AMPTE DATABASE REGENERATION - Structure of UKS databases


Document No.  92064PRO0155
Date          23 September 1992
Author        M A Hapgood
Title         Structure of UKS databases
Project       AMPTE DATABASE REGENERATION
Organisation  SPACE SCIENCE DEPARTMENT
              RUTHERFORD APPLETON LABORATORY
              SCIENCE AND ENGINEERING RESEARCH COUNCIL


1. INTRODUCTION

This document describes the current structure of the UKS catalogues in the AMPTE database. All files are held on computer.

1.1 TIME AND ORBIT FIELDS

The following standard field names are used in most files.

    UTY    = Year (two digits)
    UTD    = Day number in year (Jan 1 = Day 1)
    ORBIT  = AMPTE-UKS orbit number
    PASS   = Spacecraft motion relative to Earth: A=outbound, B=inbound

All these fields have dimension 1. Three of them, ORBIT, UTY and UTD, are type S (two byte integers). PASS is a character field (type C). The numeric fields all have zero null values.

1.2 DURATION FIELDS

Several files contain 'durations' which define periods of time by specifying the beginning and end of the period, e.g. to describe the crossing of a region of the magnetosphere. Each time is given as a UT hour and as seconds in the hour. Durations occupy two R-EXEC fields each of dimension 2. The first field holds UT hours and the second field holds the seconds of the hour. Values for the start time are held in the first element of each field and those for the end time in the second element. For example, a period from 10:30 to 11:20 UT would be recorded as (10,11) and (1800,1200). All elements are two byte integers (type S).

2. CATALOGUES OF OPERATIONAL DETAILS

2.1 DATA-TAKING PERIODS

This catalogue (sometimes called the ORBITS catalogue) lists all data-taking periods for AMPTE-UKS. It is in file UKS_ORBITS.REX in directory GDF[DUA0:[GDF_CATALOGUE.AMPTE.UKS].

2.1.1 COMPILATION

The catalogue was compiled in 1985 by Peter A. Smith. The catalogue criterion was an examination of summary plots.

2.1.2 DEFINITION

 
Name             Dim  Type   Width  Dec  Null              Bytes
------------  ------  ----  ------  ---  ---------------  ------
UTY                1  S          2    -                0       2
UTD                1  S          3    -                0       2
UTH                2  S          2    -                0       4
Seconds            2  S          6    -                0       4
ORBIT              1  S          5    -                0       2
PASS               1  C          2    -                        2
IRMhr              2  S          2    -               -1       4
IRMsec             2  S          6    -               -1       4
AP                 1  S          3    -                0       2
GAPS               1  C          5    -                        5
SCIENTIST          1  C         13    -                       13

where:

 
    UTH,Seconds  =  Data taking period (duration).

    IRMhr,IRMsec =  Corresponding IRM data-taking period (duration).

    AP           =  The Ap index of geomagnetic activity on this day.

    GAPS         =  Code to indicate the presence of gaps in the data
                    series, e.g. LARGE, FEW. * = ?; blank =?.

    SCIENTIST    =  Name of duty scientist during the data taking period.

Note that the Ap index is not considered to have any units.

2.2 EPHEMERIS INFORMATION

This catalogue lists information on the orbits of UKS and IRM. It is in file POSITION.REX in directory GDF[DUA0:[GDF_CATALOGUE.AMPTE].

The ephemeris contains several vector fields. These are reals (type R) with dimension 3. The three elements are X, Y and Z components in GSE coordinates.

2.2.1 COMPILATION

The catalogue was compiled in 1985 by Peter A. Smith. Positions and velocities were calculated from orbital elements using GEODYN software. UKS elements were determined by tracking and analysis at RAL. IRM elements were supplied from Germany. The spacecraft separation distance was determined by VHF transponder for the first month of operation. Following transponder failure, this distance was estimated by measuring the time separation between UKS and IRM flying through the beam of the receiving antenna at RAL. The vector separation was estimated by subtraction of individual spacecraft positions.

2.2.2 DEFINITION

 
Name             Dim  Type   Width  Dec  Null              Bytes
------------  ------  ----  ------  ---  ---------------  ------
UTY                1  S          2    -                0       2
UTD                1  S          3    -                0       2
UTH                1  S          2    -                0       2
Seconds            1  S          6    -                0       2
SEPARATION         1  R         10    1          0.00000       4
UKS                3  R          6    2          0.00000      12
UKS_IRM            3  R          7    1          0.00000      12
UKSVEL             3  R          7    2          0.00000      12
IRMVEL             3  R          7    2          0.00000      12
IRM                3  R          6    2          0.00000      12
MJD                1  P         11    5  0.0000000000000       8
DAY                1  P          9    5  0.0000000000000       8
UTM                1  S          2    -                0       2

where:

 
    UTH        =  Hours of Universal Time.

    Seconds    =  Seconds of Universal Time within an hour.

    SEPARATION =  Distance between UKS and IRM (in km).

    UKS        =  Position of UKS (in Earth radii).

    UKS_IRM    =  UKS to IRM separation vector (in km).

    UKSVEL     =  Velocity of UKS (in km/s).

    IRMVEL     =  Velocity of IRM (in km/s).

    IRM        =  Position of IRM (in Earth radii).

    MJD        =  Time expressed in Modified Julian Days.

    DAY        =  Time in days from 0UT on 31 December of preceding year.

    UTM        =  Minutes of Universal Time within an hour.

Note that MJD is time measured in days from 00:00 hours Universal Time on 17 November 1858. This is the standard textbook definition of MJD; some groups (e.g. ESOC) use different non-standard definitions.

The non-standard time fields DAY and UTM at the end of each record are provided to maintain compatibility with GDF software. It is not anticipated that this will have any impact on the interface with ESIS.

2.3 COMMENTS LOG

This catalogue lists comments on spacecraft performance. It is in file UKS_COMMENTS.REX in directory GDF[DUA0:[GDF_CATALOGUE.AMPTE.UKS].

2.3.1 COMPILATION

The catalogue was compiled in 1985 by Trefor Edwards from the log recorded manually during spacecraft operations in 1984/5.

2.3.2 DEFINITION

Name             Dim  Type   Width  Dec  Null              Bytes
------------  ------  ----  ------  ---  ---------------  ------
UTY                1  S          2    -                0       2
UTD                1  S          3    -                0       2
ORBIT              1  S          5    -                0       2
PASS               1  C          2    -                        2
SEQNO              1  I          5    -               -1       4
COMMENTS           1  C         51    -                       51

where:

 
    SEQNO    = Reference number of comment. Sequential within each
               data-taking period.

    COMMENTS = Comment as free text.

3. PHENOMENOLOGICAL CATALOGUES

3.1 UKS CROSSINGS OF MAGNETOSPHERIC BOUNDARIES

This catalogue lists crossings of the bow shock and the magnetopause which were observed by AMPTE-UKS. It is in file UKS_BOUNDARY.REX in directory GDF[DUA0:[GDF_CATALOGUE.AMPTE.UKS].

3.1.1 COMPILATION

The catalogue was compiled in 1985 by Peter A. Smith. The criterion for determining a crossing was to find abrupt changes in the magnetic field and/or particle distributions during an examination of summary plots and spectrograms.

3.1.2 DEFINITION

 
Name             Dim  Type   Width  Dec  Null              Bytes
------------  ------  ----  ------  ---  ---------------  ------
UTY                1  S          2    -                0       2
UTD                1  S          3    -                0       2
UTH                1  S          2    -                0       2
Seconds            1  S          6    -                0       2
ORBIT              1  S          5    -                0       2
PASS               1  C          2    -                        2
BDY                1  C          2    -                        2
X                  1  R          5    2          0.00000       4
Y                  1  R          6    2          0.00000       4
Z                  1  R          5    2          0.00000       4
R                  1  R          5    2          0.00000       4
DIST               1  R          6    2          0.00000       4

where:

 
    UTH,Seconds =  Universal Time of boundary crossing

    BDY         =  Which boundary: magnetopause (MP) or bow shock (BS).

    X,Y,Z       =  GSE coordinates of the boundary crossing in
                   Earth radii.

    R           =  radial distance of the boundary crossing in
                   Earth radii.

    DIST        =  sub-solar distance of the magnetopause or bow shock
                   boundary computed using Fairfield's model, in
                   Earth radii.

3.2 UKS OBSERVATIONS OF SPACE PLASMA REGIONS

This catalogue lists periods when AMPTE-UKS made measurements in particular regions of the space plasma environment. It is in file UKS_REGIONS.REX in directory GDF[DUA0:[GDF_CATALOGUE.AMPTE.UKS].

3.2.1 COMPILATION

The catalogue was compiled in 1985 by Peter A. Smith. The criterion for determining the catalogue was to divide each data-taking period into a series of one or more intervals (in different regions) using the boundary crossing times to define the transition from one region to the next. Thus this catalogue is a refinement of the catalogues of data-taking periods and boundary crossings.

3.2.2 DEFINITION

Name             Dim  Type   Width  Dec  Null              Bytes
------------  ------  ----  ------  ---  ---------------  ------
UTY                1  S          2    -                0       2
UTD                1  S          3    -                0       2
UTH                2  S          2    -                0       4
Seconds            2  S          6    -                0       4
ORBIT              1  S          5    -                0       2
PASS               1  C          2    -                        2
REGION             1  C          3    -                        3
VEL                1  I          4    -               -1       4

where:

 
    UTH,Seconds =   Data-taking period in region (duration field).

    REGION      =   Which region the UKS is in: magnetosphere (MSP),
                    magnetosheath (MSH) or solar wind (SW).

    VEL         =   Solar wind speed (in km/s) measured by UKS (available
                    only if REGION=SW). 

3.3 FLUX TRANSFER EVENTS OBSERVED BY UKS

This is a catalogue of flux transfer events (FTEs) observed by the AMPTE-UKS magnetometer. It is in file UKS_FTECAT.REX in directory GDF[DUA0:[GDF_CATALOGUE.AMPTE.UKS].

3.3.1 COMPILATION

The catalogue was compiled in 1986 by Mark Saunders and Richard Rijnbeek of Imperial College. The events were identified according to the criterion developed by Rijnbeek etal. (1984) in an analysis of FTEs observed on the ISEE 1 and 2 spacecraft. This criterion is a magnetic perturbation in the boundary normal component of the magnetic field with duration > 1 min and a peak-to-peak magnitude > 10 nT. A survey of the catalogued events is available in the paper by Southwood et al. (1986).

The data were typed in by Mike Hapgood from a paper listing held by Dave Hall and dated 16 January 1986.

3.3.2 DEFINITION

 
Name             Dim  Type   Width  Dec  Null              Bytes
------------  ------  ----  ------  ---  ---------------  ------
UTY                1  S          2    -                0       2
UTD                1  S          3    -                0       2
UTH                1  S          2    -               99       2
Seconds            1  S          6    -             5940       2
Quality            1  C          1    -                        1
ORBIT              1  S          5    -                0       2
PASS               1  C          1    -                        1
Location           1  C          5    -                        5
Polarity           1  C          3    -                        3
MPhr               1  S          2    -                0       2
MPsec              1  S          6    -                0       2
MPq                1  C          1    -                        1
R                  1  R          4    1         -9.90000       4
LT                 2  B          2    -               99       2
GSMlat             1  R          5    1        -99.90000       4

where:

    UTH,Seconds =  Universal Time of FTE

    Quality     =  Quality of FTE time: blank=OK, ?=uncertain

    Location    =  Region in which FTE occurs: BL = boundary layer,
                   MS = magnetosheath, MP = magnetopause.

    Polarity    =  FTE polarity (see notes below).

    MPhr,MPsec  =  Universal Time of magnetopause crossing

    MPq         =  Quality of crossing time: blank=OK, E=?, P=?

    R           =  Radial distance at magnetopause in Earth radii
 
    LT          =  GSM local time (hours and minutes) at magnetopause
                   crossing (as two separate integer elements storing
                   hours and minutes).

    GSMlat      =  GSM latitude at magnetopause crossing in degrees.

Polarity is defined as follows:

REFERENCES

  1. Rijnbeek, R.P., Cowley, S.W.H., Southwood, D.J. and Russell, C.T. (1984) "A survey of dayside flux transfer events observed by ISEE 1 and 2 magnetometers", J. Geophys. Res. 89, 786-800.

  2. Southwood, D.J., Saunders, M.A., Dunlop, M.W., Mier-Jedrzejowicz, W.A.C. and Rijnbeek, R.P. (1986) "A survey of flux transfer events recorded by the UKS spacecraft magnetometer", Planet. Space Sci. 34, 1349-1359.


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