The results of the Laboratory of Nonlinear Dynamical Systems (2020)
Calculation and analysis of daily Lagrangian maps in the altimetric velocity field over the past 25 years have made it possible to find an area near the southern tip of Kamchatka, where mesoscale anticyclonic eddies moving from the north regularly stagnate over the Kuril-Kamchatka trench for many months. With the help of such maps, 24 stationary eddies were identified and studied in 1993-2019. It is shown that they are “genetically” related to eddies generated behind capes in Kamchatka bays and then migrating southward with the current. In this case, the stationary vortex is an accumulator of merging vortices. A typical eddy stagnated over the trench for 8 months and was investigated during the cruise of the R/V Akademik Oparin in September 2017. CTD-survey showed a typical vertical structure with a warm surface layer, cold and freshened subsurface layer and a warm intermediate layer of water trapped in the core. Using Lagrangian maps of various indicators, the life cycle of this eddy from birth to decay was analyzed and it was found that this anticyclone was screened by smaller cyclones along its periphery. This configuration kept it stable and stagnant over the trench for a long time. The analysis of various factors and mechanisms supporting the stagnation of the Kamchatka eddies above the trnch and their subsequent decay has been carried out.
Fig. 1 - Quasi-stationary Kamchatka eddy in 2017 above the trench (left) in the field of sea surface temperature and (right) in the field of the calculated Lyapunov exponent. The CTD sections are shown with the station at the center of eddy no. 88, which coincides with the calculated elliptical point of the eddy center with an accuracy of several kilometers.
Prants S.V., Budyansky M.V., Lobanov V.B., Sergeev A.F. and Uleysky M.Yu. Observation and Lagrangian analysis of quasi-stationary Kamchatka trench eddies // Journal of Geophysical Research (Oceans). 2020. V. 125, № 6. e2020JC016187 https://doi.org/10.1029/2020JC016187 WOS Q1
Last Updated (Thursday, 18 February 2021 10:48)