Geoscience Reference
In-Depth Information
Fig. 4.17
Modeled (from
left
to
right
): (
1
) electric potential difference map; (
2
) zonal and
(
3
) meridional components of the electric field generated by external electric current flowing
between the Earth and the ionosphere; and (
4
) regional map of the TEC deviations relative to
the nondisturbed conditions for 08 UT/03 LT (
top panel
) and 10 UT/05 LT (
bottom panel
).
Star
, earthquake epicenter position (Haiti);
diamond
, magnetically conjugated point;
black curve
,
terminator
reproduce the main features of the TEC variations. In both the GPS observations
and the model cases we have (1) areas of increased TEC exist and are localized in
the near-epicenter area; (2) magnetic conjugation took place; (3) TEC disturbances
at the magnetically conjugated area were stronger by magnitude than in the
near-epicenter region; (4) the amplitude of TEC enhancements reached 50% and
more; (5) negative structures (areas of the TEC reduction) existed westward and
equatorward relative to the positive ones; (6) approaching the sunrise terminator
with the well-conducting sunlit ionosphere triggered a shift of the anomaly to the
night side and caused the subsequent suppression of the TEC variations, both at
the epicenter and in the magnetically conjugated regions; and (7) the anomalies did
