Abstract. Seasonal and interannual variability of sea level fluctuations in the northwestern Pacific Ocean and the Far Eastern seas was analyzed using the empirical orthogonal function decomposition of the original data series. The study is based on a data set of altimetric observations from the IMMOAD SSHA for the period 1993–2021, which included additional tidal correction and monthly averaging of data at each point along the satellite tracks. It was shown that the first three modes of decomposition have a similar spatial structure with opposite patterns of sea-level variations in the northern (the coast of the Bering and Okhotsk Seas) and southern (the zone influenced by the warm Kuroshio Current) regions. The variations in the temporal function of the first mode are dominated by an annual cycle, with a maximum in autumn and a minimum in spring. While this pattern is also dominant in the second mode (with maximum in winter and minimum in summer), there are weaker oscillations with periods of 10–11 and 21–22 years as well. The third mode characterizes interannual variations with a period of 10-11 years, which are correlated with the variability of the Pacific Decadal Oscillation (PDO) index. The fourth mode describes complex processes in the area influenced by the Kuroshio Current.

For citation: Shevchenko G.V., Tskhay Zh.R. Spatiotemporal variability of sea level fluctuations according to IMMOAD SSHA data after additional correction of the tidal component. Geosistemy perehodnykh zon = Geosystems of Transition Zones, 2026, vol. 10, No. 3, p. 289–298. (In Russ.).
https://doi.org/10.30730/gtrz.2026.10.3.289-298, https://www.elibrary.ru/jwkvrm

Для цитирования: Шевченко Г.В., Цхай Ж.Р. Пространственно-временная изменчивость колебаний уровня океана по данным IMMOAD SSHA после дополнительной коррекции приливной составляющей. Геосистемы переходных зон, 2026, т. 10, № 3, с. 289–298.
https://doi.org/10.30730/gtrz.2026.10.3.289-298, https://www.elibrary.ru/jwkvrm

1. Liu H., Feng X., Tao A., Zhang W. Intraseasonal variability of sea level in the Western North Pacific. Journal of Geophysical Research: Oceans, 2021, 126, 2021,126(6):1–19. https://doi.org/10.1029/2021JC017237.

2. Wang J., Li J., Yin J., Tan W., Liu Y. Sea level seasonal, interannual and decadal variability in the tropical Pacific Ocean. Remote Sensing. 2021,13(19):3809. https://doi.org/10.3390/rs13193809

3. Shevchenko G.V., Romanov A.A., Tsoy A.T., On the accuracy of removing the tidal component from IMMOAD SSHA satellite altimetry data. Current problems in remote sensing of the Earth from the space. 2023,(20)4:20–29. (in Russ.). https://doi.org/10.21046/2070-7401-2023-20-4-20-29.

4. Beckley B.D., Callahan P.S., Hancock D. W. et al. On the “cal-mode” correction to TOPEX satellite altimetry and its effect on the global mean sea level time series. Geophysical Research: Oceans. 2017,122(12):8371-8384. https://doi.org/10.1002/2017JC013090.

5. Beckley B., Zelensky N.P., Holmes S.A. et al. Merged_tp_J1_ostm_ost_all_V50. Ver. 5.0. PO.DAAC, CA, USA, 2021. https://doi.org/10.5067/ALTTS-TJA50.

6. Belonenko T.V., Koldunov V.V., Staritzin D.K., Foux V.R., Shilov I.O. Sea-surface level variability in the north-western Pacific. Saint Petersburg: SMIO-PRESS, 2009, 309 p. (in Russ.).

7. Belonenko T. V., Satellite altimetry of the North-Western Pacific, Izvestia: Herzen University J. Humanities and Sciences, 2013,163:120-128. (in Russ.). EDN: RTEPKJ

8. Belonenko T.V., Fuks V.R. Annual and semiannual wave disturbances of the Northwestern Pacific level. Russian Meteorology and Hydrology. 2001,8:51–57. (in Russ.).

9. Koldunov V.V. Interannual and seasonal fluctuations in the level of the northern part of the Pacific Ocean. Bulletin of St. Petersburg University. Issue 7. 2007,2:142–148. (in Russ.).

10. Belonenko T.V., Koldunov V.V., Foux V.R. Kinematics of the standing-progressive waves of Rossby in the sea and ocean. Fundamental and Applied Hydrophysics. 2013,6(1):23–31. (In Russ.). EDN: QAVBCT

11. Belonenko T.V. Rossby waves observation in the Northwestern Pacific. Current problems in remote sensing of the Earth from the space. 2012,9(3):209–215. (in Russ.). EDN: PBMRUT

12. Travkin V.S., Belonenko T.V., Kochnev A.V. Topographic waves in the Kuril region. Current problems in remote sensing of the Earth from the space. 2022,19(5):222–234. https://doi.org/10.21046/2070-7401-2022-19-5-222-234. (In Russ.).

13. Kulik V.V., Prants S.V., Uleysky M.Y., Budyansky M.V. Lagrangian characteristics in the western North Pacific help to explain variability in Pacific saury fishery. Fisheries Research. 2022,252(10):106361. (In Russ.). https://doi.org/10.1016/j.fishres.2022.106361.

14. Shevchenko G.V., Romanov A.A. On the importance of tidal correction for calculation of mean sea level surfaces from IMMOAD SSHA satellite altimetry data. Current problems in remote sensing of the Earth from the space. 2023,20(6):80–91. (In Russ.). https://doi.org/10.21046/2070-7401-2023-20-6-80-91

15. Romanov A.A., Romanov A.A. Selected properties of the spatial correlation function of sea surface height anomalies based on satellite altimetry data in the Far Eastern Region. Cosmonautics and rocket engineering. 2024,3:89–97. (In Russ.). EDN: VOMKMR

16. Romanov A.A., Romanov A.A., Shevchenko G.V. Determination of the main parameters of the temporal autocorrelation function of surface level anomalies at some points in the Far Eastern Pacific Ocean. Current problems in remote sensing of the Earth from the space. 2024,21(5):36–46 (In Russ.) https://doi.org/10.21046/2070-7401-2024-21-5-36-46

17. Bagrov N.A. Analytical representation of a sequence of meteorological fields by means of empirical orthogonal components. 1959,74:3–24. (Trudy TsIP). (In Russ.).

18. Lander A.V., Levshin L.P., Pisarenko V.F., Pogrebinsky G.A. On the spectral-time analysis of oscillations. Computational and Statistical Methods for Interpreting Seismic Data. Computational Seismology. Issue 6. М.: Nauka, 1973, с. 15-23. (In Russ.).

19. 27-year sea level rise – TOPEX/JASON. URL: https://svs.gsfc.nasa.gov/4853 (accessed 15.06.2026).