Boucharel J., Santiago L., Almar Rafaël, Kestenare Elodie. (2021). Coastal wave extremes around the Pacific and their remote seasonal connection to climate modes. Climate, 9 (12), p. 168 [17 p.].
Titre du document
Coastal wave extremes around the Pacific and their remote seasonal connection to climate modes
Boucharel J., Santiago L., Almar Rafaël, Kestenare Elodie
Source
Climate, 2021,
9 (12), p. 168 [17 p.]
At first order, wind-generated ocean surface waves represent the dominant forcing of open-coast morpho-dynamics and associated vulnerability over a wide range of time scales. It is therefore paramount to improve our understanding of the regional coastal wave variability, particularly the occurrence of extremes, and to evaluate how they are connected to large-scale atmospheric regimes. Here, we propose a new "2-ways wave tracking algorithm" to evaluate and quantify the open-ocean origins and associated atmospheric forcing patterns of coastal wave extremes all around the Pacific basin for the 1979-2020 period. Interestingly, the results showed that while extreme coastal events tend to originate mostly from their closest wind-forcing regime, the combined influence from all other remote atmospheric drivers is similar (55% local vs. 45% remote) with, in particular, ~22% coming from waves generated remotely in the opposite hemisphere. We found a strong interconnection between the tropical and extratropical regions with around 30% of coastal extremes in the tropics originating at higher latitudes and vice-versa. This occurs mostly in the boreal summer through the increased seasonal activity of the southern jet-stream and the northern tropical cyclone basins. At interannual timescales, we evidenced alternatingly increased coastal wave extremes between the western and eastern Pacific that emerge from the distinct seasonal influence of ENSO in the Northern and SAM in the Southern Hemisphere on their respective paired wind-wave regimes. Together these results pave the way for a better understanding of the climate connection to wave extremes, which represents the preliminary step toward better regional projections and forecasts of coastal waves.
Plan de classement
Sciences du milieu [021]
;
Limnologie physique / Océanographie physique [032]
