Trends and Regional Features of Variability of the Northeast Pacific Ocean Thermal Conditions North of 30°N over the Last Four Decades

I. D. Rostov, E. V. Dmitrieva, N. I. Rudykh

V. I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch of Russian Academy of Sciences, Vladivostok, Russian Federation



Purpose. The study is purposed at revealing the regional features of modern climatic changes in water temperature in the northeastern extratropical zone of the Pacific Ocean, at assessing the characteristics of temperature trends on the ocean surface and in its upper layer and their relationship with the large- scale processes in the ocean and atmosphere.

Methods and Results. Based on the NOAA climatic data sets, and using the statistical methods of analysis and the apparatus of empirical orthogonal functions, the characteristics of the interannual variability of water temperature on the surface and in the upper 1000-meter layer were determined in different regions of the area under study. Temperature trends, correlations with the influencing factors and their statistical significance for some 20-year periods of previous 40 years were quantitatively assessed.

Conclusions. In the first decades of the 21st century, the warming trends are explicit on the surface and in the upper 200-meter layer of the northeastern and central regions of the area. As compared to the previous 20-year period, the magnitude of positive SST trends increased, on average, by about 4 times over the entire water area. In course of the past two decades, the heat content of the upper 200- meter layer increased by 5% and that of the whole 1000-meter layer – by 2%, which is 1.5 times less than in the northwestern sector of the Pacific extratropical zone where, unlike the surface, the rate of water column warming was higher. As for the area under study, on the whole, the correlations between the heat content fluctuations in the upper 200-meter ocean layer and the changes in influencing factors are manifested through the climatic indices NPGO, PDO, NP, PNA, SOI, AD and the atmospheric pressure gradients between the leading centers of the atmosphere action.


northeastern part of the Pacific Ocean, extratropical zone, modern climate changes, regional features, water temperature, heat content, warming trends, climate indices, correlations


The work was carried out within the framework of the state assignment of POI FEB RAS on theme 0211-2021-0008. State registration No. 121021700346-7. The authors are thankful to the program developers for the possibility to use the climatic data posted on the NOAA sites. The authors are grateful to the reviewer for constructive comments.

Original russian text

Original Russian Text © I. D. Rostov, E. V. Dmitrieva, N. I. Rudykh, 2023, published in MORSKOY GIDROFIZICHESKIY ZHURNAL, Vol. 39, Iss. 4 (2023)

For citation

Rostov, I.D., Dmitrieva, E.V. and Rudykh, N.I., 2023. Trends and Regional Features of Variability of the Northeast Pacific Ocean Thermal Conditions North of 30°N over the Last Four Decades. Physical Oceanography, 30(4), pp. 410-427.


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