The Barents Sea is a marginal sea of the Arctic Ocean and contains substantial hydrocarbon resources.In recent years,the Barents Sea has emerged as one of the Arctic regions with the most pronounced sea ice variabilit...The Barents Sea is a marginal sea of the Arctic Ocean and contains substantial hydrocarbon resources.In recent years,the Barents Sea has emerged as one of the Arctic regions with the most pronounced sea ice variability.To analyze sea ice changes in the Barents Sea,sea ice data from the National Snow and Ice Data Center were utilized.A remarkable decline in sea ice has been witnessed in the northern and eastern regions.This phenomenon has expanded the ice-free operational area for marine structures,highlighting the significance of wave factors.A site within this area was chosen to estimate the wave parameters.The wave data from ERA5 were categorized according to wave energy in each season.Four mixture joint distribution models for the wave height and period were constructed based on the mixture distribution method and copula theory,and environmental contours were developed and compared with the conditional probability method.Despite differences in the design parameter results,the mixture models demonstrate good performance in sample fitting,particularly in the distribution tails.Among these models,the Gaussian copula offers the best fit.展开更多
The spring(April-May-June)Barents Sea ice has been proven to affect the summer surface air temperature over the Tibetan Plateau(TP).However,its impact on summer(June-July-August)TP precipitation,a crucial climate comp...The spring(April-May-June)Barents Sea ice has been proven to affect the summer surface air temperature over the Tibetan Plateau(TP).However,its impact on summer(June-July-August)TP precipitation,a crucial climate component,remains unexplored.We investigate the physical linkage between spring Barents Sea ice and subsequent summer TP precipitation from 1979 to 2018.Our results indicate that above-normal spring Barents Sea ice leads to excessive summer TP precipitation,and vice versa.During spring,more Barents Sea ice induces remarkable cooling and subsidence over there and surrounding areas.The cooling over the Barents Sea can persist into summer,triggering a meridional wave-like pattern along the longitude of 60°E and,in turn,an anomalous atmospheric subsidence over the Caspian Sea and the eastern region adjacent to it.This alters 200 h Pa convergence and modulates the Silk Road pattern(SRP).As a result,cyclonic anomalies form to the west of the TP,which enhance moisture transport toward the TP and increase its precipitation during summer.Numerical experiments reproduce these physical processes and further support our conclusions.展开更多
Possible influences of the Barents Sea ice anomalies on the Eurasian atmospheric circulation and the East China precipitation distribution in the late spring and early summer (May-June) are investigated by analyzing t...Possible influences of the Barents Sea ice anomalies on the Eurasian atmospheric circulation and the East China precipitation distribution in the late spring and early summer (May-June) are investigated by analyzing the observational data and the output of an atmospheric general circulation model (AGCM). The study indicates that the sea ice condition of the Barents Sea from May to July may be interrelated with the atmospheric circulation of June. When there is more than average sea ice in the Barents Sea, the local geopotential height of the 500-hPa level will decrease, and the same height in the Lake Baikal and Okhotsk regions will increase and decrease respectively to form a wave-chain structure over North Eurasia. This kind of anomalous height pattern is beneficial to more precipitation in the south part of East China and less in the north.展开更多
This study reveals a significant relationship,on the interannual timescale,between a dipole mode,the second leading mode,of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia.Re...This study reveals a significant relationship,on the interannual timescale,between a dipole mode,the second leading mode,of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia.Related to the dipole mode,with the heavier sea ice in the north and lighter sea ice in the southeast Barents Sea in spring,the East Asian summer subtropical rainy belt tends to move northward.The significant relationship is established through a wave train over northern Eurasia in the lower troposphere in June.The wave train enhances the northern East Asian low,which induces more rainfall to the north of the East Asian subtropical rainy belt and then attracts the subtropical rainy belt to move northward.This study suggests that the dipole mode of spring sea-ice anomalies in the Barents Sea may be a good precursor for the prediction of East Asian summer rainfall.展开更多
This is the first report of the Barents Sea Ice Edge (BIE) project. The BIE position has varied between latitude 76<span style="white-space:nowrap;">°</span>N and above 82<span style=&...This is the first report of the Barents Sea Ice Edge (BIE) project. The BIE position has varied between latitude 76<span style="white-space:nowrap;">°</span>N and above 82<span style="white-space:nowrap;">°</span>N during the last 440 years. During the period 10,000 to 6000 years ago, Arctic climate was significantly warmer than today. We review various oceanic and atmospheric factors that may have an effect on the BIE position. The Gulf Stream beat with respect to alternations in flow intensity and N-S distribution plays a central role for the changes in climate and BIE position during the last millennium. This occurred in combination with external forcing from total solar irradiation, Earth’s shielding strength, Earth’s geomagnetic field intensity, Earth’s rotation, jet stream changes;all factors of which are ultimately driven by the planetary beat on the Sun, the Earth and the Earth-Moon system. During the last 20 years, we see signs of changes and shifts that may signal the end of the late 20<sup>th</sup> century warm period. The BIE position is likely to start advancing southward in next decade.展开更多
In the Arctic (mainly in its European sector) there is statistically detectable seasonal reversal wind pattern. The combination of seasonally warm (cold) land surfaces in arctic areas together with cool (cool) sea sur...In the Arctic (mainly in its European sector) there is statistically detectable seasonal reversal wind pattern. The combination of seasonally warm (cold) land surfaces in arctic areas together with cool (cool) sea surface of Arctic seas not covered by ice is conducive to the formation of a monsoon like system. On the other hand, the predominance of the cyclonic regime during all seasons makes it difficult to answer the question of whether the Arctic region belongs to the monsoon type pattern. In this study, the monsoon features of atmospheric circulation over the Barents and Kara Seas were analysed. To extract specific monsoon signs, atmospheric circulation systems (separately for areas of each sea) were divided into ten weather types. Their appearance and statistics were compared with indicators of regional circulation. A significant part of intra-annual monsoon variability is associated with the configuration of such modes as the North Atlantic Oscillation and the <em>Scandinavia</em> teleconnection patterns. For example, during the winter season, the monsoon currents (from land to sea) occur only with a positive North Atlantic Oscillation index. With the prevalence of other modes of variability, the direction of the winds can be different, and the regular monsoon circulation pattern is changed by chaotic regime. In summer, northern streams (from sea to land) are realized on the western periphery of cyclones, regenerating and stabilizing over the Kara Sea. As for anomalies, the nature of the monsoons is manifested in the statistics of extreme winds even without selecting data on the regimes of variability. So, in winter, maximum speeds fall on the southern streams, and in the summer—on the northern ones. Large precipitation anomalies during all seasons, as one would expect, are encountered most often with the cyclonic type of circulation.展开更多
Dramatic changes in the sea ice characteristics in the Barents Sea have potential consequences for the weather and climate systems of mid-latitude continents,Arctic ecosystems,and fisheries,as well as Arctic maritime ...Dramatic changes in the sea ice characteristics in the Barents Sea have potential consequences for the weather and climate systems of mid-latitude continents,Arctic ecosystems,and fisheries,as well as Arctic maritime navigation.Simulations and projections of winter sea ice in the Barents Sea based on the latest 41 climate models from the Coupled Model Intercomparison Project Phase 6(CMIP6)are investigated in this study.Results show that most CMIP6 models overestimate winter sea ice in the Barents Sea and underestimate its decreasing trend.The discrepancy is mainly attributed to the simulation bias towards an overly weak ocean heat transport through the Barents Sea Opening and the underestimation of its increasing trend.The methods of observation-based model selection and emergent constraint were used to project future winter sea ice changes in the Barents Sea.Projections indicate that sea ice in the Barents Sea will continue to decline in a warming climate and that a winter ice-free Barents Sea will occur for the first time during 2042-2089 under the Shared Socioeconomic Pathway 585(SSP5-8.5).Even in the observation-based selected models,the sensitivity of winter sea ice in the Barents Sea to global warming is weaker than observed,indicating that a winter ice-free Barents Sea might occur earlier than projected by the CMIP6 simulations.展开更多
This is the second paper in a series of two, which analyze the position of the Barents Sea ice-edge (BIE) based on a 442-year long dataset to understand its time variations. The data have been collected from ship-logs...This is the second paper in a series of two, which analyze the position of the Barents Sea ice-edge (BIE) based on a 442-year long dataset to understand its time variations. The data have been collected from ship-logs, polar expeditions, and hunters in addition to airplanes and satellites in recent times. Our main result is that the BIE position alternates between a southern and a northern position followed by Gulf Stream Beats (GSBs) at the occurrence of deep solar minima. We decompose the low frequency BIE position variations in cycles composed of dominant periods which are related to the Jose period of 179 years, indicating planetary forcings. We propose that the mechanism transferring planetary signals into changes in BIE position is the solar wind (SW), which provides magnetic shielding of the Earth in addition to geomagnetic disturbances. Increase in the solar wind produces pressure which decelerates the Earth’s rotation. It also transfers electrical energy to the ring current in the earth’s magnetosphere. This current magnetizes the earth’s solid core and makes it rotate faster. To conserve angular momentum the earth’s outer fluid mantle rotates slower with a delay of about 100 years. In addition will geomagnetic storms, initiated by solar coronal mass ejections (CMEs) penetrate deep in the Earth’s atmosphere and change pressure pattern in the Arctic. This effect is larger during solar minima since the magnetic shielding then is reduced. The Arctic may then experience local warming. The transition of solar activities to a possibly deep and long minimum in the present century may indicate Arctic cooling and the BIE moving south this century. For the North Atlantic region, effects of the BIE expanding southward will have noticeable consequences for the ocean bio-production from about 2040.展开更多
By analyzing the observation data and performing the numerical simulation tests,it is shown that the Kara and the Barents Sea area is a key region to influence climate variation over the Northern Hemisphere.The variat...By analyzing the observation data and performing the numerical simulation tests,it is shown that the Kara and the Barents Sea area is a key region to influence climate variation over the Northern Hemisphere.The variation of winter sea-ice area in the key region is closely associated with that of the EU teleconnection pattern at 500 hPa and East Asia winter monsoon(EAWM) intensity.When a heavy sea-ice prevails in the key region,the EU teleconnection pattern at 500 hPa is excited easily(there are positive 500 hPa height anomalies over around Japan and West Europe),and winter Siberia high is weakened,meanwhile,sea level pressure(SLP)has positive anomalies over the Northern Pacific.Therefore,EAWM will be weakened,winter temperature over East Asia is above normal and the frequency of cold-air activity in February in China will be decreased.When the light sea-ice occurs in the key region,the results will be opposite.展开更多
New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high reso- lution of up to 1...New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high reso- lution of up to 1-2 nT, mapping weak anomalies of 5-10 nT caused by mineralization effects at the contacts of hydrocarbons with host rocks, estimating depths to upper and lower boundaries of anom- alous magnetic sources, and estimating thickness of magnetic layers and boundaries of tectonic blocks. Horizontal dimensions of tectonic blocks in the so-called ＂seismic gap＂ region in the central Kuril Arc vary from 10 to 100 km, with typical dimensions of 25-30 km. The area of the ＂seismic gap＂ is a zone of intense tectonic activity and recent volcanism. Deep sources causing magnetic anomalies in the area are similar to the ＂magnetic belt＂ near Hokkaido. In the southern and central parts of Barents Sea, tectonic blocks with widths of 30-100 kin, and upper and lower boundaries of magnetic layers ranging from depths of 10 to 5 km and 18 to 30 km are calculated. Models of the magnetic layer underlying the Mezen Basin in an inland part of the White Sea-Barents Sea paleorift indicate depths to the lower boundary of the layer of 12-30 km. Weak local magnetic anomalies of 2-5 nT in the northern and central Caspian Sea were identified using the new methods, and drilling confirms that the anomalies are related to concentrations of hydrocarbon. Two layers causing magnetic anomalies are identified in the northern Caspian Sea from magnetic anomaly spectra. The upper layer lies immediately beneath the sea bottom and the lower layer occurs at depths between 30-40 m and 150-200 m.展开更多
The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding ...The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding the sea ice concentration in the wind wave module;however,they simply suppose that the wind cannot penetrate the ice layer and ignore the possibility of wind forcing waves below the ice cover.To improve the simulation performance of wind wave modules in the marginal ice zone(MIZ),this study proposes a parameterization scheme by directly including the sea ice thickness.Instead of scaling the wind input with the fraction of open water,this new scheme allows partial wind input in ice-covered areas based on the ice thickness.Compared with observations in the Barents Sea in 2016,the new scheme appears to improve the modeled waves in the high-frequency band.Sensitivity experiments with and without wind wave modules show that wind waves can play an important role in areas with low sea ice concentration in the MIZ.展开更多
Both planktonic and benthic foraminifera were identified in a sediment core collected from the northern Norwegian Sea to reconstruct the paleoceanographic evolution since the last glaciation.The assemblages and distri...Both planktonic and benthic foraminifera were identified in a sediment core collected from the northern Norwegian Sea to reconstruct the paleoceanographic evolution since the last glaciation.The assemblages and distribution patterns of dominant foraminiferal species with special habitat preferences indicated that three marine environments occurred in the northern Norwegian Sea since 62 ka BP:(1)an environment controlled by the circulation of the North Atlantic Current(NAC);(2)by polynya-related sinking of brines and upwelling of intermediate water surrounding the polynya;(3)by melt-water from Barents Sea Ice Sheet(BSIS).At 62-52.5 ka BP,a period with the highest summer insolation during the last glaciatial period,intensification of the NAC led to higher absolute abundances and higher diversity of foraminiferal faunas.The higher abundance of benthic species Cibicidoides wuellerstorfi indicates bottom water conditions that were well-ventilated with an adequate food supply;however,higher abundances of polar planktonic foraminiferal species Neogloboquadrina pachyderma(sin.)indicate that the near-surface temperatures were still low.During mid-late Marine Isotope Stage(MIS)3(52.5-29 ka BP),the marine environment of the northern Norwegian Sea alternately changed among the above mentioned three environments.At 29-17ka BP during the last glacial maximum,the dominant benthic species Bolivina arctica from the Arctic Ocean indicates an extreme cold bottom environment.The BSIS expanded to its maximum extent during this period,and vast polynya formed at the edge of the ice sheet.The sinking of brines from the formation of sea ice in the polynyas caused upwelling,indicated by the upwelling adapted planktonic species Globigerinita glutinata.At 17-10 ka BP,the northern Norwegian Sea was controlled by melt-water.With the ablation of BSIS,massive amounts of melt water discharged into the Norwegian Sea,resulting in strong water column stratification,poor ventilation,and an oligotrophic bottom condition,which ledto a drastic decline in the abundance and diversity of foraminifera.At 10-0 ka BP,the marine environment was transformed again by the control of the NAC,which continues to modern day.The abrupt decrease in relative abundance of Neogloboquadrina pachyderma(sin.)indicates a rise in near-surface temperature with the strengthening of the NAC and without the influence of the BSIS.展开更多
The linkage between the sea ice concentration(SIC)over the Barents–Kara Seas in November–December(SIC_BKS_ND)and the stratospheric polar vortex(SPV)in subsequent January(SPV_Jan)is investigated.It is found that SIC_...The linkage between the sea ice concentration(SIC)over the Barents–Kara Seas in November–December(SIC_BKS_ND)and the stratospheric polar vortex(SPV)in subsequent January(SPV_Jan)is investigated.It is found that SIC_BKS_ND is positively(negatively)correlated with SPV_Jan for the period 1979–1995(1996–2009).Further analyses reveal that,during 1979–1995(1996–2009),SIC_BKS_ND is relatively higher(lower),accompanied by smaller(larger)interannual variability with its center shifting northwest(southeast).Meanwhile,the polar front jet waveguide is relatively stronger(weaker).The simultaneous anomalous eastward-propagating Rossby waves excited by anomalously low SIC_BKS_ND are stronger(weaker),which results in the stronger(weaker)negative–positive–negative wave-train structure of geopotential height anomalies over Eurasia,with the location of these anomalous height centers shifting remarkably westward(eastward).Such changes tend to enhance(suppress)vertically propagating tropospheric planetary waves into the lower stratosphere at high-latitude via constructive(destructive)interference of anomalous tropospheric wave-train structure with the climatological planetary waves,subsequently weakening(strengthening)SPV_Jan.However,in conjunction with anomalously high SIC_BKS_ND,the interference of the tropospheric wave-train structure anomalies and their climatologies shows an opposite distribution to that of low SIC_BKS_ND anomalies,which leads to a strong(weak)SPV_Jan anomaly during 1979–1995(1996–2009).展开更多
By using a 2-layer AGCM designed by Institute of Atmospheric Physics,Chinese Academy of Sciences.this paper investigates influences of thickness and extent variations in Arctic sea ice on the atmosphere circulation,pa...By using a 2-layer AGCM designed by Institute of Atmospheric Physics,Chinese Academy of Sciences.this paper investigates influences of thickness and extent variations in Arctic sea ice on the atmosphere circulation,particularly on climate variations in East Asia.The simulation resuhs have indicated that sea ice thickness variation in the Arctic exhibits significant influences on simulation results,particularly on East Asian monsoon.A nearly reasonable distribution of sea ice thickness in the model leads directly to stronger winter and summer monsoon over East Asia.and improves the model's simulation results for Siberia high and Icelandic low in winter.On the other hand,sea ice thickness variation can excite a teleconnection wave train across Asian Continent,and in low latitudes,the wave propagates from the western Pacific across the equator to the eastern Pacific.In addition,the variation of sea ice thickness also influences summer convective activities over the low latitudes including South China Sea and around the Philippines. Effects of winter sea ice extents in the Barents Sea on atmospheric circulation in the following spring and summer are also significant.The simulation result shows that when winter sea ice extent in the target region is larger (smaller) than normal.(1)in the following spring (averaged from April to June).positive (negative) SLP anomalies occupy the northern central Pacific.which leads directly to weakened (deepened)Aleutian low.and further favors the light (heavy) sea ice condition in the Bering Sea:(2)in the following summer,thermal depression in Asian Continent is deepened (weakened).and the subtropical high in the northwestern Pacific shifts northward (southward) from its normal position and to be strengthened (weakened).展开更多
In the Mei-yu region,there has been noticeable increase in the occurrence of compound hot drought(CHD)events in recent years.However,the underlying causes of these occurrences remain poorly understood.To address this ...In the Mei-yu region,there has been noticeable increase in the occurrence of compound hot drought(CHD)events in recent years.However,the underlying causes of these occurrences remain poorly understood.To address this knowledge gap,we conducted a comprehensive study utilizing observational datasets,reanalysis datasets,and four numerical experiments to investigate the associated physical mechanisms.Our findings indicated that the prevalence of CHD events in the Mei-yu region is influenced strongly by two key factors:the decline in Barents Sea ice during February and the presence of a La Ni?alike pattern of sea surface temperature(SST)in April.The decline in Barents Sea ice generates an anomalous Rossby wave in the Arctic that propagates southeastward.The La Ni?a-like SST pattern regulates a Rossby wave over western America,propagating along the subtropical jet stream.These two Rossby waves induce northward movement and strengthened intensity of the subtropical westerly jet in East Asia.The local circulation patterns in the Mei-yu region are influenced by the position and intensity of the subtropical jet,leading to downward motion in accordance with the secondary circulation theory for high-altitude jet streams.Consequently,these local circulation patterns might contribute to occurrence of CHD events.Moreover,our analysis revealed that the impact of Barents Sea ice and the La Nina-like SST pattern can explain approximately two-thirds of the mild CHD events in the Mei-yu region,and that the influence of each is relatively independent.This research underscores influences of polartropical systems on climate extremes in eastern Asia.展开更多
Sea trials to test size selectivity equipment in trawls are often limited in time because they are costly,and the results can be influenced by multiple factors that are often overlooked.In the Barents Sea gadoid trawl...Sea trials to test size selectivity equipment in trawls are often limited in time because they are costly,and the results can be influenced by multiple factors that are often overlooked.In the Barents Sea gadoid trawl fishery,the use of a size sorting grid in front of the codend is compulsory.The flexigrid,a netting section containing two flexible grids,is the most widely used grid section in this fishery.However,earlier selectivity studies with this device have shown inconclusive results.It has been speculated that the differences observed resulted from the difference in age and usage of the grid sections in the studies compared.To reveal whether potential changes in the device construction over time can lead to differences in size selection properties,we performed comparative fishing trials where we compared a brand new flexigrid section and a well-used flexigrid section used continuously by a commercial trawler for approximately four years.The results showed that the new flexigrid released significantly more cod below~60 cm than the used flexigrid.However,when the grids were fished with a subsequent diamond mesh codend,there was no difference in the overall selectivity of the two gears,meaning that the size selectivity in the codend compensates for the potential reduction in selectivity performance of the grids.This study shows the importance of considering the age and earlier use of size selection devices like sorting grids before they are compared with other devices,as their size selection properties can change significantly over time and with use.展开更多
The range of the Greenland halibut Reinhardtius hippoglossoides(Walbaum,1792)includes vast areas in the northern parts of the Atlantic and Pacific oceans,as well as the seas of the Arctic Ocean.Despite its commercial ...The range of the Greenland halibut Reinhardtius hippoglossoides(Walbaum,1792)includes vast areas in the northern parts of the Atlantic and Pacific oceans,as well as the seas of the Arctic Ocean.Despite its commercial importance and decades of study,many aspects of its life cycle and reproduction remain poorly understood.Here,we evaluate the size distribution of Greenland halibut in the catches of research surveys in the Barents,Kara,and Laptev seas and conduct micro-and macroscopic studies of their gonads in the Laptev Sea.The size of Greenland halibut individuals increases from west to east,which is associated with the settling of pelagic juveniles and the subsequent residency of growing individuals near their settling sites.To the greatest extent,this size imbalance is manifested in the areas most remote from spawning grounds,i.e.the Kara and Laptev seas.The process of maturation in large individuals of Greenland halibut in the Arctic seas is characterized by a state of inhibitionwaiting in the early stages of gametogenesis(previtellogenesis).The data obtained indicate that Greenland halibut in the North Atlantic and the Siberian Arctic have a continuous range.The continental slope of the Barents Sea is a spawning and maturing ground,while the northern parts of the Barents and Kara seas,as well as the continental slope of the Laptev Sea,are feeding grounds for juveniles.The results of this study might serve as a necessary basis for monitoring condition of halibut stocks as well as for reallocation of the total allowable catch between countries that exploited them in the Norwegian and Barents seas.展开更多
The Pechora is the greatest river of the European Russian Arctic,flowing into the Barents Sea.Its estuarine area includes a vast delta,represented by extensive lowlands that are dissected by the complicated network of...The Pechora is the greatest river of the European Russian Arctic,flowing into the Barents Sea.Its estuarine area includes a vast delta,represented by extensive lowlands that are dissected by the complicated network of arms and branches.Despite the Pechora Delta is considered to be microtidal,tides with a range of 0.5-1 m during the low water period have a significant impact on the nature of currents in the main branches and the distribution of runoff among them during the tidal cycle.Tidal sea level fluctuations as well as storm surges determine the reversing pattern of currents over a significant extent of the delta branches.The modern field equipment combined with 2D hydrodynamic modeling has allowed to understand the contemporary flow features and evaluate their possible alterations under climate changes.The climate impact under considered scenarios is more pronounced during the low flow period,and this can lead to the propagation of tidal currents and an increase in water levels in the city of Naryan-Mar(100 km upstream from the mouth).From a flood risk perspective,sea level rise can be offset by a reduction in flood runoff.展开更多
基金the National Natural Science Foundation of China(No.52171284)the Natural Science Foundation of Shandong Province(No.ZR2023QE016).
文摘The Barents Sea is a marginal sea of the Arctic Ocean and contains substantial hydrocarbon resources.In recent years,the Barents Sea has emerged as one of the Arctic regions with the most pronounced sea ice variability.To analyze sea ice changes in the Barents Sea,sea ice data from the National Snow and Ice Data Center were utilized.A remarkable decline in sea ice has been witnessed in the northern and eastern regions.This phenomenon has expanded the ice-free operational area for marine structures,highlighting the significance of wave factors.A site within this area was chosen to estimate the wave parameters.The wave data from ERA5 were categorized according to wave energy in each season.Four mixture joint distribution models for the wave height and period were constructed based on the mixture distribution method and copula theory,and environmental contours were developed and compared with the conditional probability method.Despite differences in the design parameter results,the mixture models demonstrate good performance in sample fitting,particularly in the distribution tails.Among these models,the Gaussian copula offers the best fit.
基金supported by the National Natural Science Foundation of China(Grant No.42221004)the Open Research Fund of TPESER(Grant No.TPESER202205)。
文摘The spring(April-May-June)Barents Sea ice has been proven to affect the summer surface air temperature over the Tibetan Plateau(TP).However,its impact on summer(June-July-August)TP precipitation,a crucial climate component,remains unexplored.We investigate the physical linkage between spring Barents Sea ice and subsequent summer TP precipitation from 1979 to 2018.Our results indicate that above-normal spring Barents Sea ice leads to excessive summer TP precipitation,and vice versa.During spring,more Barents Sea ice induces remarkable cooling and subsidence over there and surrounding areas.The cooling over the Barents Sea can persist into summer,triggering a meridional wave-like pattern along the longitude of 60°E and,in turn,an anomalous atmospheric subsidence over the Caspian Sea and the eastern region adjacent to it.This alters 200 h Pa convergence and modulates the Silk Road pattern(SRP).As a result,cyclonic anomalies form to the west of the TP,which enhance moisture transport toward the TP and increase its precipitation during summer.Numerical experiments reproduce these physical processes and further support our conclusions.
基金This study was supported jointly by the Project ZKCX2-SW-210the"National Key Programme for Developing Basic Sciences of China"(G1998040900)the National Natural Science Foundation of China under Grant No.40135020.
文摘Possible influences of the Barents Sea ice anomalies on the Eurasian atmospheric circulation and the East China precipitation distribution in the late spring and early summer (May-June) are investigated by analyzing the observational data and the output of an atmospheric general circulation model (AGCM). The study indicates that the sea ice condition of the Barents Sea from May to July may be interrelated with the atmospheric circulation of June. When there is more than average sea ice in the Barents Sea, the local geopotential height of the 500-hPa level will decrease, and the same height in the Lake Baikal and Okhotsk regions will increase and decrease respectively to form a wave-chain structure over North Eurasia. This kind of anomalous height pattern is beneficial to more precipitation in the south part of East China and less in the north.
基金supported by the National Natural Science Foundation of China[grant numbers 41375086 and 41775062]the Youth Innovation Promotion Association of the Chinese Academy of Sciences(CAS)supported by the Youth Innovation Promotion Association of CAS and the National Natural Science Foundation of China[grant number 41630530].
文摘This study reveals a significant relationship,on the interannual timescale,between a dipole mode,the second leading mode,of spring sea-ice anomalies in the Barents Sea and the following-summer rainfall in East Asia.Related to the dipole mode,with the heavier sea ice in the north and lighter sea ice in the southeast Barents Sea in spring,the East Asian summer subtropical rainy belt tends to move northward.The significant relationship is established through a wave train over northern Eurasia in the lower troposphere in June.The wave train enhances the northern East Asian low,which induces more rainfall to the north of the East Asian subtropical rainy belt and then attracts the subtropical rainy belt to move northward.This study suggests that the dipole mode of spring sea-ice anomalies in the Barents Sea may be a good precursor for the prediction of East Asian summer rainfall.
文摘This is the first report of the Barents Sea Ice Edge (BIE) project. The BIE position has varied between latitude 76<span style="white-space:nowrap;">°</span>N and above 82<span style="white-space:nowrap;">°</span>N during the last 440 years. During the period 10,000 to 6000 years ago, Arctic climate was significantly warmer than today. We review various oceanic and atmospheric factors that may have an effect on the BIE position. The Gulf Stream beat with respect to alternations in flow intensity and N-S distribution plays a central role for the changes in climate and BIE position during the last millennium. This occurred in combination with external forcing from total solar irradiation, Earth’s shielding strength, Earth’s geomagnetic field intensity, Earth’s rotation, jet stream changes;all factors of which are ultimately driven by the planetary beat on the Sun, the Earth and the Earth-Moon system. During the last 20 years, we see signs of changes and shifts that may signal the end of the late 20<sup>th</sup> century warm period. The BIE position is likely to start advancing southward in next decade.
文摘In the Arctic (mainly in its European sector) there is statistically detectable seasonal reversal wind pattern. The combination of seasonally warm (cold) land surfaces in arctic areas together with cool (cool) sea surface of Arctic seas not covered by ice is conducive to the formation of a monsoon like system. On the other hand, the predominance of the cyclonic regime during all seasons makes it difficult to answer the question of whether the Arctic region belongs to the monsoon type pattern. In this study, the monsoon features of atmospheric circulation over the Barents and Kara Seas were analysed. To extract specific monsoon signs, atmospheric circulation systems (separately for areas of each sea) were divided into ten weather types. Their appearance and statistics were compared with indicators of regional circulation. A significant part of intra-annual monsoon variability is associated with the configuration of such modes as the North Atlantic Oscillation and the <em>Scandinavia</em> teleconnection patterns. For example, during the winter season, the monsoon currents (from land to sea) occur only with a positive North Atlantic Oscillation index. With the prevalence of other modes of variability, the direction of the winds can be different, and the regular monsoon circulation pattern is changed by chaotic regime. In summer, northern streams (from sea to land) are realized on the western periphery of cyclones, regenerating and stabilizing over the Kara Sea. As for anomalies, the nature of the monsoons is manifested in the statistics of extreme winds even without selecting data on the regimes of variability. So, in winter, maximum speeds fall on the southern streams, and in the summer—on the northern ones. Large precipitation anomalies during all seasons, as one would expect, are encountered most often with the cyclonic type of circulation.
基金the Chinese Natural Science Foundation(Grant No.41941012)the Basic Scienti fic Fund for National Public Research Institute of China(ShuXingbei Young Talent Program)under contract No.2019S06,Shandong Provincial Natural Science Foundation(ZR2022JQ17)the Tais-han Scholars Program(No.tsqn202211264).
文摘Dramatic changes in the sea ice characteristics in the Barents Sea have potential consequences for the weather and climate systems of mid-latitude continents,Arctic ecosystems,and fisheries,as well as Arctic maritime navigation.Simulations and projections of winter sea ice in the Barents Sea based on the latest 41 climate models from the Coupled Model Intercomparison Project Phase 6(CMIP6)are investigated in this study.Results show that most CMIP6 models overestimate winter sea ice in the Barents Sea and underestimate its decreasing trend.The discrepancy is mainly attributed to the simulation bias towards an overly weak ocean heat transport through the Barents Sea Opening and the underestimation of its increasing trend.The methods of observation-based model selection and emergent constraint were used to project future winter sea ice changes in the Barents Sea.Projections indicate that sea ice in the Barents Sea will continue to decline in a warming climate and that a winter ice-free Barents Sea will occur for the first time during 2042-2089 under the Shared Socioeconomic Pathway 585(SSP5-8.5).Even in the observation-based selected models,the sensitivity of winter sea ice in the Barents Sea to global warming is weaker than observed,indicating that a winter ice-free Barents Sea might occur earlier than projected by the CMIP6 simulations.
文摘This is the second paper in a series of two, which analyze the position of the Barents Sea ice-edge (BIE) based on a 442-year long dataset to understand its time variations. The data have been collected from ship-logs, polar expeditions, and hunters in addition to airplanes and satellites in recent times. Our main result is that the BIE position alternates between a southern and a northern position followed by Gulf Stream Beats (GSBs) at the occurrence of deep solar minima. We decompose the low frequency BIE position variations in cycles composed of dominant periods which are related to the Jose period of 179 years, indicating planetary forcings. We propose that the mechanism transferring planetary signals into changes in BIE position is the solar wind (SW), which provides magnetic shielding of the Earth in addition to geomagnetic disturbances. Increase in the solar wind produces pressure which decelerates the Earth’s rotation. It also transfers electrical energy to the ring current in the earth’s magnetosphere. This current magnetizes the earth’s solid core and makes it rotate faster. To conserve angular momentum the earth’s outer fluid mantle rotates slower with a delay of about 100 years. In addition will geomagnetic storms, initiated by solar coronal mass ejections (CMEs) penetrate deep in the Earth’s atmosphere and change pressure pattern in the Arctic. This effect is larger during solar minima since the magnetic shielding then is reduced. The Arctic may then experience local warming. The transition of solar activities to a possibly deep and long minimum in the present century may indicate Arctic cooling and the BIE moving south this century. For the North Atlantic region, effects of the BIE expanding southward will have noticeable consequences for the ocean bio-production from about 2040.
基金This paper is supported by the National Key Program"96-908".
文摘By analyzing the observation data and performing the numerical simulation tests,it is shown that the Kara and the Barents Sea area is a key region to influence climate variation over the Northern Hemisphere.The variation of winter sea-ice area in the key region is closely associated with that of the EU teleconnection pattern at 500 hPa and East Asia winter monsoon(EAWM) intensity.When a heavy sea-ice prevails in the key region,the EU teleconnection pattern at 500 hPa is excited easily(there are positive 500 hPa height anomalies over around Japan and West Europe),and winter Siberia high is weakened,meanwhile,sea level pressure(SLP)has positive anomalies over the Northern Pacific.Therefore,EAWM will be weakened,winter temperature over East Asia is above normal and the frequency of cold-air activity in February in China will be decreased.When the light sea-ice occurs in the key region,the results will be opposite.
基金supported by the Russian Fund of Fundamental Research(Grant No.11-05-00280)
文摘New methods are presented for processing and interpretation of shallow marine differential magnetic data, including constructing maps of offshore total magnetic anomalies with an extremely high reso- lution of up to 1-2 nT, mapping weak anomalies of 5-10 nT caused by mineralization effects at the contacts of hydrocarbons with host rocks, estimating depths to upper and lower boundaries of anom- alous magnetic sources, and estimating thickness of magnetic layers and boundaries of tectonic blocks. Horizontal dimensions of tectonic blocks in the so-called ＂seismic gap＂ region in the central Kuril Arc vary from 10 to 100 km, with typical dimensions of 25-30 km. The area of the ＂seismic gap＂ is a zone of intense tectonic activity and recent volcanism. Deep sources causing magnetic anomalies in the area are similar to the ＂magnetic belt＂ near Hokkaido. In the southern and central parts of Barents Sea, tectonic blocks with widths of 30-100 kin, and upper and lower boundaries of magnetic layers ranging from depths of 10 to 5 km and 18 to 30 km are calculated. Models of the magnetic layer underlying the Mezen Basin in an inland part of the White Sea-Barents Sea paleorift indicate depths to the lower boundary of the layer of 12-30 km. Weak local magnetic anomalies of 2-5 nT in the northern and central Caspian Sea were identified using the new methods, and drilling confirms that the anomalies are related to concentrations of hydrocarbon. Two layers causing magnetic anomalies are identified in the northern Caspian Sea from magnetic anomaly spectra. The upper layer lies immediately beneath the sea bottom and the lower layer occurs at depths between 30-40 m and 150-200 m.
基金funded by the National Key R&D Program of China (Grant No. 2022YFE0106300)the National Natural Science Foundation of China (Grant Nos. 41922044, 42106226 and 42106233)+4 种基金the Fundamental Research Funds for the Central Universities (Grant No. 3132023133)the China Postdoctoral Science Foundation (Grant No. 2020M683022)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2020B1515020025)the fundamental research funds for the Norges Forskningsråd. (Grant No. 328886)the Research Council of Norway for financial support through the research project “Multi-scale integration and digitalization of Arctic sea ice observations and predic tion models (328960)” and basic funding for research institutes
文摘The global wave model WAVEWATCH III®works well in open water.To simulate the propagation and attenuation of waves through ice-covered water,existing simulations have considered the influence of sea ice by adding the sea ice concentration in the wind wave module;however,they simply suppose that the wind cannot penetrate the ice layer and ignore the possibility of wind forcing waves below the ice cover.To improve the simulation performance of wind wave modules in the marginal ice zone(MIZ),this study proposes a parameterization scheme by directly including the sea ice thickness.Instead of scaling the wind input with the fraction of open water,this new scheme allows partial wind input in ice-covered areas based on the ice thickness.Compared with observations in the Barents Sea in 2016,the new scheme appears to improve the modeled waves in the high-frequency band.Sensitivity experiments with and without wind wave modules show that wind waves can play an important role in areas with low sea ice concentration in the MIZ.
基金funded by the Scientific Research Foundation of the Third Institute of Oceanography,Ministry of Natural Resources(Grant no.2018006)Shandong Provincial Natural Science Foundation(Grant no.ZR2019BD054)the project of the Chinese Arctic and Antarctic Administration,State Oceanic Administration(Grant no.CHINARE 2016-03-02).
文摘Both planktonic and benthic foraminifera were identified in a sediment core collected from the northern Norwegian Sea to reconstruct the paleoceanographic evolution since the last glaciation.The assemblages and distribution patterns of dominant foraminiferal species with special habitat preferences indicated that three marine environments occurred in the northern Norwegian Sea since 62 ka BP:(1)an environment controlled by the circulation of the North Atlantic Current(NAC);(2)by polynya-related sinking of brines and upwelling of intermediate water surrounding the polynya;(3)by melt-water from Barents Sea Ice Sheet(BSIS).At 62-52.5 ka BP,a period with the highest summer insolation during the last glaciatial period,intensification of the NAC led to higher absolute abundances and higher diversity of foraminiferal faunas.The higher abundance of benthic species Cibicidoides wuellerstorfi indicates bottom water conditions that were well-ventilated with an adequate food supply;however,higher abundances of polar planktonic foraminiferal species Neogloboquadrina pachyderma(sin.)indicate that the near-surface temperatures were still low.During mid-late Marine Isotope Stage(MIS)3(52.5-29 ka BP),the marine environment of the northern Norwegian Sea alternately changed among the above mentioned three environments.At 29-17ka BP during the last glacial maximum,the dominant benthic species Bolivina arctica from the Arctic Ocean indicates an extreme cold bottom environment.The BSIS expanded to its maximum extent during this period,and vast polynya formed at the edge of the ice sheet.The sinking of brines from the formation of sea ice in the polynyas caused upwelling,indicated by the upwelling adapted planktonic species Globigerinita glutinata.At 17-10 ka BP,the northern Norwegian Sea was controlled by melt-water.With the ablation of BSIS,massive amounts of melt water discharged into the Norwegian Sea,resulting in strong water column stratification,poor ventilation,and an oligotrophic bottom condition,which ledto a drastic decline in the abundance and diversity of foraminifera.At 10-0 ka BP,the marine environment was transformed again by the control of the NAC,which continues to modern day.The abrupt decrease in relative abundance of Neogloboquadrina pachyderma(sin.)indicates a rise in near-surface temperature with the strengthening of the NAC and without the influence of the BSIS.
基金Supported by the National Natural Science Foundation of China(41730964 and 42088101)Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(311021001).
文摘The linkage between the sea ice concentration(SIC)over the Barents–Kara Seas in November–December(SIC_BKS_ND)and the stratospheric polar vortex(SPV)in subsequent January(SPV_Jan)is investigated.It is found that SIC_BKS_ND is positively(negatively)correlated with SPV_Jan for the period 1979–1995(1996–2009).Further analyses reveal that,during 1979–1995(1996–2009),SIC_BKS_ND is relatively higher(lower),accompanied by smaller(larger)interannual variability with its center shifting northwest(southeast).Meanwhile,the polar front jet waveguide is relatively stronger(weaker).The simultaneous anomalous eastward-propagating Rossby waves excited by anomalously low SIC_BKS_ND are stronger(weaker),which results in the stronger(weaker)negative–positive–negative wave-train structure of geopotential height anomalies over Eurasia,with the location of these anomalous height centers shifting remarkably westward(eastward).Such changes tend to enhance(suppress)vertically propagating tropospheric planetary waves into the lower stratosphere at high-latitude via constructive(destructive)interference of anomalous tropospheric wave-train structure with the climatological planetary waves,subsequently weakening(strengthening)SPV_Jan.However,in conjunction with anomalously high SIC_BKS_ND,the interference of the tropospheric wave-train structure anomalies and their climatologies shows an opposite distribution to that of low SIC_BKS_ND anomalies,which leads to a strong(weak)SPV_Jan anomaly during 1979–1995(1996–2009).
基金This work was supported by the National Natural Science Foundation ot" China under Grant of No.49905003.
文摘By using a 2-layer AGCM designed by Institute of Atmospheric Physics,Chinese Academy of Sciences.this paper investigates influences of thickness and extent variations in Arctic sea ice on the atmosphere circulation,particularly on climate variations in East Asia.The simulation resuhs have indicated that sea ice thickness variation in the Arctic exhibits significant influences on simulation results,particularly on East Asian monsoon.A nearly reasonable distribution of sea ice thickness in the model leads directly to stronger winter and summer monsoon over East Asia.and improves the model's simulation results for Siberia high and Icelandic low in winter.On the other hand,sea ice thickness variation can excite a teleconnection wave train across Asian Continent,and in low latitudes,the wave propagates from the western Pacific across the equator to the eastern Pacific.In addition,the variation of sea ice thickness also influences summer convective activities over the low latitudes including South China Sea and around the Philippines. Effects of winter sea ice extents in the Barents Sea on atmospheric circulation in the following spring and summer are also significant.The simulation result shows that when winter sea ice extent in the target region is larger (smaller) than normal.(1)in the following spring (averaged from April to June).positive (negative) SLP anomalies occupy the northern central Pacific.which leads directly to weakened (deepened)Aleutian low.and further favors the light (heavy) sea ice condition in the Bering Sea:(2)in the following summer,thermal depression in Asian Continent is deepened (weakened).and the subtropical high in the northwestern Pacific shifts northward (southward) from its normal position and to be strengthened (weakened).
基金supported by the National Natural Science Foundation of China(42088101)the National Key Research and Development Program of China(2022YFF0801704)the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)(316323005)。
文摘In the Mei-yu region,there has been noticeable increase in the occurrence of compound hot drought(CHD)events in recent years.However,the underlying causes of these occurrences remain poorly understood.To address this knowledge gap,we conducted a comprehensive study utilizing observational datasets,reanalysis datasets,and four numerical experiments to investigate the associated physical mechanisms.Our findings indicated that the prevalence of CHD events in the Mei-yu region is influenced strongly by two key factors:the decline in Barents Sea ice during February and the presence of a La Ni?alike pattern of sea surface temperature(SST)in April.The decline in Barents Sea ice generates an anomalous Rossby wave in the Arctic that propagates southeastward.The La Ni?a-like SST pattern regulates a Rossby wave over western America,propagating along the subtropical jet stream.These two Rossby waves induce northward movement and strengthened intensity of the subtropical westerly jet in East Asia.The local circulation patterns in the Mei-yu region are influenced by the position and intensity of the subtropical jet,leading to downward motion in accordance with the secondary circulation theory for high-altitude jet streams.Consequently,these local circulation patterns might contribute to occurrence of CHD events.Moreover,our analysis revealed that the impact of Barents Sea ice and the La Nina-like SST pattern can explain approximately two-thirds of the mild CHD events in the Mei-yu region,and that the influence of each is relatively independent.This research underscores influences of polartropical systems on climate extremes in eastern Asia.
基金the Norwegian Fisheries and Aquaculture Research Fund(project number 901633)for funding the project.
文摘Sea trials to test size selectivity equipment in trawls are often limited in time because they are costly,and the results can be influenced by multiple factors that are often overlooked.In the Barents Sea gadoid trawl fishery,the use of a size sorting grid in front of the codend is compulsory.The flexigrid,a netting section containing two flexible grids,is the most widely used grid section in this fishery.However,earlier selectivity studies with this device have shown inconclusive results.It has been speculated that the differences observed resulted from the difference in age and usage of the grid sections in the studies compared.To reveal whether potential changes in the device construction over time can lead to differences in size selection properties,we performed comparative fishing trials where we compared a brand new flexigrid section and a well-used flexigrid section used continuously by a commercial trawler for approximately four years.The results showed that the new flexigrid released significantly more cod below~60 cm than the used flexigrid.However,when the grids were fished with a subsequent diamond mesh codend,there was no difference in the overall selectivity of the two gears,meaning that the size selectivity in the codend compensates for the potential reduction in selectivity performance of the grids.This study shows the importance of considering the age and earlier use of size selection devices like sorting grids before they are compared with other devices,as their size selection properties can change significantly over time and with use.
文摘The range of the Greenland halibut Reinhardtius hippoglossoides(Walbaum,1792)includes vast areas in the northern parts of the Atlantic and Pacific oceans,as well as the seas of the Arctic Ocean.Despite its commercial importance and decades of study,many aspects of its life cycle and reproduction remain poorly understood.Here,we evaluate the size distribution of Greenland halibut in the catches of research surveys in the Barents,Kara,and Laptev seas and conduct micro-and macroscopic studies of their gonads in the Laptev Sea.The size of Greenland halibut individuals increases from west to east,which is associated with the settling of pelagic juveniles and the subsequent residency of growing individuals near their settling sites.To the greatest extent,this size imbalance is manifested in the areas most remote from spawning grounds,i.e.the Kara and Laptev seas.The process of maturation in large individuals of Greenland halibut in the Arctic seas is characterized by a state of inhibitionwaiting in the early stages of gametogenesis(previtellogenesis).The data obtained indicate that Greenland halibut in the North Atlantic and the Siberian Arctic have a continuous range.The continental slope of the Barents Sea is a spawning and maturing ground,while the northern parts of the Barents and Kara seas,as well as the continental slope of the Laptev Sea,are feeding grounds for juveniles.The results of this study might serve as a necessary basis for monitoring condition of halibut stocks as well as for reallocation of the total allowable catch between countries that exploited them in the Norwegian and Barents seas.
基金supported by the Russian Foundation for Basic Research(Projects No.18-05-60021)supported by Governmental Assignments to the Water Problems Institute,Russian Academy of Sciences(FMWZ-2022-0001)+1 种基金Dept.of Hydrology,Faculty of Geography,Lomonosov Moscow State University(I.10)The scenarios of Pechora runoff changes were developed under support of RSF№24-17-00084.
文摘The Pechora is the greatest river of the European Russian Arctic,flowing into the Barents Sea.Its estuarine area includes a vast delta,represented by extensive lowlands that are dissected by the complicated network of arms and branches.Despite the Pechora Delta is considered to be microtidal,tides with a range of 0.5-1 m during the low water period have a significant impact on the nature of currents in the main branches and the distribution of runoff among them during the tidal cycle.Tidal sea level fluctuations as well as storm surges determine the reversing pattern of currents over a significant extent of the delta branches.The modern field equipment combined with 2D hydrodynamic modeling has allowed to understand the contemporary flow features and evaluate their possible alterations under climate changes.The climate impact under considered scenarios is more pronounced during the low flow period,and this can lead to the propagation of tidal currents and an increase in water levels in the city of Naryan-Mar(100 km upstream from the mouth).From a flood risk perspective,sea level rise can be offset by a reduction in flood runoff.
