太平洋夏季水对加拿大海盆海冰的影响   总被引：1，自引：0，他引：1  

宋雪珑  周生启 《海洋学报》2014,36(11):38-45

近年来,北极海冰发生了大面积减少,减少的原因仍存在着争议。基于2003-2011年的水文和遥感卫星数据,对北冰洋加拿大海盆的太平洋水和海冰进行研究。通过对比2006年和2007年太平洋水位温与海冰密集度的空间分布,发现太平洋水暖异常于2007年1-3月进入加拿大海盆的中部,并可能导致了2007年夏季海冰大面积的融化。2003-2011年,在加拿大海盆的中部,太平洋水位温与海冰密集度存在着时间上的负相关。选取2007年8月,发现两者在空间上也存在着负相关。这很可能说明太平洋水暖异常在流动的过程中,向上输送了热量,在一定程度上,融化了海冰,从而触发海冰-反照率正反馈,导致海冰的减少。因此,通过白令海峡进入北冰洋的太平洋夏季水,对北极海冰面积的减少有着重要影响。  相似文献   

Whose Norms Prevail? Policy Networks,International Organizations and “Sustainable Forest Management”     

Fred Gale  Timothy Cadman 《社会与自然资源》2014,27(2):170-184

This article investigates the origin of international norms, arguing that one pathway is via the strategic action of sector-specific policy networks. Evidence is adduced from an examination of the contested norm of sustainable forest management (SFM). It is argued that a Canadian forestry policy network, under pressure internally and externally to demonstrate its environmental and social credentials, promoted an “economistic” SFM norm in regional negotiations known as the Montreal Process. The article outlines the policy network approach, applies it to the Canadian forest sector, and analyzes how a policy network centered in the Canadian Forest Service and the Canadian Council of Forest Ministers worked to have the network's preferred conception of SFM internationally endorsed. The article highlights the importance of investigating which social actors champion which international norms and encourages reflexive policymaking by calling into question the degree to which international norms actually reflect a genuine global consensus.  相似文献   

The Influence of Culture on Wildfire Mitigation at Peavine Métis Settlement,Alberta, Canada     

Amy Christianson  Tara K. Mcgee  Lorne L'Hirondelle 《社会与自然资源》2014,27(9):931-947

This article presents findings of a study that explored how culture influenced support for wildfire mitigation in Peavine Métis Settlement, an Aboriginal community located in Alberta, Canada. Community-based research was completed using interviews, focus groups, and participant observation. The results show that cultural factors appeared to influence wildfire mitigation preferences. Participants indicated the current state of the forest was not natural, and that mitigation activities would likely improve forest health. Participants supported Settlement Council-led wildfire mitigation activities at both the residential and community level due to a preference for communal action and collective problem solving. Participants also were found to distrust “outsiders” and preferred programs developed by members of their own community. The results of this study show that wildfire mitigation programs based on local culture can be well supported in an Aboriginal community.  相似文献   

夏季加拿大海盆海冰边缘区声体积后向散射强度研究   总被引：1，自引：1，他引：0  

刘洪宁  吕连港  刘娜  杨光兵  姜莹  杨春梅  刘宗伟  林丽娜 《海洋学报》2015,37(11):127-134

声信号的体积后向散射强度是声传播过程中一个关键的参数。海冰边缘区的声体积后向散射强度研究对深入认识北极声场环境有着十分重要的意义。本文利用中国第六次北极科学考察获取的数据资料研究了海冰边缘区声体积后向散射强度特性。结果表明:加拿大海盆海冰边缘区是声体积后向散射强度的明显过渡区。无冰海面(海冰密集度小于15%)海洋深层水的声体积后向散射强度明显大于密集海冰区域的海水(海冰密集度大于50%)。讨论了声体积后向散射强度与海冰融化之间的关系,造成融冰区声体积后向散射强度增大的原因是水下悬浮泥沙、浮游生物等悬浮物质增加。根据海冰密集海域的海水后向散射强度弱的特点,对北极下放式声学多普勒测流仪(LADCP)观测的设置提出建议。  相似文献   

The Beaufort Gyre variation and its impacts on the Canada Basin in 2003–2012   总被引：1，自引：1，他引：0  

钟文理  赵进平  史久新  曹勇 《海洋学报(英文版)》2015,34(7):19-31

The Beaufort Gyre (BG) was spun up in the last decade which is an important factor in regulating the variation of the upper ocean. The heat content and freshwater content of the upper ocean increased g...  相似文献   

加拿大海盆深层双扩散对流的观测分析   总被引：1，自引：0，他引：1  

谢玲玲  李明明  李敏 《海洋学报(英文版)》2015,34(11):71-79

The Canada Basin(CB) is the largest sub-basin in the Arctic, with the deepest abyssal plain of 3 850 m. The double-diffusive process is the possible passage through which the geothermal energy affects the above isolated deep waters. With the temperature-salinity-pressure observations in 2003, 500-m-thick transition layers and lower1 000-m-thick bottom homogenous layers were found below 2 400 m in the central deep CB. Staircases with downward-increasing temperature and salinity are prominent in the transition layers, suggesting the doublediffusive convection in deep CB. The interface of the stairs is about 10 m thick with 0.001–0.002°C temperature difference, while the thicknesses of the homogenous layers in the steps decrease upward from about 60 to 20 m.The density ratio in the deep central CB is generally smaller than 2, indicating stronger double-diffusive convection than that in the upper ocean of 200–400 m. The heat flux through the deepest staircases in the deep CB varies between 0.014 and 0.031 W/m2, which is one-two orders smaller than the upper double-diffusive heat flux,but comparable to the estimates of geothermal heat flux.  相似文献   

Review of shark legislation in Canada as a conservation tool     

《Marine Policy》2015

Sharks are threatened from overfishing due to their life cycle biology, and unsustainably high catch rates to supply fins for shark fin soup. Canada, a leader in shark conservation uses numerous legislative tools to help conserve sharks. These tools include international treaty obligations under the Northeastern Atlantic Fisheries Organization [NAFO] and the International Commission for the Conservation of Atlantic Tuna [ICCAT], as well as national and provincial legislation including the Fisheries Act, Pacific and Atlantic Fisheries Regulations, and Coastal Fisheries Protection Act. Through the use of these legislative tools Canada has successfully banned shark finning in its waters, and implemented closed seasons, gear restrictions, and species restrictions to help manage shark populations. However, Canada still allows the sale of shark fin products locally, and allows the exportation of shark fins internationally. In order for Canada to maintain its leadership status Canada must increase legislative protection of sharks by following international best practices, and ban the sale and exportation of shark fin products. This would ensure that Canada does not play a role in global supply or demand of shark fins. Doing so would strengthen Canada's position as a leader in shark conservation, and improve the legislation currently used as a conservation tool.  相似文献   

Patterns of controversy and consensus in German,Canadian, and US online news on climate change     

《Global Environmental Change》2020

Individual action and support for policy to tackle climate change have been linked to perceptions of political and scientific controversy and consensus concerning the issue. Recent media effects research indicates that presentation of agreement or conflict between actors’ opinions influences how audiences respond to news about climate change and policy. While some national case studies have investigated portrayals of actors’ positions on important questions regarding climate change in the media, they are largely absent from comparative research. This study addresses this gap by analysing portrayals of actor-issue-positions and the emerging patterns of controversy and consensus in German, Canadian, and US coverage. Studying a sample of occurrences of climate change-related issues (N = 902) in-depth, the results show German media present political consensus about the need to limit emissions and societal controversy about the efficacy of specific mitigation measures. Presenting mainly consensus, Canadian media report more on climate change’s impact, leaving aside the issue of efficacy. In the US, media emphasise political controversy — about the need to limit emissions and occasionally about climate change’s impact on humans. The findings, consistent with other recent publications, can best be explained by journalists selectively indexing of seemingly relevant actor-issue-positions.  相似文献   

‘They took our beads,it was a fair trade,get over it’: Settler colonial logics,racial hierarchies and material dominance in Canadian agriculture     

《Geoforum》2017

Canada is in a liminal space, with renewed struggles for and commitments to indigenous land and food sovereignty on one hand, and growing capital interest in land governance and agriculture on the other. While neoliberal capital increasingly accumulates land-based control, settler-farming communities still manage much of Canada’s arable land. This research draws on studies of settler colonialism, racial hierarchy and othering to connect the ideological with the material forces of settler colonialism and show how material dominance is maintained through colonial logics and racially ordered narratives. Through in-depth interviews, I investigate how white settler farmers perceive and construct two distinctly ‘othered’ groups: Indigenous peoples and migrant farmers and farm workers. Further, I show the disparate role of land and labour in constructing each group, and specifically, the cultural and material benefits of these constructions for land-based settler populations. At the same time, settler colonial structures and logics remain reciprocally coupled to political conditions. For instance, contemporary neoliberalism in Canadian agriculture modifies settler colonial structures to be sure. I argue, however, that political economic analyses of land and food production in Canada (such as corporate concentration, land grabbing and farm consolidation) ought to better integrate the systemic forces of settler colonialism that have conditioned land access in the first place. Of course, determining who is able to access land—and thus, who is able to grow food—continues to be a territorial struggle. Thus, in order to shift these conditions we ought to examine how those with access and control have acquired and maintained it.  相似文献   

The unintended consequences of regulatory complexity: The case of cruise tourism in Arctic Canada     

《Marine Policy》2017

The cruise tourism industry in the Canadian Arctic has the potential be an important contributor to the northern economy, but undue complexity in the permitting and regulatory process represents a major barrier to cruise operators and as a result seems to be limiting development potential and other cultural and educational benefits related to tourism in the region. Based on a set of interviews and follow-up interviews with Arctic cruise operators and government permit issuers (n=48), investigative phone calls (n=22), and follow-up verification calls (n=20+), analysis of the management system that currently governs cruise tourism in Arctic Canada is provided including recommendations for improvement. There are currently over 30 permits, approvals, and notification processes for cruise companies operating in the Canadian Arctic (collective called ‘permits and permissions'). Permits and permissions are required for vessel safety, environmental protection, gaining access to national parks, and visiting heritage and archaeological sites among others. They are issued by numerous agencies under multiple jurisdictions and statutes with no integration or organizing system. The result is a process that is overly complex, repetitious, and costly for operators. In comparison, the permitting systems in Greenland and Svalbard are more streamlined, causing some cruise companies to consider abandoning Canadian waters in favour of these less bureaucratic regions. Federal and territorial attention is required to create efficiencies in the cruise permitting process in Arctic Canada if the economic, socio-cultural, and educational benefits of the industry are to be fully realized.  相似文献