PROBLEMS OF GEOCOSMOS

Proceedings of the 7th International Conference "Problems of Geocosmos" (St. Petersburg, Russia, 26-30 May 2008)
data of the towed installation with diverse in space by magnetometers [Fonarev et al., 1997]. In case of
MAGSAT, CHAMP satellite magnetic measurement surveys of such capability is not present. However, in
case of satellite magnetic surveys on the recurring orbits with very close coordinates, is possible that also
allows successfully use the DSTM method. In the solution of this problem the large help can be rendered by
reliable satellite magnetic measurements by vehicles “МАGSАТ” and “СНАМР” [Rotanova et al., 2004;
Rotanova et al., 2005]. The doubtless virtue of satellite surveys consists of speed of realization of magnetic
measurements in huge territories that saves to correct of errors connected with the changes of the secular
variation of the geomagnetic field. But thus, observed geomagnetic field from “СНАМР”, “MAGSAT”
artificial satellites of the Earth (ASE) is total reflection of various determined and random physical processes
and appearances happening in various layers of the Earth. By one from methods of separation of a magnetic
field of the Earth is a method of differential magnetic measurement.
The “СНАМР” or “MAGSAT” satellite survey of the geomagnetic field in considered temporary
period, it can be presented as a sum of “constant” and “permanent” fields stipulated by sources, located both
inside the Earth, and outside of boundaries of the hard Earth (magnetosphere sources) [Kharitonov et al.,
2005]. It is possible to consider study spatial-temporary structures of the geomagnetic field (Fs), measured
aboard satellites [Rotanova et al., 1999, Tsvetkov et al., 2004] as a sum of vectors of several components of
geomagnetic field:
Fs(ϕ, λ, h, t) = Fm(ϕ, λ, h, t) + Fa(ϕ, λ, h, t) + Fv(ϕ, λ, h, t), (1)
where Fm – the component of vector of an induction of the main geomagnetic field stipulated by sources in
the core of the Earth; Fa – the component of vector of an induction of the geomagnetic field stipulated by
heterogeneities of mantle of the Earth; Fv - component of vector of an induction of the permanent
geomagnetic field stipulated by sources external magnetosphere origin and irregular earthquake signals; ϕ,
λ, h, t – geographic latitude, longitude, altitude and time of measurement point.
Usually for the description of a main geomagnetic field is used the spherical harmonic series of the
Gauss. For calculations the model of the main geomagnetic field with the length of a series equal to 13
harmonics developed [Bondar et al., 2000]. For the analysis of a spatial structure of the geomagnetic field
conducted mathematical processing and interpretation along 100 orbits ASE “СНАМР” covering territory
from 0 up to 60 degrees of east longitude and within the limits of geographical altitudes from + 60 up to - 60
degrees [Rotanova et al., 2005].
Thus, the difference fields for each from selected of hundred orbits was calculated. The obtained
thus difference fields are stipulated external magnetosphere current systems and internal sources of the
Earth: by a magnetization at the Earth’s crust, electromagnetic heterogeneities in the mantle of the Earth, is
present small component, connected with accidental errors of measurements.
One from methods of allocation of a magnetic field connected with the interned Earth’s mantle
heterogeneities of researched regions at a hum noise of the field connected with external solarmagnetosphere
sources and earthquakes too are the methods differential magnetic investigations [Fonarev et
al., 1997; Fonarev, 2005, Kharitonov et al., 2005; Tsvetkov et al., 2004]. As, was shown above, from the
satellite measured data the main magnetic field (Fs) was previously eliminated. The residual field is present
in regional magnetic anomalies of mantle origin (Fa) and variation of a variable magnetic field (Fv). In the
schedule of change of values of the module (Ba), the vertical component (Za), the east component (Ya) of the
incremental geomagnetic field, northern component (Xa) of the incremental geomagnetic field is shown,
which a visible, that in all components of an incremental geomagnetic field is very complex on a hum noise
of anomalies. For extraction from the satellite magnetic data of the anomalies of the external origin and the
earthquake signals we shall consider the formulas differential magnetic investigations, from which we leaned
at computer calculations [Fonarev et al., 1997; Fonarev, 2005; Kharitonov et al., 2005; Kharitonov et al.,
2006]. If the satellite is gone rectilinearly along an axis Х with the speed ϋ, the magnetometer installed on
board of satellite, through a slice of time equal Δt = 1 s can calculate through expression
F(ϕ, λ, h, t) = Fs(ϕ, λ, h, t) [exp(- i w Δt) – 1] exp(- i w t), (2)
where Fs - component of vector of an induction, w = (2π / T) - circular frequency of the measured field.
It is possible to determine of slice of times Δtv and Δtа, at which difference of the residual
geomagnetic field under the data of the satellite СНАМР Fv and Fa will be less sensitivity of the
magnetometer (έ) installed on board this satellite, from the formula (3).
Δtv < ε / (Wv Fv), Δtа < ε / (Wа Fа) (3)
However, there is one limitation of the given DSTM method, when it is impossible to divide variations of the
variable geomagnetic field called by sources of the external origin and earthquake signals and measured on
band of the satellite by anomalies of the “constant” field, created by sources in the lithosphere of the Earth.
Wа Fa = Wv Fv (4)
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