南极冰盖边缘近250年来气温变化的地域分布特征

通过对南极冰盖边缘17支浅冰芯氧同位素的对比研究,揭示了整个南极冰盖边缘近50年来、150年来和250年来气温变化的地域分布特征。近50年来,南极冰盖边缘的氧同位素温度有的呈现上升趋势,有的呈现下降趋势,但气温变化的地域规律性不强;近150年来,南极冰盖边缘的同位素温度的升高和降低趋势大致呈现出一种交替分布的态势;近250年来,南极冰盖边缘所有的氧同位素温度都记录了小冰期的降温事件。气温的这种地域分布特征可能是南大洋独特的环流形式--环南极波 (ACW) --在特殊地形 (如大的冰盆) 影响下,在南极冰盖边缘的表现形式,并且随着时间尺度的不同,南大洋独特的环流形式 、ACW和地形的影响强度各异。     

冰对海洋结构的临界力

将海冰作为浮在海水上的半无限大的平板,将海水的浮力作为弹性地基,把海冰与桩柱的作用力看作为集中力,海冰的破坏看作为集中力作用下的平板失稳问题,给出了冰排在集中力作用下的压曲微分方程,数值计算结果给出了海冰在桩柱作用下的临界载荷的表达式,为海洋结构的设计提供了依据.     

冰芯中含硫有机物——MSA的研究

冰芯中MSA含量具有季节性变化规律, 夏季出现峰值, 冬季为低值. 一定地区MSA高含量和海冰扩展存在相关关系, 有的地区MSA含量还与ENSO事件有一定相关性. MSA/ nssSO₄^2-比值对温度和来源区域都有很好的指示意义. 在一定的条件下冰芯中的MSA可以发生迁移和再定位, 由此也对利用冰芯MSA含量反演当时大气气溶胶中成分含量的准确性提出了质疑. 总结了近几年来冰芯研究中的MSA和_nssSO₄^2-, 特别是极地冰芯MSA的研究进展, 并对利用MSA来研究全球变化的前景进行了预测和展望.     

荧光法在赤潮图像分析中应用

为解决探测和分析包含复杂背景沉淀物样品中的微藻的问题,利用微藻类在一定波长光的照射下会产生荧光的特性,对裸甲藻等多种藻类进行荧光实验处理。并在荧光实验的基础上进行阈值分割,轮廓和纹理分析及图像识别等后继图像处理,实验证明,荧光法可以有效的去除背景噪声,使得后继的图像处理容易和有效,从而解决了探测和分析包含复杂背景的沉淀物样品中微藻的问题。     

小冰期气候的研究进展

小冰期是近2ka来的一个重要气候事件,又是目前全球变暖的背景事件,已成为古气候和古环境研究的热点。对此,科学工作者已经做了大量的研究。本文广泛综合前人研究的成果,介绍了小冰期的概况,认为1450-1890年是小冰期的时限,在此期间有三次冷期和两次暖期。冷期发生在1450-1510年、1560-1690年和1790-1890年,其中第二次冷期表现最甚;暖期发生在1510-1560年和1690-1790年。太阳活动和火山活动是小冰期气候变化的主要因素。并重点从冰芯、树轮、湖泊沉积、历史文献和沙漠地层等方面综述了近年来国内外对小冰期气候变化的研究现状。     

Characterization of the summer pack ice biotic community of Canada Basin

1Introduction Theoccurrenceofseaiceisoneofthemostim- portantcharacteristicsoftheArcticOcean.Mostofsea iceispackice.Thepermanentpackiceareaisaswide as7.8×106km2,morethanhalfofthemaximumice coveringarea.Studieshaveshownthatthepackicebi- oticcommunityplaysasignificantroleinthearctic marineecosystem.Previousstudieshaveshownthat highprimaryproductionoccursinthearcticseasand theprimaryproductioninseaicecontributesabout onefourthofthetotal(Legendreetal.,1992;Chenet al.,2002).Studiesinrecentyearsh…     

海藻提取物在当归上的应用效果

用海藻提取物在中草药当归(angelica)上进行喷施效果试验。结果表明,在当归生长期对其施用不同浓度的海藻提取物均可明显增加当归产量,提高等级,降低病级,并对当归的生长发育有明显的促进作用,其中以500倍稀释液的海藻提取物处理效果最为明显,其隶属函数值和最大．对当归的综合效应最为明显。该试验为海藻提取物的综合利用提供了理论依据。     

Research of Influence of Aniline on the Growth of Ocean Algae

This article discusses the interaction of aniline and ocean algae based on the standard appraisal method of chemical medicine for algae toxicity. It is showed by experimental results that aniline has pretty toxic effects on algae. Suspended substances in water can offset some effects of aniline. It also discusses the dynamic constant of first order degradation reaction rate of algae on aniline from the point of view of chemical dynamics.     

An Isentropic Mass Circulation View on the Extreme Cold Events in the 2020/21 Winter

Three extreme cold events successively occurred across East Asia and North America in the 2020/21 winter.This study investigates the underlying mechanisms of these record-breaking persistent cold events from the isentropic mass circulation(IMC)perspective.Results show that the midlatitude cold surface temperature anomalies always co-occurred with the high-latitude warm anomalies,and this was closely related to the strengthening of the low-level equatorward cold air branch of the IMC,particularly along the climatological cold air routes over East Asia and North America.Specifically,the two cold surges over East Asia in early winter were results of intensification of cold air transport there,influenced by the Arctic sea ice loss in autumn.The weakened cold air transport over North America associated with warmer northeastern Pacific sea surface temperatures(SSTs)explained the concurrent anomalous warmth there.This enhanced a wavenumber-1 pattern and upward wave propagation,inducing a simultaneous and long-lasting stronger poleward warm air branch(WB)of the IMC in the stratosphere and hence a displacement-type Stratospheric Sudden Warming(SSW)event on 4 January.The WB-induced increase in the air mass transported into the polar stratosphere was followed by intensification of the equatorward cold branch,hence promoting the occurrence of two extreme cold events respectively over East Asia in the beginning of January and over North America in February.Results do not yield a robust direct linkage from La Ni?a to the SSW event,IMC changes,and cold events,though the extratropical warm SSTs are found to contribute to the February cold surge in North America.     

Till kinematics in the Stargard drumlin field,NW Poland constrained by microstructural proxies

Deciphering the relationships between streamlined subglacial landforms and deposits therein helps to constrain the dynamics of past ice sheets. Here we present microstructural analyses of till from the largest drumlin field in the North European Lowland generated by a major palaeo-ice stream of the Scandinavian Ice Sheet. Data derived from thin sections and X-ray microtomography (μCT) reveal multiple microstructures including microshears, circular structures, grain stacks and crushed grains. Long axes of micro-clasts measured in thin sections are directionally clustered and have low, down-ice-oriented dip angles. Some samples reveal subordinate clustering oriented at high angles to the main direction. The μCT data show low clustering strengths of clasts and no systematic fabric pattern in the entire set of samples. There is no correspondence between the clast orientations and the directions of drumlin long axes, suggesting that the till is antecedent in relation to the drumlin-shaping process. The observations indicate spatially and temporally variable, shallow-seated brittle and ductile deformation controlled by porewater pressure fluctuations and generated time-transgressively parallel to till accretion. Consistently with previous studies, the data suggest that the Stargard drumlins are erosional remnants of a pre-existing terrain shaped by material removal from the inter-drumlin areas.