ftp://spdf.gsfc.nasa.gov/pub/data/omni/high_res_omni/HRO_format.txt
This files gives the format of the High Resolution OMNI (HRO)
data set. The content of the HRO data set is much more fully explained
at http://omniweb.gsfc.nasa.gov/html/HROdocum.html
The common format for the 1-min and 5-min* OMNI data sets is
Year I4 1995 ... 2006
Day I4 1 ... 365 or 366
Hour I3 0 ... 23
Minute I3 0 ... 59 at start of average
ID for IMF spacecraft I3 See footnote D below
ID for SW Plasma spacecraft I3 See footnote D below
# of points in IMF averages I4
# of points in Plasma averages I4
Percent interp I4 See footnote A below
Timeshift, sec I7
RMS, Timeshift I7
RMS, Phase front normal F6.2 See Footnotes E, F below
Time btwn observations, sec I7 DBOT1, See Footnote C below
Field magnitude average, nT F8.2
Bx, nT (GSE, GSM) F8.2
By, nT (GSE) F8.2
Bz, nT (GSE) F8.2
By, nT (GSM) F8.2 Determined from post-shift GSE components
Bz, nT (GSM) F8.2 Determined from post-shift GSE components
See footnote "gsm" below
RMS SD B scalar, nT F8.2
RMS SD field vector, nT F8.2 See footnote E below
Flow speed, km/s F8.1
Vx Velocity, km/s, GSE F8.1
Vy Velocity, km/s, GSE F8.1
Vz Velocity, km/s, GSE F8.1
Proton Density, n/cc F7.2
Temperature, K F9.0
Flow pressure, nPa F6.2 See footnote G below
Electric field, mV/m F7.2 See footnote G below
Plasma beta F7.2 See footnote G below
Alfven mach number F6.1 See footnote G below
X(s/c), GSE, Re F8.2
Y(s/c), GSE, Re F8.2
Z(s/c), GSE, Re F8.2
BSN location, Xgse, Re F8.2 BSN = bow shock nose
BSN location, Ygse, Re F8.2
BSN location, Zgse, Re F8.2
Ancilary Data
AE-index, nT I6 See footnote H below
AL-index, nT I6 See footnote H below
AU-index, nT I6 See footnote H below
SYM/D index, nT I6 See footnote H below
SYM/H index, nT I6 See footnote H below
ASY/D index, nT I6 See footnote H below
ASY/H index, nT I6 See footnote H below
PC(N) index, F7.2 See footnote I below
Magnetosonic mach number F5.1 See Footnote K below
The data may be read with the format statement
(2I4,4I3,3I4,2I7,F6.2,I7, 8F8.2,4F8.1,F7.2,F9.0,F6.2,2F7.2,F6.1,6F8.2,7I6,F7.2, F5.1)
* Note For 5-min data we added fluxes from GOES at the end of each record
in format:
Proton Flux >10 MeV, 1/(cm**2-sec-ster) F9.2 See footnote J below
Proton Flux >30 MeV, 1/(cm**2-sec-ster) F9.2
Proton Flux >60 MeV, 1/(cm**2-sec-ster) F9.2
Footnote A:
Percent interp: The percent (0-100) of the points contributing to
the 1-min magnetic field averages whose phase front normal (PFN)
was interpolated because neither the MVAB-0 nor Cross Product
shift techniques yielded a PFN that satisfied its respective tests
(see detailed documentation for these).
Footnote C:
The DBOT (Duration Between Observing Times) words: For a
given record, we take the 1-min average time shift and estimate,
using the solar wind velocity and the location of the observing
spacecraft, the time at which the corresponding observation
would have been made at the spacecraft. Then we take the
difference between this time and the corresponding time of
the preceding 1-min record and define this as DBOT1. This
difference would be one minute in the absence of PFN and/or
flow velocity variations. When this difference becomes negative,
we have apparent out-of- sequence arrivals of phase planes.
That is, if plane A is observed before plane B at the spacecraft,
plane B is predicted to arrive at the target before plane A.
Searching for negative DBOT enables finding of such cases.
DBOT2 is like DBOT1 except that the observation time for
the current 1-min record is compared to the latest (most time-
advanced) previous observation time and not to the observation
time of the previous record. Use of DBOT2 helps to find
extended intervals of out-of-sequence arrivals.
We do not capture out-of-sequence-arrival information at 15-s
resolution but only at 1-min resolution. The standard deviation
in the 1-min averaged time shifts may be used to help find cases
of out-of-sequence 15-s data.
Footnote gsm:
The computation of standard By and Bz, GSM is taken from the GEOPACK-2008
at http://geo.phys.spbu.ru/~tsyganenko/Geopack-2008.html)
software package developed by Drs. Nikolai Tsyganenko.
Footnote D:
The following spacecraft ID's are used:
ACE 71
Geotail 60
IMP 8 50
Wind 51
Footnote E:
Note that standard deviations for the two vectors are given
as the square roots of the sum of squares of the standard deviations
in the component averages. The component averages are given in
the records but not their individual standard deviations.
Footnote F:
There are no phase front normal standard deviations in the 5-min
records. This word has fill (99.99) for such records.
Footnote G:
Derived parameters are obtained from the following equations.
Flow pressure = (2*10**-6)*Np*Vp**2 nPa (Np in cm**-3,
Vp in km/s, subscript "p" for "proton")
Electric field = -V(km/s) * Bz (nT; GSM) * 10**-3
Plasma beta = [(T*4.16/10**5) + 5.34] * Np / B**2 (B in nT)
Alfven Mach number = (V * Np**0.5) / (20 * B)
For details on these, see http://omniweb.sci.gsfc.nasa.gov/ftpbrowser/bow_derivation.html
Footnote H:
Provisional high res. Indices where taken from World Data Center for Geomagnetism,
Kyoto: http://swdcwww.kugi.kyoto-u.ac.jp/aeasy/
Footnote I:
PC(N) index was taken from World Data Center for Geomagnetism, Copenhagen:
href="ftp://ftp.space.dtu.dk/WDC/indices/pcn/PCN_definitive/"
Footnote J:
Proton fluxes from GOES were taken from http://satdat.ngdc.noaa.gov/sem/goes/data/new_avg/
Footnote K: Magnetosonic Mach Number = V/Magnetosonic_speed
Magnetosonic speed = [(sound speed)**2 + (Alfv speed)**2]**0.5
The Alfven speed = 20. * B / N**0.5
The sound speed = 0.12 * [T + 1.28*10**5]**0.5
About Magnetosonic speed check http://ftpbrowser.gsfc.nasa.gov/bow_derivation1.html also
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