Relationship between Antarctic sea ice and the climate in summer of China

The variations of sea ice are different in different regions in Antarctica, thus have different impacts on local atmospheric circulation and global climatic system. The relationships between the sea ice in Ross Sea and Weddell Sea regions and the synoptic climate in summer of China are investigated in this paper via diagnostic analysis methods by using global sea ice concentration gridded data covering Jan. 1968 through Dec. 2002 obtained from Hadley Center, combined with Geopotential Height on 500hPa and 100hPa over North Hemisphere and monthly precipitation and air temperatures data covering the corresponding period over 160 meteorological stations in China obtained from CMA （ China Meteorological Administration）. Results disclose that both these two regions are of indicative meanings to the climate in summer of China. The Ross Sea Region is the key sea ice region to the precipitation in Northeast China in summer. More sea ice in this region in September will result in less precipitation in Northeast China in the following June. Weddell Sea Region is the key sea ice region to the air temperature in Northeast China in summer. More sea ice in this region in September will contribute to lower air temperature in Northeast China in the following June.     

Spatio-temporal Variation of Arctic Sea Ice in Summer from 2003 to 2013

The variation in Arctic sea ice has significant implications for climate change due to its huge influence on the global heat balance. In this study, we quantified the spatio-temporal variation of Arctic sea ice distribution using Advanced Microwave Scanning Radiometer(AMSR-E) sea-ice concentration data from 2003 to 2013. The results found that, over this period, the extent of sea ice reached a maximum in 2004, whereas in 2007 and 2012, the extent of summer sea ice was at a minimum. It declined continuously from 2010 to 2012, falling to its lowest level since 2003. Sea-ice extent fell continuously each summer between July and mid-September before increasing again. It decreased most rapidly in September, and the summer reduction rate was 1.35 × 10~5 km~2/yr, twice as fast as the rate between 1979 and 2006, and slightly slower than from 2002 to 2011. Area with 90% sea-ice concentration decreased by 1.32 × 10~7 km~2/yr, while locations with 50% sea-ice concentration, which were mainly covered by perennial ice, were near the North Pole, the Beaufort Sea, and the Queen Elizabeth Islands. Perennial Arctic ice decreased at a rate of 1.54 × 10~5 km~2 annually over the past 11 years.     

Sea Salt Sodium Record in a Shallow Ice Core from East Antarctica as a Potential Proxy of the Antarctic Sea Ice Extent in Southern Indian Ocean

Antarctic sea ice has experienced an increasing trend in recent decades, especially in the Ross Sea and Indian Ocean sectors. Sea ice variability affects greatly the maritime airmass transport from high latitude to Antarctic continent. Here we present a new ice core record of sea salt sodium(ssNa+) concentration at annual-resolution in the Princess Elizabeth Land spanning from 1990 to 2016, showing that this marker could be used as a potential proxy for reconstructing the sea ice extent(SIE) in the Southern Indian Ocean(SIO) given their significant correlation(R =-0.6, P 0.01) over the past 27 years. The correlation and composite analyses results show that the ssNa~+ at the 202 km inland from Zhongshan Station and the SIE changes in SIO are closely related to the Indian Ocean Dipole(IOD) and Southern Annular Mode(SAM). The northward wind in central SIO occurs during positive IOD and the strengthened westerlies occurs during positive SAM, both of which favor increased sea ice in SIO and lead to the decreased ssNa~+ concentration at the coastal site.     

Antarctica Sea-ice Oscillation and Its Possible Impact on Monsoon of South Sea

Antarctic sea-ice oscillation index with a seesaw pattern is defined using NCEP/NCAR reanalysis girds data of monthly Antarctica sea-ice concentration from 1979 to 2002. The relationships between the index of winter and the summer precipitations in China as well as the onset date of the summer East Asia monsoon are presented. The study result shows that the grids of correlation coefficients passed 5% confidence level between Antarctic sea-ice oscillation index and Antarctic sea-ice concentration are more than 1/3 of all grids of Antarctica sea-ice, that means the index can represent 1/3 sea-ice area. The winter index has a significant correlation with abnormal summer (June-August) precipitation in China. The area of positive correlation lies in the Yangtze River basin and its south, and that of negative correlation lies mainly in the north of Yangtze River basin. While the winter index is positive (negative), the onset date of South China Sea monsoon is earlier (later), with a probability of 79% (80%). Consequently, a conceptual model is given in term of discussing the possible process between the winter Antarctic sea ice and the monsoon precipitation in China.     

北极海冰范围时空变化及其与海温气温间的数值分析

本文利用美国国家冰雪中心提供的1989-2014年海冰范围资料,分析了北极海冰范围的年际变化和季节变化规律。分析发现,北极海冰范围呈减少趋势,每年减小\begin{array}{c}5.91\times {10}^4\mathit{k}{m}^2\end{array},夏季减少趋势显著,冬季减少趋势弱。北极海冰范围显现相对稳定的季节变化规律,海冰的结冰和融化主要发生在各个边缘海,夏季期间的海冰具有融化快、冻结快的特征。结合海温、气温数据,进行北极海冰范围与海温、气温间的数值分析,结果表明北极海冰范围变化通过影响北极海温变化进而影响北极气温变化。海冰范围的季节变化滞后于海温和气温的季节变化。基于北极考察走航海温气温数据,进行楚科奇海海冰范围线与海温气温间的数值分析,发现楚科奇海海冰范围线所在区域的海温、气温与纬度高低、离陆地远近有关。     

A coupled multi-category sea ice model and POM for Baffin Bay and the Labrador Sea

An overview of the seasonal variation of sea-ice cover in Baffin Bay and the Labrador Sea is given. A coupled ice-ocean model, CECOM, has been developed to study the seasonal variation and associated ice-ocean processes. The sea-ice component of the model is a multi-category ice model in which mean concentration and thickness are expressed in terms of a thickness distribution function. Ten categories of ice thickness are specified in the model. Sea ice is coupled dynamically and thermodynamically to the Princeton Ocean Model. Selected results from the model including the seasonal variation of sea ice in Baffin Bay, the North Water polynya and ice growth and melt over the Labrador Shelf are presented.     

Interdecadal oscillations of temperatures in 1903 - 2002 over the Antarctic Peninula

In the paper, by use of the monthly mean temperature data of 12 stations in the vicinity of Antarctic Peninsula, the temperature series during 1903 - 2000 is founded and the interdecadal oscillation of the temperature are discussed. The results indicate that 1） There are three jumps during 1919 - 1923, 1947 - 1953 and 1976 - 1982 in recent hundred years and the stable climate step between two jump points lasted about 30 years. 2） Annual mean temperature is increased by 0. 730℃ in an echelon during 1903 -2000, the warming extent is dissimilarity in each season, the maximum of warming is in the winter and the minimum of warming is in summer. 3） The ice decline trend is presented in the index of Ice concentration in the vicinity sea of Antarctic Peninsula, which shows a -0. 2053/10a drop, and the decrease trend of the ice concentration index in summer half year （Dee-May） is found much more obviously than that in winter half year （Jun-Nov）. 4） There is better negative relationship between the temperature and the Ice concentration index in Antarctic Peninsula and its vicinity sea, which correlation coefficient of is exceed the significance level of 5% in summer, autumn and annual.     

基于NSIDC海冰产品的FY北极海冰数据集优化

北极海冰对全球气候起着非常重要的调制作用,海冰范围是海冰监测的基本参数。近40年,北极地区持续变暖,北极海冰显著减少,进而引发北极自然环境恶化、北半球极端天气频发、全球海平面上升等一系列环境和气候问题。准确获取北极海冰范围及其演变趋势,确定海冰变化对全球气候系统的响应,是研究和预测全球气候变化趋势的关键之一。HasISST和OISST海冰数据集在海冰监测中应用最为广泛,可为北极地区长时间序列海冰变化研究提供基础数据,但这2套数据集空间分辨率相对较低,应用于北极关键区对中国气候响应研究方面存在很大的局限,为解决这一问题和弥补国内海冰监测微波遥感数据的空白,2011年6月27日,国家卫星气象中心（National Satellite Meteorological Center, NSMC）发布了FY（Fengyun, FY）北极海冰数据集,该数据集利用搭载在FY卫星上的微波成像仪（Microwave Radiation Imager, MWRI）数据,使用Enhance NASA Team算法制作,该算法利用前向辐射传输模型模拟北极地区4种海表类型（海水、新生冰、一年冰和多年冰）在不同大气条件下MWRI辐射亮温,进而得到每种大气条件下0~100%的海冰覆盖度查找表（海冰覆盖度每次增加1%）,通过观测值与模拟值的比对得到海冰覆盖度,由该数据集计算得到的北极海冰范围在大部分区域与实际情况相符。该产品虽已进行通道间匹配误差修正和定位精度偏差订正,但由于其搭载的微波成像仪（Microwave Radiation Imager, MWRI）天线长度有限,造成传感器探测到的地物回波信号相对较弱,难以区分海冰和近岸附近的陆地,影响了该数据集的精度和应用。为解决这一问题,本文基于美国冰雪中心（National Snow and Ice Data Center, NSIDC）发布的海冰产品对FY海冰数据集进行优化,NSIDC产品利用判断矩阵对海岸线附近的像元进行识别,并对误差像元进行不同程度的修正,由NSIDC产品计算得到的北极海冰范围与实际情况更为符合。数据集优化大大提高了FY海冰数据集的精度,研究结果表明,优化后FY海冰数据集与NSIDC产品相关系数高达0.9997,且二者日、月、年平均最大海冰范围偏差仅为3.5%、1.9%、0.9%,且FY海冰数据集优化过程对其较好的空间分异特征无明显影响。该数据集可正确地反映北极海冰范围及其变化情况,且海岸线附近海冰的分布情况更准确,可为北极海冰变化研究提供可靠的基础数据。     

Interannual Variability and Scenarios Projection of Sea Ice in Bohai Sea Part I: Variation Characteristics and Interannual Hindcast

The Bohai Sea is one of the southernmost areas for sea ice formation in the northern hemisphere.Sea ice disasters in this body of water severely affect marine activities and the safety of coastal residents.In this study,we analyze the variation characteristics of the sea ice in the Bohai Sea and establish an annual regression model based on predictable mode analysis method.The results show the following:1)From 1970 to 2018,the average ice grade is(2.6±0.8),with a maximum of 4.5 and a minimum of 1.0.Liaodong Bay(LDB)has the heaviest ice conditions in the Bohai Sea,followed by Bohai Bay(BHB)and Laizhou Bay(LZB).Interannual variation is obvious in all three bays,but the linear decreasing trend is significant only in BHB.2)Three modes are obtained from empirical orthogonal function analysis,namely,single polarity mode with the same sign of anomaly in all of the three bays and strong interannual variability(82.0%),the north–south dipole mode with BHB and LZB showing an opposite sign of anomalies to that in LDB and strong decadal variations(14.5%),and a linear trend mode(3.5%).Critical factors are analyzed and regression equations are established for all the principal components,and then an annual hindcast model is established by synthesizing the results of the three modes.This model provides an annual spatial prediction of the sea ice in the Bohai Sea for the first time,and meets the demand of operational sea ice forecasting.     

GRACE估计南极冰川质量变化的泄露影响及其改正

利用2003-01～2013-12期间GRACE数据反演得到地球表面质量变化,使用全球正向建模恢复法改正泄露影响,获得南极冰盖质量变化。比较GRACE直接估计和泄露影响改正后的结果发现,南极冰盖在2003～2013年质量变化信号衰减20.3%,西南极有26.4%的质量消融信号泄露到了周边,东南极的泄露影响更高达70%。改正后的结果表明,南极冰盖绝大部分质量消融发生在西南极和南极半岛,质量积累发生在东南极的Ronne冰架和Amery冰架;西南极冰盖质量变化速度达到-152.47±2.00 Gt/a,基本上等同于南极全岛的质量消融速度,而南极半岛的冰盖融化速度为-27.44±0.75 Gt/a,基本与东南极的冰盖质量积累速度27.27±5.12Gt/a抵消;南极全岛冰川整体质量以-152.64±7.00 Gt/a速度消失,并以-18.85±4.87 Gt/a2的加速度加速融化,导致海平面以0.41 mm/a的速度上升。     

Impact of the El Nino on the Variability of the Antarctic Sea Ice Extent

1　IntroductionManymeteorologistsandoceanographerspaidmuchattentiontothestudyofthemechanismofENSOformanyyears,suchasBjerknes(1 966) ,Wyrtki(1 975) ,McCreary(1 983 ) ,Philander(1 984) ,ZhangandChao(1 993 )andMcCPhaden(1 998)havemadegreatdevelopmentinthestudyofENSO .Especiallyinthe 1 990’s,withtheincreasingofthedatainthedeepocean ,thesomeonearguedthattheENSOepisodehadcloserelation shipwiththeeasterntransportationoftheanomalousseasurfacetemperatureinthewestPacific(LiandMu 1 999;Huang 2…     

Isolation of novel psychrophilic bacteria from Arctic sea ice

The phylogenetic diversity of cuhurable psychrophilic bacteria associated with sea ice from the high latitude regions of Canadian Basin and Chukchi Sea, Arctic, was investigated. A total of 34 psychropilic strains were isolated using three methods of （ Ⅰ ） dilution plating （ at 4 ℃ ）, （ Ⅱ ） bath culturing （ at - 1 ℃ ） and dilution plating, and （ Ⅲ） cold shock （ -20 ℃ for 24 h）, bath culturing and dilution plating under aerobic conditions. Sea-ice samples were exposed to -20 ℃ for 24 h that might reduce the number of common microorganisms and encourage outgrowth of psyehrophilic strains. This process might be able to be introduced to isolation psychrophilic bacteria from other environmental samples in future study. 16S rDNA nearly full-length sequence analysis revealed that psychrophilic strains felled in two phylo- genetic divisions, γ-proteobacteria （in the genera ColweUia,Marinobaeter、Shewanella,Glaciecola,Marinomortas and Pseudoalteromortas ） and Cytophaga-Flexibacter-Baeteroides （ Flavobacterlum and Psyehroflexus）. Fifteen of bacterial isolates quite likely represented novel species （16S rDNA sequence similarity below 98% ）. One of strains （BSi20002） from Canadian Basin showed 100% sequence similarity to that of Marinobacter sp. ANT8277 isolated from the Antarctic Weddell sea ice, suggesting bacteria may have a bipolar distribution at the species level.     

Winter climate change and sea ice-atmosphere interaction at high northern latitudes in ERA40 dataset

1 IntroductionGreen house gases, such as CO2,CH4, N2O and so on are released to the atmosphereconstantly by human activities. These gases insert positive radiative forcing to the climate.Meanwhile, aerosol, which are also released by human activities, ins…     

Characteristics of change of the SST in the tropical western Pacific and the tropical Indian Ocean and its response to the change of the Antarctic ice area

In this paper, by using ocean surface temperature data (COADS), the study is made of the characteristics of the monthly and annual changes of the SST in the tropical western Pacific and Indian Oceans, which have important influences on the climate change of the whole globe and the relation between ENSO(E1 Nino-Southern Oscillation) and the Antarctic ice area is also discussed. The result indicates that in the tropical western Pacific and the Indian Oceans the change of Sea Surface Temperture (SST) is conspicuous both monthly and armaully, and shows different change tendency between them. This result may be due to different relation in the vibration period of SST between the two Oceans. The better corresponding relationship is obvious in the annual change of SST in the tropical Indian Ocean with the occurrence El Nino and LaNlra. The change of the SST in the tropical western Pacific and the tropical Indian Oceans has a close relation to the Antarctic ice area, especially to the ice areas in the eastern-south Pole and Ross Sea, and its notable correlative relationship appears in 16 months when the SST of the tropical western Pacific and the Indian Oceans lag back the Antarctic ice area.     

Definition of Arctic and Antarctic Sea Ice Variation Index

1　Introduction Itiswellknownthatseaiceinthepolarregionplaysanimportantroleintheglobal climatechangesasapartofclimatesystem(Carleton1989;YuanandMartinson2000, 2001;ChengandBian2002;LiuandMartinson2002;LiuandZhang2004;Gigorand Wallace2002etal).Infact,numerousmodelingstudiessuggestanimportantinfluence throughtheseaicefieldsalone(Grumbine1994,Meehl1990,Rindetal.1995).Inor dertounderstandthevariabilityofArcticandAntarcticseaicealongwiththepossiblecon nectionswithclimaticanomaliesindetail…     

A coupled regional Arctic sea ice-ocean model: configuration and application

A regional sea ice-ocean coupled model for the Arctic Ocean was developed, based on the MITgcm ocean circulation model and classical Hibler79 type two categorythermodynamics-dynamics sea ice model. The sea ice dynamics and thermodynamicswere considered based on Viscous-Plastic (VP) and Winton three-layer models, respectively. A detailed configuration of coupled model has been introduced. Special attention has been paid to the model grid setup, subgrid paramerization, ice-ocean coupling and open boundary treatment. The coupled model was then applied and two test run examples were presented. The first model run was a climatology simulation with 10 years (1992?002) averaged NCAR/NCEP reanalysis data as atmospheric forcing. The second model run was a seasonal simulation for the period of 1992?007. The atmospheric forcing was daily NCAR/NCEP reanalysis. The climatology simulation captured the general pattern of the sea ice thickness distribution of the Arctic, i.e., the thickest sea ice is situated around the CanadaArchipelago and the north coast of the Greenland. For the second model run, themodeled September Sea ice extent anomaly from 1992?007 was highly correlated with the observations, with a linear correlation coefficient of 0.88. Theminimum of the Arctic sea ice area in the September of 2007 was unprecedented. The modeled sea ice area and extent for this minimum was overestimated relative to the observations. However, it captured the general pattern of the sea ice retreat.     

北极熊栖息地稳定性的遥感评估方法

北极熊是北极最重要的哺乳动物之一,近年来数量却在减少。海冰作为北极熊狩猎、活动和繁殖的平台,是其栖息地的重要组成部分。因此其种群栖息地变化主要依赖于海冰变化。本文基于美国雪冰中心的海冰密集度和NOAA提供的ETOPO1基岩数据,分析了北极海冰密集度、开阔水域面积、海冰消退时间、海冰出现时间、开阔水域季节长度的年际变化,进而评价北极熊栖息地的稳定性。结果表明,海冰密集度呈现降低的趋势,开阔水域面积增大,多年冰数量减少,大多变为一年冰。海冰消退时间提前,海冰出现时间延后,开阔水域季节长度大幅增加,与1992年相比增加了72 d。19个栖息地中,巴伦支海是开阔水域面积和季节长度变化贡献最大的海域,增加速度分别为9.71×10³ km²/a和71.69 d/10a。以开阔水域季节长度变化率为依据,将北极熊栖息地划分为稳定、次稳定和不稳定3个等级。总共有3个稳定栖息地,包括分布在相对其他栖息地而言纬度较低的楚科奇海、西哈得孙湾和南哈得孙湾。13个次稳定栖息地,包括拉普捷夫海、喀拉海、东格陵兰、巴芬湾、戴维斯海峡、福克斯湾、布西亚湾、麦克林托克海峡、梅尔维尔子爵海峡、挪威湾、北波弗特、南波弗特和兰开斯特海峡。3个不稳定栖息地,均位于70°N以北,包括北极盆地、巴伦支海和凯恩盆地。稳定区主要位于低纬度,不稳定区全部位于高纬度。该分级结果表明高纬度地区虽然海冰覆盖多,但是年际变化十分显著,不稳定的3个区域内北极熊对海冰变化适应时间更少,年际迁移变化大,对北极熊的生存发展更为不利。     

Relationship of Arctic sea ice and Northern Hemispheric 500 hPa Polar vortices

Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated.     

Preliminary results on relationship between thermal diffusivity and porosity of sea ice in the Antarctic

The in situ sea-ice temperature, salinity and density observed from Chinese Antarctic Zhongshan Station have been applied to calculate the vertical profile of sea ice porosity. Based on numerical method, a number of schemes on sea-ice thermal diffusivity versus porosity have been accessed and one optimized scheme is identified by an optimal control model with an advanced distributing parameter system. For simplicity, the internal heating source item was neglected in the heat conduction equation during the identification procedure. In order to illustrate the applicability of this identified scheme, the vertical ice temperature profiles have been simulated and compared with measurements, respectively by using identified scheme and by classical thermodynamic formulae.The comparisons indicated that the scheme describing sea-ice thermal diffusivity and porosity is reasonable. In spite of a minor improvement of accuracy of results against in situ data, the identified scheme has a more physical meaning and could be used potentially in various applications.