Wind and Temperature Intermediate Data from the Wind and Temperature Spectrometer (WATS) Experiment on Dynamics Explorer-2
Entry ID: DE_WATS_1

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Summary
Abstract: The Wind and Temperature (WATS) experiment on the Dynamics Explorer-2
(DE-2) spacecraft consists of a closed source neutral mass
spectrometer with two rectangular baffles which are swept across the
incoming neutral beam. The modulation of the neutral flux by the
baffles allows measurement of the temperature and gas velocity. The
mass was commandable and was usually selected to be N2 or O.

The data set consists of neutral density temperature and vertical and
zonal winds for atomic mass number 28 and 16 (measured as 32). One or
two of these masses may be measured at the same time, but any
differences in the temperature or wind is thought to be due to
experimental error with the greatest error in the mass 16
measurements.

The data are called 'intermediate' because there are corrections that
need to be applied in order to produce a final data set. The
corrections are not fully understood at this time and new corrections
may sometimes be necessary. The value of the intermediate data set is
that it contains the original data without any loss of resolution and
it may be used, as is, for spectral analysis and by other
investigators who have already included in their programs some of the
correction factors. When new correction factors are calculated they
are sent to investigators instead of sending a new data set.

Each record in the data set consists of 11 4-byte words in binary format as
follows:

WORD TYPE CONTENTS
1 integer julian date
2 integer time in milliseconds
3 integer mode (3 or 4)=horizontal (5 or 6)=vertical
4 integer out/in flag 1=baffle going out 2=baffle going in
5 integer mass in amu - usually 28 or 32
6 real number density (number/cc)
7 real temperature (deg k)
8 real velocity (m/s) spacecraft coordinates
9 binary engineering bits
10 binary engineering bits
11 real velocity (m/s) geographic coordinates

The resolution is 2 4 6 or 8 seconds depending upon how many of the
two second measurements are repeated in the eight second measurement
cycle. A routine mode was two horizontal and two vertical
measurements which would give a time spacing of 2 6 2 6 2 6
.... seconds for the velocity and a resolution of 2 seconds for the
temperature which is obtained from both baffles. For higher time
resolution in density and composition information the DE-2 NACS
measurements should be used.

The error in the temperature is about 3% at an altitude of 250 km and
it increases with altitude proportional to the inverse of the square
root of the density of the mass being measured. Since the error
increases as the atmospheric density of the measured gas decreases,
the mass was usually selected to be the dominant species. The error
in the velocities is about 10 meters/second at 250 km with the same
altitude dependence as in the temperature. In addition to this
statistical error, there is an uncertainty of about 24 meters/second
in the velocity due to errors in angle sensing of the baffle arm.

The original version consists of data in the DE Sigma-9 tape library
with the velocity in spacecraft coordinates. A data tape contains one
file per satellite pass and is unsorted in time. The version
described here contains velocities in geographical coordinates and is
sorted in time.

For more information, background and access to data, see:
http://nssdc.gsfc.nasa.gov/space/

The three PI-generated WATS data tapes are available from NSSDC
(81-070B-04C). In addition NSSDC distributes the DE-2 Unified Abstract
(UA) tape which includes data from the NACS, WATS, LANG, FPI, RPA and
IDM instruments at 16 second time resolution (81-070B-04D). The
orbit/attitude files and associated software are included on the UA
tape, but not on the MAF tapes.

The variability of thermospheric and ionospheric parameters measured
by NACS, WATS and LANG is illustrated in a computer generated movie
that is available from NSSDC on video tape (81-070B-04A) or on 16mm
film (81-070B-04B). See:
http://nssdc.gsfc.nasa.gov/

Related URL
Link: GET DATA
Description: Access to WATS and other Dynamics Explorer Data


Geographic Coverage
 N: 90.0 S: -90.0  E: 180.0  W: -180.0

Data Set Citation
Dataset Originator/Creator: NASA
Dataset Title: Wind and Temperature Intermediate Data from the Wind and Temperature Spectrometer (WATS) Experiment on Dynamics Explorer-2
Online Resource: http://nssdc.gsfc.nasa.gov/


Temporal Coverage
Start Date: 1981-08-05
Stop Date: 1983-02-18


Location Keywords
GEOGRAPHIC REGION > GLOBAL
VERTICAL LOCATION > IONOSPHERE
VERTICAL LOCATION > THERMOSPHERE


Science Keywords
ATMOSPHERE >ATMOSPHERIC CHEMISTRY >TRACE GASES/TRACE SPECIES    [Definition]
ATMOSPHERE >ATMOSPHERIC WINDS >UPPER LEVEL WINDS    [Definition]
SPECTRAL/ENGINEERING >PLATFORM CHARACTERISTICS >ATTITUDE CHARACTERISTICS    [Definition]
SPECTRAL/ENGINEERING >PLATFORM CHARACTERISTICS >ORBITAL CHARACTERISTICS    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE PROPERTIES >PARTICLE DENSITY    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE PROPERTIES >PARTICLE SPEED    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE PROPERTIES >PARTICLE TEMPERATURE    [Definition]
SUN-EARTH INTERACTIONS >SOLAR ENERGETIC PARTICLE FLUX >NEUTRAL PARTICLE FLUX    [Definition]
ATMOSPHERE >ATMOSPHERIC CHEMISTRY >NITROGEN COMPOUNDS >MOLECULAR NITROGEN    [Definition]
ATMOSPHERE >ATMOSPHERIC CHEMISTRY >OXYGEN COMPOUNDS >MOLECULAR OXYGEN    [Definition]


ISO Topic Category
CLIMATOLOGY/METEOROLOGY/ATMOSPHERE
GEOSCIENTIFIC INFORMATION


Platform
DE-2 >Dynamics Explorer-2    [Information]


Instrument
SPECTROMETERS    [Information]
WATS >Wind and Temperature Spectrometer    [Information]


Keywords
IONOSPHERIC SCIENCE
SPACE PHYSICS
THERMOSPHERIC STUDIES


Originating Center
NASA/GSFC CODE 614


Data Center
National Space Science Data Center, Space Science Data Operation Office, Goddard Space Flight Center, NASA    [Information]
Data Center URL: http://nssdc.gsfc.nasa.gov/
Dataset ID: 81-070B-04A,B,C,D

Data Center Personnel
Name: DIETER BILITZA
Phone: 301-286-0190
Fax: 301-286-1771
Email: Dieter.Bilitza-1 at nasa.gov
Contact Address:
NASA
Goddard Space Flight Center
Mailstop 672.0
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


Personnel
DIETER BILITZA
Role: TECHNICAL CONTACT
Phone: 301-286-0190
Fax: 301-286-1771
Email: Dieter.Bilitza-1 at nasa.gov
Contact Address:
NASA
Goddard Space Flight Center
Mailstop 672.0
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


GEORGE R. CARIGNAN
Role: INVESTIGATOR
Email: carignan at engin.umich.edu
Contact Address:
College of Engineering
University of Michigan
2306 EECS Building
City: Ann Arbor
Province or State: MI
Postal Code: 48109-2116
Country: USA


ALAN E. HEDIN
Role: INVESTIGATOR


JOHN C. MAURER
Role: INVESTIGATOR
Contact Address:
Space Physics Research Laboratory
University of Michigan
City: Ann Arbor
Province or State: MI
Postal Code: 48104
Country: USA


HASSO B. NIEMANN
Role: INVESTIGATOR
Email: Hasso.B.Niemann at nasa.gov
Contact Address:
NASA
Goddard Space Flight Center
Mailstop 699.0
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


NELSON W. SPENCER
Role: INVESTIGATOR


LAWRENCE E. WHARTON
Role: INVESTIGATOR
Phone: 301-614-6121
Email: Lawrence.E.Wharton at nasa.gov
Contact Address:
NASA
Goddard Space Flight Center
Mailstop 613.2
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA


Publications/References
Spencer, N.W., L. E. Wharton, H. B. Niemann, A. E. Hedin, G. R. Carignan, and
J. C. Maurer, The Dynamics Explorer wind and temperature spectrometer, Space
Science Instrumentation, 5, 417-428, 1981.

Creation and Review Dates
Last DIF Revision Date: 2008-05-28

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