Formate and acetate records in the Muztagata ice core, Northwest Tibetan Plateau

Formic and acetic acids (HCOOH, CH3COOH), originating mainly from biosphere (release by plants, combustion of biomass, motor exhaust and oxidation of organism, etc.), are two simple organic chemical com- pounds in troposphere. Though the concentration of these two organic acids is low in atmosphere, they are the main [1] sources of free acidity in precipitation of remote regions , and contribute minor chemical constituents to the balance between anions and cations, especially to some atm…     

Relationship between calcium and atmospheric dust recorded in Guliya ice core

By the analyses of Guliya ice core on the Tibetan Plateau, it was found that the calcium (Ca^2 ) originated from the terrestrial source is the main cation of soluble aerosol and a good proxy of the atmospheric component and environment in the mountain ice core located in the mid-low latitude arid regions. Evident variation of Ca^2 concentration has been found in the Guliya ice core since the Last lnterglaciation with two relatively strong increase periods and two weak increase periods. These variations are generally related to climatic changes: high Ca^2 concentration periods coincide with cold periods and low Ca^2 concentration periods coincide with warm periods. However, Ca^2 concentration does not always decrease (increase) with climate warming (cooling). The magnitude and phase of Ca^2 concentration does not always match temperature either. The changes of atmospheric circulation, land surface condition and atmospheric humidity might be important factors which influence Ca^2 concentration besides temperature.     

Signals of Antarctic Circum-polar Wave over the Southern Indian Ocean as recorded in an Antarctica ice core

Oxygen stable isotopic and ionic records, covering a period of 1745--1996, are recovered in DT001 ice core drilled in Princess Elizabeth Land, East Antarctica.Using empirical orthogonal function (EOF) analysis of the annually resolved glaciochemical time series, we find the first EOF (EOFI) represents sea-salt aerosols and is the proxy of sea level pressure (SLP) over a quasi-stationary low in the Southern Indian Ocean (SIO). δ^18O represents the sea surface temperature (SST) of the same ocean area. In the past two decades, four climatic waves as represented by SLP and SST proxies are found in the DT001 ice core, which in coincident with four Antarctic Circum-polar Waves (ACW) as revealed by NCEP/NCAR reanalysis. The phase difference between SST and SLP in the ice core is also coincident with that in ACW. Both ice-core record and reanalysis suggestthat there were no signals of ACW during 1958--1980, none during the overall recording period between 1745--1996, as there is no regular phase difference between SST and SLP.The ACW signal after early 1980s is probably attributable to the climate shift occurring over Antarctic Peninsula-Drake Passage region.     

Trend in the atmospheric heat source over the central and eastern Tibetan Plateau during recent decades: Comparison of observations and reanalysis data

The trend in the atmospheric heat source over the central and eastern Tibetan Plateau (CE-TP) is quantitatively estimated using historical observations at 71 meteorological stations, three reanalysis datasets from 1980-2008, and two satellite radiation datasets from 1984-2007. Results show that a weakening of sensible heat (SH) flux over the CE-TP continues. The most significant trend occurs in spring, induced mainly by decelerated surface wind speeds. The ground-air temperature difference shows a notable increasing trend over the last 5 years. Trends in net radiation flux of the atmospheric column over the CE-TP, evaluated by two satellite radiation datasets, are clearly different. Trends in the atmospheric heat source calculated by the three reanalysis datasets are not completely consistent, and even show opposite signals. Results from the two datasets both show a weakening of the heat source but the magnitude of one is significantly stronger, whereas an increase is indicated by the other data. Therefore, it is challenging to accurately calculate the trend in the atmospheric heat source over the CE-TP, particularly from the estimates of the reanalysis datasets.     

青藏高原中西部湖泊生物标志物记录的过去两千年气候变化

以青藏高原中西部湖泊达则错和阿翁错为研究对象,通过分析湖泊沉积物岩芯中GDGTs、长链不饱和烯酮与叶蜡化合物单体氢同位素等生物分子标志物获得过去2000 a以来青藏高原中西部定量的温度与降水同位素记录,以期探讨晚全新世以来不同时段青藏高原气候变化区域特征,并揭示过去2000 a季风与西风对青藏高原影响范围的变化.结果表明:(1)青藏高原气候变化存在强烈的区域性特征,两个湖泊均存在中世纪暖期(MWP),但是暖期持续的时间有所不同,高原西部(阿翁错) MWP持续时间明显长于高原中部(达则错);达则错有明显的小冰期(LIA)降温,阿翁错没有发现明显的LIA,可能受样品分辨率低的影响;过去200 a达则错温度有缓慢降低趋势,可能是冰融水补给湖泊温度变化滞后于气候变化的表现.(2)过去2000 a印度夏季风在青藏高原的最北界线可能发生了北移,在距今1000～2000 a,夏季风边界线位于阿翁错以北、达则错以南;但在过去1000 a印度季风边界线移动到阿翁错和达则错以北.     

滇东北新生代盆地构造反转与生物气藏的形成

利用二维地震测线,结合地质和钻井等资料,通过开展详细的构造和沉积解释,分析滇东北褶皱带上的曲靖、越州和陆良3个残余型陆相沉积盆地的构造特征、形成演化和成因联系,特别对渐新世末和上新世末2期重要的构造反转进行较系统地综合研究,分析构造反转活动对生物气成藏条件的控制作用。研究结果表明:渐新世末的构造反转避免了蔡家冲组沉积有机质的大量消耗,促使了蔡家冲组主力烃源岩的二次产气,保障了第四纪以来生物气成藏的有机物质和气源的持续供给;上新世末的构造反转控制了生物气成藏要素的有利时空配置,控制了滇东北新生代盆地生物气藏的形成。中央断凹带及其与断褶带和斜坡带的过渡区带具有良好的生物气生成、运聚和保存条件,为生物气藏富集区带。     

2010年夏季北半球气温异常偏高现象及其成因

利用常规气象观测资料、NCEP/NCAR再分析资料,对2010年夏季6-8月北半球异常高温现象进行了分析.结果表明,夏季北半球大部分地方地面气温偏高,局部地区气温异常偏高,地而气温距平值达+6℃;北半球对流层平均气温正距平值达近30年以来最大值,并且各月平均气温异常偏高的区域,在对流层各层次都表现为一致的偏高;北半球对...     

Climatic and environmental implications from n-alkanes in glacially eroded lake sediments in Tibetan Plateau: An example from Ximen Co

Gas chromatography-mass spectrometry was used to identify a series of n-alkanes in the sediments of a typical glacially eroded lake in the eastern Tibetan Plateau.By comparing the distribution patterns of n-alkanes in lake sediments,surface soils and cow manure,it was shown that n-C 27-n-C 33 alkanes in the soil ecosystem of Ximen Co are derived from vascular plant species and that the distribution pattern of n-C 27-n-C 33 alkanes remains unchanged during the feeding and digestion processes of herbivores.The relative percentage of C 27,C 29 and C 31 n-alkanes decreased from the bottom to the top of the sediment core showing a trend of degradation of higher plants in the Ximen Co lake region during the formation of the 44 cm core.210 Pb dating,combined with pre-existing AMS 14 C dating results showed that the depositional core reflects climatic and environmental variations since about 900 years before present.The n-alkane indexes (ACL 27-33,P aq,P wax) are comparable with regional temperature variation,especially recording the Little Ice Age event (LIA).This study highlights that n-alkanes are valid proxies for paleo-climate and paleo-environment reconstruction,despite the same distribution patterns in n-alkane molecular fossils derived from a typical glacially eroded lake.     

Change of bacterial community in the Malan Ice Core and its relation to climate and environment

In order to understand the relationship between the community structure of bacteria in ice core and the past climate and environment, we initiated the study on the microorganisms in the three selected ice samples from the Malan ice core drilled from the Tibetan Plateau. The 16S ribosomal DNA (rDNA) molecules were directly amplified from the melt water samples, and three 16S rDNA clone libraries were established. Among 94 positive clones, eleven clones with unique restriction pattern were used for partial sequence and compared with eight reported sequences from the same ice core. The phylotypes were divided into 5 groups: alpha, beta, gamma proteobacteria; CFB, and other eubacteria group. Among them, there were many “typical Malan glacial bacteria“ pertaining to psychrophilies and new bacteria found in the ice core. At a longer time scale, the concentration distribution of “typical Malan glacial bacteria“ with depth showed negative correlation with temperature variations and was coincident with dirty layer. It implied the influence of temperature on the microbial record through impact on the concentrations of the “typical Malan glacial bacteria“. In addition, the nutrition contained in ice was another important factor controlling the distribution of microbial population in ice core section. Moreover, the result displayed an apparent layer distribution of bacterial community in the ice core section, which reflected the microbial response to the past climatic and environmental conditions at the time of deposition.     

Simulated change in the near-surface soil freeze/thaw cycle on the Tibetan Plateau from 1981 to 2010

The near-surface freeze/thaw cycle in cold regions plays a major role in the surface energy budget,hydrological activity,and terrestrial ecosystems.In this study,the Community Land Model,Version 4 and a suite of high-resolution atmospheric data were used to investigate the changes in the near-surface soil freeze/thaw cycle in response to the warming on the Tibetan Plateau from1981 to 2010.The in situ observations-based validation showed that,considering the cause of scale mismatch in the comparison,the simulated soil temperature,freeze start and end dates,and freeze duration at the near-surface were reasonable.In response to the warming of the Tibetan Plateau at a rate of approximately 0.44°C decade-1,the freeze start-date became delayed at an area-mean rate of1.7 days decade-1,while the freeze end-date became advanced at an area-mean rate of 4.7 days decade-1.The delaying of the freeze start-date,which was combined with the advancing of the freeze end-date,resulted in a statistically significant shortening trend with respect to the freeze duration,at an area-mean rate of 6.4 days decade-1.Such changes would strongly affect the surface energy flux,hydrological processes,and vegetation dynamics.We also found that the rate of freeze-duration shortening at the near-surface soil layer was approximately 3.0 days decade-1lower than that at a depth of 1 m.This implied that the changes in soil freeze/thaw cycles at the near surface cannot be assumed to reflect the situation in deeper soil layers.The significant correlations between freeze duration and air temperature indicated that the shortening of the near-surface freeze duration was caused by the rise in air temperature,which occurred especially in spring,followed by autumn.These results can be used to reveal the laws governing the response of the near-surface freeze/thaw cycle to climate change and indicate related changes in permafrost.     

四川盆地震旦系下古生界天然气成藏过程和特征

四川盆地震旦系-下古生界具有三套泥质油系烃源岩,具有很好的生油潜力和生烃强度。受加里东隆升作用的影响,烃源岩有二次生、排烃的特征,三叠纪是主要圈闭形成期和二次生油的主峰期,大量的石油运聚至乐山-龙女寺古隆起范围内形成震旦系-下古生界古油藏。随着古油藏埋深的增加,温度和压力的增高,石油裂解成天然气,古油藏自身形成气源,在原地系统形成古气藏。这一过程持续到喜马拉雅期,之后受喜马拉雅运动的影响,强烈隆升和剥蚀,圈闭重新调整,气藏重新分配,最终形成现今气藏。因此,四川盆地震旦系-下古生界天然气的成藏过程是一个古油藏→古气藏→现今气藏的过程,具有生排差异、多期运聚、早聚晚藏的特征。     

吉林省自东向西城乡连续空间大气汞分布特征研究

为了解水平中尺度气象条件控制下连续空间区域内大气汞污染特征,使用车载塞曼效应汞分析仪(Zeeman RA915+),由吉林省东部汪清县不间断行车至西部镇赉县,同步测定了近1 000 km沿线“城市-乡村”连续空间大气汞质量浓度分布情况.结果表明:研究区域内大气汞含量平均值为(5.99±3.19)ng/m3,最高值出现在城市区(长春市),最低值出现在乡村区(汪清县,敦化市和白城市辖区内).研究区域内大气汞含量空间分布特征表现为由中部地区向东西部地区呈逐渐递减趋势;规模较大的城镇区高于规模较小的城镇区,城镇区显著高于乡村区;东部地区与西部地区具有不同的大气汞浓度空间特征,上述特征与区域内大气汞含量受燃煤汞排放过程控制有关.研究区域城镇全域(含乡村)大气汞含量特征表现为长春地区(9.07±6.36) ng/m3,吉林地区(7.02±2.70)ng/m3,延边地区(5.08±2.06) ng/m3,松原与白城地区(4.70±0.98)ng/m3;城镇辖区内(不含乡村)大气汞含量长春市(16.41±8.65)ng/m3最高,镇赉县(3.47±0.60)ng/m3最低.     

近11年兰州空气污染特征及其边界层结构影响的分析

利用来自环保部门的空气污染资料,分析了近11年兰州市空气污染特征;结合气象地面和探空观测资料,分析了山谷地形条件下大气边界层结构对兰州空气污染的影响.结果是兰州近11年的空气污染有整体减轻趋势,但污染仍很严重,空气质量大多年份都达不到国家二级水平,污染物主要为可吸入颗粒物.严重污染时期集中在秋末、冬季和春季,秋冬季空气污染较稳定,主要受可高达1000 m的深厚稳定边界层影响,而春季空气污染指数标准偏差较大.11年空气污染指数的月平均次高峰出现在3月,相对以往研究提前了1个月.     

Modern stalagmite oxygen isotopic composition and its implications of climatic change from a high-elevation cave in the eastern Qinghai-Tibet Plateau over the past 50 years

An oxygen isotope record of a stalagmite from Huanglong Cave in the eastern Qinghai-Tibet Plateau dated with 230Th and 210Pb methods provides variations of the Asian monsoon with an average resolu-tion of 1 year over the past 50 years. This study shows that the δ18O of dripwater in the cave represents the annual mean δ18O of local meteoric precipitation and the stalagmites were deposited in isotopic equilibrium. A comparison of the stalagmite δ18O record with instrumentally meteorological data indi-cates that shifts of the δ18O are largely controlled by the amount effect of meteoric precipitation con-veyed through the southwest monsoon(the Indian monsoon) and less affected by temperature. Therefore,the variations of δ18O record reflect the changes in monsoon precipitation on inter-annual time scales under the influence of the southwest monsoon. Like many other stalagmite δ18O records in the Asian monsoon regions,the δ18O record of the stalagmite from Huanglong Cave also reveals a gradually enriched trend during the past 50 years,i.e. relatively enriched in 18O. This trend may indicate the decline of the Asian monsoon intensity which is consistent with the decrease of monsoon indices. The weakening of the modern Asian monsoon well matched with the temperature changes in strato-sphere,which may illustrate that the weakening of the monsoon mainly results from the lowering of solar radiation.     

Evolution of the East Asian monsoon and its response to uplift of the Tibetan Plateau since 1.8 Ma recorded by major elements in sediments of the South China Sea

Evolution of the East Asian monsoon and its response to uplift of the Tibetan Plateau has been investigated in the study of global change. Core sediment samples drilled in the South China Sea during ODP Leg184 are the best materials for studying long-term variability of the East Asian monsoon. R-mode factor analysis of major elements in the fine grain-sized carbonate-free sediments (<4 μm) of the upper 185 mcd splice of ODP Site 1146 drilled during Leg184 in the South China Sea shows that Ti, TFe2O3, MgO, K2O, P, CaO, and Al2O3 are representative of a terrestrial factor. The variation in the terrestrial factor score is subject to chemical erosion in the source region and thus indicates the evolution of the East Asian summer monsoon. The terrestrial factor score has three stepwise decreases at ~1.3 Ma, ~0.9 Ma, and ~0.6 Ma, indicating the phased weakening of the East Asian summer monsoon is related to wholly stepwise, quick uplifts of the Tibetan Plateau since 1.8 Ma. The periodic fluctuation of the terrestrial factor score since ~0.6 Ma indicates that the glacial-interglacial cycles have been the main force driving the evolution of the East Asian monsoon. As in the case of Chinese loess, the long-term evolution of the East Asian monsoon recorded in sediments of the South China Sea reflects a coupled effect of the glacial-interglacial cycle and uplift of the Tibetan Plateau.     

恩格斯《劳动在从猿到人的转变中的作用》的自然观及其当代启示

恩格斯的自然观立足于实践,以辩证法为方法论,探寻人与自然的关系问题。在《劳动在从猿到人的转变中的作用》一文中,恩格斯所阐发的自然观主要包括对劳动在人与自然分化过程中的作用的详细考察、对人与自然和谐统一关系的精辟论述和对人与自然矛盾解决的途径的系统阐释。它给我们的启示在于认清当代生态危机实质是人与人之间的利益对抗关系在人与自然关系上的极端表现;解决当代生态危机的根本出路在于从根本上变革不合理的资本主义社会关系和社会制度;处理好人和人之间在占有和使用自然资源上的利益关系,是实现我国现代化建设实践和环境保护双重胜利的关键。     

Northern Tibetan Plateau cooling and aridification linked to Cenozoic global cooling: Evidence from <Emphasis Type="Italic">n</Emphasis>-alkane distributions of Paleogene sedimentary sequences in the Xining Basin

The Xining Basin on the northeastern Tibetan Plateau holds the longest continuous Cenozoic stratigraphic record in China. The sequence record contains considerable information on the history of Tibetan uplift and associated climatic change. In particular, high resolution n-alkane biomarker proxy and pollen records have been obtained from the Paleogene sediments of the Xiejia section of the basin. A combination of the n-alkane and palynological records reveals that the paleoclimate in the Xining Basin experienced a long-term cooling trend from 50.2 to 28.2 Ma with a distinctive ecological event spanning 37.5 to 32.7 Ma. Since this ecological event, a vertical zonation of vegetation from lowland arid grasses, to middle-elevation subtropical broad-leaf plants, to high-elevation coniferous trees was established. We interpret that these changes in climate and vegetation were probably responses to a combination of long term global cooling since the Eocene climatic optimum and uplift of the surrounding mountains on the northern Tibetan Plateau in the early Cenozoic.     

石羊河上游1956-2009年出山径流量特征及其对气候变化的响应

利用石羊河上游气象站1956-2009年逐日气象资料及天祝县六条河流1956-2009年年出山径流量资料,应用FAO Penman-Monteith模型、小波变换及累积距平等方法分析石羊河上游天祝县出山径流量特征及其对气候变化的响应,结果表明:1956-2009年石羊河上游天祝县出山径流量在波动中总体呈微弱减少趋势,径流量变化倾向率为-0.288×10~8m~3/10a,其中,减少速度最快的是黄羊河,年径流量变化倾向率为-0.069×10~8m~3/10a.1950s,1960s及1980s为丰水期,1970s,1990s为枯水期,进入21世纪,尤其是2002-2009年径流量有所增加;降水量波动呈微弱增加趋势,降水量变化倾向率为1.165mm/10a,径流量与降水量存在显著正相关震荡,两者变化过程具有极吻合的同步性;气温整体呈明显上升趋势,气温变化倾向率为0.298℃/10a,尤其是20世纪80年代中后期以来,增温趋势更加明显;潜在蒸发量在波动中呈增加趋势,其变化倾向率为2.206mm/10a,径流量与气温、蒸发量呈显著负相关震荡;通过小波方差检验,径流量与降水量、气温及潜在蒸发量等各气候要素均分别存在22年左右、7-8年和3年左右的的显著变化周期,而且第一主周期均为准22年,径流量对气候变化响应明显.     

论清至民国桂西地区社会经济变迁中的政府与民间力量

明清以前,桂西地区基本上处于封闭状态。清至民国时期,在移民运动的影响下,政府运用行政力量,进一步瓦解土司的社会基础,同时及时调解和处理农业生产中的“来土矛盾”,维护外来移民的利益,使其获得了发展的基本条件。随着社会环境的日益开放,东南沿海地区的商人在这里建立会馆、码头,本地民众积极捐款修建桥梁、公路,共同培育商品市场,从而促进了经济结构的改变。民族经济融合是社会发展的重要动力之一。