Geoscience Reference
In-Depth Information
ionosphere (http://nova.stanford.edu/projects/mgs/eds-public.html).
Rishbeth and Mendillo
14
got the peak densities of the two Martian iono-
spheres layers measured by MGS during March 9-27, 1999, and compared
their properties with that of the terrestrial
E
and
F
1layers.Butforthe
majority of the profiles measured by MGS, the observational features of the
secondary layer have not been explored.
In this paper, more than 3,000 ionospheric electron profiles are used to
investigate the behaviors of the secondary layer.
2. Data Analysis
Among all of the accessible MGS data sets, two data sets are obtained
in periods both lasting for more than half year which is the longest and
hence suitable for statistical study. One period is from November 1, 2000
to June 6, 2001 (period I), the other is from November 1, 2002 to July 2,
2003 (period II).
The profiles can be catalogued into four types according to the appear-
ance of the secondary layer, say, the variation of the electron density
N
with the altitude
z
at the point of inflexion (as shown in Fig. 1):
∂N/∂z
=0 and
∂
2
N/∂
2
z<
0
,
Type 1 :
∂N/∂z
=0 and
∂
2
N/∂
2
z
=0
,
Type 2 :
Type 3 :
∂N/∂z >
0
,
Type 4 :
no inflexion
.
Fig. 1. Catalogues of the ionospheric profiles obtained by MGS/RS according to the
appearance of the secondary layer (see text for details).
