8 research outputs found
Calculating of extreme thicknesses and strength characteristics of the first-year ice cover of the Kara Sea using a thermodynamic model
Get PDFUsing the example of the Kara Sea, the possibility to calculate values of the thickness and strength characteristics of ice of rare occurrence for areas of marine waters with seasonal ice cover, where field observations are absent, is considered. A method for obtaining climatic characteristics of meteorological elements for conditions of different occurrence (extreme values) has been developed. It is based on the selection of a statistical distribution law for the «freezing degree-days» (FDD). On the basis of the obtained sums of the degree-days, the restoration of daily values of the air temperature is carried out. This technique can be applied to areas of the Arctic seas with seasonal ice cover. The obtained climatic characteristics allow us to estimate the strength properties and thickness of sea ice using a thermodynamic model. The proposed method makes it possible to calculate values of the thickness and strength characteristics of ice for the entire water area of the Kara Sea. For average climatic conditions, the calculated estimates of the periods of stable ice formation, thickness and strength characteristics of ice are in good agreement with the results of field observations. It is established that the moment of maximum ice strength does not coincide with the time when the ice reaches its maximum thickness. The characteristics of the ice cover calculated for conditions of rare occurrence also do not contradict the values observed in nature. The differences in the duration of the ice season in the south-western part of the sea from the north-eastern part, obtained under climatic conditions of different occurrence, are shown
Dynamics of polynya in the River Ob Bay and predicting of its location
Get PDFDynamics of the ice edge of (flaw lead) a large polynya in the River Ob Bay was investigated over the period 1997–2016 on the basis of satellite data. More than 800 satellite images were analyzed during the investigation. Relationship between the obtained time series of changing latitude of the ice edge and time series of air temperature, wind and indices of Wangenheim–Girs, the Arctic Oscillation (AO), and North Atlantic Oscillation (NAO) was studied by means of the correlation analysis. The statistical analysis made it possible to reveal that southern position of the ice edge in autumn indicated to warmer winter months. Boundaries of the polynya during every next decade were identically determined by its position during the preceding period, and therewith the pronounced trend of the ice edge shift to south was noticed in 1997–2012. In addition, periodic fluctuations with two different periods were found against the background of trend. During 1996– 2006 the fluctuations were quasi-biennial while after 2006 the period of fluctuations increased up to 4–5 years. Effort to predict the ice edge position aimed at determination of the polynya boundaries in January-February of 2016 was undertaken; data on the air temperature and latitude of the ice edge position for preceding period were used as the predictors. The difference between the prediction and actual data was equal to 0.01 ÷ −0.43 of latitude with the average value for six decades equal to 0.11°. Analysis of inter-annual variability of the edge position indicated that the most close relationship took place with the Vangenheim–Girs index E in May (coefficient of correlation r = −0.73). Maximal values of r exceeding ±0.7 were calculated for the Arctic Oscillation indices in February with a positive shift of one year. When investigating long-term large-scale changes of climatic parameters, analysis of anomalies of average latitude values of the polynya southern boundary had been performed. This allowed to reveal that period of 2005–2006 was a point of inflection. This substantiates the known thesis (conclusion) that a well developed polynya exerts the warming effect on adjacent territories
Influence of climate warming on the strength characteristics of ice in the Ob Bay
Get PDFThe article presents results of investigation of the climate warming effects in the northern polar region of the Earth, in particular on some characteristics of ice in the northern part of the Ob Bay (the area of the most active economic activity of the Russian Federation in the last decade). It is determined that over the past 40 years, morphometric and strength characteristics of ice have significantly changed. Estimates of ice thickness obtained using simple empirical formulas (depending on the sum of the degree-days of frost) show that the ice thickness decreased here by an average of 10 15%. The strength characteristics of ice were analyzed for two periods: the maximum strength of ice (for this area it is March) and the maximum development of ice thickness (usually it is May). It was found that the strength properties of ice (bending and compression) for both periods decreased by 10-12%. Thus, in recent decades, under the influence of climate warming in the Ob Bay, the thickness and strength of the ice cover have significantly decreased. This circumstance will be favorable for further development of the considered water area by Russian oil and gas companies
Особенности совместного влияния интенсификации судоходства и изменения климата на распространение припая в Обской губе
Get PDFAll 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.В последние годы круглогодичное судоходство в Обской губе активно осуществляется в три пункта: нефтеналивной терминал «Ворота Арктики», портовые терминалы Сабетта и «Утренний». Регулярная зимняя навигация началась в 2013–2015 гг. Количество судов за ноябрь–май уже составляет около 380 за сезон. Зимнее плавание в припае осуществляется по ледовым каналам, что должно отражаться на стабильности припая. Целью исследования являлось определение влияния судоходства на распространение припая в Обской губе на фоне климатических изменений. В работе использовались данные по температуре воздуха, ледовым условиям и количестве судов в зимний период. Параметром суровости зимних условий являлась сумма градусо-дней мороза (СГДМ). Среднесезонное положение южной границы заприпайной полыньи служило параметром стабильности припая. Такой подход снижал влияние кратковременных колебаний температурных и ледовых условий. Анализ данных за последние 25 лет подтвердил значимое влияние судоходства на распространение припая. Из-за зимней навигации дополнительное смещение границы заприпайной полыньи на юг (для зимних условий от средних до очень легких) составило 25–50 миль. Более тяжелые зимние условия не фиксировались, и оценки для них не были получены. Выявленные изменения являются значимыми для региона. Переход от припая к дрейфующим льдам приведет к перестройке других природных процессов, что необходимо учитывать при освоении региона, поскольку изменится воздействие на инженерные объекты
Особенности турбулентного теплообмена вблизи всторошенных участков морского льда
Get PDFThe studies of the features of turbulent heat exchange were carried out for the first time in domestic practice near ice ridge areas of sea ice using an unmanned aerial vehicle (UAV) as part of the expedition "Transarktika-2019" onboard the R/V “Akademik Tryoshnikov”. An original measuring complex designed in AARI, was used to assess the characteristics of the ice surface (ice ridges, flat areas of ice). This made it possible to obtain comparative estimates of the albedo and surface temperature of different morphometric structures of the sections of the ice field, where the expedition's ice camp was organized. Measurements of air temperature and wind velocity were carried in the atmospheric surface layer on flat snow-covered areas of sea ice out from the windward and leeward sides of the ridge in parallel with the UAV flights. As a result of the experiments, it was found that the ice ridges areas have a lower albedo and surface temperature compared to neighboring areas of flat sea ice on average. Turbulent heat fluxes from the windward side of the hummock ridge exceed similar values recorded from the leeward side under conditions of unstable stratification in the atmospheric surface layer and exceed the fluxes calculated for conditions of flat ice on the sections with absence of hummocks, on average. In total, the nature and intensity of turbulent heat conduction in the ice ridges area differs from the analogous values observed on the flat sea ice cover. It is possible that the assessment of heat conduction with the atmosphere requires a certain revision, against the background (within the conditions) of thin first-year ice increasing which is more prone to hummocking than multi-year ice
Расчёт экстремальных толщин и прочностных характеристик однолетнего ледяного покрова Карского моря с помощью термодинамической модели
Get PDFUsing the example of the Kara Sea, the possibility to calculate values of the thickness and strength characteristics of ice of rare occurrence for areas of marine waters with seasonal ice cover, where field observations are absent, is considered. A method for obtaining climatic characteristics of meteorological elements for conditions of different occurrence (extreme values) has been developed. It is based on the selection of a statistical distribution law for the «freezing degree-days» (FDD). On the basis of the obtained sums of the degree-days, the restoration of daily values of the air temperature is carried out. This technique can be applied to areas of the Arctic seas with seasonal ice cover. The obtained climatic characteristics allow us to estimate the strength properties and thickness of sea ice using a thermodynamic model. The proposed method makes it possible to calculate values of the thickness and strength characteristics of ice for the entire water area of the Kara Sea. For average climatic conditions, the calculated estimates of the periods of stable ice formation, thickness and strength characteristics of ice are in good agreement with the results of field observations. It is established that the moment of maximum ice strength does not coincide with the time when the ice reaches its maximum thickness. The characteristics of the ice cover calculated for conditions of rare occurrence also do not contradict the values observed in nature. The differences in the duration of the ice season in the south-western part of the sea from the north-eastern part, obtained under climatic conditions of different occurrence, are shown.Для оценки прочностных свойств и толщины морского льда использована методика получения климатических данных при условии разной повторяемости, которая может применяться для арктических морей с сезонным ледяным покровом. Проведены расчёты толщины и прочностных характеристик льда Карского моря для разных климатических условий. Полученные расчётные значения сроков устойчивого ледообразования, а также толщины и прочностных характеристик льда хорошо совпадают с результатами натурных наблюдений
Динамика кромки заприпайной полыньи в Обской губе и прогноз её широтного положения
Get PDFDynamics of the ice edge of (flaw lead) a large polynya in the River Ob Bay was investigated over the period 1997–2016 on the basis of satellite data. More than 800 satellite images were analyzed during the investigation. Relationship between the obtained time series of changing latitude of the ice edge and time series of air temperature, wind and indices of Wangenheim–Girs, the Arctic Oscillation (AO), and North Atlantic Oscillation (NAO) was studied by means of the correlation analysis. The statistical analysis made it possible to reveal that southern position of the ice edge in autumn indicated to warmer winter months. Boundaries of the polynya during every next decade were identically determined by its position during the preceding period, and therewith the pronounced trend of the ice edge shift to south was noticed in 1997–2012. In addition, periodic fluctuations with two different periods were found against the background of trend. During 1996– 2006 the fluctuations were quasi-biennial while after 2006 the period of fluctuations increased up to 4–5 years. Effort to predict the ice edge position aimed at determination of the polynya boundaries in January-February of 2016 was undertaken; data on the air temperature and latitude of the ice edge position for preceding period were used as the predictors. The difference between the prediction and actual data was equal to 0.01 ÷ −0.43 of latitude with the average value for six decades equal to 0.11°. Analysis of inter-annual variability of the edge position indicated that the most close relationship took place with the Vangenheim–Girs index E in May (coefficient of correlation r = −0.73). Maximal values of r exceeding ±0.7 were calculated for the Arctic Oscillation indices in February with a positive shift of one year. When investigating long-term large-scale changes of climatic parameters, analysis of anomalies of average latitude values of the polynya southern boundary had been performed. This allowed to reveal that period of 2005–2006 was a point of inflection. This substantiates the known thesis (conclusion) that a well developed polynya exerts the warming effect on adjacent territories.На основе спутниковых данных рассматривается динамика кромки заприпайной полыньи в Обской губе за период 1997–2016 гг. Граница полыньи в каждую последующую декаду почти однозначно определялась её положением в предшествующий период. Анализ межгодовой изменчивости положения кромки показал, что наибольшая связь прослеживается с индексом Вангенгейма–Гирса Е в мае. Максимальные значения r, превышающие ±0,7, получены для февральских индексов Арктической осцилляции со сдвигом на один год
Влияние потепления климата на прочностные характеристики льда в Обской губе
Get PDFThe article presents results of investigation of the climate warming effects in the northern polar region of the Earth, in particular on some characteristics of ice in the northern part of the Ob Bay (the area of the most active economic activity of the Russian Federation in the last decade). It is determined that over the past 40 years, morphometric and strength characteristics of ice have significantly changed. Estimates of ice thickness obtained using simple empirical formulas (depending on the sum of the degree-days of frost) show that the ice thickness decreased here by an average of 10 15%. The strength characteristics of ice were analyzed for two periods: the maximum strength of ice (for this area it is March) and the maximum development of ice thickness (usually it is May). It was found that the strength properties of ice (bending and compression) for both periods decreased by 10-12%. Thus, in recent decades, under the influence of climate warming in the Ob Bay, the thickness and strength of the ice cover have significantly decreased. This circumstance will be favorable for further development of the considered water area by Russian oil and gas companies.Рассматриваются изменения прочностных и морфометрических характеристик припайного льда в Обской губе за последние 30–40 лет. Использованы расчётные метеорологические характеристики, полученные по наблюдениям регулярной сети Росгидромета России. Установлено, что в Обской губе толщина припайного льда уменьшилась на 10–15%, а его прочностные характеристики снизились на 10–12%
