试论未来全球气候变化     

魏东岩 《化工矿产地质》1997,19(3):167-170

未来全球气候变化是人们关注的重大课题。从内蒙古盐湖近２０ｋａ气候演变的研究可知，地质时期和历史时期气候波动变化是有规律可循的。用已经了解的这种变化规律来予测未来气候变化是有价值的。研究表明，未来１ｋａ左右全球为暖期，之后将进入下一个冰期。  相似文献   

Geothermal Regime of Meso-Cenozoic Basins and Their Tectonic Background in East China     

 Zhuang XinguoZhuang XinguoGeothermal Regime of Meso-Cenozoic Basins  Their Tectonic Background in East ChinaFaculty of Earth Resources  China University of Geosciences  Wuhan  《中国地质大学学报(英文版)》1997,(1)

ＧｅｏｔｈｅｒｍａｌＲｅｇｉｍｅｏｆＭｅｓｏ－ＣｅｎｏｚｏｉｃＢａｓｉｎｓａｎｄＴｈｅｉｒＴｅｃｔｏｎｉｃＢａｃｋｇｒｏｕｎｄｉｎＥａｓｔＣｈｉｎａ＊ＺｈｕａｎｇＸｉｎｇｕｏＦａｃｕｌｔｙｏｆＥａｒｔｈＲｅｓｏｕｒｃｅｓ，ＣｈｉｎａＵｎｉｖｅｒｓｉｔ...  相似文献   

Secondary ferrimagnetic minerals in Welsh soils: a comparison of mineral magnetic detection methods and implications for mineral formation   总被引：20，自引：0，他引：20  

J. A. Dearing  P. M. Bird  R. J. L. Dann  S. F. Benjamin 《Geophysical Journal International》1997,130(3):727-736

A study of mineral magnetic parameters was carried out on a Late Pleistocene and Holocene sedimentary sequence (of nearly 18 m) from Lake Bledowo (central Poland). Sediments of Lake Bledowo have already been analysed for bulk sediment mineralogy and biogenic materials. The mineral magnetic stratigraphy confirms the major changes in palaeo-environmental conditions that have been deduced from other methods. The most important mineral magnetic change results from the authigenetic formation of ferrimagnetic greigite, Fe₃S₄, during the beginning of lacustrine conditions (± 12 000 yr BP). Our data also indicate a detrital origin of overlying ferrimagnetic iron oxides. It is suggested that they originate from brown soils developed on the boulder clay constituting the west side of the lake shore. Variations of ferrimagnetic iron oxide size are related to the early diagenetic processes in the sediment. Larger particles are present in periods with early diagenesis of organic matter in anoxic conditions. This indicates the dissolution of fine magnetic particles by iron-oxide-reducing bacteria and results in homogeneous magnetic grain sizes, despite their origin from soils, characterized by a multimodal grain-size distribution.  相似文献   

陇南山区农业气候资源特征与开发利用     

余优森  尹东  费晓玲  任三学 《山地学报》1997,(4)

分析了甘肃陇南山区农业气候资源的分布特征及其水平、垂直差异,提出了合理开发利用的农业决策建议,指出应利用资源优势建立名特优小商品生产基地。  相似文献   

The Sahelian desertification debate: a view from the American south-west     

Charles F. Hutchinson 《Journal of Arid Environments》1996,33(4):519-524

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祁连山地区1310年以来湿润指数及其年际变幅的变化与突变分析   总被引：23，自引：0，他引：23  

张志华  吴祥定 《第四纪研究》1996,16(4):368-378

本文通过用树木年轮资料重建的祁连山地区5～7月份1310年以来的湿润指数序列，建立了一个反映该地区湿润指数年际变幅序列，对这两个序列分别进行了等级分类和干湿、强弱的时段分析，并用最大熵谱分析法对这两个序列的不同时段分别进行了周期分析。采用HK突变检验方法对这两个序列分别进行了突变分析，发现祁连山地区的湿润指数及其年际变幅存在明显的突变年份。  相似文献   

应用Kriging方法研究格尔木河流域地下水位动态观测网的优化配置   总被引：4，自引：0，他引：4  

宋儒 《中国煤田地质》1997,(4)

地下水动态是水文地质研究的一个重要方面，如何获满足一定精度要求全面而合理的地下水位动态资料具有现实经济效益。本文研究格尔木河流域地下水位动态测网，通过选取理想的变差函，运有Ｋｒｉｇｉｎｇ方法进行地下水位的线性无偏最优估计和计算估计误差的标准差，结合给定的允许误差限评判地下水位动态观测网的配置是否合适，并提出调整现有观测网的方案  相似文献   

中国东部6区域近1000年干湿序列的重建和气候跃变分析   总被引：54，自引：6，他引：54       下载免费PDF全文

张德二  刘传志  江剑民 《第四纪研究》1997,17(1):1-11

本文利用我国的历史气候记载，为东部6区域重建了最近1033年的时间分辨率为1年的区域于湿气候序列，讨论其可靠性，并分析其变化的准周期性和跃变特征。跃变分析采用移动t检验方法，分析各区域干湿气候的世纪尺度和10～20年尺度的跃变现象，辨识跃变信号的参考年代，指出北方各区域的跃变趋势相同，但有时与长江下游地区相反，以及跃变信号在寒冷气候背景下较多出现等特点。  相似文献   

Solar modulation of cosmogenic nuclide production over the last millennium: comparison between C and Be records     

Edouard Bard  Grant M. Raisbeck  Franoise Yiou  Jean Jouzel 《Earth and Planetary Science Letters》1997,150(3-4):453-462

For about the last 30 years it has been recognized that the high frequency component of the tree rings ¹⁴C/¹²C record is dominated by the modulation of the cosmic ray flux by the solar wind. In particular, it has been demonstrated that the three most recent periods of low sunspot occurrence were characterized by high values of atmospheric ¹⁴C/¹²C. During the last millennium other periods of high ¹⁴C/¹²C values were observed but their solar origin is still debatable. In the present work we compare these fluctuations with an independent record of cosmogenic ¹⁰Be measured in ice from the South Pole to check the solar origin of the observed ¹⁴C/¹²C variations. In order to compare quantitatively the results obtained on ¹⁰Be and ¹⁴C, it is necessary to take into account the different behaviour of these two cosmogenic isotopes, and especially the damping effect of the carbon cycle in the case of ¹⁴C. As an input to a 12-box numerical model we used the relative fluctuations of the ¹⁰Be concentrations record measured in South Pole ice and converted it into a synthetic ¹⁴C record. We took into account the fact that ¹⁰Be modulation is enhanced in polar regions due to the orientation of the geomagnetic field. As expected, the fluctuations of the modelled ¹⁴C record are much smaller (a factor of 20) than those observed for the raw ¹⁰Be record. In addition, the variations are smoother and shifted in time by a few decades. The ¹⁰Be-based ¹⁴C variations closely resemble the ¹⁴C measurements obtained on tree rings (R = 0.81). In particular, it is easy to identify periods of maximal ¹⁴C/¹²C which correspond to solar activity minima centred at about 1060, 1320 (Wolf), 1500 (Spörer), 1690 (Maunder) and 1820 (Dalton) yr A.D. Cross-correlation calculations suggest that there is no significant lag between the ¹⁰Be-based ¹⁴C and the tree-ring ¹⁴C records. Our study strongly suggests the dominance of the solar modulation on the cosmonuclide production variations during the last millennium.  相似文献   

从天山乌鲁木齐河源1号冰川变化估计近百年来该地区夏季升温   总被引：6，自引：6，他引：6  

王宁练  刘时银 《冰川冻土》1997,19(3):207-213

通过冰川波动历史来揭示气候变化是一种重要的方法。然而，以往有关这一方面的研究大都是一些定性的。文章试图依据冰种变化来定量的研究气候变化，并且通过近百年来天山乌鲁木齐河源１号冰川的变化，揭示出本世纪以来该河源地区夏季气温上升约０．２３￣０．２５℃，同时，对于该冰川不同长度规模时的气候敏感性也进行了讨论。  相似文献