TY - JOUR

T1 - Shelf Waves in the Great Australian Bight Based on Satellite Altimetry Data

AU - Sandalyuk, N. V.

AU - Belonenko, T. V.

AU - Koldunov, A. V.

N1 - Publisher Copyright: © 2021, Pleiades Publishing, Ltd.

PY - 2021/12

Y1 - 2021/12

N2 - Abstract: In this study we analyze shelf waves in the Great Australian Bight using satellite altimetry data. The phase velocity of the first mode of topographic waves is shown to be 1.8 m/s for an average shelf width of 200 km and 2.7 m/s for a maximal shelf width of 300 km. The estimates of the phase velocity are in good agreement with the estimates calculated from the spacetime spectra. Waves with periods of 22, 30, and 38 days are identified from the graphs of two-dimensional FFT spectra. The wavelengths of the identified periods vary over a wide range from 1500 to 2500 km. The theoretical dispersion curves correspond to the empirical parameters of topographic waves for a period of 38 days. Using the maximal cross-correlation method (averaging over the period 1993–2018), we can divide the Great Australian Bight water area into two parts: on the shelf, waves are directed eastward at an average velocity of 20 cm/s (averaging over 26 years); in the rest of the water area, the Rossby waves propagate westward at a velocity of up to 15 cm/s. The method of decomposing time series into fluctuations of a certain period confirm the results of the analysis of two-dimensional spectra. The intensity of oscillations is found to vary significantly in time and space. Spatiotemporal diagrams of level fluctuations with periods of 22, 30, and 38 days along the contours of 50, 100, and 200 m show a significant variability of the wave velocity both in time and on various segments of the contour. For all three contours, the wave velocity increases in the eastern part of the Great Australian Bight compared to other parts of the shelf.

AB - Abstract: In this study we analyze shelf waves in the Great Australian Bight using satellite altimetry data. The phase velocity of the first mode of topographic waves is shown to be 1.8 m/s for an average shelf width of 200 km and 2.7 m/s for a maximal shelf width of 300 km. The estimates of the phase velocity are in good agreement with the estimates calculated from the spacetime spectra. Waves with periods of 22, 30, and 38 days are identified from the graphs of two-dimensional FFT spectra. The wavelengths of the identified periods vary over a wide range from 1500 to 2500 km. The theoretical dispersion curves correspond to the empirical parameters of topographic waves for a period of 38 days. Using the maximal cross-correlation method (averaging over the period 1993–2018), we can divide the Great Australian Bight water area into two parts: on the shelf, waves are directed eastward at an average velocity of 20 cm/s (averaging over 26 years); in the rest of the water area, the Rossby waves propagate westward at a velocity of up to 15 cm/s. The method of decomposing time series into fluctuations of a certain period confirm the results of the analysis of two-dimensional spectra. The intensity of oscillations is found to vary significantly in time and space. Spatiotemporal diagrams of level fluctuations with periods of 22, 30, and 38 days along the contours of 50, 100, and 200 m show a significant variability of the wave velocity both in time and on various segments of the contour. For all three contours, the wave velocity increases in the eastern part of the Great Australian Bight compared to other parts of the shelf.

KW - altimetry

KW - dispersion curves

KW - Great Australian Bight

KW - sea level anomalies

KW - shelf waves

UR - http://www.scopus.com/inward/record.url?scp=85124943196&partnerID=8YFLogxK

U2 - 10.1134/S0001433821090619

DO - 10.1134/S0001433821090619

M3 - Article

AN - SCOPUS:85124943196

VL - 57

SP - 1117

EP - 1126

JO - Izvestiya - Atmospheric and Oceanic Physics

JF - Izvestiya - Atmospheric and Oceanic Physics

SN - 0001-4338

IS - 9

ER -