The connection of phytoplankton biomass in the Marguerite Bay polynya of the western Antarctic Peninsula to the Southern Annular Mode

Antarctic coastal polynyas are biological hotspots in the Southern Ocean that support the abundance of hightrophic-level predators and are important for carbon cycling in the high-latitude oceans.In this study,we examined the interannual variation of summertime phytoplankton biomass in the Marguerite Bay polynya(MBP)in the western Antarctic Peninsula area,and linked such variability to the Southern Annular Mode(SAM)that dominated the southern hemisphere extratropical climate variability.Combining satellite data,atmosphere reanalysis products and numerical simulations,we found that the interannual variation of summer chlorophyll-a(Chl-a)concentration in the MBP is significantly and negatively correlated with the spring SAM index,and weakly correlated with the summer SAM index.The negative relation between summer Chl-a and spring SAM is due to weaker spring vertical mixing under a more positive SAM condition,which would inhibit the supply of iron from deep layers into the surface euphotic layer.The negative relation between spring mixing and spring SAM results from greater precipitation rate over the MBP region in positive SAM phase,which leads to lower salinity in the ocean surface layer.The coupled physical-biological mechanisms between SAM and phytoplankton biomass revealed in this study is important for us to predict the future variations of phytoplankton biomasses in Antarctic polynyas under climate change.

Specific Relationship between the Surface Air Temperature and the Area of the Terra Nova Bay Polynya,Antarctica

Antarctic polynyas play an important role in regional atmosphere?ice?ocean interactions and are considered to help generate the global deep ocean conveyer belt.Polynyas therefore have a potential impact on the Earth’s climate in terms of the production of sea ice and high-salinity shelf water.In this study,we investigated the relationship between the area of the Terra Nova Bay polynya and the air temperature as well as the eastward and northward wind based on the ERA5 and ERAInterim reanalysis datasets and observations from automatic weather stations during the polar night.We examined the correlation between each factor and the polynya area under different temperature conditions.Previous studies have focused more on the effect of winds on the polynya,but the relationship between air temperature and the polynya area has not been fully investigated.Our study shows,eliminating the influence of winds,lower air temperature has a stronger positive correlation with the polynya area.The results show that the relationship between the polynya area and air temperature is more likely to be interactively influenced.As temperature drops,the relationship of the polynya area with air temperature becomes closer with increasing correlation coefficients.In the low temperature conditions,the correlation coefficients of the polynya area with air temperature are above 0.5,larger than that with the wind speed.

Characterization of the unprecedented polynya events north of Greenland in 2017/2018 using remote sensing and reanalysis data

Based on an ice concentration threshold of 90%,it has been identified that two polynya events occurred in the region north of Greenland during the 2017/2018 ice season.The winter event lasted from February 20 to March 3,2018 and the summer event persisted from August 2 to September 5,2018.The minimum ice concentration derived from Advanced Microwave Scanning Radiometer 2(AMSR2)observations was 72%and 65%during the winter and summer events,respectively.The occurrence of both events can be related to strengthened southerly winds associated with an increased east-west zonal surface level air pressure gradient across the north Greenland due to perturbation of mid-troposphere polar vortex.The relatively warm air temperature during the 2017/2018 freezing season in comparison with previous years,together with the occurrence of the winter polynya,formed favourable pre-conditions for ice field fracturing in summer,which promoted the formation of the summer polynya.Diminished southerly winds and increased cover of new ice over the open water were the dominant factors for the disappearance of the winter polynya,whereas increased ice inflow from the north was the primary factor behind the closure of the summer polynya.Sentinel-1 Synthetic Aperture Radar(SAR)images were found better suited than AMSR2 observations for quantification of a new ice product during the polynya event because the SAR images have high potential for mapping of different sea ice regimes with finely spatial resolution.The unprecedented polynya events north of Greenland in 2017/2018 are important from the perspective of Arctic sea ice loss because they occurred in a region that could potentially be the last“Arctic sea ice refuge”in future summers.

An overview of Antarctic polynyas: sea ice production, forcing mechanisms, temporal variability and water mass formation

Polynyas are irregular open water bodies within the sea ice cover in polar regions under freezing weather conditions.In this study,we reviewed the progress of research work on dynamical forcing,sea ice production(SIP),and water mass formation for both coastal polynyas and open-ocean polynyas in the Southern Ocean,as well as the variability and controlling mechanisms of polynya processes on different time scales.Polynyas play an irreplaceable role in the regulation of global ocean circulation and biological processes in regional ocean ecosystems.The coastal polynyas(latent heat polynyas)are mainly located in the Weddell Sea,the Ross Sea and on the west side of protruding topographic features in East Antarctica.During the formation of coastal polynyas,which are mainly forced by offshore winds or ocean currents,brine rejection triggered by high SIP results in the formation of high salinity shelf water,which is the predecessor of the Antarctic bottom water-the lower limb of the global thermohaline circulation.The open-ocean polynyas(sensible heat polynyas)are mainly found in the Indian sector of the Southern Ocean,which are formed by ocean convection processes generated by topography and negative wind stress curl.The convection processes bring nutrients into the upper ocean,which supports biological production and makes the polynya regions an important sink for atmospheric carbon dioxide.The limitations and challenges in polynya research are also discussed.

Thinner Sea Ice Contribution to the Remarkable Polynya Formation North of Greenland in August 2018

In August 2018,a remarkable polynya was observed off the north coast of Greenland,a perennial ice zone where thick sea ice cover persists.In order to investigate the formation process of this polynya,satellite observations,a coupled iceocean model,ocean profiling data,and atmosphere reanalysis data were applied.We found that the thinnest sea ice cover in August since 1978(mean value of 1.1 m,compared to the average value of 2.8 m during 1978-2017) and the modest southerly wind caused by a positive North Atlantic Oscillation(mean value of 0.82,compared to the climatological value of-0.02) were responsible for the formation and maintenance of this polynya.The opening mechanism of this polynya differs from the one formed in February 2018 in the same area caused by persistent anomalously high wind.Sea ice drift patterns have become more responsive to the atmospheric forcing due to thinning of sea ice cover in this region.

Horizontal distribution of tintinnids(Ciliophora)in surface waters of the Ross Sea and polynya in the Amundsen Sea(Antarctica)during summer 2019/2020

Information on tintinnid horizontal distribution in the Antarctic Continental Zone is scarce.During the summer of 2019/2020,tintinnid diversity and horizontal distribution in surface waters were investigated in the Ross Sea and Amundsen Sea polynya.Eight tintinnid species were found and the dominant species showed obvious horizontal distribution characteristics.In the Ross Sea,three tintinnid community groups were identified.Cymatocylis cristallina and Laackmanniella prolongata(group I)were dominant species and were mainly distributed in stations closer to the coast than were species in the other two groups.Codonellopsis gaussi(group II)and Cy.convallaria(group III)were mainly distributed in nearshore and offshore stations,respectively.In the Amundsen Sea polynya,the dominant species Cy.cristallina,L.prolongata and Salpingella faurei(group I)were mainly distributed in stations closer to the coast than were species in the other two groups.Cy.convallaria(group III)was mainly distributed in offshore stations.The distribution area where C.gaussi and C.cristallina were found in high abundance and abundance proportion of loricae with protoplasts was divided by the approximate boundary of the Antarctic Slope Front Current and Coastal Current in the Ross Sea.The highest abundance proportion in the Ross Sea was the 32-36μm lorica oral diameter(LOD)size class(75.7%),and the 36-40μm LOD size class(56.0%)was found in the Amundsen Sea polynya.Temperature-salinity-plankton diagrams of the two seas revealed that temperature may be the main reason for species distribution.Our results contribute to a better understanding of horizontal distribution of the microbial food web,and serve as a baseline for future studies of pelagic community change in the Antarctic Continental Zone.

Formation and Transportation of High-Salinity Water Produced in Polynyas South of the St.Lawrence Island

The authors studied variations of temperature and salinity in seawater under sea ice using hydrologic data collected from polynyas south of the St.Lawrence Island during March of 2008 and 2009.The results indicate that the high-salinity water found during the cruises of 2008 and 2009 was due to the formation of polynyas.The salinity observed in 2008 was higher than that in 2009 as a result of higher salt production in 2008.The spatial distributions of high-salinity cores differed between the two cruises.In March 2008, a southeastward flow was formed under the persistent northerly wind in the observation region, which transported the high-salinity water produced by the polynyas to the southeast.The similar flow, however, did not exist in March 2009 because the northerly wind over the study area was interrupted by a southerly wind.Accordingly, the polynyas and the high-salinity water pro-duced by them existed for a short time.As a result, the high-salinity water in 2009 did not spread very far, and stayed within the polynyas.In addition, during the 2009 cruise, two stages of observations in the polynyas showed the core of high-salinity water was shifted to the southwest of the St.Lawrence Island.This result suggested that a southwestward flow might have existed in the area at the onset of the northerly wind, which was consistent with the alongshore and/or offshore flows caused by the northerly wind.

Impacts of atmospheric and oceanic factors on monthly and interannual variations of polynya in the East Siberian Sea and Chukchi Sea

As a key region of Northeast Passage,the polynya along the Siberian coast in the East Siberian and Chukchi Seas is important to local dynamic and thermodynamic processes,sea ice production and marine ecosystem.The detailed variations of polynya and the contributions of atmospheric and oceanic factors to the polynya have not been explored quantitatively.AMSR-E satellite data from January to April during the period 2003-2011 were used to study the impacts of wind stress and ocean heat transport on variations of polynya in the East Siberian Sea and Chukchi Sea.The study region was divided into six domains.Four sets of AMSR-E data with resolutions of 6.25 km and 12.5 km were compared based on two algorithms of sea ice concentration(referred to as 6.25 km-IC and 12.5 km-IC)and sea ice thickness(referred to as 6.25 km-h and 12.5 km-h).The monthly and yearly polynya areas in the four cases and six domains had remarkable differences.The two cases of 6.25 km-h and 12.5 km-h had larger areas of polynya than the other two cases of 6.25 km-IC and 12.5 km-IC.The difference in polynya area between the 6.25 km-h and 12.5 km-h cases was much smaller than the difference between the 6.25 km-IC and 12.5 km-IC cases.The study of atmospheric and oceanic mechanisms on polynya is influenced significantly by the sensitivity of polynya areas.In general,the impact of wind stress and ocean heat transport on the polynyas had noticeable monthly and interannual variations and was dependent on the locations of the polynyas.The alongshore and offshore wind had stronger correlations with the polynya area than ocean heat transport.Although the higher resolution(6.25 km)AMSR-E data are best for the study of atmospheric and oceanic impacts on polynya area,the coarse resolution(12.5 km)AMSR-E data based on sea ice thickness can also be used.Wind direction dominated the polynya area in the East Siberian Sea and wind speed dominated the polynya area in the Chukchi Sea.The variation in ocean heat transport was influenced mainly by variation in volume transport rather than variation in water temperature.

南极阿蒙森海冰间湖的时空变化及其影响因素

本文利用由卫星微波辐射计数据反演获得的薄冰厚度和产冰速率数据,分析了南极阿蒙森海冰间湖(Amundsen Sea Polynya,ASP)在2003—2010年和2013—2020年期间的时空变化特征,结合大气再分析数据中的表面风速和气温数据,进一步探究了影响阿蒙森海冰间湖变化的因素。研究表明,阿蒙森海冰间湖位于斯维茨固定冰舌(Thwaites Fast-ice Tongue,TFT)以西的沿岸海域,大体呈现反L形,即在风的作用下,阿蒙森海冰间湖从TFT西侧向西发展,从多特森冰架(Dotson Ice Shelf,DIS)沿岸向北发展。此外,阿蒙森海冰间湖在南极冬半年的4—10月期间基本维持开放状态,但是其面积与产冰速率在相邻的两天常常发生大幅度变化,并且与其上空的风速之间具有良好的相关性。研究发现,东风分量通过调节冰间湖内部海冰的输运,主导了阿蒙森海冰间湖的面积变化;南风分量携带来自DIS沿岸陆地的冷空气加剧阿蒙森海冰间湖表面的热损失,是冰间湖产冰速率增加的决定因素。

Characteristics of particle fluxes in the Prydz Bay polynya, Eastern Antarctica

The settling of particulate carbon in seawater is a key component of the ocean carbon cycle. We deployed a set of sediment trap in the polynya of Prydz Bay from December 2010 to December 2011 to investigate the seasonal variations in particle fluxes. There was a clear seasonal variation in the particle fluxes, with maximum and minimum fluxes recorded during the summer and winter, respectively. The average total flux over the sampling period was 193.58 mg m^(-2)d^(-1), and the average fluxes of organic carbon(C_(org)), inorganic carbon(C_(inorg)), and biogenic silica(Si_(bio)) were 721.78, 28.67, and 2382.80 μmol m^(-2) d^(-1), respectively. Si_(bio)was the main contributor to the total mass flux, and strongly correlated with C_(org). The high Si_(bio)/C_(org)molar ratios(>1) suggest that C_(org)was transported to deep sea in association with Si_(bio). By comparing remote sensing data of sea ice and chlorophyll in the upper water column, we found that the dynamics of carbon fluxes were closely related to changes in sea ice. Algae in sea ice may have a key role in biological pump processes in early summer. Apart from the ice algae bloom period, variations in carbon fluxes generally corresponded with phytoplankton blooms in the upper water. The ballast effect controlled the particle settling velocity and the efficiency of the biological pump. Sea ice rafts initiated the first particle export event and enhanced the particle settling efficiency during melting period. As diatoms might become less dominant in the ice-free area, sea ice loss may cause the efficiency of the biological pump efficiency to decrease over the long term.

基于海冰密集度的南极威德尔冰间湖监测与评价

海冰密集度产品在冰间湖的监测与研究中应用广泛。本文使用8种典型的被动微波遥感海冰密集度产品(NSIDC-BT-25km、NSIDC-NT2-25km、NSIDC-NT2-12.5km、NSIDC-NTBT-25km、EUMETSAT-BTBR-25km、EUMETSAT-BTBR-10km、UH-ASI-12.5km和UB-ASI-6.25km)以及5种常用的海冰密集度阈值(15%、40%、50%、60%和70%)对南极威德尔海2016—2017年出现的冰间湖进行监测,并使用形态学后处理操作对监测结果进行优化;在此基础上,对比不同阈值条件、海冰密集度反演算法以及空间分辨率差异对冰间湖面积和范围的影响,并进一步探究形态学操作对监测结果的影响。结果表明:NSIDC-NTBT-25km产品对阈值的敏感性最高,NASATeam2(NT2)算法反演的海冰密集度产品对阈值的敏感性最低,并且其监测的冰间湖面积和范围相较于Bootstrap(BT)和ARTIST Sea Ice(ASI)算法产品的监测结果整体偏小;高空间分辨率产品监测到的冰间湖开放时间更早,面积和范围更大,持续时间也更长;空间分辨率对NT2算法产品影响最小,对ASI算法产品影响最大。形态学后处理操作虽对监测结果有一定影响,但与反演算法和空间分辨率所带来的影响相比均要小。

北极加速变暖条件下西北航道的海冰分布变化特征

近年来北极的加速变暖使西北航道的通航成为可能。利用AMSR-E的6.25km分辨率日平均海冰密集度卫星数据,研究了2002—2008年北极西北航道的海冰密集度变化特征。通过统计分析沿西北航道各条线路冰障流段代表站点的融化期、轻冰期、无冰期、无冰天数和轻冰天数,以及海冰分布和变化的细节,加深了对西北航道海冰季节变化和年际变化以及空间分布的主要特征,特别是与通航相关的冰情信息的了解。研究指出西北航道南路比北路容易开通,航道上的海冰通常是从冰间湖及固定冰与流冰间的水道处开始融化,各线路冰障流段存在的时间呈减小趋势,整条线路无冰天数/轻冰天数呈增加趋势。讨论了研究区域海冰空间分布的特征和成因,提出了以整条线路无冰天数/轻冰天数作为衡量通航程度的指标之一,并初步分析了西北航道通航的影响因子。

Emery冰架北缘热盐结构的不均匀性及其成因

根据2005—2006年夏季中国南极第22次南极科学考察的海洋水文资料（64°00′～69°15′S，68°00′～76°00′E），分析了普里兹湾内Emery冰架北缘浮冰区的水团性质。发现Emery冰架东西两端的表层热含量明显高于Emery冰架北缘中部。此外冰架北缘中部海域的上混合层和季节跃层的深度也明显小于东西两端。冰架北缘的底层热盐结构则无明显的东西差异。海洋遥感的证据表明：冰架北缘的表层水的不均匀性与浮冰和冰间湖的空间分布有着密切的联系。

利用海冰密集度数据分析北极冰间湖变化

冰间湖内存在强烈的海-气相互作用和结冰析盐过程,在极区以及全球气候系统中起着重要作用。本文基于数字图像处理技术,从AMSR-E高分辨卫星遥感海冰密集度数据中提取了长时间序列的冰间湖变化信息,研究北极冰间湖内的净水面积、净水表面的净热通量(向上为正)、产冰量和产盐量的季节和年际变化,比较不同冰间湖区域之间的差异。研究结果表明:总净水面积分别在结冰初期和末期存在极大值,而由于总净水面积季节变化幅度不是很大,总产冰量和产盐量的季节变化主要受净热通量影响,在1月份存在极大值;在不同冰间湖区域内净水面积的季节变化中,进入结冰期越早的冰间湖内净水面积越快达到首次极大值;净热通量的年际变化趋势总体上是减小的,总净水面积是增加大的,其中靠近太平洋和大西洋入流口的冰间湖内净热通量减小的速率要比其他区域快,靠近亚欧大陆的冰间湖内净水面积增长速率要比其他区域大;总产冰量的年际变化同总净水面积基本一致,也是呈增加趋势。最后通过研究冰间湖的年际变化信息同海冰范围变化的相关性,发现如果连续多年冰间湖内年平均净热通量为负的异常,那么海冰范围将出现一次极小值。

南极普里兹湾海冰季节性变化的高分辨率数值模拟

普里兹湾海冰以一年冰为主,海冰覆盖存在较大的季节性变化。海冰的分布及其季节性变化主要受当地大气环流及海流的影响。基于一个海洋-海冰耦和模式,模拟研究了该海区海冰的季节性变化特征。海洋模式基于MIT环流模式(MITgcm),海冰动力学模式参考Hibler类型的VP模型,热力学过程取自Winton三层模型。模式区域覆盖整个普里兹湾(75°～55°S,50°～100°E),水平分辨率为(1/6)°×(1/12)°,垂向为50层。大气强迫场选用每6 h一次的NCEP再分析资料。模拟的海冰范围季节性变化与遥感资料拟合较好。每年的3～8月份,普里兹湾海冰快速生长,9～10月份达到最大值,随后海冰开始融化,2月份达到最小值。从9月份开始,受大陆沿岸局地风场的影响,在模拟区域范围内,形成了3个典型的沿岸冰间湖。和观测资料对比,模式较好地捕捉到了3个典型冰间湖的时间及空间分布。沿岸地形及海流对海冰厚度的分布具有重要影响,在西向沿岸流及西冰架地形的影响,在地形的上游形成海冰堆积,厚度最大超过3 m。同时,在下游方向,沿66°S形成一个厚冰带。

南极威德尔海冰间湖形成机制的研究进展

针对南极威德尔海冰间湖的特点及影响 ,本文介绍了有关威德尔海冰间湖形成研究的进展情况 ,并对存在的问题以及未来的发展进行了分析和阐述。结果说明 :动力因素、热力因素和热动力因素都只是威德尔海冰间湖形成和维持的某一方面的控制和影响因子。对威德尔海冰间湖更深入的研究 ,应该充分考虑较大尺度的海洋 -海冰 -大气相互作用。

2011年初冬南极普里兹湾冰间湖区上层水体结构演化研究

利用5头活动于南极普里兹湾的象海豹携带的CTD观测获得的2011年3—6月埃默里冰架前缘冰间湖区域海水温盐剖面数据,研究了该海域上层水体结构在初冬的演化过程。结果显示,可将该演化过程分为三个阶段:第一阶段海水温度从层化到均匀,3月下旬次表层仍维持暖水特征,随着表层海水冷却作用,次表层暖水逐渐消失,上下水体温度趋于均匀并接近冰点,温度剖面从"逆温型"演变到"均匀型";第二阶段海水盐度从层化到上下均匀,也就是从"均匀型"演变到"渐变型",海水结冰析盐过程使上层海水盐度增加,增强垂直对流混合,上下层盐度达到均匀;第三阶段冷却结冰持续,海水盐度继续增大,形成盐度随深度减小、温度随深度增大的"渐变型"结构。根据温盐剖面数据计算三个阶段的海-气之间的热通量分别是-90.93、-82.20和-43.44 W·m-2。考虑海水盐分的增加主要源于海冰形成,由此推算三个阶段内平均的海冰形成速率分别是5.4、4.9和2.5 cm·d-1。在南极初冬时期,随着海水上层低温高盐化演变持续,海水向大气释放的热通量逐渐减少,海冰形成速率也呈减少趋势。

Sources of particulate organic matter in the Chukchi and Siberian shelves: clues from carbon and nitrogen isotopes

The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial variability and origin of POM.Theδ13CPOC values were in the range of−29.5‰to−17.5‰with an average of−25.9‰±2.0‰,and theδ15NPN values ranged from 3.9‰to 13.1‰with an average of 8.0‰±1.6‰.The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf,while theδ13C andδ15N values were just the opposite.Abnormally low C/N ratios(<4),lowδ13CPOC(almost−28‰)and highδ15NPN(>10‰)values were observed in the Wrangel Island polynya,which was attributed to the early bloom of small phytoplankton.The contributions of terrestrial POM,bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model.The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward,indicating the influence of Russian rivers.The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward,suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf.The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery.A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed,indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM,the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.

Variability of size-fractionated phytoplankton standing stock in the Amundsen Sea during summer

The size-fractionated composition of phytoplankton greatly influences the transfer efficiency of biomass in pelagic food chains and the biological carbon flux from surface waters to the deep sea.To better understand phytoplankton abundance and composition in polynya,ice zone,and open ocean regions of the Amundsen Sea Sector of the Southern Ocean(110°W-150°W),its size-fractionated distribution and vertical structure are reported for January to February 2020.Vertical integrated(0-200 m)chlorophyll(Chl)a concentrations within Amundsen polynya regions are significantly higher than those within ice zone(t test,p<0.01)and open ocean(t test,p<0.01)regions,averaging 372.3±189.0,146.2±152.1,and 49.0±20.8 mg·m^(−2),respectively.High Chl is associated with shallow mixed-layer depths and near-shelf regions,especially at the southern ends of 112°W and 145°W.Netplankton(>20μm)contribute 60%of the total Chl in Amundsen polynya and sea ice areas,and form subsurface chlorophyll maxima(SCM)above the pycnocline in the upper water column,probably because of diatom blooms.Net-,nano-,and picoplankton comprise 39%,32%,and 29%of total Chl in open ocean stations,respectively.The open-ocean SCM migrates deeper and is below the pycnocline.The Amundsen Sea SCM is moderately,positively correlated with the euphotic zone depth and moderately,negatively correlated with column-integrated net-and nanoplankton Chl.

南极麦肯齐湾冰间湖的时空变化及主要影响因素分析

利用2003—2009年AMSR-E日平均海冰密集度数据,对南极普里兹湾埃默里冰架前缘中西部的麦肯齐湾冰间湖进行了分析。针对冰架前缘冰间湖的特点,本文在阈值法和连通域法的基础上,提出了生长点法作为识别此类冰间湖的方法。研究发现,该冰间湖的开始时间为每年的3月中下旬,结束时间为每年的10月末到11月初,平均出现天数为226d。冰间湖的面积每天都发生变化,表现出天气尺度的变化特征。全年累计的冰间湖面积平均为(8.33±1.55)×105 km2。冰间湖最大面积为1.69×104 km2,出现在2004年。结合NCEP再分析数据中的日平均风速资料的分析发现,在6～8月,冰间湖的天气尺度变化主要是受风场的影响,冰间湖面积与离岸风速有很好的相关性。