GES DISC Data Guide:
UARS Project Guide Document

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The Earth's upper atmosphere, beginning only 10-15 km above the surface, remains a frontier largely unexplored from space. As the first major element in NASA's Earth Science Enterprise (formerly Mission to Planet Earth), the Upper Atmosphere Research Satellite (UARS) will carry out the first systematic, comprehensive study of the stratosphere and furnish important new data on the mesosphere and thermosphere. UARS chemistry and dynamics sensors will make measurements of temperature, pressure, wind velocity, and gas species concentrations in the altitude ranges shown in the figure below. .

UARS Project Information

The goal of upper atmosphere research is to understand the chemistry, dynamics, and energy balance above the troposphere as well as the coupling between these processes and between atmosphere regions. This implies an understanding of the mechanisms that control upper atmosphere structure and variability, as well as an understanding of how the upper atmosphere responds to natural and man-made causes. Together, these will help define the role of the upper atmosphere in climate and climate variability. The UARS platform provides simultaneous, coordinated measurements of atmospheric internal structure (trace constituents, physical dynamics, radiative emission, thermal structure, density) and measurements of the external influences acting upon the upper atmosphere (solar radiation, tropospheric conditions, electric fields). In addition, the combination of orbit and instrument design will provide nearly global coverage.

Mission Objectives

The UARS mission objectives include the study of:  Upper atmosphere energy input and loss,  Upper atmosphere global photochemistry,  Upper atmosphere dynamics,  Coupling among these processes, and  The coupling between the upper and lower atmosphere  Ten instruments on the spacecraft will accomplish these specific objectives by performing measurements of chemical species composition, temperature, winds, and energy inputs of the upper atmosphere.

Four UARS instruments devoted to measurements of constituents will spectroscopically determine the concentrations of many different chemical species and derive the variation of atmospheric temperature with altitude by observing infrared emissions from carbon dioxide.	Cryogenic Limb Array Etalon Spectrometer (CLAES) Improved Stratospheric and Mesospheric Sounder (ISAMS) Microwave Limb Sounder (MLS) Halogen Occultation Experiment (HALOE)
Two instruments, utilizing high-resolution interferometry, will study upper atmosphere winds by sensing the Doppler shift in light absorbed by or emitted from atmospheric molecules.	High Resolution Doppler Imager (HRDI) Wind Imaging Interferometer (WINDII)
An additional four investigations will obtain estimates of the energy incident on the atmosphere by measuring solar ultraviolet radiation and the flux of charged particles from the Earth's magnetosphere.	Solar-Stellar Irradiance Comparison Experiment (SOLSTICE) Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) Particle Environment Monitor (PEM) Active Cavity Radiometer Irradiance Monitor (ACRIM II)

NOTE: ACRIM II is not part of the UARS project. It was included on the UARS platform as an instrument of opportunity. ACRIM II data are archived at the Langley Atmospheric Science Data Center (ASDC).

Discipline

Earth Science

Geographic Region

UARS operates 585 km above the Earth in a near circular orbit inclined 57 degrees to the equator. This orbit permits UARS sensors to view up to the 80 degree latitude bands providing essentially global coverage of the stratosphere and mesosphere. This also permits the UARS instrument to make measurements over the full range of local times at all geographic locations approximately every 36 days.

Brief Description

The UARS system includes both the flight observatory and ground based elements consisting of both mission unique and institutional elements. The institutional elements can be further broken down into communications elements on the one hand, and the ground system elements needed to support flight operations and data capture on the other.

The observatory consists of ten science instruments, an Instrument Module (IM) including mission unique hardware, and the Multimission Modular Spacecraft (MMS). It provides precision pointing for the science instruments on an Earth oriented platform, periodic routine maneuvers to maintain a favorable sun orientation, and the ability to communicate through the Space Network S-band service. UARS is also compatible with the Deep Space Network (DSN) for support during emergency situations.

Flight operations are performed through Goddard Space Flight Center (GSFC) institutional mission support systems. These facilities provide for satellite command and control, definitive orbit and attitude computations, command management, and data capture.

Instrument data processing is accomplished in the mission specific Central Data Handling Facility (CDHF) at GSFC. Data analysis and theoretical studies are being conducted by members of the UARS science team through use of Remote Analysis Computers (RACs) located at the Principal Investigators' (PIs) facilities. PIs also have access to the CDHF data base archival system..

Detailed Project Description

For more information about the UARS project, consult the UARS project home page or refer to the documents listed in the Reference section below.

Data Availability

Data Types

The UARS mission data are processed and stored in five fundamental levels.

Level 0

The basic telemetry data from the instruments after time reversal and decommutation into specific sensor files. Level 0 data have a common format.

Level 1

This data consists of the physical parameters actually measured by the sensors (e.g., atmospheric radiances in the case of the limb sounding instruments). Level 1 data have sensor specific file formats.

Level 2

The geophysical parameters calculated from Level 1 data, such as atmospheric temperature profiles, gas concentrations, winds, or solar spectral irradiances. Atmospheric data at Level 2 are related directly to the instrument measurement "footprint", i.e., the character of the altitude scan is determined by a given instrument's scan rate, integration time, and viewing direction, as well as the spacecraft's orbital velocity. Level 2 data also have sensor specific file formats.

Level 3A

Atmospheric data that reflects the geophysical information of Level 2 data transformed into a common format and equally spaced along the measurement trajectory in time ("Level 3AT", at 65.536 second centers) or latitude ("Level 3AL", every four degrees). Level 3A data have common file formats.

Level 3B

Atmospheric data that consists of two daily latitude-longitude cross sections at approximately one half scale height altitude intervals. (The two cross sections reflect segregation by north-going and south-going satellite data, which differ by 12 hours local time at the equator.) These data are stored as 13 Fourier coefficients for each height around the latitude circles defined by Level 3AL. Level 3B data also have a common file format.

Note: SOLSTICE (Level 3AS/3BS), SUSIM (Level 3AS/3BS), PEM (Level 3AT/3TP), and HALOE (Level 3AT) data differ from the above definitions and are appropriate to the specific measurements being performed.

Currently Available UARS Data

UARS Data Available from The GES DISC
	Version	Data Coverage
CLAES Level 3AL/3AT	91	10/25/1991 - 05/05/1993
HALOE Level 2	19	10/11/1991 - 11/21/2005
HALOE Level 3AT	19	10/11/1991 - 09/24/2001
HRDI Level 3AL/3AT	11	11/06/1991 - 01/30/1999
ISAMS Level 3AL/3AT	102	09/26/1991 - 07/29/1992
MLS Level 3AL/3AT	53	09/18/1991 - 07/28/1999
PEM Level 2	1	09/15/1991 - 08/23/2005
PEM Level 3AT/3TP	4 / 34	10/01/1991 - 12/31/1999
SOLSTICE Level 3BS	18	10/03/1991 - 12/31/1999
SUSIM Level 3BS	22	10/11/1991 - 08/01/2005
WINDII Level 3AL/3AT	11	11/04/1991 - 08/19/1997
NMC Correlative	-	09/12/1991 - 09/30/2001
UKMO Correlative	-	10/17/1991 - 09/30/2001

1. CLAES H₂O data are version 7 and start at 01/09/1992
   
2. ISAMS H₂O data are version 9
   
3. MLS L3AT H₂O are version 6 (aka V0104); MLS SO₂ and UTH data are version 4; H₂O and O₃ at 183 GHz are available between 09/18/1991 and 04/15/1993
   
4. PEM HEPS and MEPS electron and proton data are version 4, the PEM AXIS x-ray energy deposition data are version 3

Output Delivery Methods/Media
Output Media	Method
Electronic / FTP	Mirador or WHOM Archive Search

Additionally, UARS Level 0, 1 and 2 data products can be found on the GES DISC anonymous FTP server.

Data Access

 

Archive Location:	Goddard Earth Sciences (GES) Data and Information Services Center (DISC)
Data Manager Contact Information:	Name: GES DISC Help Desk Address: NASA Goddard Space Flight Center  Code 610.2  Greenbelt, MD 20771 Telephone Voice: 1-301-614-5224 Fax: 301-614-5268 Electronic Mail: help-disc@listserv.gsfc.nasa.gov
Associated Costs:	Data are available to the public at no cost.

Principal Investigator Information

Charles H. Jackman, Project Scientist

Anne R. Douglass, Deputy Project Scientist

Refer to the UARS Project Science Office for additional information on the project scientists.

Instrument Principal Investigators
CLAES	Aidan E. Roche	Lockheed Palo Alto Research Laboratory
HALOE	James M. Russell III	NASA/Langley Research Center
HRDI	Paul B. Hays	University of Michigan
ISAMS	Fred Taylor	Oxford University, England
MLS	Joe W. Waters	NASA/Jet Propulsion Laboratory
PEM	J. David Winningham	Southwest Research Institute
SOLSTICE	Gary J. Rottman	University of Colorado
SUSIM	Tom Cook	Naval Research Laboratory
WINDII	Gordon Shepherd	York University, Canada

Additional information on the instrument principal investigators and co-investigators can be found by selecting a specific instrument on the UARS Project home page.

Theoretical and Collaborative Principal Investigators

Information on the UARS theoretical investigator team can be found on the UARS home page.

Guest Investigations in Support of the UARS Mission

Forty guest investigators were selected to use UARS measurements to improve knowledge of the atmosphere above the troposphere and of solar variability. UARS provides measurements relating to the chemistry, dynamics, and overall energy balance of the atmosphere primarily between about 15 and 100 km. The primary focus of these investigations will be on the physical and chemical problems of the stratosphere, mesosphere, and lower thermosphere. The investigators will rely on extensive theoretical activity, coupled with data and model analysis, to carry out their investigations.

References

1. Evaluation of the UARS Data, Reprinted from the Journal of Geophysical Research, American Geophysical Union publication, 1996
2. Reber, Carl A., The Upper Atmosphere Research Satellite, EOS Trans. AGU, 71, 1867, 1990.
3. 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.
4. Geophysical Research Letters, Vol. 20, 1993.
5. Upper Atmosphere Research Satellite, A Program to Study Global Ozone Change, NASA publication, 1989.
6. Mission Operations Report, Upper Atmosphere Research Satellite (UARS), NASA Report S-678-48-91-01.
7. Addtional UARS documentation can be located using the UARS Publication Search page.

Glossary of Terms

A number of science glossaries can be browsed via the GCMD List of Earth Science Acronyms and Glossaries page.

List of Acronyms:

Document Information

Change History

Version 2.0

Version baselined on addition to the GES Controlled Documents List, January 30, 1998.