Sea ice age is a proxy for thickness, which can be obtained through the use of satellite data. The paper presents the results of comparison of CryoSat-2, SMOS and CryoSat-2 & SMOS fusion data with detailed ice charts (October–April, 2010–2018). The AARI ice charts were chosen as references for comparison because they integrate knowledge and data from various sources, including expert analysis of operational satellite information, in-situ measurements at coastal stations, data on ice conditions from ships of the Northern Sea Route (NSR). The division of satellite data elements into classes (stages of development) was performed according to the maximum likelihood classifier. The recognition result for each stage of development was evaluated by means of three criteria, in accordance with the class value of Mode, Median and Mean. The effectiveness of satellite data in determining the Kara Sea ice thickness varies depending on the sea ice stage of development and winter season time. Four stages of development (old ice, thick first-year ice, medium first-year ice, nilas) showed the best recognition results. Although the CryoSat-2 mission was designed primarily to detect climate-dependent variations of the thickness of floating ice, in terms of statistical recognition of the Kara Sea ice stages of development, CryoSat-2 data can also be used to retrieve the thickness of thick first-year ice (January–April) and the thickness of medium first-year ice (January–February). For the remaining stages within the study area, the altimetry method shows a significant uncertainty, which can be resolved for nilas, thin first-year ice and medium first-year ice (March) by using SMOS data and CryoSat-2 & SMOS fusion data. In general, altimetric data, radiometric data and combination thereof can be applied in the complex analysis of all available information to ensure hydrometeorological and navigation support. Also, it is proposed to use the data of the ICESat-2 laser altimeter and to make a general comparison with in-situ measurements.

The problem of short-term sea level forecasting in the area of Сape Kamenny in the Ob’ Bay has become important since the Novoportovsky terminal (known as “Arctic Gate”) began operating for year-round oil shipment. The tankers loading the oil from the terminal have to pass through relatively shallow waters, located to the north, limiting the vessels draft. Thereby a short-term water level forecast is required relative to the lowest theoretical level for tankers loading at the terminal. The year-round hourly observations using buoy level gauges with a satellite channel of data transmission are organized for quick level monitoring directly in the area of Cape Kamenny. The results of the harmonic analysis of water level observations in the area of Cape Kamenny for 2016–2021 showed significant seasonal variability of amplitudes and phases of the wave М₂ in the annual cycle, as well as their interannual variability due to various ice conditions of the Ob’ Bay (light, medium, heavy). Based on these results, the processing and analysis of observations data over the last month are performed by the end of each month. According to these results, the current values of harmonic constants, dependent on actual ice conditions are specified and calculation of the tide is carried out for the next month. The calculation of the forecast values of the total level is composed of calculated tide and short term (with a lead time of up to 5 days) forecast of non-periodic level fluctuations using the three-dimensional hydrodynamic model of joint water and ice circulation AARI-IOCM. At the final stage of the forecast preparation, the predicted level, usually calculated relative to the conditional long term average annual value, is bound to the lowest theoretical level (according to the current values of the level gauge) and transferred to the operator of the terminal and to the tanker. The hourly observations of water level in the area of Cape Kamenny and level forecasting have been carried out since 2017 and are still continuing.

The ice cover of the Gulf of Ob is formed in an extended zone, where the sea and fresh waters are mixed. This study aims to evaluate certain physical and mechanical characteristics of such ice. It examines data on a complex of physical and mechanical fast ice characteristics in the Ob’ Bay, obtained in the course of field studies over the last 30 years. The total amount of data available to the team of authors exceeds 200 cores, sampled in the Ob’ Bay (from Novy Port to the boundary between the Bay and the Kara Sea) in different years and in different months of the ice season.

Processed data on ice temperature are presented, as well as information on the evolution of integral ice temperature during ice season. The change of integral ice salinity in the Ob’ Bay with geographic latitude is identified and shown, and the function approximating this change is given.

The estimates of average density and porosity of ice by thickness are presented. The effect of mineral inclusions on the increase in ice density is considered.

An analysis was carried out of the correspondence between the field data on fresh and saline ice sample strength in uniaxial compression (with the load application parallel to the ice cover surface) with theoretical strength estimates from Russian and foreign scientific and methodological literature, based on the data obtained on physical and mechanical ice characteristics in the Ob’ Bay. A generalized estimate of the saline ice strength limit in the Ob’ Bay, obtained in uniaxial compression parallel to the surface of ice accumulation is given, as well as its approximation by lognormal distribution.

The results obtained in the analysis of the strength characteristics of ice in the Gulf of Ob can be used for practical purposes. The results may also prove useful in terms of contribution to theoretical knowledge on the experimental mechanics of ice in desalinated water bodies.

All year–round navigation in the Ob’Bay has been operating for more than ten years. In recent years it has been performed most actively at three points: the port terminals Sabetta and «Utrenniy» (on the opposite coasts in the northern part of the bay) and the oil loading terminal «Vorota Arktiki» (in the southern part of the bay, off cape Kamenny). Regular winter navigation to Sabetta began in 2013 and to cape Kamenny in 2015. In recent years, the number of vessels in November–May has already risen to about 380 per season. The winter navigation in the fast ice is performed along ice channels, which should impact on the fast ice stability. The aim of this research was to determine the influence of navigation on the fast ice distribution in the Ob’Bay in terms of climate changes. To analyze navigation impact on the fast ice distribution in the Ob’Bay, data on air temperature, ice conditions and number of vessels in the winter period were used in the work. The sum of the freezing degree days (FDD) was chosen as a parameter of winter conditions severity. The mean location of the south boundary of the flaw polynya per season was a parameter of the fast ice stability. Such an approach reduced the influence of short–term fluctuations of temperature and ice conditions. The data analysis carried out over the last 25 years has confirmed a significant influence of navigation on the fast ice distribution. It has been found that for the range from mean to mild winter conditions (an estimate using FDD), the dislocation of the flaw polynya boundary in the south direction amounted to 0.4–0.8 degrees of latitude (25–50 miles) because of winter navigation intensification. Winter conditions more severe than mean have not been recorded in the region over recent years. Therefore, such estimates were not obtained for them. The discovered changes of ice conditions are significant for the region. The transfer from fast ice to drifting ice of different types, forms and concentration will lead to the corresponding restructuring of other natural processes (water dynamics, litho-dynamic regime, etc). Subsequently the impact of hydrometeorological factors on engineering facilities can change, affecting the navigation conditions, scenarios of loading on the hydraulic structures, absolute loading values, etc. This is a factor to consider in the economic development of the region.

Fresh water supply is a basic need of the gas and oil industry of the Yamal-Gydan region. Small rivers flowing into the Ob’ and Taz Bay could be used for solving this problem. The purpose of the study is to summarise the available research data on the runoff of small rivers and to calculate the catchment areas using GIS technologies. The study covers more than 200 small rivers in the catchment area of the Ob’ and Taz Bay. It is established that there have been no stationary observations of the water runoff on them. Expedition observations of water discharges of small rivers are summarized. More than 40 small rivers are involved in water consumption. The runoff data from water users in the State Water Registry are questionable and need to be critically analyzed. Published annual runoff maps of the Yamal-Gydan region are presented in a unified form. Consolidation of the annual runoff maps showed an overall latitudinal distribution of the runoff isolines. The reliability of river runoff estimates from maps is largely determined by the accuracy of the catchment area calculations. GIS calculation of the river catchment areas has been done using two methods. Automated digitization by DEM has given incorrect results, which need to be verified. Manual digitization of catchments is labour-intensive, but gives reliable results for the lowland relief of the Yamal-Gydan region. For the first time, small rivers’ catchment areas obtained by GIS have been calculated. Difficulties arise in using the names of small rivers, which are different from one source to another. It is necessary to organize government monitoring on small rivers including obligatory measurements of water discharge, first of all on the Sabetta-Yakha, Se-Yakha and Messo-Yakha rivers, which provide fresh water to economic facilities. The modeling of runoff formation and the use of satellite image data are promising directions of runoff assessment.

The Ob’ Bay has long been the main center for the development of the Russian oil industry in the Arctic region. The rapid growth of shipping and the active creation of port infrastructure in this area are an integral part of the strategy for the development of the Russian Arctic. The main feature of the hydrometeorological regime of the Ob’ Bay is the annual presence of ice for a long time. Determining the ice performance of icebreakers, tugboats and heavy-tonnage vessels designed for the region, as well as ice loads on marine platforms and hydraulic structures, is a most important task in the creation thereof.

The paper describes research carried out in the ice model tank of the Krylov State Research Centre over the past twenty years. The research supports the design and operation of new technical facilities intended for the industrial development of the Ob’ Bay. In the completed study, two main areas of research can be distinguished, namely the interaction of ships and engineering structures with ice formations in the Ob’ Bay. The paper emphasizes a significant dependence of the possibility of conducting ice tests and proper analysis of findings on the quality of the initial data, primarily hydrology and ice parameters.

The results of ice model tests analysis, especially the ice impact on offshore and hydraulic structures for the Ob’ Bay, show the need to change approaches to determining theoretical ice loads and, as a result, to expand ice model testing programs. The simulation of the worst-case scenario, when all ice parameters are determined for a given probability and are not consistent with each other, leads to a significant overestimation of ice loads and the physical modeling of unrealistic combinations of ice conditions.

Each ice impact scenario should contain the maximum value of only one main ice parameter corresponding to the probability. The main ice parameters include the thickness, the flexural strength or compression strength and the speed of ice drift. In this case, ice parameters should be selected in accordance with the chosen main one in the modeling scenario. It should not be the result of the same maximum value calculation for the given observation period as for the main ice parameter.