中国北极科技外交论析

鉴于北极特殊的地理位置和自然环境,北极科技外交往往是各国参与北极事务的起点和实现北极利益的先导。中国也概不能外,北极科技外交对保障北极科研装备、提高北极认识水平和促进北极资源开发等都具有重要意义。回溯中国参与北极事务的历程,北极科技外交是其中的主要线索和核心内容,现已取得了一些成绩。但作为域外国家和发展中国家,中国北极科技外交还面临着缺乏顶层设计、政策和资金支持不足以及若干国际因素的掣肘。对此,中国应通过充分发挥政府的主导作用、强化和完善运行机制、扩展北极科技外交的广度和深度等加以改进。     

巴芬湾西部和格陵兰岛东部大气经向热量输送协同变化对夏季北极海冰的影响

利用欧洲中心气候再分析资料和美国国家冰雪数据中心北极海冰面积资料,分析了夏季北极海冰面积与前期大气经向热量输送年际变化的联系。结果表明：6月北半球中高纬大气的经向热量输送以瞬变热量形式为主,其中巴芬湾西部（B区）和格陵兰岛东部（G区）是瞬变热量向极区传输的两个通道,二者之间存在反位相的协同变化,且这种协同变化与夏季北极海冰面积变化密切相关。可能的机制为：6月,AD、AO和NAO三种北极大气环流型能够引起巴芬湾西部和格陵兰岛东部瞬变热量输送的协同变化,这种协同变化通过涡旋动力作用激发夏季极区大气表现为AD异常,同时影响途经区域的气温,从而通过热动力作用影响夏季北极海冰。将向极区输送的热量称为暖输送,从极区输出的热量为冷输送,则上述两个区域的瞬变热量协同输送可分为三种情况：B暖G冷、B冷G暖、B和G均冷,而B和G均暖的情况十分罕见。当B区向极区输入、G区输出热量时,有利于太平洋扇区和喀拉海的海冰偏少;当G区输入、B区输出热量时,利于喀拉海和拉普捷夫海海冰偏少;当B区和G区均输出热量时,利于波佛特海南部、喀拉海和拉普捷夫海海冰偏多,反之则相反。     

微型近红外光谱仪测量北极积雪覆盖海冰内部太阳辐照度可行性研究

The extremely low temperature, high humidity and limited power supply pose considerable challenges when using spectrometers within the Arctic sea ice. The feasibility of using a miniature low-power near-infrared spectrometer module to measure solar radiation in Arctic sea ice environments was investigated in this study.Temperature and integration time dependences of the spectrometer module were examined over the entire target operating range of –50℃ to 30℃, well below the specified operating range of this spectrometer. Using these observations, a dark output prediction model was developed to represent dark output as a function of temperature and integration time. Temperature-induced biases in the saturation output and linear operating range of the spectrometer were also determined. Temperature and integration time dependences of the signal output were evaluated. Two signal output correction models were developed and compared, to convert the signal output at any temperature within the operating temperature range and integration time to that measured at the reference temperature and integration time. The overall performance of the spectrometer was evaluated by integrating it into a refined fiber optic spectrometry system and measuring solar irradiance distribution in the ice cover with thickness of 1.85 m in the Arctic during the 9th Chinese National Arctic Research Expedition. The general shape of the measured solar irradiance above the snow surface agreed well with that measured by other commercial oceanographic spectroradiometers. The measured optical properties of the sea ice were generally comparable to those of similar ice measured using other instruments. This approach provides a general framework for assessing the feasibility of using spectrometers for applications in cold environments.     

北极冰下水声通信中改进的最小均方/四次方直接自适应均衡器

本文提出了一种适用于北极冰下水声通信的最小均方/四次方直接自适应均衡器（LMS/F-DAE）。它能处理基带复信号,与LMS相比,具有更好的均衡效果。考虑到均衡器的稀疏特性,在其代价函数中加入自适应范数（AN）作为约束。它能根据均衡器系数的大小自适应变化：对于小系数,此约束项存在以加快收敛速度;对于大系数,此约束项不存在以减小均衡误差。利用第九次中国北极科学考察得到的实验数据验证AN-LMS/F-DAE的性能。结果表明,与传统的LMS/F-DAE相比,AN-LMS/F-DAE能提升均衡器的稀疏性且均衡性能更优。     

2010-2018年北极夏季中国北极科学考察航行期间被动微波遥感海冰密集度与船基目视观测资料的比较

为了更有效地将卫星数据应用于北极航行导航,被动微波（PM）产品的海冰密集度（SIC）与从中国北极科学考察中收集到的船基目视观测（OBS）资料进行了比较。在2010、2012、2014、2016和2018年的北极夏季总共收集了3667组目测数据。PM SIC取自基于SSMIS传感器的NASA-Team（NT）、Bootstrap（BT）以及Climate Data Record（CDR）算法和基于AMSR-E/AMSR-2传感器的BT、enhanced NT（NT2）以及ARTIST Sea Ice（ASI）算法。使用PM SIC的日算术平均值和OBS SIC的日加权平均值进行比较。比较了PM SIC和OBS SIC之间的相关系数,偏差和均方根偏差,包括总体趋势以及在轻度/普通/严重冰况下的情况。使用OBS数据,浮冰尺寸和冰厚对不同PM产品SIC反演的影响可以通过计算浮冰尺寸编码和冰厚的日加权平均值来评估。我们的结果显示相关系数的范围为0.89（AMSR-E/AMSR-2 NT2）到0.95（SSMIS NT）,偏差的范围为-3.96%（SSMIS NT）到12.05%（AMSR-E/AMSR-2）,均方根偏差的范围为10.81%（SSMIS NT）到20.15%（AMSR-E/AMSR-2 NT2）。浮冰尺寸对PM产品的SIC反演有显著的影响,大多数PM产品倾向于在小浮冰尺寸情况下低估SIC,而在大浮冰尺寸情况下高估SIC。超过30 cm的冰厚对于PM产品的SIC反演没有明显影响。总体来看,在北极夏季,SSMIS NT SIC与OBS SIC之间有着最好的一致性,而AMSR-E/AMSR-2 NT2 SIC与OBS SIC的一致性最差。     

秦岭—淮河南北供暖格局变化及其影响因素

基于秦岭—淮河南北及其周边196个气象站点观测资料,构建实际和动态供暖指数,对中国南北过渡带供暖格局变化进行分析,并探讨冬季北极涛动（AO）异常与供暖效率的响应关系。结果表明：① 固定供暖策略下,1960-2016年秦岭—淮河南北实际供暖能耗偏高,呈现“南多北少,西低东高”的变化特征,且低纬度地区供暖需求下降信号早于高纬度;② 对比区域变暖前后,秦岭—淮河南北冬季供暖能耗1960-1990年和1990-2016年两阶段空间特征,发现“整体南高北低,北部东高西低”的格局并未发生变化,供暖南北波动界线依然维持在秦岭山脉—淮河平原中部;③ AO强弱波动与区域冬季供暖能耗具有明显的时空响应关系,是影响中国南北过渡带供暖格局变化的重要因素。当AO负相位时,除四川盆地和巫山山区之外,秦岭—淮河南北其他区域实际供暖能耗明显下降,特别是淮河平原和长江下游的过渡地带响应尤为明显,未来应该有针对性制定气候适应对策。     

Transition Periods Between Sea Ice Concentration and Sea Surface Air Temperature in the Arctic Revealed by an Abnormal Running Correlation

This study used the synthetic running correlation coefficient calculation method to calculate the running correlation coefficients between the daily sea ice concentration(SIC) and sea surface air temperature(SSAT) in the Beaufort-Chukchi-East Siberian-Laptev Sea(BCEL Sea), Kara Sea and southern Chukchi Sea, with an aim to understand and measure the seasonally occurring changes in the Arctic climate system. The similarities and differences among these three regions were also discussed. There are periods in spring and autumn when the changes in SIC and SSAT are not synchronized, which is a result of the seasonally occurring variation in the climate system. These periods are referred to as transition periods. Spring transition periods can be found in all three regions, and the start and end dates of these periods have advancing trends. The multiyear average duration of the spring transition periods in the BCEL Sea, Kara Sea and southern Chukchi Sea is 74 days, 57 days and 34 days, respectively. In autumn, transition periods exist in only the southern Chukchi Sea, with a multiyear average duration of only 16 days. Moreover, in the Kara Sea, positive correlation events can be found in some years, which are caused by weather time scale processes.     

北极地区地缘关系研究综述

论文检索了科学引文索引(Web of Science)和中国知网(CNKI)中北极地区地缘关系的相关文献,借助CiteSpace文献分析软件的关键词共现分析功能,系统综述了2000年以来国内外关于北极地区地缘关系的研究重点。从研究内容上看,国外研究主要关注主权政治、航道利用、资源管理和原住民权益等主体性议题,而国内则着重关注地缘政治、航道交通、资源经济和地区治理等参与性议题。就研究方法上看,国内外研究中定性与定量方法兼具,但仍以定性方法和描述性方法为主。随着北极地区的发展,研究方法和研究视角有待丰富,研究领域和研究深度亟需进一步拓展和加强。北极地区具有重要的战略意义,未来应结合现代技术,借鉴国际上的地区发展理论,开展北极地区的可持续发展研究和中国参与研究,并构建新时代北极地区地缘环境理论。     

A stochastic method for the prediction of icebreaker bow extreme stresses

It is well established that the ship-ice interaction process is quite complex and associated ice loads on the icebreaker hull is a stochastic process. Obviously, novel accurate statistical methods and models should be developed and applied to estimate extreme bow stresses.This paper studies icebreaker bow stresses based on measured distribution of ice thickness in the Arctic Ocean on the way to and from the North Pole. Since the vessel route was carefully selected searching for easier ice conditions, the Arctic Ocean crossing was not a straight linear but a meandering path. Thus, the specific ship route data was biased with respect to general ice statistics in the region, but true with respect to the route specific ice data encountered by a ship navigating in that region. Therefore the route specific ice thickness data is directly needed for ship design and navigation analysis. It is assumed that captains are competent and knowledgeable, and therefore will select a route that provides the most favourable ice conditions.This paper contributes to study of the newest Chinese self-designed polar icebreaker, serving the purpose of enhancing icebreaker operational reliability. Finite Element Method software package ANSYS/LS-DYNA has been employed to simulate bow stress pattern for a particular icebreaker operating in the Arctic Ocean. Extreme bow stresses were estimated using Naess-Gaidai method. The latter is a first application of Naess-Gaidai method to a distribution with lower bound. Thus this paper aims at introducing an efficient method of estimating route-specific icebreaker extreme bow stresses.     

北极冰下声传播特性实验研究

通过2017年8月6日在北极海域开展的一次声传播实验,开展了冰下声传播特性实验研究。结合Burke-Twersky （BT）散射模型与射线模型,分析了冰下声传播的多途到达结构,研究了接收声强变化规律,解释了接收声强在30 min内衰减20 dB的现象,分析了接收信号的时间相关性,探讨了接收信号相关性较低的原因。实验结果表明,表面接收信号主要由小角度多次反转反射声线、一次海底反射声线和二次海底反射声线依次构成,表面声道到达信号显著强于海底反射信号。试验冰站在试验期间的运动导致了声传播信号强度和相关性的迅速衰减,并通过仿真得到了验证。