O3_18_S (symmetric ozone 18 isotope) and heavy oxygen (O_18_O), as well  as 
the  line-of-sight  component  of wind.  (Isotopic abundances of ozone  are  
constrained  to  the  expected  fraction  of  the  retrieved  abundance of 
the dominant isotope, wind  is  constrained to zero with negligible or null
expected impact.)

The  Level   2  files   are  time-ordered,   with  one  record  every  MMAF
(65.536 seconds),  and one set of atmospheric profiles and other quantities
per record.   Profile  values are  retrieved for  alternate  (even-indexed)
pressure levels  on the UARS standard pressure grid (described in Reference
2).

Each type  of Level  3AT and  3AL file contains retrievals for one measured
parameter.   Types routinely  available are:  chlorine monoxide, ozone 205,
ozone 183, water vapor, nitric acid, sulfur dioxide and temperature.    The 
Level 3AT Data Sets are  obtained  directly  from  the  Level  2  Data  Set  
for  even-indexed pressure levels.   For  the odd-indexed  pressure  levels 
the Level 3AT Data  Sets  are obtained  by  averaging  values  on  adjacent 
even-indexed levels.  The  Level 3AL  Data  Sets  are  obtained  by  linear 
interpolation to the standard  4  degree  UARS latitude  grid (described in 
Reference 2).

The Level 3 Parameter Files, 3TP and 3LP, contain diagnostic quantities and
retrieval quality  indicators which  are very important for reliable inter-
pretation of  the data in the corresponding data files.  Column ozone above
a certain pressure (set to 46 hPa for Version 3 and Version 4 Data) and its 
estimated uncertainty are  also stored  in these  files for  both  183  and  
205 GHz retrievals.


Data_Set_Quality:

For MLS Level 2 Data, the header record contains information on the overall
data quality for each file.  For each data record, estimated uncertainties,
from random  error sources  and from  some sources of systematic error, are
included for  each retrieved  item.    These  estimated  uncertainties  are
obtained from  the square  root of  the diagonal  terms of  the  covariance
matrix.   They are multiplied by -1 when the ratio of estimated uncertainty
to  a   priori  uncertainty   is  greater  than  0.5.    Similar  estimated
uncertainties exist  in the  Level 3  files (3AT, 3AL, 3TP and 3LP.)  Other
Level 2  quantities providing  insight into  the data  quality are (see MLS
SFDU File Class Documentation for Level 2):

     FLAG_AP        FLAG_CHISQ_SPIKE    FLAG_CHISQ_SPIKE_NUM
     FLAG_CLI       FLAG_NEG            FLAG_PTAN 
     MMIF_STAT      MMAF_STAT *         BAND_INFO_MMAF.QUALITY *

(* These quantities are also in the Level 3 Parameter files.)

Values will  appear in the PROFILE vector whether or not data were received
from the  instrument.   These values  are a  combination of a priori values
(obtained from  climatology  and  contemporary  NMC  data)  and  instrument
measurements.  If no instrument data are received, the retrieval relaxes to
the a  priori and  the estimated  uncertainty value  will be negative.  The
parameter MMAF_STAT  in the Level 2 Data and Level 3 Parameter files, gives
information on  whether each  major frame has good data, no  data, bad data
or other possible problem. The Level 2 data parameter PROFILE_ERRED (organi-
zed  identically to  the  PROFILE  vector)  reflects  the "error  reduction 
factor" (a value of 1 indicates no error reduction and that all information 
is from a priori; a value near zero  indicates all  information is from MLS 
measurements; a value of 0.5 indicates the a priori contribution is 25 %).





Data_Processing_Overview:

The MLS  geophysical data  products are  obtained from  measurements  by  a
sequential estimation retrieval technique using algorithms which follow the
theory described in Reference 14.

MLS Level  2/3A Processing  uses Level  1 calibrated radiance and ancillary
data as  input, and  routinely processes  one full  day's data in each run.
Other inputs  are: user  selected options and parameters (all echoed in the
Level 2  Data File  header record),  a file of processing coefficients  for
use in  the retrieval  process, a  file of  space radiance offsets, default
climatological data,  optional UARS  Climatological Atmospheric  Data,  and
optional National  Meteorological  Center  (NMC)  Data.    Note,  the  UARS
Climatological Atmospheric  Data and NMC Data are normally used as a priori
information except  in rare instances when they are unavailable.  MLS Level
2/3A Processing  produces the  Level 2  Product, the  Level 2  Log file, an
optional file  of diagnostic data for a selected range of major frames, the
Level 3A  products, the  Level 3 Parameter Files, and a file of "last major
frame quantities" used to begin the next day's processing.

MLS Level  2/3A Processing  consists of  two programs (MLS_TANTRAK and MLS_
RETRIV) run  sequentially.   MLS_TANTRAK creates temporary files containing
the Level  1 radiances  and ancillary  data mapped  onto the tangent track.
The retrieval program steps through these data in a sequential manner.

The MLS_RETRIV program processes tangent track files in a forward direction
in time.   (The program can optionally process in both forward and backward
directions but  this option has not  been  used for Version 3 or  Version 4 
Data Products.) During the  forward pass,  MLS_RETRIV reads  tangent  track  
data one  major frame at a time, and loops through  each MMIF  updating the 
retrieved quantities, using a sequential estimation algorithm. At the start 
of  each  MMIF a  new a priori tangent pressure (PTAN63_APR) is calculated; 
at  the  end of each minor frame, the retrieved  tangent  pressure (PTAN63) 
is saved.  At  the  beginning  of  each major frame, new a  priori profiles  
are calculated. At the end  of  each  major frame  the  retrieved  profiles  
are  written  to  the  output file.  

In MLS Level 2  processing, for data version up to 4, geophysical parameter 
values are retrieved for even-indexed levels  of the standard UARS pressure 
grid.  The Level 3AT and 3TP Data  Sets are  obtained from  Level 2 data by  
copying values for the even-indexed levels,  and  by  averaging  quantities  
from adjacent pressure levels to  fill in values on the odd-indexed levels.  
The Level 3AL and 3LP Data Sets are obtained by interpolating the Level 3AT 
and 3TP Data Sets to the UARS latitude grid.


Data_Usage:

Level 2 data  sets provide atmospheric profiles every 65.536 seconds, which
is  the  duration  of  a  MLS  Major  Frame  (MMAF), equivalent to the UARS
Engineering Major  Frame (EMAF).  Sensitivity  for ozone, water  vapor  and 
temperature decreases in the lower stratosphere and in the  mesosphere. ClO 
retrievals  are  noisy  for  individual  profiles, and  useful  only  under 
conditions of enhanced concentrations (more than about 1 ppbv) in the lower 
stratosphere.  Averaged values should be used for  better  signal to noise.  
HNO3 is also fairly noisy, for individual  profiles. Also, V4  software  do 
not properly retrieve HNO3 under conditions of high SO2, because of strongly
corelated signals (from SO2 and HNO3) and HNO3 in general has not been vali-
dated or scrutinized to the extent that other MLS instruments have.

Mesospheric  ozone may lose  some  accuracy  for  observations  across  the  
terminator regions (REF_SOLAR_ILLUM = 3 or 4), because of rapid  variations 
along  the line of sight which are not taken into account in the production 
processing.   Sensitivity  to water  vapor is lost just  below 46 hPa,  and  
sensitivity  for  temperature  is  lost  below  46  hPa  due to saturation.

It is  emphasized that  the data  file estimated  uncertainties, and  their
signs,  together   with  other   parameter  file  diagnostics  and  quality
indicators  (identified  in  Data_Set_Quality  above)  should  be  examined
carefully to  ensure the  validity of any data used in scientific analyses.
The usefulness  and significance  of these  quality  indicators  vary  from
parameter to  parameter, and demand some experience and insight for prudent
interpretation.   The MLS  Team would  appreciate being quickly informed of
any apparent  anomalies which  are found  in the  data and  which  are  not
flagged by  the quality  indicators.   Such information  will  help  us  to
improve the  quality of  these data  in future  reprocessing.   Feedback on
documentation errors would also be appreciated.


Data_Organization:

There is  one File Class each for the Level 2, Level 3AT and Level 3AL Data
Files, and for the Level 3TP and Level 3LP Parameter Files.


File_Class_Relationships:     

All of  the information  in the Level 3AT and 3AL Files is contained in (or
can be  directly calculated  from) the  Level 2  Data Set.    The  Level  3
Parameter Files  provide important  information to  help qualify  the other
Level 3 files.


Lit_References:

1.   Consultative Committee for Space Data Systems, CCSDS 620.0-B-1,
     Standard Formatted Data Units -- Structure and Construction Rules,
     November 1987.

2.   Computer Sciences Corporation, CSC/SD-86/6704/UD6, UARS Central Data
     Handling Facility (CDHF) Software System (UCSS) Programmer's Guide to
     Production Software Support Services, February 1993.

3.   UARS Project Data Book, General Electric, (now Martin Marietta) Astro-
     Space Division, P.O. Box 8555, Philadelphia, Pennsylvania 19101, April
     1987.

4.   Reber, C. A., C. E. Trevathan, R. J. McNeal, and M. R. Luther, The
     Upper Atmosphere Research Satellite (UARS) Mission, J. Geophys. Res.
     98, D6, 10643-10647, 1993.

5.   Barath, F. T., et al, The Upper Atmosphere Research Satellite
     Microwave Limb Sounder Instrument, J. Geophys. Res. 98, D6, 10751-
     10762, 1993.

6.   Waters, J. W., et al, Stratospheric ClO and ozone from the Microwave
     Limb Sounder on the Upper Atmosphere Research Satellite, Nature, 362,
     597-602, 1993.

7.   L. Froidevaux, J. W. Waters, W. G. Read, L. S. Elson, W. G. Read,
     D. A. Flower, and R. F. Jarnot, Global ozone observations from UARS MLS:
     an overview of zonal mean results, Journal of Atmos. Sci. (special issue
     on UARS early scientific results), vol. 51, pp. 2846-2866, 1994.
     
8.   W. A. Lahoz, A. O'Neill, E. S. Carr, R. S. Harwood, L. Froidevaux,
     W. G. Read, J. W. Waters, J. B. Kumer, J. L. Mergenthaler, A. E. Roche,
     G. E. Peckham, and R. Swinbank, "Three-dimensional evolution of water   
     vapour distributions in the northern hemisphere as observed by MLS,   
     Journal of Atmos. Sci. (special issue on UARS early scientific results),
     vol. 51, pp. 2914-2930, 1994.
     
9.   G. L. Manney, L. Froidevaux, J. W. Waters, R. W. Zurek, W. G. Read,
     L. S. Elson, J. B. Kumer, J. L. Mergenthaler, A. E. Roche, A. O'Neill,
     R. S. Harwood, I. MacKenzie and R. Swinbank, Chemical depletion of ozone
     in the Arctic lower stratosphere during winter 1992-93," Nature, vol.370,
     pp. 429-434, 1994.

10.  Read, W. G., L. Froidevaux and J. W. Waters, Microwave Limb Sounder
     Measurements of Stratospheric SO2 from the Mt Pinatubo Volcano,
     Geophys. Res. Lett., 20, 1299-1302, 1993.

11.  M. L. Santee, W. G. Read, J. W. Waters, L. Froidevaux, G. L. Manney,
     D. A. Flower, R. F. Jarnot, R. S. Harwood, and G. E. Peckham,
     Interhemispheric differences in polar stratospheric HNO3, H2O, ClO and O3,
     Science, vol. 267, pp. 849-852, 1995.

12.  W. G.Read, J. W. Waters, L. Froidevaux, D. A. Flower, R. F. Jarnot, D.
     L. Hartmann, R. S. Harwood, and R. B. Rood, Upper-tropospheric water
     vapor from UARS MLS, Bull. Am.  Meteorol.  Soc., vol. 76, pp. 2381-2389,
     1995.

13.  Waters, J. W., Microwave Limb Sounding, Chapter 8 in Atmospheric
     Remote Sensing by Microwave Radiometry, M. A. Janssen editor, John
     Wiley and Sons Inc., New York, 1993.
               
14.  Rodgers, C. D., Retrieval of Atmospheric Temperature and Composition
     from Remote Measurements of Thermal Radiation, Rev. Geophys. and Sp.
     Phys., 14, 609-624, 1976.

15.  R. F. Jarnot, R. E. Cofield, J. W. Waters, D. A. Flower, and G. E. Peckham
     Calibration of the Microwave Limb Sounder on the Upper Atmosphere Research
     Satellite, J. Geophys. Res. 101, D6, 9957-9982, 1996

16.  E. F. Fishbein, R E. Cofield, L. Froidevaux, R. F. Jarnot, T. A. Lungu, 
     W G. Read, Z. Shippony, J.W. Waters, I. S. ,McDermid, T J. McGee, 
     U. Singh, W. Gross, A. Hauchecome, P. Keckhut, M. E. Gelman and R. M. 
     Nagatani, Validation of UARS Microwave Limb Sounder temperature and 
     pressure measurements, J. Geophys. Res. 101, D6, 9983-10016, 1996

17.  L. Froidevaux,  W. G. Read, T A. Lungu, R. E. Cofield, E. F. Fishbein, 
     D. A. Flower, R. F. Jarnot, B. P. Ridenoure, Z. Shippony, J. W. Waters, 
     J. J. Margitan, L. S. McDermid, R. A. Stachnik.  G. E. Peckham, 
     G. Braathen, T. Deshler, J. Fishman, D. J. Hofmann, and S. J. Oltmans, 
     Validation of UARS Microwave Limb Sounder ozone measurements, J. Geophys.
     Res. 101, D6, 10017-10061, 1996

18.  J. W. Waters, W. G. Read, L. Froidevaux, T. A. Lungu, V. S. Perun, R. A. 
     Stachnik, R. F. Jarnot, R. E. Cofield, E. F. Fishbein, D. A. Flower, 
     J. R. Burke, J. C. Hardy, L. L. Nakamura, B. P. Ridenoure, Z Shippony, 
     R. P. Thurstans, L. M.  Avallone, D. W. Toohey, R. L. deZafra, and 
     D. T Shindell, Validation of UARS Microwave Limb Sounder ClO measurements,
     J. Geophys. Res. 101, D6, 10091-10128, 1996

19.  W. A. Lahoz.  M. R. Suttie, L. Froidevaux, R. S. Harwood, C. L. Lau,
     T. A. Lungu, G. E. Peckham, H. C. Pumphrey, W. G. Read, Z. Shippony,
     R. A. Suttie, J. W. Waters, G. E. Nedoluha, S. J. Oltmans, 
     J. M. Russell III, and W. A. Traub, Validation of UARS Microwave Limb 
     Sounder 183 GHz H2O measurements, J. Geophys. Res. 101, D6, 10129-10150, 
     1996 

20.  D. A. Flower, T. A. Lungu, C. C. Voge, UARS MLS SFDU Whole Data Set
     Document, 1993
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End of Document    UARS MLS SFDU Whole Data Set Document      June, 1996