This article presents the initiation and implementation of a systematic scientific and political cooperation in the Arctic related to environmental pollution and climate change,with a special focus on the role of the ...This article presents the initiation and implementation of a systematic scientific and political cooperation in the Arctic related to environmental pollution and climate change,with a special focus on the role of the Arctic Monitoring and Assessment Programme(AMAP).The AMAP initiative has coordinated monitoring and assessments of environmental pollution across countries and parameters for the entire Arctic region.Starting from a first scientific assessment in 1998,AMAP's work has been fundamental in recognizing,understanding and addressing environmental and human health issues in the Arctic,including those of persistent organic pollutants(POPs),mercury,radioactivity,oil,acidification and climate change.These scientific results have contributed at local and international levels to define and take measures towards reducing the pollution not only in the Arctic,but of the whole globe,especially the contaminant exposure of indigenous and local communities with a traditional lifestyle.The results related to climate change have documented the rapid changes in the Arctic and the strong feedback between the Arctic and the rest of the world.The lessons learned from the work in the Arctic can be beneficial for other regions where contaminants may accumulate and affect local and indigenous peoples living in a traditional way,e.g.in the Himalayas.Global cooperation is indispensable in reducing the longrange transported pollution in the Arctic.展开更多
自动驾驶对地图提出的高精度、高鲜度、高覆盖等要求,现阶段难以同时满足,本文针对高、低精度数据空间位置差异但特征相似度极高的特点,提出了一种将低精度观测信息转化为高精地图要素置信度的方法,在不改变高精地图更新频率的前提下,...自动驾驶对地图提出的高精度、高鲜度、高覆盖等要求,现阶段难以同时满足,本文针对高、低精度数据空间位置差异但特征相似度极高的特点,提出了一种将低精度观测信息转化为高精地图要素置信度的方法,在不改变高精地图更新频率的前提下,完善地图安全策略。该方法采用矩形邻域二级匹配原理和匹配度测量模型,缩小匹配范围和量化匹配度,从而准确匹配目标;再根据特征向量分析,判断目标要素当前状态;采用计分规则将状态转化为地图要素置信度得分。该方法运用在多省高快速高精地图置信度更新试验中,仅用普通行车记录仪图片提供的观测信息,即可更新HD地图限速标牌存在置信度,还验证了由新的观测触发和由底图更新触发两种置信度更新模式。试验结果表明,观测冗余度和置信度保持率呈正相关,当观测冗余度约为15时,可达到60 d 80%以上目标要素保持高置信,且准确率超过96%。本文方法为高精地图鲜度与安全冲突提供了一种行之有效的解决方案,可促进高精地图安全应用策略进一步深化。展开更多
Hydrological studies for sizing urban drainage systems in the Amazon have often been neglected and little investigated for rainwater projects. This research evaluated alternative hydrological models used in sizing urb...Hydrological studies for sizing urban drainage systems in the Amazon have often been neglected and little investigated for rainwater projects. This research evaluated alternative hydrological models used in sizing urban drainage network projects in subdivisions with subsidized houses in the Amazonian region in Brazil. Statistical tests of these models were performed for both original and alternative scenarios. The methodological steps we conducted as follows: 1) evaluate the dimensioning of infrastructure project networks, considering two case studies contemplated by the Calha Norte Program (CNP) in the state of Amapá;2) test the statistical significance of the dimensioning of network diameters (α < 0.05), considering a) benchmark project (MD or M1) approved by the Ministry of Defense;b) determination of concentration time (C<sub>t</sub>) and rainfall intensity-duration-frequency (IDF) relationships, as well as estimating diameters using alternative models. The results indicated a significant influence on the diameters of the projected rainfall networks (p < 0.05), suggesting that alternative models predicted more unfavorable flow peaks than the original model. We conclude that the benchmarking model underestimated the diameter of the project compared to alternative models, which means the optimized C<sub>t</sub> parameter significantly impacts dimensioning estimates in rainwater projects in these Amazonian municipalities. This suggests that underestimated parameters in MD may cause inefficiency in the stormwater system projects in future similar scenarios.展开更多
Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This st...Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This study relates litter levels to water holding capacity and effective water retention among forest fragments under different passive restoration stages:46,11,and 8 years to better understand litter hydrological functions in the Cerrado.Water retention capacity and effective water retention capacity of litters(unstructured materials,branches and leaves)in the field were monitored on a monthly basis.Total litter accumulation at 46 years was significantly higher than that of the other succession stages.Unstructured litter mass was significantly higher than that of leaves and branches.The 46-year stage had the highest water holding capacity in the leaf fraction,followed by unstructured material and branches.Although the water holding capacity was lower in the oldest resto-ration,this site showed the highest efficiency under field conditions.The process was quickly reestablished,as the 11-year restoration showed results closer to that for the 46-year stage in comparison to the area at 8 years.Thus,passive restoration plays a key role in soil water mainte-nance due to the influence of litter in Cerrado savannas.Deforestation and the imminent need of restoring degraded sites,highlight the need for further studies focused on bet-ter understanding of the process of forest restoration and its temporal effect on soil water recovery dynamics.展开更多
基金Katrin Vorkamp acknowledges funding from the Danish Environmental Protection AgencyRoland Kallenborn acknowledges funding from the Norwegian University of Life Sciences(NMBU)and the University of the Arctic(UArctic).
文摘This article presents the initiation and implementation of a systematic scientific and political cooperation in the Arctic related to environmental pollution and climate change,with a special focus on the role of the Arctic Monitoring and Assessment Programme(AMAP).The AMAP initiative has coordinated monitoring and assessments of environmental pollution across countries and parameters for the entire Arctic region.Starting from a first scientific assessment in 1998,AMAP's work has been fundamental in recognizing,understanding and addressing environmental and human health issues in the Arctic,including those of persistent organic pollutants(POPs),mercury,radioactivity,oil,acidification and climate change.These scientific results have contributed at local and international levels to define and take measures towards reducing the pollution not only in the Arctic,but of the whole globe,especially the contaminant exposure of indigenous and local communities with a traditional lifestyle.The results related to climate change have documented the rapid changes in the Arctic and the strong feedback between the Arctic and the rest of the world.The lessons learned from the work in the Arctic can be beneficial for other regions where contaminants may accumulate and affect local and indigenous peoples living in a traditional way,e.g.in the Himalayas.Global cooperation is indispensable in reducing the longrange transported pollution in the Arctic.
文摘自动驾驶对地图提出的高精度、高鲜度、高覆盖等要求,现阶段难以同时满足,本文针对高、低精度数据空间位置差异但特征相似度极高的特点,提出了一种将低精度观测信息转化为高精地图要素置信度的方法,在不改变高精地图更新频率的前提下,完善地图安全策略。该方法采用矩形邻域二级匹配原理和匹配度测量模型,缩小匹配范围和量化匹配度,从而准确匹配目标;再根据特征向量分析,判断目标要素当前状态;采用计分规则将状态转化为地图要素置信度得分。该方法运用在多省高快速高精地图置信度更新试验中,仅用普通行车记录仪图片提供的观测信息,即可更新HD地图限速标牌存在置信度,还验证了由新的观测触发和由底图更新触发两种置信度更新模式。试验结果表明,观测冗余度和置信度保持率呈正相关,当观测冗余度约为15时,可达到60 d 80%以上目标要素保持高置信,且准确率超过96%。本文方法为高精地图鲜度与安全冲突提供了一种行之有效的解决方案,可促进高精地图安全应用策略进一步深化。
文摘Hydrological studies for sizing urban drainage systems in the Amazon have often been neglected and little investigated for rainwater projects. This research evaluated alternative hydrological models used in sizing urban drainage network projects in subdivisions with subsidized houses in the Amazonian region in Brazil. Statistical tests of these models were performed for both original and alternative scenarios. The methodological steps we conducted as follows: 1) evaluate the dimensioning of infrastructure project networks, considering two case studies contemplated by the Calha Norte Program (CNP) in the state of Amapá;2) test the statistical significance of the dimensioning of network diameters (α < 0.05), considering a) benchmark project (MD or M1) approved by the Ministry of Defense;b) determination of concentration time (C<sub>t</sub>) and rainfall intensity-duration-frequency (IDF) relationships, as well as estimating diameters using alternative models. The results indicated a significant influence on the diameters of the projected rainfall networks (p < 0.05), suggesting that alternative models predicted more unfavorable flow peaks than the original model. We conclude that the benchmarking model underestimated the diameter of the project compared to alternative models, which means the optimized C<sub>t</sub> parameter significantly impacts dimensioning estimates in rainwater projects in these Amazonian municipalities. This suggests that underestimated parameters in MD may cause inefficiency in the stormwater system projects in future similar scenarios.
基金This work is supported by the International Paper Co.from Brazil(Process 23112.000670/2015-59)by Brazilian National Council for Scientific and Technological Development(CNPq)in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior-Brasil(CAPES)-Finance Code 001.
文摘Although forests play important roles in the hydrological cycle,there is little information that relates the water retention capacity of litter in areas under passive restoration,especially in Cerrado savannas.This study relates litter levels to water holding capacity and effective water retention among forest fragments under different passive restoration stages:46,11,and 8 years to better understand litter hydrological functions in the Cerrado.Water retention capacity and effective water retention capacity of litters(unstructured materials,branches and leaves)in the field were monitored on a monthly basis.Total litter accumulation at 46 years was significantly higher than that of the other succession stages.Unstructured litter mass was significantly higher than that of leaves and branches.The 46-year stage had the highest water holding capacity in the leaf fraction,followed by unstructured material and branches.Although the water holding capacity was lower in the oldest resto-ration,this site showed the highest efficiency under field conditions.The process was quickly reestablished,as the 11-year restoration showed results closer to that for the 46-year stage in comparison to the area at 8 years.Thus,passive restoration plays a key role in soil water mainte-nance due to the influence of litter in Cerrado savannas.Deforestation and the imminent need of restoring degraded sites,highlight the need for further studies focused on bet-ter understanding of the process of forest restoration and its temporal effect on soil water recovery dynamics.
