30
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
which is probably connected with the influence of runoff variations of the Lena river. The mean
values of Hand g for all the stations are H = 4.0 cm, g = 208°. The average tide Ssa for all the
stations gives the amplitude exceeding the predicted one based on the equilibrium theory by a
factor of 3.3. The average phase lag differs from the theoretical value (180°) by 28°. These
estimations of the tide Ssa suggest its existence being close to the dynamical form. The
perturbations of the observed tide Ssa are likely associated with the shallow-water constituents
such as S2 - K2 , T2 - R2 , KI - PI' Maksimov (1970) also represented the semi-annual tide as
a gravitational rather than a meteorological tide.
Vorobyev (1976) extracted the semi-annual tide using Fourier analysis from the yearly series
of sea level at 26 stations in Arctic seas for the years 1950-1970. Vorobyev's averages in the
Laptev sea are 4.5 cm for the observed amplitude and 188° for the phase lag. These results are
close to our mean values of the semi-annual tide and suggest that the harmonic constants of the
tide Ssa are stable.
Results were obtained for the solar third-annual tide Sta (121.75 days). The amplitude of the
tide Sta varies between 0.6 and 4.2 cm. The third-annual tide represents a meteorological rather
than gravitational tide.
The lunar elliptic tide Mm (27.55 days) has amplitude of 1.6 to 2.4 cm with the phase
changing eastward. The observed mean amplitude tide Mm (2.00 cm) in the Laptev sea is 1.45
times more than the mean equilibrium amplitude (with the factor 0.69). The observed phase
lags deviated from equilibrium (phase 180°) roughly by 50-80 degrees.
Vorobyev (1966) calculated the tides Mm and Mf using Darvin's method from yearly series
of the sea level at 4 stations in the Laptev sea. These results are, in general, less reliable than
ours given in Table 1. It has been found experimentally that a reliable extraction of these tides
is possible by analyzing uninterrupted daily mean series with duration of no less than 10 years.
Vorobyev' values for Tiksi (averaged for 14 years) of the tide Mm are 3.6 cm for the amplitude
and 239° for the phase. Our results are 2.30 cm for the amplitude and 240.2° for the phase.
Vorobyev's large value of the amplitude was caused mainly by noise.
Values of the admittance amplitudes and phases indicate that the Mm tide deviates much from
equilibrium tide. Apparently, the resonant conditions are observed in the Laptev Sea for the
period of about a month. In the Kara Sea according to our results for 20 stations the mean
admittance amplitude of the Mm tide constitutes only 0.98. It is possible that the monthly tide
may be influenced by local Rossby-like oscillations or the response driven by local or basinscale forcing by wind or atmospheric pressure (Miller et aI., 1993).
The distribution of the observed amplitude and phase of the Mf tide (13.66 days) in the
Laptev Sea exhibits deviations from equilibrium that are as large as those for the tide Mm. The
amplitude of the fortnightly tide in the central part of the sea constitute 0.8-1.2 cm and increases
up to 1.9 cm off the islands of Severnaya Zemlya. The phase has a progressive character of
eastward motion. The mean admittance amplitude of the tide Mf in the Laptev Sea equals 0.50.
Schwiderski (1982) computed the fortnightly tide in the Arctic Ocean. Schwiderski's model
results disagreed with the observed values because of his calculations had been based on
meagre data.
Analyses of spektra
Analysis of the spectral density maximum revealed that significant peaks were observed in
spectra of the daily mean sea-level for the periods 1 year, 28-30, 7-8, 5.2-5.3, 4.3, 3.0-3.3,
2.4-2.5 and 2.1-2.2 days (Figure 2). However, half-year peak and third- year peak indicated in
Dvorkin et al. (1989), Bannov-Baikov (1974) are poorly identified in our spectra. All the
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
which is probably connected with the influence of runoff variations of the Lena river. The mean
values of Hand g for all the stations are H = 4.0 cm, g = 208°. The average tide Ssa for all the
stations gives the amplitude exceeding the predicted one based on the equilibrium theory by a
factor of 3.3. The average phase lag differs from the theoretical value (180°) by 28°. These
estimations of the tide Ssa suggest its existence being close to the dynamical form. The
perturbations of the observed tide Ssa are likely associated with the shallow-water constituents
such as S2 - K2 , T2 - R2 , KI - PI' Maksimov (1970) also represented the semi-annual tide as
a gravitational rather than a meteorological tide.
Vorobyev (1976) extracted the semi-annual tide using Fourier analysis from the yearly series
of sea level at 26 stations in Arctic seas for the years 1950-1970. Vorobyev's averages in the
Laptev sea are 4.5 cm for the observed amplitude and 188° for the phase lag. These results are
close to our mean values of the semi-annual tide and suggest that the harmonic constants of the
tide Ssa are stable.
Results were obtained for the solar third-annual tide Sta (121.75 days). The amplitude of the
tide Sta varies between 0.6 and 4.2 cm. The third-annual tide represents a meteorological rather
than gravitational tide.
The lunar elliptic tide Mm (27.55 days) has amplitude of 1.6 to 2.4 cm with the phase
changing eastward. The observed mean amplitude tide Mm (2.00 cm) in the Laptev sea is 1.45
times more than the mean equilibrium amplitude (with the factor 0.69). The observed phase
lags deviated from equilibrium (phase 180°) roughly by 50-80 degrees.
Vorobyev (1966) calculated the tides Mm and Mf using Darvin's method from yearly series
of the sea level at 4 stations in the Laptev sea. These results are, in general, less reliable than
ours given in Table 1. It has been found experimentally that a reliable extraction of these tides
is possible by analyzing uninterrupted daily mean series with duration of no less than 10 years.
Vorobyev' values for Tiksi (averaged for 14 years) of the tide Mm are 3.6 cm for the amplitude
and 239° for the phase. Our results are 2.30 cm for the amplitude and 240.2° for the phase.
Vorobyev's large value of the amplitude was caused mainly by noise.
Values of the admittance amplitudes and phases indicate that the Mm tide deviates much from
equilibrium tide. Apparently, the resonant conditions are observed in the Laptev Sea for the
period of about a month. In the Kara Sea according to our results for 20 stations the mean
admittance amplitude of the Mm tide constitutes only 0.98. It is possible that the monthly tide
may be influenced by local Rossby-like oscillations or the response driven by local or basinscale forcing by wind or atmospheric pressure (Miller et aI., 1993).
The distribution of the observed amplitude and phase of the Mf tide (13.66 days) in the
Laptev Sea exhibits deviations from equilibrium that are as large as those for the tide Mm. The
amplitude of the fortnightly tide in the central part of the sea constitute 0.8-1.2 cm and increases
up to 1.9 cm off the islands of Severnaya Zemlya. The phase has a progressive character of
eastward motion. The mean admittance amplitude of the tide Mf in the Laptev Sea equals 0.50.
Schwiderski (1982) computed the fortnightly tide in the Arctic Ocean. Schwiderski's model
results disagreed with the observed values because of his calculations had been based on
meagre data.
Analyses of spektra
Analysis of the spectral density maximum revealed that significant peaks were observed in
spectra of the daily mean sea-level for the periods 1 year, 28-30, 7-8, 5.2-5.3, 4.3, 3.0-3.3,
2.4-2.5 and 2.1-2.2 days (Figure 2). However, half-year peak and third- year peak indicated in
Dvorkin et al. (1989), Bannov-Baikov (1974) are poorly identified in our spectra. All the