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Gita J. Laidler 《Climatic change》2006,78(2-4):407-444
Sea ice is influential in regulating energy exchanges between the ocean and the atmosphere, and has figured prominently in scientific studies of climate change and climate feedbacks. However, sea ice is also a vital component of everyday life in Inuit communities of the circumpolar Arctic. Therefore, it is important to understand the links between the potential impacts of climate change on Arctic sea ice extent, distribution, and thickness as well as the related consequences for northern coastal populations. This paper explores the relationship between sea ice and climate change from both scientific and Inuit perspectives. Based on an overview of diverse literature the experiences, methods, and goals which differentiate local and scientific sea ice knowledge are examined. These efforts are considered essential background upon which to develop more accurate assessments of community vulnerability to climate, and resulting sea ice, change. Inuit and scientific perspectives may indeed be the ideal complement when investigating the links between sea ice and climate change, but effective and appropriate conceptual bridges need to be built between the two types of expertise. The complementary nature of these knowledge systems may only be realized, in a practical sense, if significant effort is expended to: (i) understand sea ice from both Inuit and scientific perspectives, along with their underlying differences; (ii) investigate common interests or concerns; (iii) establish meaningful and reciprocal research partnerships with Inuit communities; (iv) engage in, and improve, collaborative research methods; and, (v) maintain ongoing dialogue. 相似文献
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Gita J. Laidler James D. Ford William A. Gough Theo Ikummaq Alexandre S. Gagnon Slawomir Kowal Kevin Qrunnut Celina Irngaut 《Climatic change》2009,94(3-4):363-397
The observations of community members and instrumental records indicate changes in sea ice around the Inuit community of Igloolik, in the Canadian territory of Nunavut. This paper characterizes local vulnerability to these changes, identifying who is vulnerable, to what stresses, and why, focusing on local and regional use of sea ice for the harvesting of renewable resources and travel. This analysis is coupled with instrumental and sea ice data to evaluate changing temperature/wind/sea ice trends over time, to complement local observations. We demonstrate the relationships between changing sea ice conditions/dynamics and harvesting activities (i.e. dangers and accessibility), with specific emphasis on ringed seal and walrus seasonal hunting, to illustrate current sea ice exposures that hunters are facing. Community members are adapting to such changes, as they have done for generations. However, current adaptive capacity is both enabled, and constrained, by social, cultural, and economic factors that manifest within the modern northern Hamlet. Enabling factors include the ability of hunters to manage or share the risks associated with sea ice travel, as well as through their flexibility in resource use, as facilitated by sophisticated local knowledge and land/navigational skills. Constraining factors include the erosion of land-based knowledge and skills, altered sharing networks, as well as financial and temporal limitations on travel/harvesting. The differential ability of community members to balance enabling and constraining factors, in relation to current exposures, comprises their level of vulnerability to sea ice change. 相似文献
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Synoptic-scale atmospheric circulation patterns drive wind forcing of dynamic and thermodynamic processes in Arctic sea ice. Synoptic typing and compositing are common techniques used to identify a limited number of prevailing weather classifications that govern a region's climate. This work investigates atmospheric circulation patterns (surface to 250?hPa) for the southern Beaufort Sea and corresponding surface wind regimes within each synoptic type. Significant changes (p?<?0.05) in relative frequencies of a number of synoptic types were attributed to declining summer sea ice. Corresponding upper-level circulation anomalies show increasingly meridional atmospheric circulation. Synoptic Types 9 and 11 were identified as key October-November-December circulation features that represent deepening of the Aleutian low with concomitant strengthening of pressure gradients over the southern Beaufort Sea. Classification of coastal-based wind observations shows a shift towards increased easterly wind forcing. A case study of surface wind data from the CCGS Amundsen (2009–2011) provided a direct example of the surface wind regime within the marginal ice zone within each synoptic type during a period of reduced Arctic sea-ice cover. 相似文献
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北极海冰融化影响东亚冬季天气和气候的研究进展以及学术争论焦点问题 总被引：3，自引：1，他引：2
北极历来是影响东亚冬季天气、气候的关键区域之一。北极表面增暖要比全球平均快2~3倍,即所谓北极的放大效应。随着全球增暖的持续以及北极海冰的持续融化,北极的生态环境正在发生显著的变化,进而可能对北半球中、低纬度的天气、气候产生影响。本文概述了有关北极海冰融化影响冬季东亚天气、气候的主要研究进展,特别是自2000年以来,北极海冰异常偏少影响东亚冬季气候变率以及极端严寒事件的可能途径、存在的科学问题,以及学术界的争论焦点。秋、冬季节是北极海冰快速形成时期,此时北极海冰对大气环流的影响要强于大气对海冰的影响。近二十年来的研究结果表明,北极海冰异常偏少,不仅影响北冰洋局地的气温和降水变化,而且通过复杂的相互作用和反馈过程,对北半球中、低纬度的天气、气候产生影响。北极海冰通过以下两个可能机制来影响东亚冬季的天气、气候:（1）北极海冰的负反馈机制;（2）由海冰异常偏少引起的平流层-对流层相互作用机制。秋、冬季节北极海冰持续异常偏少,特别是,巴伦支海-喀拉海海冰异常偏少,既可以加强冬季西伯利亚高压（东亚冬季风偏强）,也可以导致冬季风偏弱。导致海冰影响不确定性的部分原因是:（1）夏季北极大气环流状态影响北极海冰异常偏少对冬季大气环流的反馈效果;（2）冬季大气环流对北极海冰异常偏少响应的位置、强度不同造成的。秋、冬季节北极海冰持续异常偏少,在适宜的条件下（例如,前期夏季北极大气环流的热力和动力条件,有利于加强北极海冰偏少对冬季大气的反馈作用）,可以激发出有利于冬季亚洲大陆极端严寒过程的大气环流异常。目前学术界争论焦点主要集中在以下两个方面:（1）关于北极增暖、北极海冰融化对中纬度区域影响的争论;（2）关于1980年代后期以来,冬季欧亚大陆表面气温呈现降温趋势的原因。目前,有关北极海冰融化影响冬季欧亚大陆次季节变化以及极端天气、气候事件的过程和机制,我们认知非常有限,亟需开展深入细致的研究。 相似文献
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Managing Arctic marine resources to be resilient to environmental changes requires knowledge of how climate change is affecting marine food webs and fisheries. Changes to fishery resources will have major implications for coastal Indigenous communities whose livelihoods, health, and cultures are strongly connected to fisheries. Understanding these broad social-ecological changes requires a transdisciplinary approach bringing together contrasting and complementary disciplines and ways of knowing. Here, we examine climatic proxies, ecological, and fishery indicators (stable isotopes, fish condition, and lipid content), and interviews with Inuit fishers to assess how marine ecosystem changes have influenced Arctic Char (Salvelinus alpinus) ecology and fisheries over a 30-year time period (1987–2016) in the Kitikmeot region of the Canadian Arctic. Inuit fishers reported several observations of environmental changes, including longer ice-free seasons, warmer ocean temperatures, and the arrival of new marine species. Biophysical data revealed important changes toward earlier dates of ice breakup (>12 days in some areas) and a shift in isotopic niche reflecting a changing Arctic Char diet, with increased contribution of pelagic carbon and higher trophic level prey. Fish condition was improved in years with earlier ice breakup, as observed by both Inuit fishers and biophysical indicators, while lipid content increased through time, suggesting that longer ice-free seasons may have a positive effect on Arctic Char quality as reflected by both fish condition and lipid content. Long-term impacts of continuing climate change, however, such as the northward expansion of boreal species and increasing ocean temperatures, could have negative effects on fisheries (e.g., physiological impairment in fish if temperatures exceed their thermal range). Continuous community-based monitoring that directly informs fisheries management could help communities and managers adaptively, and sustainably, manage in the face of multiple interacting changes in Arctic marine systems. 相似文献
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Since the 1990s, local residents from around the Arctic have reported changes in weather predictability. Examination of environmental measurements have not, until now, helped describe what the local inhabitants have been reporting, in part because prior studies did not focus directly on the persistence aspect of weather. Here we show that there is evidence of changes in persistence in weather over the last two decades for Baker Lake, Nunavut, Canada. Hourly data indicate that for local spring, the persistence of temperature has changed dramatically in the last 15 years with some years showing a strong drop in day-to-day persistence in the local spring afternoons, somewhat at odds with changes in persistence on a more global scale. Changes in daily persistence may have implications for human health, agriculture, and ecosystems worldwide. More importantly, the approach of merging indigenous knowledge with scientific methods may offer unexpected benefits for both. 相似文献
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利用江苏省2005年自动站与基本气象站测风资料, 以及基本站1971—2000年测风资料, 探讨了风速及风功率密度的短序列订正方法, 并将各自动站数据分别订正到3个代表年。结果表明:应用该订正方法订正年平均风速, 其平均误差百分率为3.38%;用基本站作为假设自动站对其作平均气候状况下的订正, 再与自身观测值比较, 得到年平均风速订正的平均误差百分率为7.13%, 风功率密度订正的平均误差百分率为13.26%, 最大误差百分率为21.98%, 最小误差百分率为4.46%, 订正效果较为理想。 相似文献
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近百年中国东部夏季降水年代际变化特征及其原因 总被引：15，自引：4，他引：11
本文利用测站降水观测资料分析过去一百多年中国东部华北、长江流域以及华南夏季降水的年代际变化特征发现,尽管这三个地区的夏季降水具有不同的年代际转折时期,但是均同时在1910年代初期、1920年代初期、1940年代中期、1960年代中期、1970年代末期以及1990年代初期发生了跃变。近一百年间不同年代际时期东部夏季降水的分布型主要以南正北负或者南负北正的偶极型为主,并且无论是偶极型分布还是三极型分布,两个相邻年代际时期中国东部降水分布型发生完全反向变化的概率较高（60%）。此外,夏季的PDO、冬季的AO以及春季的北极海冰也同时在1920年代末期、1940年代中期、1970年代末期以及1990年代中期左右发生了跃变,这几次跃变时期与中国东部三个不同地区夏季降水发生跃变的时期一致,表现出近百年来太平洋年代振荡（PDO）、北极涛动（AO）以及北极海冰这三个因子对中国东部夏季降水年代际变化的协同作用。在年代际时间尺度上,夏季的PDO与华北夏季降水显著负相关。PDO的年代际变化能够在500 hPa位势高度场中激发出太平洋—日本（PJ）型年代际遥相关波列;同时在850 hPa风场中激发出类似于影响华北夏季降水年代际变化的大气环流型,从而影响华北降水的年代际变化。冬半年的AO与长江流域夏季降水存在显著正相关关系。冬季到春季正位相的AO导致亚洲大陆南部处于湿冷状态,土壤湿度的记忆性可将这种状态延续到夏季。因此,夏季海陆热力对比减弱,东亚夏季风发生年代际减弱,相应地长江流域的降水年代际增多。春季北极海冰与华南夏季降水显著负相关,北极海冰的年代际异常能在500 hPa位势高度场中激发出与静止Rossby波异常传播相联系的欧亚—华南年代际遥相关波列,从而影响华南降水的年代际变化。 相似文献
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The importance of a national or regional network of meteorological stations for improving weather predictions has been recognized for many years. Ground-based automatic weather stations typically observe weather at a height of 2-10 m above ground level(AGL); however, these observations may have two major shortcomings. Large portions of data cannot be used if the station height is significantly lower than the model surface level; and such observations may contain large representativity errors as near-surface observations are often affected by the local environment, such as nearby buildings and tall trees. With the recent introduction of a significant number of mobile communication towers that are typically over40 m AGL in China, a campaign has been proposed to use such towers to build a future observing system with an observing height of 40 m. A series of observing system simulation experiments has been conducted to assess the potential utility of such a future observing system as part of a feasibility study. The experiments were conducted using the Weather Research and Forecasting model and its Rapid Update Cycle data assimilation system. The results revealed the possibility of improving weather forecasting by raising present weather stations to a height of 40 m; this would not only enable more observations to pass the terrain check, but should also reduce interpolation errors. Additionally, improvements for temperature, humidity and wind forecasting could be achieved as the accuracy of the initial conditions increases. 相似文献
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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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0808号台风凤凰前部龙卷的环境场和雷达回波分析 总被引：5，自引：0，他引：5
用多普勒天气雷达、常规观测和地面加密观测资料对2008年7月29-30日发生在江苏的台风凤凰前部系列龙卷过程进行了详细分析.结果如下:该龙卷发生在台风前部风切变区里,低空较强的垂直风切变、极不稳定的大气层结和深厚的正涡度区,为龙卷的发生提供了热力和动力条件.龙卷回波的反射率因子特征表现为最大反射率因子梯度位于回波的后侧,一般都有弱回波区和后侧入流缺口相伴随.东台龙卷产生于飑线型弓形回波的顶点,具有相对较大的反气旋性切变.高邮龙卷中低层具有弱的气旋性涡旋,宝应龙卷回波的内部环流特征明显,有明显的中气旋结构.在业务工作中,强回波质心高度和垂直累积液态含水量的骤降、径向速度风场中气旋性涡旋的迅速发展是对龙卷的提前警戒很好的参考指标. 相似文献
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A mesoscale boundary-layer model (BLM) is used for running 12-h low-level wind forecasts for the La Plata River region. Several
experiments are performed with different boundary conditions that include operational forecasts of the Eta/CPTEC model, local
observations, as well as a combination of both. The BLM wind forecasts are compared to the surface wind observations of five
weather stations during the period November 2003–April 2004. Two accuracy measures are used: the hit rate or percentage of
cases with agreement in the wind direction sector, and the root-mean-squared error (RMSE) of the horizontal wind components.
The BLM surface wind forecasts are always more accurate, since its averaged hit rate is three times greater and its averaged
RMSE is one half smaller than the Eta forecasts. Despite the large errors in the surface winds displayed by the Eta forecasts,
its 850 hPa winds and surface temperature forecasts are able to drive the BLM model to obtain surface winds forecasts with
smaller errors than the Eta model. An additional experiment demonstrates that the advantage of using the BLM model for forecasting
low-level winds over the La Plata River region is the result of a more appropriate definition of the land–river surface temperature
contrast. The particular formulation that the BLM model has for the geometry of the river coasts is fundamental for resolving
the smaller scale details of the low-level local circulation. The main conclusion of the study is that operational low-level
wind forecasts for the La Plata River region can be improved by running the BLM model forced by the Eta operational forecasts.
L. Sraibman and G. J. Berri—Members of Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) of Argentina.
An erratum to this article can be found at 相似文献
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本文利用常规探测资料,分析了1983年3月25日发生在珠江三角洲地区的一次强对流天气过程背景流场的几个重要特征,如高空急流的结构与变化、辐散风场及与之相联系的背景次级环流、风场垂直切变和水平切变等. 相似文献
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1998年青藏高原东侧边界层风场与长江暴雨洪水的关系 总被引：6，自引：0，他引：6
应用1998年6～8月四川省和重庆市探空资料,分析了青藏高原东侧大气边界层风场演变与长江上游暴雨和长江洪水的关系.结果表明:1998年夏季长江上游的暴雨天气与高原东侧成都边界层风场变化密切相关,当成都边界层为东北风时,高原东侧边界层维持气旋式偏东流场,长江上游未来产生暴雨等强对流天气;当为西南风等其他风向时,高原东侧边界层维持反气旋式偏南流场,未来是无降水天气;高原东侧边界层的动力激发作用是1998年长江上游暴雨产生的重要机制.并且,再次证明了西邻青藏高原的成都是长江上游天气变化关键点的观点. 相似文献
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为了进一步提高GRAPES_Meso的分析和预报效果,该文在GRAPES_Meso三维变分同化系统中建立了同化GNSS/RO反演的大气资料的观测算子,实现了对GNSS/RO反演的大气资料的同化应用,并通过2013年7月1个月的同化和预报试验分析了GNSS/RO反演大气资料对GRAPES_Meso模式系统分析和预报的影响。结果表明:增加了GNSS/RO反演大气资料的同化后,GRAPES_Meso位势高度场的分析误差明显减小,平均分析误差减小约8%,预报误差略有减小,平均预报误差减小约1%;湿度场的分析误差和预报误差变化不明显,常规观测资料稀少的青藏高原地区的降水预报技巧有所提高,小雨到大雨的ETS (equitable threat score) 评分提高约0.01,对全国及其他分区的降水预报技巧总体上有正效果。 相似文献
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南极和北极是地球上的气候敏感地区, 也是多个国际科学计划研究全球气候变化的关键地区。极地大气科学考察与研究是极地科学研究的重要组成部分。中国气象科学研究院的极地大气科学考察与研究始于20世纪80年代, 25年来有较大进展。中国气象科学研究院参加了我国组织的23次南极考察、2次北冰洋考察和3次北极考察; 承担了南极长城站和中山站、北极黄河站气象业务建设和维持, 以及中-澳合作南极冰盖3个无人自动气象站工作; 进行了常规地面气象、Brewer大气臭氧、近地面物理、冰雪和大气化学等观测, 获得了较为系统的极地大气环境资料。开展了有关极地大气科学与全球变化的研究, 在极地天气气候特征及气候变化时空多样性、极地海冰变化和南极海冰涛动、极地近地面物理特征和海-冰-气相互作用、中山站臭氧变化特征及南极臭氧洞和大气化学、气候代用资料获取和古气候环境以及极地大气环境变化对东亚环流和中国天气气候影响等方面的研究取得了新进展。中国极地大气科学正积极通过多学科交叉、走国际合作道路, 努力提高对极地在全球变化中作用的认识水平, 并积极探索极地变化对我国气候、环境的影响。 相似文献
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近20年来中国极地大气科学研究进展 总被引：14，自引：0，他引：14
南极、北极和青藏高原是地球上的 3大气候敏感地区 ,是多个国际计划研究全球变化的关键地区。中国的南极和北极实地考察研究 ,分别始于 2 0世纪 80和 90年代 ,起步较晚 ,但近 2 0余年来有较大的进展。极地大气科学考察与研究是极地科学研究的重要组成部分。讫今为止 ,中国已组织了 2 0次南极考察和 3次北极考察 ,建立了中国南极长城站、中山站和北极黄河站等 3个常年科学考察站 ;进行了常规地面气象、Brewer大气臭氧、近地面物理、高层大气物理、冰雪和大气化学等观测 ,获得了较为系统的极地大气科学第一手资料 ;开展了有关极地与全球变化的研究 ,取得了新的进展。南极地区大气温度、臭氧和海冰的气候变化在时间和空间上都是多样的。南极地区的增暖主要发生在南极半岛地区 ,在南极大陆主体并不明显 ,近 10余年来还有降温趋势。中国南极长城站和中山站的观测资料也证实了这一点。此外 ,还揭示了南极半岛西侧和罗斯海外围的海冰变化具有“翘翘板”特征 ,由此定义的南极涛动指数可用来讨论南极海冰状况和海冰关键区的活动 ;用实地考察资料研究了极地不同下垫面的近地面物理和海 -冰 -气相互作用特征 ,给出了边界层特征参数 ;讨论了极地天气气候和大气环境特征及其对东亚大气环流和中国天气气候的影响 ;利用 相似文献
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利用常规观测、自动气象站、多普勒雷达等资料分析珠江三角洲台风龙卷的活动特征及其产生的环境条件。结果表明:台风龙卷发生在6—10月,时间多为10—20时,出现在台风登陆后1.3～21.3 h的时段内;多数龙卷位于台风中心的东北象限,台风中心在广东湛江一广西东南部或北部湾附近时是珠江三角洲龙卷发生的高风险期。高层辐散、低层辐合及中低空强东南急流在珠江口附近叠加是龙卷产生的有利环流背景。强或弱龙卷环境条件的共同特征为低抬升凝结高度、强深层和低层垂直风切变及较大风暴相对螺旋度(SRH),主要差异是强龙卷的深层和低层垂直风切变与SRH更大;相似台风路径下,有/无龙卷环境条件的明显差异在于0～1 km低层垂直风切变和SRH,两值越大出现超级单体或中气旋的可能性越大,龙卷发生概率也就越高。台风龙卷风暴母体属于低质心的微型超级单体风暴;低层有强或中等强度中气旋,有时强中气旋中心伴有龙卷涡旋特征(TVS);龙卷出现在钩状回波顶端或TVS附近。与西风带超级单体龙卷相比,台风龙卷中气旋的尺度更小、垂直伸展高度更低。 相似文献