The internal seiche field in the changing South Aral Sea (2006–2013)
Internal standing waves (seiches) in the South Aral Sea are studied for the first time. The study, based on numerical simulations and field data, focuses on two different campaigns: the first in autumn 2006, when the stratification was weak and there was a mild prevailing northeasterly wind, and the...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-02-01
|
| Series: | Hydrology and Earth System Sciences |
| Online Access: | http://www.hydrol-earth-syst-sci.net/21/1093/2017/hess-21-1093-2017.pdf |
| Summary: | Internal
standing waves (seiches) in the South Aral Sea are studied for the first
time. The study, based on numerical simulations and field data, focuses on
two different campaigns: the first in autumn 2006, when the stratification
was weak and there was a mild prevailing northeasterly wind, and the second
in autumn 2013, when the stratification was strong and there was a mild
easterly wind. Between these two campaigns, the sea surface level decreased
by 3.2 m. The periods of the fundamental modes were identified as 36 and
14 h, respectively. In both years, either second or third vertical
modes were found. In general, the vertical modes in 2013 were higher because of the
broad and strong pycnocline. For both years, it was found that the deep
quasi-homogeneous mixed upper layer could sustain internal waves under
mild wind conditions. The observed first and second vertical modes in 2006
are the first and second horizontal modes and the second and third vertical modes
in 2013 are the second and third horizontal modes. The results suggest that, due
to sea level variations, the neck connecting the Chernyshev Bay to the main
body of the lake can become a critical location for the development of a
nodal line for all principal oscillation modes. Rotation effects on waves
were not analyzed in this study. |
|---|---|
| ISSN: | 1027-5606 1607-7938 |