In this work,the selected icebreaker model experiment is performed in a towing tank.We focus on the influence of seawater salinity on ship ice resistance in the ice floe field and the innovative ice model and ship mod...In this work,the selected icebreaker model experiment is performed in a towing tank.We focus on the influence of seawater salinity on ship ice resistance in the ice floe field and the innovative ice model and ship model test technology,including the similitude rule of ship model tests,test principles,and validation with full-scale ship data.A formula for calculating the relationship between the temperature and salinity of the water is constructed,which can be used to simulate the role of seawater in freshwater ice pools.On this basis,the effect of salinity on the resistance of ships sailing in broken ice fields is studied.A technique in which artificial ice made of polyethylene spheres is used to simulate ice resistance is proposed.With a series of ship model experiments in spherical and triangular ice fields,the effects of salinity and velocity on the ice resistance test of the ship model are analyzed.A relationship of the ice resistance of the ship model to the spherical ice field and the triangular ice field is proposed.The conversion results are consistent with onsite data of the full-size ship,which verifies the method of converting the test results of the ship model to the prototype.展开更多
Ice-breaking methods have become increasingly significant with the ongoing development of the polar regions.Among many ice-breaking methods,ice-breaking that utilizes a moving load is unique compared with the common c...Ice-breaking methods have become increasingly significant with the ongoing development of the polar regions.Among many ice-breaking methods,ice-breaking that utilizes a moving load is unique compared with the common collision or impact methods.A moving load can generate flexural-gravity waves(FGWs),under the influence of which the ice sheet undergoes deformation and may even experience structural damage.Moving loads can be divided into above-ice loads and underwater loads.For the above-ice loads,we discuss the characteristics of the FGWs generated by a moving load acting on a complete ice sheet,an ice sheet with a crack,and an ice sheet with a lead of open water.For underwater loads,we discuss the influence on the ice-breaking characteristics of FGWs of the mode of motion,the geometrical features,and the trajectory of motion of the load.In addition to discussing the status of current research and the technical challenges of ice-breaking by moving loads,this paper also looks ahead to future research prospects and presents some preliminary ideas for consideration.展开更多
In the vast tand of Northeast China,we are slowly starting an ultimate journey of the ice and snow carnival and exploration of folk customs.This is a magic kingdom of ice and snow ,from the meticulously crafted wonder...In the vast tand of Northeast China,we are slowly starting an ultimate journey of the ice and snow carnival and exploration of folk customs.This is a magic kingdom of ice and snow ,from the meticulously crafted wonders of the ice city to the snowcovered wonderland of rime ice.展开更多
Sea ice and snow are the most sensitive and important crucial components of the global climate system,affecting the global climate by modulating the energy exchange between the ocean and the atmosphere.The sea near Zh...Sea ice and snow are the most sensitive and important crucial components of the global climate system,affecting the global climate by modulating the energy exchange between the ocean and the atmosphere.The sea near Zhongshan Station in Antarctica is covered by landfast sea ice,with snow depth influenced by both thermal factors and wind.This region frequently experiences katabatic winds and cyclones from the westerlies,leading to frequent snow blowing events that redistribute the snow and affects its depth,subsequently impacting the thermodynamic growth of sea ice.This study utilized the one-dimensional thermodynamic model ICEPACK to simulate landfast sea ice thickness and snow depth near Zhongshan Station in 2016.Two parameterization schemes for snow blowing,the Bulk scheme,and the ITDrdg(ITD/ridges)scheme are evaluated for their impact on snow depth.The results show that simulations using snow blowing schemes more closely align with observed results,with the ITDrdg scheme providing more accurate simulations,evidenced by root mean square errors of less than 10 cm for both snow depth and sea ice thickness.Snow blowing also impacts the thermodynamic growth of sea ice,particularly bottom growth.The sea ice bottom increases by 9.0 cm using the ITDrdg scheme compared to simulations without the snow blowing,accounting for 12.5%of total sea ice bottom growth.Furthermore,snow blowing process also influences snow ice formation,highlighting its primary role in affecting snow depth.Continued field observations of snow blowing are necessary to evaluate and improve parameterization schemes.展开更多
近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、...近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、基因结构和启动子顺式作用元件展开生物信息学分析。茶树CsICEs基因的启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件,其可能参与多种逆境胁迫响应。转录组分析和RT-qPCR验证结果发现,低温下CsICE43基因的表达量上升了4.24倍,其可能与茶树低温响应相关。以茶树品种‘保靖黄金茶1号’的cDNA为模板,克隆获得了CsICE43基因,其在不同组织中的表达模式存在差异,在顶芽和嫩叶中特异性高表达。蛋白氨基酸序列和系统进化树分析表明,CsICE43基因包含与ICE家族其他成员一致的S-rich、bHLH、ACT等保守结构域,且与毛花猕猴桃(Actinidiaeriantha)的亲缘关系较近。在STRING在线网站中以拟南芥AtICEs为模型,推测茶树CsICE43蛋白与HOS1、MYB15、DREB1/2存在潜在的互作关系。亚细胞定位试验表明CsICE43定位于细胞核,与跨膜结构分析结果一致。综上所述,本研究发现CsICE43基因可能与茶树低温响应关联,为深入挖掘其基因功能与抗寒分子机理提供了一定的理论基础。展开更多
As a crucial component of the Earth’s climate system,Antarctic sea ice has demonstrated significant variability over the satellite era.Here,we identify a remarkable decadal transition in the total Antarctic Sea Ice E...As a crucial component of the Earth’s climate system,Antarctic sea ice has demonstrated significant variability over the satellite era.Here,we identify a remarkable decadal transition in the total Antarctic Sea Ice Extent(SIE).The stage from 1979 to 2006 is characterized by high-frequency(i.e.,seasonal to interannual)temporal variability in SIE and zonal asymmetry in Sea Ice Concentration(SIC),which is primarily under the control of the Amundsen Sea Low(ASL).After 2007,however,sea ice changes exhibit a more spatially homogeneous pattern in SIC and a more temporally long-lasting mode in SIE.Further analysis reveals that sea ice-ocean interaction plays a major role in the low-frequency(i.e.,multiannual)variability of Antarctic sea ice from 2007−22.The related physical process is inferred to manifest as a strong coupling between the surface and the subsurface ocean layers,involving enhanced vertical convection and the downward delivery of the surface anomalies related to ice melting and freezing processes,thus maintaining the SIE anomalies for a longer time.Furthermore,this process mainly occurs in the Amundsen-Bellingshausen Sea(ABS)sector,and the weakened subsurface ocean stratification is the key factor triggering the coupling process in this region.We find that the Circumpolar Deep Water(CDW)over the ABS sector continued to shoal before 2007 and remained stable thereafter.It is speculated that the shoaling of the CDW may be a possible driver leading to the weakening of the subsurface stratification.展开更多
Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(mill.km^(2)). This was not a record low, which occurred in 2012, when the minimum ...Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(mill.km^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 mill.km^(2), 0.794 mill.km^(2) less than the minimum in 2023. However, the ice extent had decreased by 0.432 mill.km^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. In general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.展开更多
Ice-going ships play a crucial role in polar transportation and resource extraction.Different from the existing modeling approach which assumes that ships remain stationary,dynamic overset grid technology and DFBI(Dyn...Ice-going ships play a crucial role in polar transportation and resource extraction.Different from the existing modeling approach which assumes that ships remain stationary,dynamic overset grid technology and DFBI(Dynamic Fluid-Body Interaction)method are employed in this paper to enable the free-running motion of the ship in modeling.A numerical model capable of simulating a ship navigating through pack ice area is proposed,which uses Computational Fluid Dynamics(CFD)method to solve the flow field and applies the Discrete Element Method(DEM)to simulate ship-ice and ice-ice interactions.Besides,the proposed high-precision method for generating pack ice area can be used in conjunction with the proposed numerical model.By comparing the numerical results with the available model test data and experimental observations,the effectiveness of the numerical model is validated,demonstrating its strong capability of predicting resistance and simulating ship navigation in pack ice,as well as its significant potential and applicability for further studies.展开更多
为探究ICE(inducer of CBF expression)转录因子在高丛蓝莓花果发育进程中可能的调控机制,通过对VcICE基因家族进行全基因组鉴定及生物信息学分析,采用实时荧光定量PCR(qRT-PCR)技术分析VcICE基因亚家族成员在蓝莓花芽膨大和果实发育进...为探究ICE(inducer of CBF expression)转录因子在高丛蓝莓花果发育进程中可能的调控机制,通过对VcICE基因家族进行全基因组鉴定及生物信息学分析,采用实时荧光定量PCR(qRT-PCR)技术分析VcICE基因亚家族成员在蓝莓花芽膨大和果实发育进程中的相对表达水平.结果表明:在高丛蓝莓‘Draper’基因组中鉴定出8个VcICE成员,系统进化分析将其划分为2个亚家族,各亚家族成员均包含S-rich,bHLH和ACT等保守结构域;VcICE基因启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件;VcICE亚家族基因在高丛蓝莓‘O’Neal’和‘Bluerain’花芽膨大与果实发育进程中的相对表达差异显著.研究结果以期为深入了解VcICE转录因子在蓝莓花果发育进程中的功能提供理论参考.展开更多
This is an in-depth journey to experience the ice and snow of Changbai Mountain.In these few days,you will explore Changbai Mountain and enjoy powder skiing;gallop on the ski trail;watch the stunning wonders of snow r...This is an in-depth journey to experience the ice and snow of Changbai Mountain.In these few days,you will explore Changbai Mountain and enjoy powder skiing;gallop on the ski trail;watch the stunning wonders of snow rime on thousands of trees;conquer the ice and snow wilderness on a snowmobile and start an in depth magical mystery tour in lilin Province.展开更多
Using nine ice-tethered buoys deployed across the marginal ice zone(MIZ)and pack ice zone(PIZ)north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate...Using nine ice-tethered buoys deployed across the marginal ice zone(MIZ)and pack ice zone(PIZ)north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate(MOSAiC)in 2019-2020,we characterized the spatiotemporal variations in sea ice kinematics and deformation between October 2019 and July 2020 in the Transpolar Drift(TPD).From October to November,the buoys were in the upstream area of the TPD;spatial variations of deformation rates were significantly correlated with initial ice thickness(R=−0.84,P<0.05).From December 2019 to March 2020,the buoys were in the high Arctic and the ice cover was consolidated;heterogeneity in ice kinematics as measured across the buoys reduced by 65%.From April to May 2020,the buoys were in the downstream TPD;amplified spatial variations in ice kinematics were observed.This is because two buoys had drifted over the shallow waters north of Svalbard earlier;trajectory-stretching exponents derived from the data from these two buoys indicate deformation rates(10.6 d^(−1))that were about twice those in the deep basin(4.2 d^(−1)).By June 2020,a less consolidated ice pack and enhanced tidal forcing in the Fram Strait MIZ resulted in ice deformation with a semi-diurnal power spectral density of>0.25 d^(−1),which is about 1.5 times that in PIZ.Therefore,in both the upstream and downstream regions of the TPD,the transition between the MIZ and the PIZ contributes to the spatial and seasonal variations of sea ice motion and deformation.The results from this study can be used to support the characterization of the momentum balance and influencing factors during the ice advection along the TPD,which is a crucial corridor for Arctic sea ice outflow to the north Atlantic Ocean.展开更多
Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algori...Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algorithm using the data from the scatterometer and radiometer sensors onboard the Chinese Haiyang-2B(HY-2B)satellite to identify MYI and first-year ice(FYI).The proposed method was established based on K-means and fuzzy clustering(K-means+FC)and was used to focus on the transition zone where the ice condition is complex due to the highly commixing of MYI and FYI,leading to the high challenge for accurate classification of sea ice.The K-means algorithm was applied to preliminarily classify MYI using the combination of scatterometer and radiometer data,followed by applying fuzzy clustering to reclassify MYI in the transition zone.The HY-2B K-means+FC results were compared with the ice type products[including the Ocean and Sea Ice Satellite Application Facility(OSI SAF)sea ice type product and the Equal-Area Scalable Earth-Grid sea ice age dataset],and showed agreement in the time series of MYI extent.Intercomparisons in the transition zone indicated that the HY-2B K-means+FC results can identify more old ice than the OSI SAF product,but with an underestimation in identifying second-year ice.Comparisons between K-means and Kmeans+FC results were performed using regional ice charts and Sentinel-1 synthetic aperture radar(SAR)data.By adding fuzzy clustering,the MYI is more consistent with the ice charts,with the overall accuracy(OA)increasing by 0.9%–6.5%.Comparing against SAR images,it is suggested that more scattered MYI floes can be identified by fuzzy clustering,and the OA is increased by about 3%in middle freezing season and 7%–20%in early and late freezing season.展开更多
Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades,yet detailed on-site observations remain limited.Here we present the measured records of surf...Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades,yet detailed on-site observations remain limited.Here we present the measured records of surface mass balance,ice velocity and surface ice temperature of Baishui River Glacier No.1 in Yulong Snow Mountain from 2018 to 2022.Our observations reveal an annual mean mass balance of-1.29±0.16 m w.e.,demonstrating a significant seasonal imbalance between reduced accumulation(multi-year average of 0.51±0.07 m w.e.)and enhanced ablation(multi-year average of 1.80±0.26 m w.e.),which provides crucial evidence for explaining the long-term mass loss.The average annual ice velocity,predominantly controlled by monsoon season dynamics which contribute 69%–74%of the total movement,was measured at 26.91±2.76 m yr^(-1)and exhibited a decreasing trend of 1.73 m yr^(-1).The ice temperature fluctuated between-13.41℃to-0.04℃,with an average of-6.04℃.The ice temperature and air temperature synchronized well in the nonmonsoon period,while the temperature rise was not synchronized and slightly delayed in the monsoon period.展开更多
Antarctic coastal polynyas play a vital role in atmosphere-ocean interactions and local ecosystems.This study investigates the interannual variability of springtime coastal polynyas over the Ross Sea based on satellit...Antarctic coastal polynyas play a vital role in atmosphere-ocean interactions and local ecosystems.This study investigates the interannual variability of springtime coastal polynyas over the Ross Sea based on satellite-retrieved sea-ice concentration(SIC)data from 1992 to 2021.Firstly,the springtime coastal polynya areas display large interannual variability as well as a positive trend of about 2000 km^(2)(10 yr)^(-1) over the 30 years.Secondly,based on composite analysis,in spring,we find that a deepened Amundsen Sea Low(ASL)induces stronger meridional winds over the eastern Ross Sea,leading to stronger sea-ice advection and expansion of coastal polynya areas.This is accompanied by more solar radiation absorption in early summer(about 16 W m^(2)),resulting in upper-ocean warming(~0.4℃)and significant sea-ice loss in late summer(~50%SIC).Additionally,the physical processes are validated by 500-year piControl simulations of a state-of-the-art Earth system model.Based on the same composite analysis,the results show that the sea-ice decline is consistent with the deepening of the ASL and the increase of the meridional sea-ice advection of the preceding spring,which is highly consistent with that of observations.This further confirms the circulations-polynyas-sea-ice physical linkages.Since the springtime ASL is strongly modulated by the tropical Pacific variability and the stratospheric polar vortex,changes in the polynya areas of the Ross Sea can be traced back to remote regions.展开更多
Arctic sea ice is an essential component of the climate system and plays an important role in global climate change.This study calculates the volume flux through Fram Strait(FS)and the sea ice volume in the Greenland ...Arctic sea ice is an essential component of the climate system and plays an important role in global climate change.This study calculates the volume flux through Fram Strait(FS)and the sea ice volume in the Greenland Sea(GS)from 1979 to 2022,and analyzes trends before and after 2000.In addition,the contributions of advection and local processes to sea ice volume variations in the GS during different seasons are compared.The influence of the surface air temperature(SAT)and the sea surface temperature(SST)on sea ice volume variations is discussed,as well as the impact of atmospheric circulation on sea ice.Results indicate no significant trend in the sea ice volume flux through FS from 1979 to 2022.However,the sea ice volume in the GS exhibited a notable decreasing trend.Compared with the period of 1979-2000,the sea ice volume decreasing trend accelerated significantly during the period of 2001-2022.During winter,ice advection from the central Arctic Ocean exert a strong influence on the sea ice volume variations in the GS,whereas during summer,local processes,including the interactions with the atmosphere and ocean,as well as the dynamic process of sea ice itself,exert a considerable impact.The sea ice volume in the GS declined rapidly after 2000.Furthermore,the effects of local processes on sea ice have intensified,with the SST exerting a stronger influence on the sea ice volume variations in the GS than the SAT.The positive Arctic oscillation and dipole anomaly are important drivers for the transport of Arctic sea ice to the GS.The Winter North Atlantic oscillation intensifies ocean heat content,affecting sea ice in the GS.展开更多
Thermodynamic and dynamic processes(TDP)significantly modulate the rapid variability of Arctic sea ice,with complex interactions between them.This study quantifies the Arctic sea ice budget of volume from 1989 to 2021...Thermodynamic and dynamic processes(TDP)significantly modulate the rapid variability of Arctic sea ice,with complex interactions between them.This study quantifies the Arctic sea ice budget of volume from 1989 to 2021 using data from NSIDC and PIOMAS.Results show that thermodynamic processes dominate seasonal Arctic sea ice budget variation,covering 40%of the sea ice zone,strongest at the margins and in the seasonal ice zone.Dynamic processes play a relay role,contributing less than half of that from thermodynamic processes.Their influence is strongest in winter and weakest in summer,closely linked to sea ice drift circulation.TDP exhibit opposite seasonal cycles,with thermodynamic processes inversely correlated with sea ice volume changes.Dynamic processes are most negatively correlated with thermodynamic processes when they precede by 21 d.After strong thermodynamic processes,dynamic processes become more pronounced,peaking 76 d later,indicating a seasonal coupled effect where dynamic processes sustain and amplify the sea ice changes initiated by thermodynamic processes.Significant long-term trends in TDP are identified.Thermodynamic processes have increased over the past three decades,particularly in June to July and October to November.Dynamic processes decreases from June to August but increases in September.This study enhances understanding of the complex interplay between TDP modulate Arctic sea ice changes and highlights potential decadal trends under climate change.展开更多
A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the ...A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas.展开更多
Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier...Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier stability.The Ross Ice Shelf(RIS),the largest body of floating ice on Earth,plays an essential role in any changes in the mass balance of the Antarctic Ice Sheet.The long-term elevation change trend of RIS has been calculated with multiple satellite altimetry in previous studies.However,the seasonal variations were less revealed.Based on crossover analysis and indirect observation adjustments,this study proposed a new method for constructing seasonal records for surface elevation changes in the RIS using ICESat laser altimetry data from 2003 to 2009.The results showed that surface elevation changes exhibited seasonal variations with fluctuations over 20 cm,and the seasonal change characteristics were closely related to the temperature.Interannual variations in RIS surface elevation decreased from 2003 to2009 at a rate of 2 cm/yr.From March 2003 to April 2007,the surface elevation decreased at 3.7 cm/yr;however,after April 2007,the surface elevation increased at 5.5 cm/yr.The more recent stages of surface elevation growth have been influenced by reductions in the summer basal melt,which is related to the decreases in ocean heat content.展开更多
In designing modern vessels, calculating the propulsion performance of ships in ice is important, including propeller effective thrust, number of revolutions, consumed power, and ship speed. Such calculations allow fo...In designing modern vessels, calculating the propulsion performance of ships in ice is important, including propeller effective thrust, number of revolutions, consumed power, and ship speed. Such calculations allow for more accurate prediction of the ice performance of a designed ship and provide inputs for designers of ship power and automation systems. Preliminary calculations of ship propulsion and thrust characteristics in ice can enable predictions of full-scale ice resistance without measuring the propeller thrust during sea trials. Measuring propeller revolutions,ship speed, and the power delivered to propellers could be sufficient to determine the propeller thrust of the vessel. At present, significant difficulties arise in determining the thrust of icebreakers and ice-class ships in ice conditions. These challenges are related to the fact that the traditional system of propeller/hull interaction coefficients does not function correctly in ice conditions. The wake fraction becomes negative and tends to minus infinity starting from a certain value of the propeller advance coefficient. This issue prevents accurate determination of the performance characteristics, thrust, and rotational speed of the propulsors. In this study, an alternative system of propeller/hull interaction coefficients for ice is proposed. It enables the calculation of all propulsion parameters in ice based on standard hydrodynamic tests with selfpropulsion models. An experimental method is developed to determine alternative propeller/hull interaction coefficients. A prediction method is suggested to determine propulsion performance in ice based on the alternative interaction coefficient system. A case study applying the propulsion prediction method for ice conditions is provided. This study also discusses the following issues of ship operation in ice: the scale effect of icebreaker propellers and the prospects for introducing an ice interaction coefficient.展开更多
基金financially supported by Jiangsu Province University(High Tech Ship)Collaborative Innovation Center(Grant No.XTCXKY20230008).
文摘In this work,the selected icebreaker model experiment is performed in a towing tank.We focus on the influence of seawater salinity on ship ice resistance in the ice floe field and the innovative ice model and ship model test technology,including the similitude rule of ship model tests,test principles,and validation with full-scale ship data.A formula for calculating the relationship between the temperature and salinity of the water is constructed,which can be used to simulate the role of seawater in freshwater ice pools.On this basis,the effect of salinity on the resistance of ships sailing in broken ice fields is studied.A technique in which artificial ice made of polyethylene spheres is used to simulate ice resistance is proposed.With a series of ship model experiments in spherical and triangular ice fields,the effects of salinity and velocity on the ice resistance test of the ship model are analyzed.A relationship of the ice resistance of the ship model to the spherical ice field and the triangular ice field is proposed.The conversion results are consistent with onsite data of the full-size ship,which verifies the method of converting the test results of the ship model to the prototype.
基金Supported by the National Natural Science Foundation of China(Nos.52192693,52192690,52371270,U20A20327)the National Key Research and Development Program of China(Nos.2021YFC2803400).
文摘Ice-breaking methods have become increasingly significant with the ongoing development of the polar regions.Among many ice-breaking methods,ice-breaking that utilizes a moving load is unique compared with the common collision or impact methods.A moving load can generate flexural-gravity waves(FGWs),under the influence of which the ice sheet undergoes deformation and may even experience structural damage.Moving loads can be divided into above-ice loads and underwater loads.For the above-ice loads,we discuss the characteristics of the FGWs generated by a moving load acting on a complete ice sheet,an ice sheet with a crack,and an ice sheet with a lead of open water.For underwater loads,we discuss the influence on the ice-breaking characteristics of FGWs of the mode of motion,the geometrical features,and the trajectory of motion of the load.In addition to discussing the status of current research and the technical challenges of ice-breaking by moving loads,this paper also looks ahead to future research prospects and presents some preliminary ideas for consideration.
文摘In the vast tand of Northeast China,we are slowly starting an ultimate journey of the ice and snow carnival and exploration of folk customs.This is a magic kingdom of ice and snow ,from the meticulously crafted wonders of the ice city to the snowcovered wonderland of rime ice.
基金The National Natural Science Foundation of China under contract Nos 42306255 and 41976217the National Key R&D Program of China under contract No.2018YFA0605903。
文摘Sea ice and snow are the most sensitive and important crucial components of the global climate system,affecting the global climate by modulating the energy exchange between the ocean and the atmosphere.The sea near Zhongshan Station in Antarctica is covered by landfast sea ice,with snow depth influenced by both thermal factors and wind.This region frequently experiences katabatic winds and cyclones from the westerlies,leading to frequent snow blowing events that redistribute the snow and affects its depth,subsequently impacting the thermodynamic growth of sea ice.This study utilized the one-dimensional thermodynamic model ICEPACK to simulate landfast sea ice thickness and snow depth near Zhongshan Station in 2016.Two parameterization schemes for snow blowing,the Bulk scheme,and the ITDrdg(ITD/ridges)scheme are evaluated for their impact on snow depth.The results show that simulations using snow blowing schemes more closely align with observed results,with the ITDrdg scheme providing more accurate simulations,evidenced by root mean square errors of less than 10 cm for both snow depth and sea ice thickness.Snow blowing also impacts the thermodynamic growth of sea ice,particularly bottom growth.The sea ice bottom increases by 9.0 cm using the ITDrdg scheme compared to simulations without the snow blowing,accounting for 12.5%of total sea ice bottom growth.Furthermore,snow blowing process also influences snow ice formation,highlighting its primary role in affecting snow depth.Continued field observations of snow blowing are necessary to evaluate and improve parameterization schemes.
文摘近年来全球极端低温天气频发,严重影响了茶树的产量和品质。ICE(Inducer of CBF expression)基因家族主要参与植物的低温胁迫响应,但在茶树领域中的相关研究还不够全面。本研究从茶树基因组中鉴定出51个茶树CsICEs基因,对其理化性质、基因结构和启动子顺式作用元件展开生物信息学分析。茶树CsICEs基因的启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件,其可能参与多种逆境胁迫响应。转录组分析和RT-qPCR验证结果发现,低温下CsICE43基因的表达量上升了4.24倍,其可能与茶树低温响应相关。以茶树品种‘保靖黄金茶1号’的cDNA为模板,克隆获得了CsICE43基因,其在不同组织中的表达模式存在差异,在顶芽和嫩叶中特异性高表达。蛋白氨基酸序列和系统进化树分析表明,CsICE43基因包含与ICE家族其他成员一致的S-rich、bHLH、ACT等保守结构域,且与毛花猕猴桃(Actinidiaeriantha)的亲缘关系较近。在STRING在线网站中以拟南芥AtICEs为模型,推测茶树CsICE43蛋白与HOS1、MYB15、DREB1/2存在潜在的互作关系。亚细胞定位试验表明CsICE43定位于细胞核,与跨膜结构分析结果一致。综上所述,本研究发现CsICE43基因可能与茶树低温响应关联,为深入挖掘其基因功能与抗寒分子机理提供了一定的理论基础。
基金supported by the National Natural Science Foundation China(Grant No.42176222).
文摘As a crucial component of the Earth’s climate system,Antarctic sea ice has demonstrated significant variability over the satellite era.Here,we identify a remarkable decadal transition in the total Antarctic Sea Ice Extent(SIE).The stage from 1979 to 2006 is characterized by high-frequency(i.e.,seasonal to interannual)temporal variability in SIE and zonal asymmetry in Sea Ice Concentration(SIC),which is primarily under the control of the Amundsen Sea Low(ASL).After 2007,however,sea ice changes exhibit a more spatially homogeneous pattern in SIC and a more temporally long-lasting mode in SIE.Further analysis reveals that sea ice-ocean interaction plays a major role in the low-frequency(i.e.,multiannual)variability of Antarctic sea ice from 2007−22.The related physical process is inferred to manifest as a strong coupling between the surface and the subsurface ocean layers,involving enhanced vertical convection and the downward delivery of the surface anomalies related to ice melting and freezing processes,thus maintaining the SIE anomalies for a longer time.Furthermore,this process mainly occurs in the Amundsen-Bellingshausen Sea(ABS)sector,and the weakened subsurface ocean stratification is the key factor triggering the coupling process in this region.We find that the Circumpolar Deep Water(CDW)over the ABS sector continued to shoal before 2007 and remained stable thereafter.It is speculated that the shoaling of the CDW may be a possible driver leading to the weakening of the subsurface stratification.
文摘Arctic sea-ice extent reaches its minimum each year in September. On 11 September 2023 the minimum was 4.969 million square kilometers(mill.km^(2)). This was not a record low, which occurred in 2012, when the minimum was 4.175 mill.km^(2), 0.794 mill.km^(2) less than the minimum in 2023. However, the ice extent had decreased by 0.432 mill.km^(2) compared with 2022. Nevertheless, the summer melting in 2023 was remarkably less than expected when considering the strong heat waves in the atmosphere and ocean, with record temperatures set around the world. In general, there is a high correlation between the long-term decrease in sea-ice extent and the increasing CO_(2) in the atmosphere, where the increase of CO_(2) in recent decades explains about 80% of the decrease in sea ice in September, while the remainder is caused by natural variability.
文摘Ice-going ships play a crucial role in polar transportation and resource extraction.Different from the existing modeling approach which assumes that ships remain stationary,dynamic overset grid technology and DFBI(Dynamic Fluid-Body Interaction)method are employed in this paper to enable the free-running motion of the ship in modeling.A numerical model capable of simulating a ship navigating through pack ice area is proposed,which uses Computational Fluid Dynamics(CFD)method to solve the flow field and applies the Discrete Element Method(DEM)to simulate ship-ice and ice-ice interactions.Besides,the proposed high-precision method for generating pack ice area can be used in conjunction with the proposed numerical model.By comparing the numerical results with the available model test data and experimental observations,the effectiveness of the numerical model is validated,demonstrating its strong capability of predicting resistance and simulating ship navigation in pack ice,as well as its significant potential and applicability for further studies.
文摘为探究ICE(inducer of CBF expression)转录因子在高丛蓝莓花果发育进程中可能的调控机制,通过对VcICE基因家族进行全基因组鉴定及生物信息学分析,采用实时荧光定量PCR(qRT-PCR)技术分析VcICE基因亚家族成员在蓝莓花芽膨大和果实发育进程中的相对表达水平.结果表明:在高丛蓝莓‘Draper’基因组中鉴定出8个VcICE成员,系统进化分析将其划分为2个亚家族,各亚家族成员均包含S-rich,bHLH和ACT等保守结构域;VcICE基因启动子区域富含光响应、植物激素、生长发育及非生物胁迫相关顺式作用元件;VcICE亚家族基因在高丛蓝莓‘O’Neal’和‘Bluerain’花芽膨大与果实发育进程中的相对表达差异显著.研究结果以期为深入了解VcICE转录因子在蓝莓花果发育进程中的功能提供理论参考.
文摘This is an in-depth journey to experience the ice and snow of Changbai Mountain.In these few days,you will explore Changbai Mountain and enjoy powder skiing;gallop on the ski trail;watch the stunning wonders of snow rime on thousands of trees;conquer the ice and snow wilderness on a snowmobile and start an in depth magical mystery tour in lilin Province.
基金supported by the National Key Research and Development Program of China(Grant no.2021YFC2803304)the National Natural Science Foundation of China(Grant nos.52192691 and 52192690)the Program of Shanghai Academic/Technology Research Leader(Grant no.22XD1403600).
文摘Using nine ice-tethered buoys deployed across the marginal ice zone(MIZ)and pack ice zone(PIZ)north of the Laptev Sea during the expedition of the Multidisciplinary drifting Observatory for the Study of Arctic Climate(MOSAiC)in 2019-2020,we characterized the spatiotemporal variations in sea ice kinematics and deformation between October 2019 and July 2020 in the Transpolar Drift(TPD).From October to November,the buoys were in the upstream area of the TPD;spatial variations of deformation rates were significantly correlated with initial ice thickness(R=−0.84,P<0.05).From December 2019 to March 2020,the buoys were in the high Arctic and the ice cover was consolidated;heterogeneity in ice kinematics as measured across the buoys reduced by 65%.From April to May 2020,the buoys were in the downstream TPD;amplified spatial variations in ice kinematics were observed.This is because two buoys had drifted over the shallow waters north of Svalbard earlier;trajectory-stretching exponents derived from the data from these two buoys indicate deformation rates(10.6 d^(−1))that were about twice those in the deep basin(4.2 d^(−1)).By June 2020,a less consolidated ice pack and enhanced tidal forcing in the Fram Strait MIZ resulted in ice deformation with a semi-diurnal power spectral density of>0.25 d^(−1),which is about 1.5 times that in PIZ.Therefore,in both the upstream and downstream regions of the TPD,the transition between the MIZ and the PIZ contributes to the spatial and seasonal variations of sea ice motion and deformation.The results from this study can be used to support the characterization of the momentum balance and influencing factors during the ice advection along the TPD,which is a crucial corridor for Arctic sea ice outflow to the north Atlantic Ocean.
基金the National Key Research and Development Program of China under contract No.2021YFC2803301the Fundamental Research Funds for the Central Universities,China under contract Nos 2042024kf0037 and 2042022dx0001the Natural Science Foundation of Wuhan under cocntract No.2024040701010030.
文摘Loss of multiyear ice(MYI)is of great importance for Arctic climate and marine systems and can be monitored using active and passive microwave satellite data.In this paper,we describe an upgraded classification algorithm using the data from the scatterometer and radiometer sensors onboard the Chinese Haiyang-2B(HY-2B)satellite to identify MYI and first-year ice(FYI).The proposed method was established based on K-means and fuzzy clustering(K-means+FC)and was used to focus on the transition zone where the ice condition is complex due to the highly commixing of MYI and FYI,leading to the high challenge for accurate classification of sea ice.The K-means algorithm was applied to preliminarily classify MYI using the combination of scatterometer and radiometer data,followed by applying fuzzy clustering to reclassify MYI in the transition zone.The HY-2B K-means+FC results were compared with the ice type products[including the Ocean and Sea Ice Satellite Application Facility(OSI SAF)sea ice type product and the Equal-Area Scalable Earth-Grid sea ice age dataset],and showed agreement in the time series of MYI extent.Intercomparisons in the transition zone indicated that the HY-2B K-means+FC results can identify more old ice than the OSI SAF product,but with an underestimation in identifying second-year ice.Comparisons between K-means and Kmeans+FC results were performed using regional ice charts and Sentinel-1 synthetic aperture radar(SAR)data.By adding fuzzy clustering,the MYI is more consistent with the ice charts,with the overall accuracy(OA)increasing by 0.9%–6.5%.Comparing against SAR images,it is suggested that more scattered MYI floes can be identified by fuzzy clustering,and the OA is increased by about 3%in middle freezing season and 7%–20%in early and late freezing season.
基金supported by the Postdoctoral Fellowship Program of CPSF(Grant No.GZC20232951)the Science and Technology program of Gansu Province(Grant No.22ZD6FA005)Program of the State Key Laboratory of Cryospheric Science and Frozen Soil Engineering(Grant No.CSFSE-TZ-2403,2410)。
文摘Temperate glaciers in the southeastern Tibetan Plateau have experienced significant mass loss and retreat in recent decades,yet detailed on-site observations remain limited.Here we present the measured records of surface mass balance,ice velocity and surface ice temperature of Baishui River Glacier No.1 in Yulong Snow Mountain from 2018 to 2022.Our observations reveal an annual mean mass balance of-1.29±0.16 m w.e.,demonstrating a significant seasonal imbalance between reduced accumulation(multi-year average of 0.51±0.07 m w.e.)and enhanced ablation(multi-year average of 1.80±0.26 m w.e.),which provides crucial evidence for explaining the long-term mass loss.The average annual ice velocity,predominantly controlled by monsoon season dynamics which contribute 69%–74%of the total movement,was measured at 26.91±2.76 m yr^(-1)and exhibited a decreasing trend of 1.73 m yr^(-1).The ice temperature fluctuated between-13.41℃to-0.04℃,with an average of-6.04℃.The ice temperature and air temperature synchronized well in the nonmonsoon period,while the temperature rise was not synchronized and slightly delayed in the monsoon period.
基金supported by the National Key R&D Program of China(Grant No.2021YFC2802504)the National Outstanding Youth Grant(Grant No.41925027)+1 种基金the National Natural Science Foundation of China(Grant No.42206251)the Innovation Group Project of the Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(Grant No.311021008).
文摘Antarctic coastal polynyas play a vital role in atmosphere-ocean interactions and local ecosystems.This study investigates the interannual variability of springtime coastal polynyas over the Ross Sea based on satellite-retrieved sea-ice concentration(SIC)data from 1992 to 2021.Firstly,the springtime coastal polynya areas display large interannual variability as well as a positive trend of about 2000 km^(2)(10 yr)^(-1) over the 30 years.Secondly,based on composite analysis,in spring,we find that a deepened Amundsen Sea Low(ASL)induces stronger meridional winds over the eastern Ross Sea,leading to stronger sea-ice advection and expansion of coastal polynya areas.This is accompanied by more solar radiation absorption in early summer(about 16 W m^(2)),resulting in upper-ocean warming(~0.4℃)and significant sea-ice loss in late summer(~50%SIC).Additionally,the physical processes are validated by 500-year piControl simulations of a state-of-the-art Earth system model.Based on the same composite analysis,the results show that the sea-ice decline is consistent with the deepening of the ASL and the increase of the meridional sea-ice advection of the preceding spring,which is highly consistent with that of observations.This further confirms the circulations-polynyas-sea-ice physical linkages.Since the springtime ASL is strongly modulated by the tropical Pacific variability and the stratospheric polar vortex,changes in the polynya areas of the Ross Sea can be traced back to remote regions.
基金The National Key Research and Development Program of China under contract Nos 2021YFC2803303 and 2021YFC2803302the National Natural Science Foundation of China under contract No.42171133the Fundamental Research Funds for the Central Universities,China,under contract No.2042022dx0001.
文摘Arctic sea ice is an essential component of the climate system and plays an important role in global climate change.This study calculates the volume flux through Fram Strait(FS)and the sea ice volume in the Greenland Sea(GS)from 1979 to 2022,and analyzes trends before and after 2000.In addition,the contributions of advection and local processes to sea ice volume variations in the GS during different seasons are compared.The influence of the surface air temperature(SAT)and the sea surface temperature(SST)on sea ice volume variations is discussed,as well as the impact of atmospheric circulation on sea ice.Results indicate no significant trend in the sea ice volume flux through FS from 1979 to 2022.However,the sea ice volume in the GS exhibited a notable decreasing trend.Compared with the period of 1979-2000,the sea ice volume decreasing trend accelerated significantly during the period of 2001-2022.During winter,ice advection from the central Arctic Ocean exert a strong influence on the sea ice volume variations in the GS,whereas during summer,local processes,including the interactions with the atmosphere and ocean,as well as the dynamic process of sea ice itself,exert a considerable impact.The sea ice volume in the GS declined rapidly after 2000.Furthermore,the effects of local processes on sea ice have intensified,with the SST exerting a stronger influence on the sea ice volume variations in the GS than the SAT.The positive Arctic oscillation and dipole anomaly are important drivers for the transport of Arctic sea ice to the GS.The Winter North Atlantic oscillation intensifies ocean heat content,affecting sea ice in the GS.
基金supported by the National Key Research and Development Program of China(Grant no.2019YFA0607004)the National Natural Science Foundation of China(Grant nos.42430411,42075024,42205029 and 42230405)。
文摘Thermodynamic and dynamic processes(TDP)significantly modulate the rapid variability of Arctic sea ice,with complex interactions between them.This study quantifies the Arctic sea ice budget of volume from 1989 to 2021 using data from NSIDC and PIOMAS.Results show that thermodynamic processes dominate seasonal Arctic sea ice budget variation,covering 40%of the sea ice zone,strongest at the margins and in the seasonal ice zone.Dynamic processes play a relay role,contributing less than half of that from thermodynamic processes.Their influence is strongest in winter and weakest in summer,closely linked to sea ice drift circulation.TDP exhibit opposite seasonal cycles,with thermodynamic processes inversely correlated with sea ice volume changes.Dynamic processes are most negatively correlated with thermodynamic processes when they precede by 21 d.After strong thermodynamic processes,dynamic processes become more pronounced,peaking 76 d later,indicating a seasonal coupled effect where dynamic processes sustain and amplify the sea ice changes initiated by thermodynamic processes.Significant long-term trends in TDP are identified.Thermodynamic processes have increased over the past three decades,particularly in June to July and October to November.Dynamic processes decreases from June to August but increases in September.This study enhances understanding of the complex interplay between TDP modulate Arctic sea ice changes and highlights potential decadal trends under climate change.
基金The National Natural Science Foundation of China under contract Nos 41976217 and 42306249the National Key Research and Development Program of China under contract No.2018YFA0605701.
文摘A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas.
基金supported by the National Key Research and Development Program of China under grant numbers 2023YFC2809103 and 2024YFC2813505the National Natural Science Foundation of China under the grant number 41706216+2 种基金the Fundamental Research Funds for the Central Universities under grant numbers 2042022kf1204,2042022kf1069,2042023gf0012,2042022dx0001the Hubei Provincial Natural Science Foundation of China under grant number 2022CFB081the State Key Laboratory of Geodesy and Earth's Dynamics,Innovation Academy for Precision Measurement Science and Technology under grant number SKLGED2023-2-6。
文摘Ice shelves are important passageways for ice sheets flowing into the ocean.Through iceberg calving and basal melting,ice shelves exert considerable influence on the mass balance of the Antarctic Ice Sheet and glacier stability.The Ross Ice Shelf(RIS),the largest body of floating ice on Earth,plays an essential role in any changes in the mass balance of the Antarctic Ice Sheet.The long-term elevation change trend of RIS has been calculated with multiple satellite altimetry in previous studies.However,the seasonal variations were less revealed.Based on crossover analysis and indirect observation adjustments,this study proposed a new method for constructing seasonal records for surface elevation changes in the RIS using ICESat laser altimetry data from 2003 to 2009.The results showed that surface elevation changes exhibited seasonal variations with fluctuations over 20 cm,and the seasonal change characteristics were closely related to the temperature.Interannual variations in RIS surface elevation decreased from 2003 to2009 at a rate of 2 cm/yr.From March 2003 to April 2007,the surface elevation decreased at 3.7 cm/yr;however,after April 2007,the surface elevation increased at 5.5 cm/yr.The more recent stages of surface elevation growth have been influenced by reductions in the summer basal melt,which is related to the decreases in ocean heat content.
基金supported by a grant No. 23-19-00039 of Russian Research Fund “Theoretical basis and application tools for developing a system of intellectual fleet planning and support of decisions on Arctic navigation”。
文摘In designing modern vessels, calculating the propulsion performance of ships in ice is important, including propeller effective thrust, number of revolutions, consumed power, and ship speed. Such calculations allow for more accurate prediction of the ice performance of a designed ship and provide inputs for designers of ship power and automation systems. Preliminary calculations of ship propulsion and thrust characteristics in ice can enable predictions of full-scale ice resistance without measuring the propeller thrust during sea trials. Measuring propeller revolutions,ship speed, and the power delivered to propellers could be sufficient to determine the propeller thrust of the vessel. At present, significant difficulties arise in determining the thrust of icebreakers and ice-class ships in ice conditions. These challenges are related to the fact that the traditional system of propeller/hull interaction coefficients does not function correctly in ice conditions. The wake fraction becomes negative and tends to minus infinity starting from a certain value of the propeller advance coefficient. This issue prevents accurate determination of the performance characteristics, thrust, and rotational speed of the propulsors. In this study, an alternative system of propeller/hull interaction coefficients for ice is proposed. It enables the calculation of all propulsion parameters in ice based on standard hydrodynamic tests with selfpropulsion models. An experimental method is developed to determine alternative propeller/hull interaction coefficients. A prediction method is suggested to determine propulsion performance in ice based on the alternative interaction coefficient system. A case study applying the propulsion prediction method for ice conditions is provided. This study also discusses the following issues of ship operation in ice: the scale effect of icebreaker propellers and the prospects for introducing an ice interaction coefficient.
