UARS Particle Environment Monitor (PEM) Level 3AT V001 (UARPE3AT) at GES DISC
Entry ID: GES_DISC_UARPE3AT_V001

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Summary
Abstract: The Particle Environment Monitor (PEM) on NASA's Upper Atmosphere
Research Satellite (UARS) measures the type, amount, energy, and
distribution of charged particles injected into the Earth's
thermosphere, mesosphere, and stratosphere.

DESCRIPTION:

PEM consists of four instruments: the Atmospheric X-Ray Imaging
Spectrometer (AXIS), the High Energy Particle Spectrometer (HEPS), the
Medium Energy Spectrometer (MEPS), and the Vector Magnetometer (VMAG).
AXIS produces global images of brehmstrahlung X-rays produced by
energetic electrons incident upon the atmosphere in the 3 to 100 keV
range. The instrument is made up of 16 silicon detector modules that
view the Earth limb-to-limb. The HEPS and MEPS instruments provide
in-situ measurements of precipitating electrons and protons. HEPS
measures electrons in 32 logarithmic steps from 30 keV to 5000 keV,
and protons are measured in 32 logarithmic steps from 0.10 MeV to 150
MeV. The MEPS instrument measures the local particle population in
the energy range from 1 eV to 32000 eV, generating a 31 point
logarithmic energy spectra every 2 seconds. MEPS consisted of five
analyzer heads that determined the electron and ion population.
Finally, the VMAG instrument observes the local magnetic field using a
3-axis fluxgate magnetometer.

The PEM instruments are distributed across the UARS spacecraft. Two
HEPS (HEPS1 and HEPS2), one MEPS (ZMEPS), and the VMAG instrument are
located on a zenith looking boom, called the Zenith Energetic Particle
System (ZEPS). An Earth pointing boom, the Nadir Energetic Particle
System (NEPS), contains one HEPS (HEPS3) and one MEPS (NMEPS). The
AXIS instrument is mounted separately on the forward part of the UARS
platform.

DATA PRODUCTS:

PEM_L3AT_DAILY
--------------

The PEM level 3AT data are time-ordered profiles spaced at intervals
of 1 UARS minute (65.536 seconds), or approximately 495 km along the
tangent track. The level 3AT format is common to all UARS instruments
to allow for intercomparison. The PEM level 3AT data consist of 18
granules per day. A data granule is defined as one PEM subtype per
day. The following subtypes are available:

1. EDEP3AT_ELEC - electron energy deposition
2. EDEP3AT_P01 - x-ray pixel 01 energy deposition
3. EDEP3AT_P02 - x-ray pixel 02 energy deposition
4. EDEP3AT_P03 - x-ray pixel 03 energy deposition
5. EDEP3AT_P04 - x-ray pixel 04 energy deposition
6. EDEP3AT_P05 - x-ray pixel 05 energy deposition
7. EDEP3AT_P06 - x-ray pixel 06 energy deposition
8. EDEP3AT_P07 - x-ray pixel 07 energy deposition
9. EDEP3AT_P08 - x-ray pixel 08 energy deposition
10. EDEP3AT_P09 - x-ray pixel 09 energy deposition
11. EDEP3AT_P10 - x-ray pixel 10 energy deposition
12. EDEP3AT_P11 - x-ray pixel 11 energy deposition
13. EDEP3AT_P12 - x-ray pixel 12 energy deposition
14. EDEP3AT_P13 - x-ray pixel 13 energy deposition
15. EDEP3AT_P14 - x-ray pixel 14 energy deposition
16. EDEP3AT_P15 - x-ray pixel 15 energy deposition
17. EDEP3AT_P16 - x-ray pixel 16 energy deposition
18. EDEP3AT_PROT - proton energy deposition

Units for energy deposition rate are in [erg/cm**3/sec]. The
horizontal resolution of the level 3AT data product is about 495 km
along the tangent track. The vertical resolution for the level 3AT
PEM profiles is defined by the UARS altitude levels (in km) given by:

Z(i) = 5 * i, i <= 12
Z(i) = 60 + (i - 12) * 3, 13 <= i <= 32
Z(i) = 120 + (i - 32) * 10, 33 <= i <= 50

The electron and proton energy deposition level 3AT data are produced
from the level 2 HEPS and MEPS data, and gridded to the 65.535 second
level 3AT format. Data is only produced at times when there are
simultaneous HEPS and MEPS measurements. For higher resolution there
is the special PEM level 3TP data product.

PEM_L3TP_DAILY
--------------

The PEM level 3TP data are a special data product, and should not be
confused with the level 3TP parameter files produced for the UARS MLS,
HALOE, ISAMS, and WINDII. The PEM 3TP data provide a higher temporal
resolution than the level 3AT data, and contain the HEPS and MEPS data
in separate files. The HEPS data are at 65.536 second resolution, and
the MEPS data are at 2.048 second resolution. The PEM level 3TP data
consist of 4 granules per day:

1. HEPS_ELEC_ED - HEPS electron energy deposition
2. HEPS_PROT_ED - HEPS proton energy deposition
3. MEPS_ELEC_ED - MEPS electron energy deposition
4. MEPS_PROT_ED - MEPS proton energy deposition

Vertical resolution and data units are the same as for the level 3AT data.

Related URL
Link: GET DATA > MIRADOR
Description: Access UARS UARPE3AT Data Product


Link: VIEW RELATED INFORMATION > USER'S GUIDE
Description: README


Geographic Coverage
 N: 80.0 S: -80.0  E: 180.0  W: -180.0

Data Set Citation
Dataset Originator/Creator: Southwest Research Institute, NASA/GSFC
Dataset Title: UARS Particle Environment Monitor (PEM) Level 3AT
Version: 001
Online Resource: http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?t...


Temporal Coverage
Start Date: 1991-10-01


Location Keywords
GEOGRAPHIC REGION > GLOBAL
VERTICAL LOCATION > MESOSPHERE
VERTICAL LOCATION > STRATOSPHERE
VERTICAL LOCATION > THERMOSPHERE


Science Keywords
SPECTRAL/ENGINEERING >X-RAY >X-RAY FLUX    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE FLUX >ELECTRON FLUX    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE PROPERTIES >ENERGY DEPOSITION    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE FLUX >PROTON FLUX    [Definition]
SUN-EARTH INTERACTIONS >IONOSPHERE/MAGNETOSPHERE DYNAMICS >MAGNETIC FIELDS/MAGNETIC CURRENTS    [Definition]


ISO Topic Category
GEOSCIENTIFIC INFORMATION
IMAGERY/BASE MAPS/EARTH COVER


Platform
UARS >Upper Atmosphere Research Satellite    [Information]


Instrument
PEM >Particle Environment Monitor    [Information]


Project
EOSDIS >Earth Observing System Data Information System    [Information]
ESIP >Earth Science Information Partners Program    [Information]
UARS >Upper Atmosphere Research Satellite    [Information]
CWIC >CEOS WGISS Integrated Catalog    [Information]


Keywords
DAILY DATA
ELECTRONS
ENERGY DEPOSTITION
ENERGY DEPOSTITION RATE
EOSDIS
FIELDS AND PARTICLES
IDN_NODE GSFC/GSFC_DAAC
MIDDLE ATMOSPHERE
PEM LEVEL 3AT
PEM LEVEL 3TP
PROTONS
UPPER ATMOSPHERE
WWW
X-RAY FLUX
X-RAYS


Originating Center
GSFC_DAAC


Data Center
Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA    [Information]
Data Center URL: http://disc.gsfc.nasa.gov/
Dataset ID: PEM 3AT
Dataset ID: PEM 3TP

Data Center Personnel
Name: GES DISC HELP DESK SUPPORT GROUP
Phone: 301-614-5224
Fax: 301-614-5268
Email: gsfc-help-disc at lists.nasa.gov
Contact Address:
Goddard Earth Sciences Data and Information Services Center
Code 610.2
NASA Goddard Space Flight Center
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


Personnel
JAMES EDWARD JOHNSON
Role: DIF AUTHOR
Phone: 301-614-5121
Email: James.Johnson at nasa.gov
Contact Address:
NASA Goddard Space Flight Center
Code 610.2
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


J. DAVID WINNINGHAM
Role: INVESTIGATOR
Phone: (210) 522-3075
Email: dwinningham at swri.edu
Contact Address:
Space Science Department
Southwest Research Institute
P.O. Drawer 28510
City: San Antonio
Province or State: TX
Postal Code: 78228-0510
Country: USA


Publications/References
Chenette, D.L., D.W.Datlowe, W.L.Imhof, T.L.Schumaker, and J.D.Tobin,
Global spectroscopy and imaging of atmospheric X-ray bremsstrahlung:
Instrumentation and initial results from the PEM/AXIS instrument
aboard the Upper Atmosphere Research Satellite, SPIE Vol. 1745, 1992.

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.

Winningham, J. D., et al., The UARS Particle Environment Monitor,
J. Geophys. Res. 98, D6, 10763-10775, 1993.

"Instrument Systems Description Document for the UARS Particle Environment
Monitor (PEM)," Southwest Research Institute Document 7845-IS-1, San Antonio,
Texas, (October 1990).

Creation and Review Dates
DIF Creation Date: 2007-02-26
Last DIF Revision Date: 2009-08-21

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