High-Resolution Radar Sensing Sea Surface States During AMK-82 Cruise

Abstract

Every year situation when the Arctic seas are free of ice is becoming more frequent. It allows scientists to study hard-to-reach areas using well-equipped research vessels instead of icebreakers. During the COVID-19 pandemic, the successful expedition of the research vessel "Academician Mstislav Keldysh" with more than 60 scientists from 15 countries across the four Arctic seas (Barents, Kara, Laptev, and East Siberian) on September-November 2020 seems like a real wonder. One of the expedition tasks was remote sensing of different hydrophysical processes by their manifestation on the sea surface using marine radar. This article proposes the method of generating high spatial resolution radar maps of the sea surface and algorithms of hydrophysical processes identification. This article also presents examples of registered processes, such as wind waves, ice fields with different types of ice (grease ice, pancake ice, nilas, and young ice), manifestations of internal waves observed in the Kara Gate and Vilkitsky Strait, as well as manifestations of intense methane seeps on the sea surface. This article contains quantitative estimations of the physical parameters of the observed processes underlying the effectiveness of Doppler marine radars in harsh conditions of the Arctic seas.

Manifestation of Gas Seepage from Bottom Sediments on the Sea Surface: Theoretical Model and Experimental Observations

“…The description of radar observations of sea waves and currents, ice fields, manifestations of internal waves, surface manifestations of gas seeps during the cruise, and data processing algorithms are given in [25]. This paper presents the results of observations of a real methane seep and its comparison with the results of theoretical calculations and model experiments given above.…”

“…After that, the theoretical results are compared with the results of a full-scale experiment on the remote sensing of an artificial gas seep, modeled from a stationary oceanographic platform in the Black Sea in 2021. Finally, the results of the remote sensing of natural methane seeps obtained in the East Siberian Sea during the 82nd cruise of the research vessel "Akademik Mstislav Keldysh" [25] are presented. All theoretical and experimental conclusions are compared.…”