The document describes the level 3 products from the Microwave Limb Sounder (MLS) on the Aura satellite. It discusses the data formats, structures and metadata for daily and monthly level 3 MLS data products distributed in swath, grid and zonal mean formats. It also provides an overview of the tools and standards used to generate the level 3 data products.

1. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
MLS Level 3 Products
Paul Wagner1, Yibo Jiang1, Christina Vuu2, David Cuddy1
Jet Propulsion Laboratory
California Institute of Technology
2
Raytheon Information Solutions – Pasadena Operations
1
December 2, 2005

2. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
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Aura Microwave Limb Sounder
Agenda
Project Overview
Aura Data Flow
MLS Data Flow Diagram
Level 3 Products
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Data Format
Swath Data Structure
Grid Data Structure
Zonal Means Data Structure
Metadata File
• Tools and Components
• Conclusion
• Useful Websites
December 2, 2005
P. Wagner, Y. Jiang, C.

3. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Project Overview
EOS MLS - Microwave Limb Sounder
Salient Features
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One of 4 instruments on the EOS Aura spacecraft
Launch date: July 15, 2004
Operational life: 5 years
Dr. Joe Waters (JPL) Principal Investigator
Thermal emission from 1 to 100 km altitude in five
millimeter and submillimeter wavelength bands
All measurements are performed simultaneously and
continuously, both day and night, and can be made even
in the presence of dense cirrus clouds and stratospheric
aerosols
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Science
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Improve understanding and assessment of:
– Stratospheric ozone depletion and chemistry
– Upper tropospheric ozone distribution and chemistry
– Climate change and variability
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Global distribution of O3, ClO, H2O, SO2, CO, N2O,
HNO3, HCl, HOCl, BrO, OH, HO2, HCN, temperature,
geopotential height, and cirrus ice
December 2, 2005
P. Wagner, Y. Jiang, C.

4. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
December 2, 2005
Aura Microwave Limb Sounder
Aura Data Flow
P. Wagner, Y. Jiang, C.

5. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
December 2, 2005
Aura Microwave Limb Sounder
Data Flow Diagram
P. Wagner, Y. Jiang, C.

6. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Data Format
• MLS Level 3 Daily Products:
– Using HDF-EOS5 Swath and Grid formats
• MLS Swaths comply with the Aura Guidelines, v1.7
– 13 daily maps and their metadata files for the following species: ClO,
CO, GPH, H2O, HCl, HCN, HNO3, N2O, O3, OH, RHI, IWC, and
Temperature
• MLS Level 3 Monthly Products:
– Using HDF-EOS5 Swath, Grid and/or Zonal Means formats
– ‘Standard’ and ‘Diagnostic’ data files for each day of the processed
month in Zonal Means format
– Two monthly data files named ‘Standard’ and ‘Diagnostic’ in Zonal
Means format
– Two monthly data files named ‘Standard’ and ‘Diagnostic’ in Grid and
Swath formats
December 2, 2005
P. Wagner, Y. Jiang, C.

7. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Swath Data Structure
File Level Attributes:
OrbitNumber – 16 (for daily) or 2 (for monthly) orbit numbers
OrbitPeriod – 16 (for daily) or 2 (for monthly) orbit periods
InstrumentName – ‘MLS Aura’
ProcessLevel – ‘L3-Daily’ or ‘L3-Monthly’
GranuleMonth – ‘3’
GranuleDay – ‘11’
GranuleYear – ‘2005’
TAI93At0zOfGranule – ‘3.846e+08’
PGEVersion – ‘v2-0’
StartUTC -- ‘2005-070T00:00:00.00000Z’
EndUTC -- ‘2005-070T23:59:99.99999Z’
Period --‘Daily’ or ‘Monthly’
Swath Name 1: Species names
Swath Level Attributes:
Pressure – Pressure values
VerticalCoordinate – ‘Pressure’
Dimensions:
nLevels -- Number of Pressure levels
nTimes – Number of times (profiles) in data set
December 2, 2005
P. Wagner, Y. Jiang, C.

8. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Swath Data Structure (Cont.)
Swath Name 1: Species names (cont.)
Data Fields:
Value
Precision
Status
Quality
Geolocation Fields:
Time
Latitude
Longitude
Pressure
SolarZenithAngle
LocalSolarTime
LineOfSightAngle
OrbitGeodeticAngle
Data Field Attributes:
MissingValue
Title
Units
UniqueFieldDefinition
Geolocation Field Attributes:
MissingValue
Title
Units
UniqueFieldDefinition
Swath Name2: Species names
Additional swaths may occur in a file
December 2, 2005
P. Wagner, Y. Jiang, C.

9. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Grid Data Structure
File Level Attributes:
OrbitNumber – 16 (for daily) or 2 (for monthly) orbit numbers
OrbitPeriod – 16 (for daily) or 2 (for monthly) orbit periods
InstrumentName – ‘MLS Aura’
ProcessLevel – ‘L3-Daily’ or ‘L3-Monthly’
GranuleMonth – ‘3’
GranuleDay – ‘11’
GranuleYear – ‘2005’
TAI93At0zOfGranule – ‘3.846e+08’
PGEVersion – ‘v2-0’
StartUTC -- ‘2005-070T00:00:00.00000Z’
EndUTC -- ‘2005-070T23:59:99.99999Z’
Period --‘Daily’ or ‘Monthly’
Grid Name 1: Species names
Grid Level Attributes:
Projection – ‘Simple Cylindrical’
GridOrigin – ‘Center’
GridSpacing – ‘(4,2)’
GridSpacingUnit – ‘Degree’
GridSpan – ‘(0,360,-82,+82)’
GridSpanUnit – ‘Degree’
December 2, 2005
P. Wagner, Y. Jiang, C.

10. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Grid Data Structure (Cont.)
Grid Name 1: Species names (cont.)
Dimensions:
XDim – Which is Longitude
YDim – Which is Latitude
nLevels -- Number of Pressure levels
Data Fields:
Value
Precision
Latitude
Longitude
Pressure
Time
Data Field Attributes:
MissingValue
Title
Units
UniqueFieldDefinition
Grid Name2: Species names
Additional grids may occur in a file
December 2, 2005
P. Wagner, Y. Jiang, C.

11. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Zonal Means Data Structure
File Level Attributes:
OrbitNumber – 16 (for daily) or 2 (for monthly) orbit numbers
OrbitPeriod – 16 (for daily) or 2 (for monthly) orbit periods
InstrumentName – ‘MLS Aura’
ProcessLevel – ‘L3-Daily’ or ‘L3-Monthly’
GranuleMonth – ‘3’
GranuleDay – ‘11’
GranuleYear – ‘2005’
TAI93At0zOfGranule – ‘3.846e+08’
PGEVersion – ‘v2-0’
StartUTC -- ‘2005-070T00:00:00.00000Z’
EndUTC -- ‘2005-070T23:59:99.99999Z’
Period --‘Daily’ or ‘Monthly’
Zonal Name 1: Species names
Zonal Level Attributes:
Pressure – Pressure values
VerticalCoordinate – ‘Pressure’
ZonalSpacing – ‘2’
ZonalSpacingUnit – ‘Degree’
Dimensions:
nLatitude – Number of Latitudes
nLevels -- Number of Pressure levels
December 2, 2005
P. Wagner, Y. Jiang, C.

12. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Level 3 Zonal Means Data Structure (Cont.)
Zonal Name 1: Species names (cont.)
Data Fields:
Value
Precision
Latitude
Pressure
Time
Data Field Attributes:
MissingValue
Title
Units
UniqueFieldDefinition
Zonal Name2: Species names
Additional zonals may occur in a file
December 2, 2005
P. Wagner, Y. Jiang, C.

13. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
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Aura Microwave Limb Sounder
Level 3 Metadata
MLS Level 3 Metadata file will be created for each data file.
MLS Level 3 Metadata file contains the following information:
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Local Granule ID
Production Date and Time
Local Version ID
PGE Version
Reprocessing Planned
Input Granule
Short Name
Beginning and Ending Date and Time
Group of Measured Parameter contains QA Flags and Statistic
Group of Orbit Calculated Spatial Domain contains Start and Stop Orbit
Numbers, Equator Crossing Date, Time and Longitude
– Group of Horizontal and Vertical Spatial Domain
December 2, 2005
P. Wagner, Y. Jiang, C.

14. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Tools and Components
• MLS Level 3 currently built with the following:
– Toolkit version 5.2.13
– HDF5 library version 1.6.3
– HDF-EOS5 library version 5.1.9
• MLS Level 3:
– Fortran 95
– Lahey compiler v6.1
– Linux with Red Hat Enterprise v 3.4.4-2
• IDL
– MLS uses version 6.2
– Version 6.1 or later required to read Aura Guidelines-compliant data
– A Level 2 reader available now; a Level 3 reader is promised
December 2, 2005
P. Wagner, Y. Jiang, C.

15. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Conclusion
• MLS Level 1 and Level 2 products continue to be produced,
and archived, having become available to users since February
2005.
• MLS Level 3 is currently under development; its release is
planned for August 2006.
• The draft version 2.0 of HDF-EOS Aura Guidelines including
the MLS Level 3 Standard was issued on October 30, 2005.
December 2, 2005
P. Wagner, Y. Jiang, C.

16. National Aeronautics and Space
Administration
Jet Propulsion Laboratory
California Institute of
Technology
Aura Microwave Limb Sounder
Useful Websites
• Microwave Limb Sounder home page
– http://mls.jpl.nasa.gov/
• EOS Data Gateway (EDG)
– http://delenn.gsfc.nasa.gov/~imswww/pub/imswelcome/
• GSFC DAAC Web-based Hierarchical Ordering Mechanism
(WHOM)
– http://disc.gsfc.nasa.gov/data/dataset/MLS/
• GSFC DAAC Datapool
– http://disc.gsfc.nasa.gov/data/datapool/MLS/
• GES-DISC DAAC Interactive Online Visualization and
Analysis Infrastructure (Giovanni)
– http://reason.gsfc.nasa.gov/Giovanni_mls3d/
December 2, 2005
P. Wagner, Y. Jiang, C.