Correlation between sea surface temperature and wind speed in Greenland Sea and their relationships with NAO variability

The North Atlantic Oscillation （NAO） is one of the major causes of many recent changes in the Arctic Ocean. Generally, it is related to wind speed, sea surface temperature （SST）, and sea ice cover. In this study, we analyzed the distributions of and correlations between SST, wind speed, NAO, and sea ice cover from 2003 to 2009 in the Greenland Sea at 10°W to 10°E, 65°N to 80°N. SST reached its peak in July, while wind speed reached its minimum in July. Seasonal variability of SST and wind speed was different for different regions. SST and wind speed mainly had negative correlations. Detailed correlation research was focused on the 75~N to 80~N band. Regression analysis shows that in this band, the variation of SST lagged three months behind that of wind speed Ice cover and NAO had a positive correlation, and the correlation coefficient between ice cover and NAO in the year 2007 was 0.61 SST and NAO also had a positive correlation, and SST influenced NAO one month in advance. The correlation coefficients between SST and NAO reached 0.944 for the year 2005, 0.7 for the year 2008, and 0.74 for the year 2009 after shifting SST one month later. NAO also had a positive correlation with wind speed, and it also influenced wind speed one month in advance. The correlation coefficients between NAO and wind speed reached 0.783, 0.813, and 0.818 for the years 2004, 2005, and 2008, respectively, after shifting wind speed one month earlier.

The relationships among aerosol optical depth, ice, phytoplankton and dimethylsulfide and the implication for future climate in the Greenland Sea

The sea-to-air flux of dimethylsulphide（DMS） is one of the major sources of marine biogenic aerosol, and can have an important radiative impact on climate, especially in the Arctic Ocean. Satellite-derived aerosol optical depth（AOD） is used as a proxy for aerosol burden which is dominated by biogenic aerosol during summer and autumn. The spring sea ice melt period is a strong source of aerosol precursors in the Arctic. However, high aerosol levels in early spring are likely related to advection of continental pollution from the south（Arctic haze）.Higher AOD was generally registered in the southern part of the study region. Sea ice concentration（SIC） and AOD were positively correlated, while cloud cover（CLD） and AOD were negative correlation. The seasonal peaks of SIC and CLD were both one month ahead of the peak in AOD. There is a strong positive correlation between AOD and SIC. Melting ice is positively correlated with chlorophyll a（CHL） almost through March to September,but negatively correlated with AOD in spring and early summer. Elevated spring and early summer AOD most likely were influenced by combination of melting ice and higher spring wind in the region. The peak of DMS flux occurred in spring due to the elevated spring wind and more melting ice. DMS concentration and AOD were positively correlated with melting ice from March to May. Elevated AOD in early autumn was likely related to the emission of biogenic aerosols associated with phytoplankton synthesis of DMS. The DMS flux would increase more than triple by 2100 in the Greenland Sea. The significant increase of biogenic aerosols could offset the warming in the Greenland Sea.

Competition within the marine microalgae over the polar dark period in the Greenland Sea of high Arctic

With the onset of winter, polar marine microalgae would have faced total darkness for aperiod of up to 6 months. A natural autumn community of Arctic sea ice microalgae was collected for dark survival experiments from the Greenland Sea during the ARKTIS-XI/2 Expedition of RV Po-larstem in October 1995. After a dark period of 161 days, species dominance in the algal assemblage have changed from initially pennate diatoms to small phytoflagellates (<20 μm). Over the entire dark period, the mean algal growth rate was - 0.01 d-1. Nearly all diatom species had negative growth rates, while phytoflagellate abundance increased. Resting spore formation during the dark period was observed in less than 4.5% of all cells and only for dinoflagellates and the diatom Chaetoceros spp. We assume that facultative heterotrophy and energy storage are the main processes enabling survival during the dark Arctic winter. After an increase in light intensity, microalgal cells reacted with fast growth within days. Phytoflagellates had the highest growth rate, followed by Nitzschia frigida. Further investigations and experiments should focus on the mechanisms of dark survival (mixotrophy and energy storage) of polar marine microalgae.

Vertical Chlorophyll and Dimethylsulfide Profile Simulations in Southern Greenland Sea

Biogenetic sulfide dimethylsulfide(DMS)plays a major role on the global climate,especially in Arctic Ocean.Accurate simulate DMS concentration is an important task.Here we introduced both biogeochemical depth-averaged model G93 and its extension model-one dimensional DMS model.Both surface concentrations,vertical profiles of chlorophyll(CHL)and DMS are simulated using the two models within southern Greenland Sea(0°E–10°E,70°N–75°N)during year 2012.As the input data for the models simulations,the spatial monthly mean of methodology forcings including sea surface temperature(SST),wind speed(WIND),cloud cover(CLD),sea ice concentration(ICE)and mixed layer depth(MLD)are calculated.Satellite 8-day time series of chlorophyll-a(CHL)are used as observation data for CHL related parameter calibrations.Simó’s imperial formula is used as the monthly DMS observation data.The Genetic Algorithm technique is used for the parameter calibrations.The simulation results show that the most DMS related surface concentrations exhibit the normal distributions with peak during May.CHL,DMS and DMSP(dimethylsulphoniopropionate)vertical profiles are obtained for July,August and September in year 2012.CHL had the higher variation of subsurface concentration maximum(SCM)in July with the lower surface concentration value.DMS had surface higher and subsurface lower profile for the all three months.DMSP also had subsurface high in July.The SCM CHL diurnal variation in the subsurface also can be resulted from diurnal changes in MLD and vertical mixing variations,plus photolysis and wind-driven ventilations.

Considerable increase in bowhead,blue,humpback and fin whales numbers in the Greenland Sea and Fram Strait between 1979 and 2014

In the frame of our long-term study of cetacean abundance and distribution in polar marine ecosystems begun in 1979, a drastic increase in the bowbead Balaena mysticetus North Atlantic ＂stock＂ was observed from 2005 on, by a factor 30 and more： from 0.0002 per count between 1979 and 2003 （one individual, n=5430 cotmts） to 0.06 per count from 2005 to 2014 （34 individuals, n=6000 counts）; the most significant part of the increase occurred from 2007 on. Other large whale species （Mysticeti） showed a similar pattern, mainly blue Balaenoptera musculus, humpback Megaptera novaeangliae and fin whales Balaenoptera physalus. This large and abrupt increase cannot logically be due to population growth, nor to survival of a hidden ＂relic＂ population, nor to a changing geographical distribution within the European Arctic, taking into account the importance of the coverage during this study. Our interpretation is that individuals passed through the Northwest and/or Northeast Passages from the larger Pacific stock into the almost depleted North Atlantic populations coinciding with a period of very low ice coverage -- at the time the lowest ever recorded. In contrast, no clear evolution was detected neither for sperm whale Physeter macrocephalus nor for Minke whale Balaenoptera acusrostrata.

Detection and Monitoring of New-Ice in the East Greenland Sea Using the SeaWinds Scatterometer

Space borne radar scatterometers are primarily designed to measure the wind vector over the world ocean; yet they also provide useful information on sea ice type and extent. In this paper, it is shown how the SeaWinds scatterometer can be used to detect new sea ice at the very beginning of its growth. Taking advantage of the very good coverage of the East Greenland Sea by SeaWinds on board the QuikSCAT satellite it has been possible to detect the early stage of formation of the sea ice peninsula, named the Odden, and to monitor its evolution during March 2001. The early sea ice detection has been validated by using RADARSAT Synthetic Aperture Radar scenes. It is also shown that microwave radiometers, such as the Special Sensor Microwave Imager (SSM/I), which are used as standard sensors for sea ice monitoring, do not detect the very early stage of sea ice growth and lag behind new sea ice occurrence by about twelve to twenty four hours.

Greenland Ice Sheet Contribution to Future Global Sea Level Rise based on CMIP5 Models

Sea level rise （SLR） is one of the major socioeconomic risks associated with global warming. Mass losses from the Greenland ice sheet （GrIS） will be partially responsible for future SLR, although there are large uncertainties in modeled climate and ice sheet behavior. We used the ice sheet model SICOPOLIS （Simulation COde for POLythermal Ice Sheets） driven by climate projections from 20 models in the fifth phase of the Coupled Model Intercomparison Project （CMIP5） to estimate the GrlS contribution to global SLR. Based on the outputs of the 20 models, it is estimated that the GrIS will contribute 0-16 （0-27） cm to global SLR by 2100 under the Representative Concentration Pathways （RCP） 4.5 （RCP 8.5） scenarios. The projected SLR increases further to 7-22 （7-33） cm with 2~basal sliding included. In response to the results of the multimodel ensemble mean, the ice sheet model projects a global SLR of 3 cm and 7 cm （10 cm and 13 cm with 2~basal sliding） under the RCP 4.5 and RCP 8.5 scenarios, respectively. In addition, our results suggest that the uncertainty in future sea level projection caused by the large spread in climate projections could be reduced with model-evaluation and the selective use of model outputs.

The Relationship between the Wintertime Blocking over Greenland and the Sea Ice Distribution over North Atlantic

The sea-ice concentration in the Northern Hemisphere, 500 hPa height, sea-level pressure and 1000-500 hPa thickness of monthly mean data are examined for the period 1953-1989, with emphasis on the winter season.Relationships between large-scale patterns of atmospheric variability and sea-ice variability are investigated, making use of the correlation method. The analysis is conducted for the Atlantic sectors. In agreement with earlier studies based upon monthly mean data on sea-ice concentration, the strongest sea-ice pattern is composed of a dipole with opposing centers of action in the Davis Straits / Labrador Sea region and the Greenland and Barents Seas. Its temporal variability is strongly coupled to the atmospheric North Atlantic Oscillation (NAO). The relationship between the two patterns is strongest with the atmosphere leading the ocean. The polarity of the NAO is associated with Greenland blocking episodes, during which the influence of the atmosphere is strong enough to temporarily halt the climatological mean advance of the ice edge in some regions and substantially accelerate it in others.The relationships between the fields are indicative of local forcing of sea-ice in most regions, with wind stress and thermodynamic fluxes at the air-sea interface both contributing.

不同类型ENSO事件对初冬北极海冰的影响

基于1951—2019年NCEP/NCAR再分析资料、Hadley环流中心海温、海冰密集度资料,通过合成分析和诊断温度异常方程,研究不同类型ENSO对初冬北极海冰的影响。结果表明,EP La Niña发展年初冬(11—12月),巴伦支—喀拉海海冰异常减少;CP La Niña发展初冬,巴伦支—喀拉海海冰异常增加。EP和CP型El Ni1o对初冬北极海冰的影响类似:格陵兰海海冰异常减少,而哈德逊—巴芬湾海冰异常增加。不同类型ENSO对初冬北极海冰的影响主要通过产生不同的大气遥相关,引起同期和前期的海表气温异常而实现。

Deep waters warming in the Nordic seas from 1972 to 2013

The warming of deep waters in the Nordic seas is identified based on observations during Chinese 5th Arctic Expedition in 2012 and historical hydrographic data. The most obvious and earliest warming occurrs in the Greenland Basin （GB） and shows a coincident accelerated trend between depths 2000 and 3500 m. The ob-servations at a depth of 3000 m in the GB reveal that the potential temperature had increased from ？1.30°C in the early 1970s to ？0.93°C in 2013, with an increase of about 0.37°C （the maximum spatial deviation is 0.06°C） in the past more than 40 years. This remarkable change results in that deep waters in the center of the Lofton Basin （LB） has been colder than that in the GB since the year 2007. As for the Norwegian Basin （NB）, only a slight trend of warming have been shown at a depth around 2000 m since the early 1980s, and the warming amplitude at deeper waters is just slightly above the maximum spatial deviation, implying no obvious trend of warming near the bottom. The water exchange rate of the Greenland Basin is estimated to be 86% for the period from 1982 to 2013, meaning that the residence time of the Greenland Sea deep water （GSDW） is about 35 years. As the weakening of deep-reaching convection is going on, the abyssal Nordic seas are playing a role of heat reservoir in the subarctic region and this may cause a positive feedback on the deep-sea warming in both the Arctic Ocean and the Nordic seas.

Petroleum resource assessment of the East Greenland Basin

The onshore and offshore parts of the East Greenland Basin are important areas for petroleum exploration at the North Pole. Although assessments by the US Geological Survey suggest a substantial petroleum potential in this area, their estimates carry a high risk because of uncertainties in the exploration data. This paper compares the reservoir-forming conditions based on data from the East Greenland Basin and the North Sea Basin. The petroleum resources of the East Greenland Basin were assessed by geochemical and analogy methods. The East Greenland Basin was a rift basin in the late Paleozoic–Mesozoic. Its basement is metamorphic rock formed by the Caledonian Orogeny in the Archean to Late Ordovician. In the basin, Devonian–Paleogene strata were deposited on the basement. Lacustrine source rock formed in the late Paleozoic and marine source rocks in the Late Jurassic. Shallow-marine sandstone reservoirs formed in the Middle Jurassic and deep-marine turbiditic sandstone reservoirs formed in the Cretaceous.The trap types are structure traps, horst and fault-block traps, salt structure traps, and stratigraphic traps. The East Greenland Basin possesses superior reservoir-forming conditions, favorable petroleum potential and preferable exploration prospects. Because of the lack of exploration data, further evaluation of the favorable types of traps, essential amount of source rock, petroleum-generation conditions and appropriate burial histories in the East Greenland Basin are required.

Improved significance testing of wavelet power spectrum near data boundaries as applied to polar research

When one applies the wavelet transform to analyze finite-length time series, discontinuities at the data boundaries will distort its wavelet power spectrum in some regions which are defined as a wavelength-dependent cone of influence （COI）. In the COI, significance tests are unreliable. At the same time, as many time series are short and noisy, the COI is a serious limitation in wavelet analysis of time series. In this paper, we will give a method to reduce boundary effects and discover significant frequencies in the COI. After that, we will apply our method to analyze Greenland winter temperature and Baltic sea ice. The new method makes use of line removal and odd extension of the time series. This causes the derivative of the series to be continuous （unlike the case for other padding methods）. This will give the most reasonable padding methodology if the time series being analyzed has red noise characteristics.

冬春季格陵兰海冰变化与初夏中国气温/降水关系的初步分析

采用英国Hadley中心GISST海冰面积资料、NCEP NCAR再分析资料以及中国地面降水和气温资料 ,运用EOF分解、小波分析和合成分析等方法 ,初步探讨了格陵兰岛两侧附近冬春季海冰面积变化特征及其与初夏 6月中国气温和降水的关系。结果表明 ,格陵兰岛东西两侧海冰面积呈显著反相变化 ,并且具有明显的年际和年代际周期性振荡。冬春季格陵兰—挪威海海冰与初夏 6月中国长江以北气温 (降水 )正相关 (反相关 ) ,与长江以南气温 (降水 )反相关 (正相关 ) ,而对于戴维斯海峡—拉布拉多海海冰则具有相反的相关型。大尺度 5 0 0hPa环流合成分析初步表明 ,冬春季格陵兰附近海冰面积变化伴随着北极极涡环流和北半球阻塞高压的持续异常 ,海冰变化可能是影响初夏中国气温和降水的因子之一。

一个海冰气耦合模式中格陵兰海海冰年际变异及其成因的个例分析

利用一个全球海冰气耦合模式模拟结果,选取冬季年际变率最大的海冰区———格陵兰海海冰区中的一个4年海冰剧烈变化过程展开分析,试图探讨此个例过程中海冰剧烈变化的原因。结果表明,在此个例中,该区域海冰年际变异主要是由大气环流异常驱动的,海表面温度和海冰密集度变化主要是对大气环流变化的响应。海表面温度变化决定着海冰范围及海冰密集度的变化,但海冰变化时通过相变潜热的释放或吸收反过来对海表面温度变化有一定影响。

1966～1991年北极海冰模拟结果与观测的对比

利用宇如聪等１９９５年建立的北极区域冰洋耦合模式，以１９６６～１９９１年期间逐月的月平均实测海平面气温和气压场为强迫场，模拟了上述２６年间北极海冰的时间演变和空间分布，着重分析了大西洋及欧洲沿岸一侧的巴伦支海和格陵兰海的海冰状况，并与目前能够得到的北极海冰密集度观测资料做了对比，结果表明：（１）模式对巴伦支海海冰年际变化的模拟是比较成功的，表现在不仅模拟的１９６９～１９７９和１９７９～１９８７这两个时段的主要变化趋势和观测事实比较一致，而且模拟出了１９７９和１９８４这两个多冰和少冰的极端年份。模拟的主要年际变化出现在巴伦支海东部和中部海域，这一点同观测事实是一致的，不过模拟的年际变化偏于新地岛西侧，而观测结果则更靠近挪威沿岸。（２）模式未能在格陵兰海模拟出与观测一致的年际变化。根据巴伦支海和格陵兰海模拟结果的对比有理由推测：巴伦支海的海冰可能更多地受到热力学过程的控制，而动力学因子对格陵兰海海冰的作用则不可忽视。（３）模拟和观测的巴伦支海和格陵兰海海冰的季节循环均滞后于气温的季节循环，但模拟结果滞后的时间更长，事实上模拟的冬季海冰极值比观测滞后１～２个月，而夏季无冰期比观测结果长两个月以上，这是模式需要改?

春季格陵兰海冰与夏季中国气温和降水的关系

采用英国 Hadley中心的 GISST海冰面积资料、NCEP/NCAR再分析资料以及中国 1 60站气温和降水资料 ,分析了春季格陵兰海冰面积与夏季中国区域气温和降水的关系。初步研究表明 ,春季格陵兰海冰面积变化和随后夏季我国黄河长江中下游之间地区气温以及 8月份华北和西南地区降水呈明显正相关 ,而和 6月黄河中上游地区降水则具有明显的负相关。同时 ,春季格陵兰海冰异常时期对应着北半球大气环流的明显变化 。

2012年夏季挪威海和格陵兰海浮游植物群落结构的色素表征

对2012年中国第5次北极科学考察期间的挪威海和格陵兰海两个断面的光合色素进行了高效液相色谱(HPLC)分级分析,通过藻类色素化学分类分析软件(CHEMTAX)获得了不同浮游植物类群对叶绿素a的贡献,进而得到该海域表层和次表层(30 m)的浮游植物群落结构。结果表明:表层总叶绿素a的浓度为23.59 ng/L,低于次表层的30.38 ng/L,其中浮游植物根据粒径划分对总叶绿素a的贡献由高到低依次是微型浮游植物、小型浮游植物和微微型浮游植物。该海域同时存在葱绿叶绿素(Prasino)、墨角藻黄素(Fuco)、别藻黄素(Allo)、多甲藻素(Perid)、玉米黄素(Zea)、19-丁墨甲藻黄素(19'BF)和19-六已墨甲藻黄素(19'HF)等色素,其浓度和分布与温盐和营养盐等环境因子存在一定的相关性。不同粒径浮游植物色素组成显示,微微型浮游植物群落中以S型定鞭藻(28%)、N型定鞭藻(21%)、硅藻(18%)和青绿藻(12%)占优;微型浮游植物群落的优势类群为S型定鞭藻(53%)、N型定鞭藻(20%)和硅藻(12%);而小型浮游植物群落主要为硅藻(63%)和甲藻(17%)。

挪威海和格陵兰海海水DMS分布特征及影响因素研究

于2012年7—9月现场测定了北极挪威海和格陵兰海区域海水二甲基硫（DMS）及其前体物质二甲巯基丙酸内盐（DMSP，分溶解态DMSPd和颗粒态DMSPp）的含量，研究了其空间分布格局及其影响因素，探讨了表层海水DMS的生物周转和去除途径。结果表明，表层海水DMS、DMSPd和DM—SPp的平均浓度分别为5．36nmol／L、15．63nmol／L和96．73nmol／L，受挪威海流和北极深层水影响，表层海水二甲基硫化物浓度呈现出由低纬度向高纬度海域递减的趋势。DMSPd和DMSPp浓度与Chlα浓度均有显著的相关性，说明浮游植物生物量是影响挪威海和格陵兰海二甲基硫化物生产的重要因素。表层海水DMS生物生产和消费速率平均值分别为18．19nmol／（L·d）、15．67nmol／（L·d）。DMS微生物周转时间变化范围为0．03～1．80d，平均值为0．49d，DMS海一气周转时间是微生物消费时间的90倍，说明夏季挪威海和格陵兰海表层海水中DMS微生物消费过程是比海一气扩散更具优势的去除机制。

春季格陵兰海冰变化及与北大西洋涛动和北极涛动的联系

采用长序列 ( 1 90 3— 1 994年 ) GISST海冰面积和海表温度 ( SST)资料、NCEP/NCAR再分析资料等 ,分析了春季格陵兰海冰面积年代际变化特征及其同北大西洋海气变化的关系。结果表明 :春季格陵兰海冰面积变化的主要特征可由海冰变化的 EOF第一主分量表示。春季海冰变化与前冬 NAO/AO以及冬春 1— 4月份北大西洋墨西哥湾流区 SST具有明显的反相变化趋势 ,且均具有准 6 0 a的周期变化特征。海洋向大气的热量输送 (感热、潜热 )受到海冰变化的显著影响 (冰多输送少 )。海冰作为大气的冷源 ,也明显影响地表净辐射的变化。进而 ,春季海冰变化可影响后期的大气环流变化 :海冰面积偏大 (偏小 ) ,冰岛低压和阿留申低压偏弱 (偏强 ) ,夏季北非和亚洲大陆的 SLP明显偏低 (偏高 ) ,两大陆夏季热低压加强 (减弱 )

北冰洋水体对格陵兰海混合增密对流的可能影响分析

格陵兰海内发生的等密度混合后产生的增密对流是重要的对流现象之一。北冰洋正在发生快速变化,其内水团变性以及环流系统的改变都将使格陵兰海等密度混合对流发生明显变化,继而对全球气候变化产生影响。以往关于等密度混合对流的研究很少,大都集中在对流发生海域。由于等密度混合的主体是大西洋回流水与北冰洋流出水体,本文目的是探讨北极内部不同海域的水体会对混合增密对流造成的可能影响。文中定义了有效对流速度,强调水平温度梯度和垂向层化强度是影响有效对流速度的决定性因素;水平温度差越大,垂向层化越弱,产生的对流越强。发生在东格陵兰极锋处的有效对流都是大西洋的水体,一部分是在格陵兰海回流的大西洋回流水;一部分是在北冰洋潜沉并回流的北极大西洋水,该水体在北冰洋循环的时间越长,温度差越大,产生的有效对流越强。而横越北冰洋的太平洋水因密度过低而不能参与等密度混合对流,加拿大海盆主盐跃层之上的水体也都不能参与对流。北冰洋几个海盆深层水的温度差异明显,有可能与格陵兰海深层水形成有效对流;但是,由于深层水流速低、湍流混合弱、水平温度梯度小,是否可以产生有效对流尚不清楚。