Psychological changes of fifteen Chinese Antarctic Research Expedition members

ＰｓｙｃｈｏｌｏｇｉｃａｌｃｈａｎｇｅｓｏｆｆｉｆｔｅｅｎＣｈｉｎｅｓｅＡｎｔａｒｃｔｉｃＲｅｓｅａｒｃｈＥｘｐｅｄｉｔｉｏｎｍｅｍｂｅｒｓＸｕｅＺｕｏｈｏｎｇ（薛祚）（ＤｅｐａｒｔｍｅｎｔｏｆＰｓｙｃｈｏｌｏｇｙ．ＰｅｋｉｎｇＵｎｄｅｒｓｉｔｙ，Ｂ...     

Studies on the plasma tryptophan and urinary 5-hydroxy-3-indoleacetic acid in expedition members residing in Antarctica

Ｓｔｕｄｉｅｓｏｎｔｈｅｐｌａｓｍａｔｒｙｐｔｏｐｈａｎａｎｄｕｒｉｎａｒｙ５┐ｈｙｄｒｏｘｙ┐３┐ｉｎｄｏｌｅａｃｅｔｉｃａｃｉｄｉｎｅｘｐｅｄｉｔｉｏｎｍｅｍｂｅｒｓｒｅｓｉｄｉｎｇｉｎＡｎｔａｒｃｔｉ┐ｃａＸｕＳｈｕｈｕａｉ（许澍淮）ａｎｄＸ...     

A study on cosmic dust particles in Antarctic ice，snow and non－Antarctic region and their origins

ＡｓｔｕｄｙｏｎｃｏｓｍｉｃｄｕｓｔｐａｒｔｉｃｌｅｓｉｎＡｎｔａｒｃｔｉｃｉｃｅ，ｓｎｏｗａｎｄｎｏｎ－ＡｎｔａｒｃｔｉｃｒｅｇｉｏｎａｎｄｔｈｅｉｒｏｒｉｇｉｎｓＷａｎｇＤａｏｄｅ（王道德）ａｎｄＤａｉＣｈｅｎｇｄａ（戴诚达）（Ｇｕａｎｇｚｈｏｕ...     

A comparative study on the ionospheric current systems in the Antarctic and Arctic regions

ＡｃｏｍｐａｒａｔｉｖｅｓｔｕｄｙｏｎｔｈｅｉｏｎｏｓｐｈｅｒｉｃｃｕｒｒｅｎｔｓｙｓｔｅｍｓｉｎｔｈｅＡｎｔａｒｃｔｉｃａｎｄＡｒｃｔｉｃｒｅｇｉｏｎｓＸｕＷｅｎｙａｏ（徐文耀）（ＩｎｓｔｉｔｕｔｅｏｆＧｅｏｐｈｙｓｉｃｓ，ＡｃａｄｅｍｉａＳｉｎｉ...     

A condition for the formation of Antarctic Bottom Water in Prydz Bay， Antarctica

ＡｃｏｎｄｉｔｉｏｎｆｏｒｔｈｅｆｏｒｍａｔｉｏｎｏｆＡｎｔａｒｃｔｉｃＢｏｔｔｏｍＷａｔｅｒｉｎＰｒｙｄｚＢａｙ，ＡｎｔａｒｃｔｉｃａＬｉａｎｇＸｉａｎｇｓａｎ（梁湘三）（ＳｅｃｏｎｄＩｎｓｔｉｔｕｔｅｏｆＯｃｅａｎｏｇｒａｐｈｙ，ＳＯＡ，Ｈａｎｇ...     

A group velocity of seismic love surface wave and lithosphere structure in Antarctic Peninsula

ＡｇｒｏｕｐｖｅｌｏｃｉｔｙｏｆｓｅｉｓｍｉｃｌｏｖｅｓｕｒｆａｃｅａｖｅａｎｄｌｉｔｈｏｓｐｈｅｒｅｓｔｒｕｃｔｕｒｅｉｎＡｎｔａｒｃｔｉｃＰｅｎｉｎｓｕｌａTX＠束沛镒＠胡家富＠滕吉文＠张中杰＠焦承民Ａｇｒｏｕｐｖｅｌｏｃｉｔｙｏｆｓｅｉｓｍｉｃｌｏｖｅ...     

Filtration rate and ingestion rate of Antarctic krill measured in vitro and in situ

ＦｉｌｔｒａｔｉｏｎｒａｔｅａｎｄｉｎｇｅｓｔｉｏｎｒａｔｅｏｆＡｎｔａｒｃｔｉｃｋｒｉｌｌｍｅａｓｕｒｅｄｉｎｖｉｔｒｏａｎｄｉｎｓｉｔｕＺｈｏｎｇＸｕｅｆｅｎｇ（仲学锋）ａｎｄＷａｎｇＲｏｎｇ（王荣）（ＩｎｓｔｉｔｕｔｅｏｆＯｃｅａｎｏｌｏｇｙ，...     

Research on the changes of China's fruit planting distribution and its influence effect: Based on the perspective of price changes of rural labor北大核心

在推导中国水果产业布局演变的影响模型基础上,以1985—2019年中国22个水果主产省为研究对象,探讨农业劳动价格、非农劳动价格和工资收入占比对我国水果产业布局演变的影响效应。结果表明:农业劳动价格、非农劳动价格和工资收入占比的提高对东部水果种植产生替代效应,造成东部各省区水果种植面积减少或增幅不明显,比重下降;农业劳动价格、非农劳动价格和工资收入占比对中部水果种植的影响具有省际异质性,产生的替代效应和收入效应相互抵消,导致中部整体水果种植比重无显著变化;西北、西南地区较低的农业劳动工价和非农劳动价格使其具有劳动成本比较优势,工资收入占比提高产生收入效应,使西北、西南地区水果种植面积大幅增加,比重上升,促成我国水果种植布局“西移内扩”。因此,优化水果产业布局要解决水果适宜区农村劳动力价格过高和非适宜区农村劳动力价格过低等问题。     

Potential control of climatic changes on flood events in the Yangtze Delta during 1100-2002

1IntroductionClimatic warming, flood hazards and their impacts on human society receive increasing attention from governments and public (IPCC, 2001). During recent years, agriculture, industry and even the development of the whole national economy suffered tremendous loss resulted from flood and waterlogging hazards.The Yangtze Delta is densely populated and economically developed. Monsoonal climate, geomorphologic characteristics and human activities inflict floods and water-logging hazar…     

The effect of environmental factors on spatial variability in land use change in the high-sediment region of China’s Loess Plateau

In areas with topographic heterogeneity, land use change is spatially variable and influenced by climate, soil properties, and topography. To better understand this variability in the high-sediment region of the Loess Plateau in which soil loss is most severe and sediment diameter is larger than in other regions of the plateau, this study builds some indicators to identify the characteristics of land use change and then analyze the spatial variability as it is affected by climate, soil property, and topography. We build two indicators, a land use change intensity index and a vegetation change index, to characterize the intensity of land use change, and the degree of vegetation restoration, respectively. Based on a subsection mean method, the two indicators are then used to assess the spatial variability of land use change affected by climatic, edaphic, and topographic elements. The results indicate that： 1） Land use changed significantly in the period 1998-2010. The total area experiencing land use change was 42,302 km2, accounting for 22.57%of the study area. High-coverage grassland, other woodland, and forest increased significantly, while low-coverage grassland and farmland decreased in 2010 compared with 1998.2） Land use change occurred primarily west of the Yellow River, between 35 and 38 degrees north latitude. The four transformation types, including （a） low-coverage grassland to medium-coverage grassland, （b） medium-coverage grassland to high-coverage grassland, （c） farmland to other woodland, and （d） farmland to medium-coverage grassland, were the primary types of land use change, together constituting 60% of the area experiencing land use change. 3） The spatial variability of land use change was significantly affected by properties of dryness/wetness, soil conditions and slope gradient. In general, land use changed dramatically in semi-arid regions, remained relatively stable in arid regions, changed significantly in clay-rich soil, remained relatively stable in clay-poor soil, changed dramatically in steeper slopes, and remained relatively stable in tablelands and low-lying regions. The increase in vegetation coincided with increasing changes in land use for each physical element. These findings allow for an evaluation of the effect of the Grain to Green Program, and are applicable to the design of soil and water conservation projects on the Loess Plateau of China.     

Psychological selection methods for winter over members of the Chinese National Antarctic Research Expedition

Ｐｓｙｃｈｏｌｏｇｉｃａｌｓｅｌｅｃｔｉｏｎｍｅｔｈｏｄｓｆｏｒｗｉｎｔｅｒ┐ｏｖｅｒｍｅｍｂｅｒｓｏｆｔｈｅＣｈｉｎｅｓｅＮａｔｉｏｎａｌＡｎｔａｒｃｔｉｃＲｅｓｅａｒｃｈＥｘｐｅｄｉｔｉｏｎＸｕｅＺｕｏｈｏｎｇ（薛祚●）ａｎｄＺｈａｎｇＹａｎ（张...     

Late Holocene changes in cyanobacterial community structure in maritime Antarctic lakes

Despite the dominance of cyanobacteria in polar freshwater aquatic ecosystems, little is known about their past biodiversity and response to climate and environmental changes. We explored the use of light microscopy of microfossils, high performance liquid chromatography of the fossil pigment composition and denaturing gradient gel electrophoresis of fossil 16S rRNA genes to study past and present-day differences in cyanobacterial community structure in response to climate changes in two adjacent maritime Antarctic lakes with contrasting depths (4 and 26 m) and light climates. Light microscopy was of limited use because of degradation of cell structures. Fossil cyanobacterial pigment concentrations were below the detection limits of our method in several sediment samples in the deep lake, but abundant and diverse in the sediment core from the shallow pond, probably as a consequence of increased light availability and/or a more diverse and abundant benthic cyanobacterial flora. Total carotenoid and chlorophyll concentrations were highest in both lakes between ca. 2,950 and 1,800 cal yr BP, which coincides with the late Holocene climate optimum recognised elsewhere in maritime Antarctica. Cyanobacterial molecular diversity was higher in the top few centimeters of the sediments in both lakes. In deeper sediments, the taxonomic turnover of cyanobacteria appeared to be relatively small in response to past climate anomalies in both lakes, underscoring the broad tolerance of cyanobacteria to environmental variability. This, however, may in part be explained by the low taxonomic resolution obtained with the relatively conserved 16S rRNA gene and/or the preferential preservation of particular taxa. Our results highlight the potential of fossil DNA in lake sediments to study colonization and succession dynamics of lacustrine cyanobacteria and warrant further investigation of the factors that affect preservation of cyanobacterial DNA.     

Meltwater production in Antarctic blue-ice areas: sensitivity to changes in atmospheric forcing

In the near coastal regions of Dronning Maud Land, Antarctica, below-surface ice-melt in blue-ice areas has been observed. The low scattering coefficients of the large-grained blue-ice allow penetration of solar radiation, thus providing an energy source below the ice surface. The sub-surface meltwater is significant enough to show up on remote-sensing imagery in the form of ice-covered lakes. Adjacent snow-accumulation areas have much higher scattering coefficients and consequently limit solar radiation penetration in these regions. These snow and ice surfaces are generally below freezing, and little surface melting occurs. To assess the response of these melt features to changes in atmospheric forcings such as cloudiness, air temperature, and snow accumulation, a physically-based model of the coupled atmosphere, radiation, snow, and blue-ice system has been developed. The model consists of a heat transfer equation with a spectrally-dependent solar-radiation source term. The penetration of radiation into the snow and blue-ice depends on the surface albedo, and the snow and blue-ice grain size and density. Model simulations show that ice melt occurring in this area is sensitive to potential variations in atmospheric forcing. Under certain conditions more traditional surface melting occurs and, under other conditions, the existing melt processes can be shut down completely. In light of the sensitivity of this system to variations in atmospheric forcing, and the ability to view melt-related features using remote sensing, a tool exists to efficiently monitor variations in Antarctic coastal climate.     

Late Holocene changes in ultraviolet radiation penetration recorded in an East Antarctic lake

Late Holocene changes in the ultraviolet radiation (UVR) penetration in a lake in the Larsemann Hills (East Antarctica) were reconstructed using sediment core proxies based on fossil pigments (scytonemins and its derivatives) and siliceous microfossils. The influence of changes in lake depth on the UVR proxy was excluded by applying a correction, based on the non-linear relation between modern scytonemin concentrations and lake depth in a regional reference data set, and the record of past lake depths inferred using a diatom based transfer function in the sediment core. Results showed four well-defined maxima in the UVR proxy during the last 1600–1800 years, centred around 1820–1780, 1580–1490, 790–580 and 680–440 AD. Several mechanisms may account for these observed changes in UVR penetration, including past variability in cloud cover, atmospheric turbidity, ozone column depth, snow cover on the lake ice, DOM concentrations and lake-ice thickness and transparency resulting from temperature fluctuations. Although some gaps remain in our knowledge of scytonemin production in relation to the limnology of Antarctic lakes, the results highlight the importance and potential of the sediments in these highly transparent water bodies as archives of changes in past UVR receipt at the Earth’s surface.     

基于主成分分析的关中地区农业粮食生产变化的影响因素研究

针对陕西省关中区域1978—2017年的农业生产数据,在分析关中40 a农业粮食生产的趋势变化后,运用主成分分析法,对影响关中农业生产中的地理环境和生产投入等主要因素进行了评价研究。结果表明:(1)关中农业粮食生产的趋势变化呈现周期为3～7 a的循环增长方式,平均每周期峰值增长率为4.5%。(2)主成分分析研究后得出,第一主成分全是地理因素指标,方差贡献率达到0.554,对关中地区农业粮食生产起着非常显著的决定影响作用,包括受灾农田面积(不含病虫害)、主要粮食作物播种面积、成灾农田面积(不含病虫害)、有效灌溉耕地面积、耕地面积;第二主成分方差贡献率为0.25,是影响粮食生产的重要因素和农业生产的生命补给。包括农业用电量、化肥、农用机械等生产资料投入和主要粮食作物稳产面积、劳动力投入因素指标;第三主成分为农药应用量,方差贡献率为0.068,影响较小。主成分累计方差贡献为0.872。通过对关中地区农业粮食生产变化的影响因素分析,可以为政府部门提出数据支撑和相关性的建议。     

南北极海冰变化及其影响因素的对比分析

海冰是海洋-大气交互系统的重要组成部分,与全球气候系统间存在灵敏的响应和反馈机制。本文选用欧洲空间局发布的1992—2008年海冰密集度数据分析了南北极海冰在时间和空间上的变化规律与趋势,并结合由美国环境预报中心(National Centers for Environmental Prediction,NCEP)和美国大气研究中心(National Center for Atmospheric Research, NCAR)联合制作的NCEP/NCAR气温数据和ENSO指数探讨了南北极海冰变化的影响因素。结果表明,北极海冰面积呈明显的减少趋势,其中夏季海冰最小月的减少更快。北冰洋中央海盆区、巴伦支海、喀拉海、巴芬湾和拉布拉多海的减少最明显。南极海冰面积呈微弱增加趋势,罗斯海、太平洋扇区和大西洋扇区的海冰增加。北极海冰面积与气温有显著的滞后1个月的负相关关系(P0.01)。北极升温显著,北冰洋中央海盆区、喀拉海、巴伦支海、巴芬湾和楚科奇海升温趋势最大,海冰减少很明显。南极在南大西洋、南太平洋呈降温趋势,海冰增加。北极海冰减少与39个月之后ONI的下降、40个月之后SOI的上升密切相关;南极海冰增加与7个月之后ONI的下降、6个月之后SOI的上升存在很好的响应关系。南北极海冰变化与三次ENSO的强暖与强冷事件有很好的对应关系。     

Paddy rice multiple cropping index changes in Southern China

Journal of Geographical Sciences - Changes in rice production in Southern China are crucial to national food security. This study employed Landsat images to map the distributions of paddy...