Glaciers and icebergs
Glaciers of the Kara sea
From scientific point of view, knowledge of glacier parameters is useful for understanding climate changes. For practice it’s vital for estimating the number and geometry of produced icebergs at present and in near future. Information on glaciers can be used in iceberg drift numerical models jointly with metocean reanalysis in order to estimate the probability and scenarios of iceberg danger.
In the long term, knowledge of the glacier structure and dynamics makes it possible to estimate the quantitative risks posed by icebergs for the development of a given area.
The formation of icebergs occurs as a result of calving off blocks of ice from the outlet part of glaciers. Glacier geometry is crucial for iceberg production. That’s why during 2012-2017 we studied calving glaciers of Novaya Zemlya, Franz Josef Land and Severnaya Zemlya with airborne radar that allowed to measure their thickness and to build 3D models. Satellite remote sensing data were used to derive glacier fronts position, ice surface flow velocity, changes of glacier margins, and parameters of iceberg distribution. The data on the flow rates of the main glaciers were compared with the satellite beacons equipped with GPS (ARGOS) installed on several glaciers.
The field campaigns activity included:
- installation of automatic weather stations (4 – on Kara sea shore, 2 of them – near the glaciers)
- glaciers studies by ground-penetrating radar (GPR) in 2014-2016
- installation of GPS satellite beacons on the glaciers in 2015-2016
- aerial photography of icebergs in 2012-2017
In addition to field studies, satellite monitoring capabilities were extensively used to analyze the dynamics of changes of glacier fronts surface velocities and size of icebergs produced in the glacial zone.
For the glaciers of the Novaya Zemlya archipelago, the data obtained were also supplemented with a series of high-resolution radar images TerraSAR-X. Based on the processed information, maps of changes in glacier fronts from the mid-20th century to 2018 were constructed. The average retreat or advance of the front over different periods was calculated.
Systematic differences in the volume of the underwater part for icebergs observed in the winter-spring period and the autumn-summer period were also demonstrated. These differences should be taken into account when interpreting satellite remote sensing data or estimating iceberg underwater part.
The size distribution of produced icebergs is related to the structure of glaciers. We also assessed the glacier areas close to flotation, zones of intensive icebergs production, present and potential intensity of icebergs production. The obtained data can be applied for simulating iceberg production in the Russian Arctic, assessing iceberg risk for offshore facilities and ensuring safety of marine operations in iceberg infested waters.
The movement of sea ice largely determines the ice loads on offshore structures, mode of their operation, choice of supply vessels, an ice management system, etc. During our comprehensive winter surveys performed in the Kara, Laptev and East Siberian Seas in 2012-2017, automatic radio buoys with the function of determining and transmitting coordinates were actively used to obtain information on the drift of ice floes and icebergs.
In our research the initial data were analyzed from the point of view of studying the drift of large areas of compacted ice, as well as obtaining the data on the drift velocities of ice formations and its variability (i.e., parameters specified in the documents regulating activities on the Arctic shelf) during periods of maximum development and decrease of ice cover. For many regions of the Russian Arctic shelf, field data on the drift of ice formations are insufficient or not available. In some areas, radio buoys were used for the first time. The use of radio buoys with the function of determining coordinates and transmitting this information is a proven practice for studying the dynamics of ice formations, both for scientific and practical purposes. Using these devices, the information on the geographical position of the ice formation, as well as a number of related parameters is transmitted via satellite communication systems to consumer. In addition to use for purely scientific purposes the use of radio buoys is recommended for collecting information necessary for the design of hydraulic structures, and for use in the composition of the equipment to ensure proper functioning of ice management systems (ISO 35106: 2017; ISO 35104: 2018).
The data set collected is unique in many respects. The information of the analysis allows us to create a plot of the movement of a specific ice formation during the operation of the buoy and to calculate various characteristics of its drift. The main estimates of the drift of ice formations obtained in winter ice research expeditions 2013-2015 in the most general form and preliminary characteristics of iceberg drift in the Russian Arctic Seas are given in our papers indicated below.
The use of buoys to measure ice drift in the seas of the Russian Arctic shelf in the period 2013-2017 allowed us to collect a unique array of direct measurement data in remote and inaccessible areas where such observations were practically never made or were not available before. The collected data allows us to clarify our ideas on the dynamics of ice in the marginal seas of the Arctic Ocean, as well as to obtain estimates of the drift parameters of ice formations necessary for engineering calculations.
Details of this research and further discussion can be found in the papers:
- 1. Preliminary results of the ice cover drift studies performed in the 2013-2017 winter surveys in the Russian Arctic seas, Proceedings of the Thirtieth (2020) International Ocean and Polar Engineering Conference, Shanghai, China, October 11-16, 2020, pp. 796-803
- 2. Outlet Glaciers as Iceberg Factories: Case Study for the Kara Sea, Proceedings of the Twenty-ninth (2019) International Ocean and Polar Engineering Conference, Honolulu, Hawaii, USA, pp. 671-677, June 16-21, 2019
- 3. The Main Results of Iceberg Drift Studies in the Russian Arctic Throughout 2012–2017, International Journal of Offshore and Polar Engineering, Vol. 29, No. 4, December 2019, pp. 391–399; https://doi.org/10.17736/ijope.2019.jc772, 2019
- 4. Geometry and Mass of Icebergs in the Russian Arctic, International Journal of Offshore and Polar Engineering, Vol. 29, No. 4, December 2019, pp. 375–382; https://doi.org/10.17736/ijope.2019.jc770, 2019
- 5. Studies of glaciers in the Russian Arctic for safe marine operations in iceberg waters, Oil Industry, pp. 92-97, № 10 2018
- 6. Studies ice formations drift on the shelf of the Russian Arctic using ARGOS automatic radio beacons, Scientific and technical Bulletin, pp. 4-9, № 4 2016
*These are Accepted Manuscripts of articles published by International Society of Offshore & Polar Engineers ISOPE available online: http://www.isope.org/publications” © 2019-2020 by the International Society of Offshore and Polar Engineers (ISOPE).