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| Titel |
Observations of acoustic-gravity waves in the troposphere by lidar |
| VerfasserIn |
Olga Borchevkina, Ivan Karpov |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250102902
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| Publikation (Nr.) |
 EGU/EGU2015-2304.pdf |
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| Zusammenfassung |
| Many experimental researches reveal disturbances of the parameters of the upper atmosphere
and ionosphere caused by the development of strong weather disturbances, seismic events on
the surface, a tsunami generated by an underwater earthquake. The physical mechanisms that
implement these various communication layers of the atmosphere and determine the
morphological characteristics of ionospheric disturbances, remain insufficiently
understood.
Hypotheses about the influence of the processes in the lower atmosphere on the condition
of the upper atmosphere and ionosphere are based on the concept of generation of
acoustic-gravity (AGW) and internal gravity (IGW) waves in the lower atmosphere and their
distribution in the upper atmosphere. That is why, the study of the processes of
generation AGW in the lower atmosphere is interest to confirm the validity of such
representations.
Regular source of perturbations of all layers of the atmosphere is the solar terminator
(ST). Observations perturbation parameters of the atmosphere and ionosphere during the
passage of the ST will determine the frequency spectrum of the resulting disturbances.
The paper presents the results of experimental researches, which demonstrating an
increase of wave activity with periods of AGW and IGW in the observations of
the lower atmosphere during the passage of the solar terminator. Observations of
variations in the parameters of the lower atmosphere during the passage of ST were
performed by the lidar. The observations were carried out in Kaliningrad (52N, 22 E) in
2012-2014.
Analysis of the observations focused on the allocation of variations with periods ranging
from 2 to 20 min., caused by the generation of AGW in ST. The duration of each observation
was for several hours. This allows us to consider the dynamics of changes in the
characteristics of such variations during observations.
Analysis of the results of observations revealed a number of features in the dynamics of
AGW during the passage of ST.
1. Increasing the amplitude variations of parametres of the lower atmosphere and
ionosphere with periods of 2-10 min is clearly apparent during the passage of the solar
terminator on the observation point.
2. In observations clearly separated infrasonic components of variation and IGW. This is a
decrease in the amplitude variations with periods of 3-5 min. This behavior variations of
atmospheric parameters associated with the difference Brunt-Vaisala frequency and the
frequency of the acoustic cutoff.
Ionospheric observations of variations of the total electron content (TEC) of the
ionosphere also reveal variations with periods of AGW. Variations of the ionospheric TEC
parameter with periods of AGW (4-10 min.) are clearly seen during the passage of
the solar terminator and continue for 1-2 hours in the illuminated region of the
ionosphere. Gain variations of the ionosphere with such periods may be due to
acoustic-gravity waves propagating from the terminator in the lower atmosphere. |
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