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Trends of opening and closing date for navigation on the Northern Sea Route in the light of changes in ice cover on the seas of the Siberian Shelf in the years 2008-2022

Marsz Andrzej A., Pastusiak Tadeusz, Styszyńska Anna

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2024

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Vol. 18 No. 3

487--492

EN

The Northern Sea Route (NSR) is a seasonal route. Its use by merchant ships that are not structurally adapted to navigation in heavy ice makes sense when it is free of ice along its entire length and can be used without the costly assistance of icebreakers. In the paper, ice cover maps were analyzed. The number of the Julian day of the year was determined on the first day on which the transit shipping season began, on the last day of the year after which this season ended, and the length of the ice-free period along the whole NSR was calculated. The analysis was carried out for the eastern and western parts of the NSR. Despite the high inter-year variability of the opening and closing times of the transit shipping season, it is possible, 2-3 months in advance, to obtain approximate information about the conditions of "ice-free" navigation on this route. For this purpose, average monthly sea ice extent of the Kara Sea in May of a given year should be used.

2

Length of navigation season in current conditions of climate change on the Northern Sea Route

Pastusiak Tadeusz

TransNav : International Journal on Marine Navigation and Safety of Sea Transportation

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2024

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Vol. 18 No. 3

493--502

EN

The paper first analyzed ice maps for the years 2008-2022. Despite the general convergence of trends of opening and closing of navigable season for concentrations 18% and 81% the Eastern Part and Western Part of the NSR looks they are under different driving factors. Found some tendencies and cyclical changes, but not working for the whole studied period. The studied period of 15 navigation seasons from statistical point of view is too short period of time to forecast trends and cycles in the near future. Next, ships traffic and ice conditions being on the NSR for the years 2012, 2013, 2015, 2017, 2018, 2020 and 2021 were examined. The navigable time windows of Arc4, arc5 and Arc7 class ships were determined. Found, the not navigable period of time for any class of merchant ships lasted 3 months.

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The use of sonar data for mapping the muddy bottom of water reservoir

Pastusiak Tadeusz

Polish Cartographical Review

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2024

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Vol. 56, No. 1

69--89

EN

The goal of the work was to find a method to determine the structure of the subsurface of the bottom of a water reservoir with relatively soft ooze-muddy sediments using the recorded parameters of the first and second sonar echoes. This would allow avoiding the use of expensive devices such as sub-bottom profilers. Sonar measurements were taken on the entire lake commencing from the depth accessible to the measuring boat with outboard transducers. The sonar screen image and the first and second echo parameters were recorded and used according to the RoxAnn method. In order to verify and extend the scope of the sonar data, measurements of the bottom depth and hardness were made using a pole at 40 control points located along five cross sections. Finally achieved numerical models of sediment structures under the bottom surface of the water reservoir for three reference surfaces: depths for initial top surface of the colloidal state (ooze) layer, top surface of dense muddy bottom and surface of solid bottom under muddy layer. Each of them was obtained by two independent methods, in which the input data was the depth measured by the sonar for the initial top surface of the colloidal state layer or roughness of the first echo. The volume between the numerical surfaces for the colloidal state layer, which is important for environmental protection purposes, was calculated using three different methods. The results were very similar. The difference of volume was within 1.7–5.7%. Each of the method of measuring any layer volume using a single beam echo sounder / sonar can be used to assess the scope of work and the costs of required restoration measures or water reservoir by removal of colloid suspension layer. The advantage of the developed method is the possibility of performing the work using a single beam echo sounder/sonar instead of an expensive sub-bottom profiler.

4

Scheduling transit voyages of vessels of various ice classes across the Northern Sea Route

Pastusiak Tadeusz

Annual of Navigation

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2019

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No. 26

114--126

EN

Main problem for scheduling vessel transit voyages through the Northern Sea Route is the difficulty in predicting distribution of ice boundaries in regions that cannot be overcome by individual ice classes of vessels. Scheduling of voyage is related to speed that vessels can develop and moment of time when vessels will be able to commence and complete passage safely through areas that are main obstacle and are blocking longest transit passage through the Northern Sea Route. This applies to voyages carried out by vessels navigating on their own and with support of icebreakers. Additional problem is lack of consistency of content of maps of ice cover, which can be used for vessels voyage planning through areas where ice cover occurs. Results of this research on influence of uncertain information related with time window of conditions favorable for navigation of vessels of different ice classes on schedule of theirs voyage on example of summer navigation season 2017 are presented in this work.