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1.
采用1958年1月—2001年12月ECMWF ERA-40的10m风场资料,以及由该风场资料驱动WAVEWATCHⅢ得到的北印度洋—南海海域44a的海浪场资料,通过EOF分析、正交小波分析和M-K检测方法,分析了北印度洋—南海海域海面风场和有效波高的年代际变化特征。结果表明：北印度洋—南海海域存在3个大风、大浪区,其中亚丁湾以东洋面风力最强,有效波高最高;表面风场和有效波高存在35、15和3a的主周期变化,并自20世纪70年代中期以来,年平均风场和有效波高均存在明显增强趋势,1977年为突变起始年;年平均海表10m风速和有效波高随时间增大主要是由冬季和春季海表10m风速和有效波高随时间增大引起的;冬、秋季海面风场与有效波高的年际、年代际变化周期较一致,冬季以35～40a的周期为主,秋季以11～12a的周期为主。 相似文献
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利用北部湾海域浮标站20152018年的海浪观测资料,对北部湾海域的灾害性海浪特征及影响天气系统进行了分析,结果表明:北部湾海域灾害性海浪平均每年出现2.5次,最多年出现4次(2016年);10月出现的灾害性海浪最多,8月的次之;灾害性海浪的最大有效波高3.0~5.0m,波向以N和NW方位最多,分别占30%;灾害性海浪过程持续时间最长为1190min,最短为20min;台风和冷空气是引发灾害性海浪的主要天气系统,台风引发的占60%,冷空气引发的占40%。其中以台风引发的灾害性海浪过程最多、海浪最高、持续时间最长。引发灾害性海浪的台风移动路径绝大部分经过北部湾;东路和中路冷空气更有利于北部湾灾害性海浪形成,灾害性海浪形成时常有一个冷高压位于四川盆地到江汉平原一带,中心气压在1030hPa以上,北海与海口的最大海平面气压差在4.3hPa以上。 相似文献
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中国首次北极科学考察队,乘“雪龙号”科学考察船,自１９９９年７月１日从上海启航,至９月９日返回上海靠港为止,历时７１天。本次北极科学考察的主要内容是进行北冰洋的海、气、冰相互作用综合研究,具体的科学目标有三个：一是探讨北极在全球变化中的作用和对中国气候的影响,二是了解北冰洋与北太平洋水团交换对北太平洋环流的变异影响,三是了解北冰洋临近海域生态系统与生物资源对中国渔业发展的影响。共有来自海洋、生物、大气、地质、海冰等近１０个学科的１２４名科学家参加了本次科学考察,其中来自大气、海洋、海冰等多学科的… 相似文献
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北极海冰减少及其与相关气象场的联系 总被引：2，自引：7，他引：2
利用 195 3— 1998年北极海冰资料及相应的海平面气压场和我国东北 4 2°N以北 2 2个台站气温资料 ,应用统计分析方法 ,研究海冰和气象场的年际和年代际变化以及它们的联系。得到如下结论 :(1)高纬各纬度带和主要海域的海冰范围都呈现明显的衰减现象 ,6 0°N以北纬带趋势项的方差贡献超过总方差一半 ,远远大于周期项的方差贡献 ,此海域更明显显示近年海冰减少的现象。 (2 )巴伦支海和格陵兰海 ,海冰的年代际变化具有明显的 10年以上的周期变化特点 ,也存在明显的减少趋势 ;而拉布拉多海和白令海海冰主要是 10年以上的周期变化。 (3)自 90年代开始 ,海冰均发生陡然减少的现象 ,对全球气候变暖现象 ,海冰的变化是十分敏感的。 (4) 4 0°N以北的各纬度带的海平面气压的总体趋势是下降的 ,北冰洋涛动指数明显显示海平面气压场的减少趋势和 90年代前后的显著性差异。 (5 )与海平面气压的下降相对应 ,我国东北的温度是明显上升的。 (6 )北冰洋涛动能制约巴伦支海、格陵兰海和拉布拉多海域的海冰范围 ,也与我国东北温度有十分密切的联系。当AO指数偏大时 ,即冬季冰岛附近海平面气压偏低时 ,巴伦支海和格陵兰海海冰范围缩小 ,而拉布拉多海海冰范围扩大 ;我国东北冬半年的温度出现明显上升。 相似文献
5.
全球气候变暖中南北半球海冰变化的差异 总被引：4，自引：0，他引：4
应用海冰面积资料,分析在全球气候变暖下,南北半球海冰季节和年际变化的差异,结果表明:冬季南半球海冰面积为北半球的1.13倍,而夏季仅为北半球的2/5,南半球海冰的季节变化比北半球更为显著,其季节振幅为北半球的1.6倍.1979--2006年,北半球海冰总面积呈显著减少趋势,夏秋季最快,特别在1990年代中后期以来,减少尤为迅速;夏秋季,整个区域海冰为均一的减少趋势,北冰洋靠近北太平洋的近海变化最为迅速,冬春季,主要发生在北太平洋海域.南半球海冰自1980年代初以来有所增多,四季整个区域海冰并未呈均一的减少趋势,而是有一显著减少中心,位于南极半岛附近,两个增多中心,分别位于罗斯海外围和西南印度洋一带.随夏一秋一冬一春的季节转换,3个中心区域位置存在东移和返回的过程. 相似文献
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华南近海两浮标点的波浪特征分析 总被引：2，自引：0，他引：2
基于汕尾和茂名海域2个近岸浮标连续1年的风、浪观测数据,分析了有效波高等参量的月统计特征,并检验了多种风-浪经验关系.统计显示：2个浮标点的波浪有共同特征,如波高都具有明显的冬半年与夏半年特征.冬半年浪较大,其中茂名点有效波高中值在1.3～2m之间,汕尾点有效波高中值在1～1.5m之间;夏半年浪较小,两浮标点有效波高均在1 m以下.2点的波浪也存在差异,如汕尾点波浪在9月份至次年3月份呈冬半年特征,而茂名点则从10月份至次年3月份呈冬半年特征;汕尾点波向呈向岸特征,而茂名点则无此特征.风-浪经验关系检验结果显示,不同经验关系的集合预报结果可较好地与实测值吻合,并分析了产生离群值的因素. 相似文献
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Slowing down of the summer Southern Hemisphere Annular Mode trend against the background of ozone recovery 
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下载免费PDF全文 Fei Zheng 《大气和海洋科学快报》2024,(1):3-10
20世纪末期,南半球热带外地区经历了显著的气候变化,包括夏季南半球环状模(SAM)的显著上升趋势,伴随着南极半岛的增暖和别林斯高晋海的海冰融化.这些趋势主要是由20世纪末期南极平流层臭氧消耗所驱动的.本文发现,自2001年左右以来,在南极平流层臭氧恢复的背景下,观测到的夏季SAM的上升趋势已经趋于平缓,验证了前人利用数值模拟预测的夏季SAM上升趋势减缓现象.与SAM在臭氧恢复后趋势只减缓但没有逆转不同,南极地表气温和海冰的趋势发生了逆转.南极半岛由变暖趋势转为降温趋势,别林斯高晋海域的海冰由融化趋势转为增多趋势. 相似文献
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2021年夏季（6—8月）大气环流特征为：北半球极涡呈单极型分布,主体位于北冰洋上空偏向西半球,强度较常年偏强;东亚地区以纬向环流为主,副热带高压较常年平均略偏西偏南。6月,北部海域温度较低,黄渤海海雾天气多发。7月,西南季风推进,热带气旋活跃。8月,副热带高压增强西伸,热带气旋活动频次偏少。夏季共有7次海雾过程,其中6月有4次,7月有3次。我国近海出现了9次8级以上大风过程,其中热带气旋大风过程6次,温带气旋入海影响的大风过程3次。浪高在2 m以上的海浪过程有10次,2 m以上大浪的天数共计38 d。我国北部及东部海域升温明显,从北到南的海面温度梯度减小。西北太平洋和南海有9个台风活动,其中台风“烟花”造成近海一次范围广、时间长、风力大的大风过程。 相似文献
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利用美国国家海洋大气总局/美国国家环境预报中心（NOAA/NCEP）发布的最新版WAV-EWATCHⅢ（version3.14）海浪模式对0801号台风＂浣熊＂进行数值模拟,并在此基础上对台风浪的发展过程和台风影响下的海面有效波高、风浪场及涌浪场的分布特征进行分析。结果表明：海面有效波高的分布和演变受台风系统强度和移动的影响;台风过程中所产生的大浪主要为风浪;涌浪场的分布与风浪场的分布几乎相反,涌浪场基本分布在远离台风中心的外围海域;涌浪场波高比风浪场波高要小。 相似文献
10.
正在全球气候变化研究中,北冰洋地区(包括北冰洋海水和海冰区以及周边陆地和岛屿积雪冻土区)受到极大的重视,因为在全球变暖中,北冰洋的变暖和海冰融化是最引起注意的问题之一。因此,气候模式对北冰洋地区气候变化的模拟评估以及对未来的预估,受到极大的重视,本文将综述近些年这方面的研究~([1-4])。 相似文献
11.
Ralf Döscher Klaus Wyser H. E. Markus Meier Minwei Qian René Redler 《Climate Dynamics》2010,34(7-8):1157-1176
The relative importance of regional processes inside the Arctic climate system and the large scale atmospheric circulation for Arctic interannual climate variability has been estimated with the help of a regional Arctic coupled ocean-ice-atmosphere model. The study focuses on sea ice and surface climate during the 1980s and 1990s. Simulations agree reasonably well with observations. Correlations between the winter North Atlantic Oscillation index and the summer Arctic sea ice thickness and summer sea ice extent are found. Spread of sea ice extent within an ensemble of model runs can be associated with a surface pressure gradient between the Nordic Seas and the Kara Sea. Trends in the sea ice thickness field are widely significant and can formally be attributed to large scale forcing outside the Arctic model domain. Concerning predictability, results indicate that the variability generated by the external forcing is more important in most regions than the internally generated variability. However, both are in the same order of magnitude. Local areas such as the Northern Greenland coast together with Fram Straits and parts of the Greenland Sea show a strong importance of internally generated variability, which is associated with wind direction variability due to interaction with atmospheric dynamics on the Greenland ice sheet. High predictability of sea ice extent is supported by north-easterly winds from the Arctic Ocean to Scandinavia. 相似文献
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FGOALS_gg1.1极地气候模拟 总被引：4，自引：0，他引：4
对中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室发展的气候系统模式FGOALS_g1.1的极地气候模拟现状进行了较为全面的评估.结果表明,FGOALS_g1.1对南北极海冰的主要分布特征、季节变化和年代际变化趋势具有一定的模拟能力.但也注意到,与观测相比,模式存在以下几方面的问题:(1)模拟的海冰总面积北极偏多,而南极偏少.北极,北大西洋海冰全年明显偏多;夏季,西伯利亚沿海海冰偏多,而波弗特海海冰偏少.南极,威德尔海和罗斯海冬季海冰偏少.南北极海冰边缘都存在异常的较大范围密集度很小的碎冰区,夏季尤为显著.(2)海冰流速在南北极海冰边缘和南极大陆沿岸附近较大.北极,模式没能模拟出波弗特涡流,并且由于模式网格中北极点的处理问题,造成其附近错误的海冰流场及厚度分布.这些海冰偏差与模式模拟的大气和海洋状况有着密切的联系.进一步分析表明,FGOALS_g1.1模拟的冰岛低压和南极绕极西风带明显偏弱,其通过大气环流和海表面风应力影响向极地的热量输送,在很大程度上导致上述的海冰偏差.此外,耦合模式中大气-海冰-海洋的相互作用可以放大子模式中的偏差. 相似文献
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北极海冰年际变化对东亚中纬度夏季陆面热力异常的指示作用及其可能原因 总被引：1，自引：0，他引：1
本文分析了夏季东亚中纬度近地面温度和春、夏北极海冰时空变化特征,探讨了格陵兰海、巴伦支海海冰异常变化与夏季东亚中纬度陆面热力异常在年际上的可能联系。结果表明:(1)1950—2014年,东亚中纬度夏季近地面温度明显增暖,并伴有明显的年际变化,年际变率最大值的区域主要位于40°N以北至贝加尔湖地区;春、夏格陵兰海和巴伦支海的海冰也呈现明显的减少趋势,同时表现出较强的年际变化特征。(2)春、夏格陵兰海、巴伦支海海冰异常对东亚中纬度夏季陆面热力异常具有一定的指示作用:春、夏格陵兰海、巴伦支海海冰异常偏多,通常对应夏季东亚中纬度近地面的东亚中纬度夏季增暖现象;反之亦然。(3)春、季格陵兰海、巴伦支海北极海冰指数(Arctic Sea Ice Index,ASII)高值年(海冰异常偏多年份),贝加尔湖及西南的蒙古高原地区通常为大范围的异常高压控制,有利于近地面温度升高;同时由于乌拉尔山阻塞高压减弱,极地南下的冷空气减弱,有利于东亚中纬度区域的温度升高。而ASII低值年的情形则相反,贝加尔湖以南地区受异常低压控制,乌拉尔山阻塞高压增强,冷空气易向南侵袭,不利于东亚中纬度近地面升温。 相似文献
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We analyzed the sea ice conditions in the Bering Sea for the time period 1979–2012, for which good data based on microwave satellite imagery, being able to look through clouds and darkness, are available. The Bering Sea, west of Alaska, is ice-free in summer, but each winter, an extensive sea ice cover is established, reaching its maximum normally in March. We found a slight increase in ice area over the time period, which is in stark contrast to the significant retreat observed in the Beaufort Sea north of Alaska and the Arctic Ocean as a whole. Possible explanation might be found in the Pacific Decadal Oscillation (PDO), which went from dominantly positive values to more negative values in the last decade. The PDO is related to the sea surface temperature (SST) in the North Pacific, negative values indicated cooler temperatures and cooler SST weakening the semipermanent Aleutian Low. When comparing the circulation pattern obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research reanalyzed data set for years of heavy ice against light ice years, an additional vectorial northerly wind component could be deduced from the pressure data. Hence, less relatively warm air is advected into the Bering Sea, which becomes of special importance in winter, when solar radiation is at its minimum. Surface observations confirmed these findings. Atmospheric pressure increased in Cold Bay, located close to the center of the semi-permanent Aleutian Low, the N–S pressure gradient (Nome–Cold Bay) in the Bering Sea decreased, wind speeds of the coastal stations became weakened, and the temperature of coastal stations decreased. 相似文献
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Centennial-scale climate change from decadally-paced explosive volcanism: a coupled sea ice-ocean mechanism 总被引：1，自引：1，他引：0
Y. Zhong G. H. Miller B. L. Otto-Bliesner M. M. Holland D. A. Bailey D. P. Schneider A. Geirsdottir 《Climate Dynamics》2011,37(11-12):2373-2387
Northern Hemisphere summer cooling through the Holocene is largely driven by the steady decrease in summer insolation tied to the precession of the equinoxes. However, centennial-scale climate departures, such as the Little Ice Age, must be caused by other forcings, most likely explosive volcanism and changes in solar irradiance. Stratospheric volcanic aerosols have the stronger forcing, but their short residence time likely precludes a lasting climate impact from a single eruption. Decadally paced explosive volcanism may produce a greater climate impact because the long response time of ocean surface waters allows for a cumulative decrease in sea-surface temperatures that exceeds that of any single eruption. Here we use a global climate model to evaluate the potential long-term climate impacts from four decadally paced large tropical eruptions. Direct forcing results in a rapid expansion of Arctic Ocean sea ice that persists throughout the eruption period. The expanded sea ice increases the flux of sea ice exported to the northern North Atlantic long enough that it reduces the convective warming of surface waters in the subpolar North Atlantic. In two of our four simulations the cooler surface waters being advected into the Arctic Ocean reduced the rate of basal sea-ice melt in the Atlantic sector of the Arctic Ocean, allowing sea ice to remain in an expanded state for?>?100 model years after volcanic aerosols were removed from the stratosphere. In these simulations the coupled sea ice-ocean mechanism maintains the strong positive feedbacks of an expanded Arctic Ocean sea ice cover, allowing the initial cooling related to the direct effect of volcanic aerosols to be perpetuated, potentially resulting in a centennial-scale or longer change of state in Arctic climate. The fact that the sea ice-ocean mechanism was not established in two of our four simulations suggests that a long-term sea ice response to volcanic forcing is sensitive to the stability of the seawater column, wind, and ocean currents in the North Atlantic during the eruptions. 相似文献
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NUMERICAL SIMULATIONS ON INFLUENCES OF VARIATION OF SEA ICE THICKNESS AND EXTENT ON ATMOSPHERIC CIRCULATION* 下载免费PDF全文
下载免费PDF全文 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 results 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 activitiesover 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). 相似文献
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By using a 2-layer AGCM designed by Institute of Atmospheric Physics,Chinese Academy ofSciences.this paper investigates influences of thickness and extent variations in Arctic sea ice onthe atmosphere circulation,particularly on climate variations in East Asia.The simulation resuhshave indicated that sea ice thickness variation in the Arctic exhibits significant influences onsimulation results,particularly on East Asian monsoon.A nearly reasonable distribution of sea icethickness in the model leads directly to stronger winter and summer monsoon over East Asia.andimproves the model's simulation results for Siberia high and Icelandic low in winter.On the otherhand,sea ice thickness variation can excite a teleconnection wave train across Asian Continent,andin low latitudes,the wave propagates from the western Pacific across the equator to the easternPacific.In addition,the variation of sea ice thickness also influences summer convective activitiesover 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 followingspring and summer are also significant.The simulation result shows that when winter sea iceextent in the target region is larger (smaller) than normal.(1)in the following spring (averagedfrom April to June).positive (negative) SLP anomalies occupy the northern central Pacific.whichleads directly to weakened (deepened)Aleutian low.and further favors the light (heavy) sea icecondition in the Bering Sea:(2)in the following summer,thermal depression in Asian Continent isdeepened (weakened).and the subtropical high in the northwestern Pacific shifts northward(southward) from its normal position and to be strengthened (weakened). 相似文献
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Abstract Changes to the Beaufort Sea shoreline occur due to the impact of storms and rising relative sea level. During the open‐water season (June to October), storm winds predominantly from the north‐west generate waves and storm surges which are effective in eroding thawing ice‐rich cliffs and causing overwash of gravel beaches. Climate change is expected to be enhanced in Arctic regions relative to the global mean and include accelerated sea‐level rise, more frequent extreme storm winds, more frequent and extreme storm surge flooding, decreased sea‐ice extent, more frequent and higher waves, and increased temperatures. We investigate historical records of wind speeds and directions, water levels, sea‐ice extent and temperature to identify variability in past forcing and use the Canadian Global Coupled Model ensembles 1 and 2 (CGCM1 and CGCM2) climate modelling results to develop a scenario forcing future change of Beaufort Sea shorelines. This scenario and future return periods of peak storm wind speeds and water levels likely indicate increased forcing of coastal change during the next century resulting in increased rates of cliff erosion and beach migration, and more extreme flooding. 相似文献
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北极海冰的气候变化与20世纪90年代的突变 总被引：5，自引：0，他引：5
应用英国Had ley气候研究中心1968~2000年的1°×1°的北半球逐月海冰密集度资料,使用EOF分解等统计方法,探讨北极海冰的气候变化趋势、海冰的突变、海冰的季节持续性和各季的特色。结果表明:(1)自1968年以来,北极海冰的减小是北半球海冰变化的总趋势;海冰的趋势变化在海冰的年际总变化中占有相当重要的地位,可达50%左右。冬春季主要减少区域在格陵兰海、巴伦支海和白令海;夏秋季海冰减少是唯一趋势,中心在北冰洋边缘的喀拉海、拉普捷夫海、东西伯利亚海、楚科奇海、波弗特海。(2)20世纪80年代中后期北极海冰已出现减小趋势,在20世纪90年代,海冰又出现范围和面积的突然减少,中心在格陵兰海和巴伦支海;即海冰减少是加速的,其变化程度已远远超过一般的自然变化。(3)海冰有很好的季节持续性,有很强的隔季相关,也有较好的隔年相关;各季节海冰分布型之间有很好的联系,表现为海冰分布型的总体变化趋势是一致的,在海冰的减少中也体现了分布型的特征。 相似文献