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13kaBP以来滇池地区古环境演 总被引:3,自引:3,他引:0
根据DC93-1孔孢粉组合、总有机碳(TOC)、总氮(TN)、碳氮比(C/N)、有机碳同位素δ^13Crog、磁化率(x)、频率磁化率(xfd)等资料,结合^14C、^210Pb和^137Cs测年,汗池地区13ka以来的古环境演化历史经历了以下几个阶段:13-10.2kaBP,气候偏凉湿,湖水深度不大;10.2-7.5kaBP,气候向暖湿过渡,湖水渐深:7.5-4.0kaBP,气候暖湿,水热条件达 相似文献
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若尔盖盆地RH孔近80万年来δ13Corg气候特征的频谱分析 总被引:2,自引:3,他引:2
运用最大熵谱方法,对若尔盖深钻800kaB.P.以来有机碳同位素序列进行了频谱分析,结果表明;1)0-800kaB.P该地区存在有准80ka,60ka,41ka和20ka的周期,其中41ka和20ka的周期来米氏计算的地倾角及岁差周期较一致;2)0-480kaB.P,以100ka周期为主,其次为41ka和20ka,与米氏计算的各天文周期相一致;3)480-800kaB.P.出现有115ka,33k 相似文献
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岱海的"中世纪暖期" 总被引:29,自引:1,他引:29
内蒙古岱海沉积物近2200a来Rb/Sr比值、CaCO3和有机碳含量的变化展现了包括中世纪暖期(MWP)及小冰期(LIA)等典型气候事件在内的环境演化过程,总体表现为暖期的沉积物Rb/Sr比值低,冷期的则高:CaCO3和有机碳含量则相反。这里,以单一流域化学风化记录表明我国北方存在明显的中世纪暖期,发生时间约900-1200aB.P..主要环境特征表现为流域化学风化的显著增强(低Rb/Sr比值)、生物生产力逐步提高(高有机碳)、湖泊水位大幅度抬升的湖泊沉积记录,其间经历的化学风化是近两千年内最强的,并且其发生时间与全球其他地区基本一致。 相似文献
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内蒙古额济纳旗嘎顺淖尔XK1孔揭示的第四纪晚期沉积特点及古环境 总被引:2,自引:0,他引:2
通过对嘎顺淖尔XK1孔沉积岩芯的岩性特征及多种环境代用指标的综合分析,初步认为:中更新世早中期,29.6 -42.5m(推测时代为距今218.3 kaBP以前),气候温凉偏干,滨湖与洪积相交替;距今218.3-172.8 kaBP气候温凉偏湿, 湖泊面积扩大,以滨浅湖-浅湖沉积为主,并一度出现半深湖环境;距今172.8-93.4 kaBP,沉积环境为湖滨相与洪积相交替,气候特点是冷凉干旱;距今93.4-67.4 kaBP,沉积环境以淡水浅湖为主,夹湖滨相.气候温偏湿;距今67.4-54.0 kaBP ,湖滨相沉积为主,气候温凉偏干;距今54-48.9 kaBP,气候暖湿的浅湖环境,气温较高;距今48.9-42.6 kaBP,凉而且干旱的气候特点,沉积相为湖滨相;42.6-0 kaBP,气候暖湿、凉干交替,浅湖相为主. 相似文献
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近1800年来云南洱海流域气候变化与人类活动的湖泊沉积记录 总被引:12,自引:3,他引:9
对云南洱海湖泊岩芯沉积物进行了多环境指标(年代学、色素、硅藻、有机碳稳定同位素、磁化率、化学元素)的分析,建立了近1800年来云南洱海流域气候与环境变化的序列,气候演化具有暖干、冷湿交替的组合呈些特征气候阶段如中世纪温暖期、小冰期气候特征在洱海源泊沉积记录中均有反映,洱海湖泊上沉积记录的气候暖干-冷湿交替变化规律,反映了西南委风影响下的气候演化特征,湖泊沉积记录中包含丰富的人类以的信息,磁化率,元 相似文献
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土壤有机碳地球化学及其与岩溶作用的关系:以桂林丫吉村岩溶?… 总被引:1,自引:0,他引:1
岩溶土壤有机碳地球化学研究表明:岩溶土壤是有机碳的巨大储库;土壤有机碳含量以松结态为主,紧结态次之,稳结态最少;土壤表层,鞍部、坡地土壤有机碳较活跃(较多松结态),为岩溶作用CO2的丰富来源。有机碳可氧化性分级分析表明:表层土壤有机碳中易氧化态占60-85%,A层土壤较B层更易被氧化;土壤来源CO2是岩溶驱动CO2的潜在动力。从鞍部-坡地-洼地,B层土壤有机碳可氧化性由弱到强递增。野外监测表明:在 相似文献
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13kaBP以来滇池地区古环境演化 总被引:6,自引:1,他引:5
根据DC93一1孔孢粉组合、总有机碳(TOC)、总氮(TN)、碳氮比(C/N)、有机碳同位素δ13Corg、磁化率(χ)、频率磁化率(χfd)等资料,结合14C、210Pb和137Cs测年,滇池地区13ka以来的古环境演化历史经历了以下几个阶段:13—10.2kaBP.气候偏凉湿,湖水深度不大;10.2-7.5kaBP,气候向暖湿过渡.湖水渐深;7.5-4.0kaBP,气候暖湿,出热条件达到最佳配制,湖水也最深.6.5kaBP前后,气温最高,这一时段古气候状况存在次级波动;4.0-2.7kaBP,气候突转干旱.湖水最浅;2.7-1.7kaBP,气候温湿,湖面扩大,湖水变深;1.7kaBP,人类活动影响的加剧,使湖泊环境的变化更为复杂. 相似文献
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若尔盖盆地RH孔有机碳同位素序列指示的古气候事件诊断 总被引:3,自引:1,他引:3
定量化是过去全球气候变化研究的必然趋势,突变事件的诊断是古气候定量化研究中极其重要的过程。本文运用M-K法和t检验法对RH孔有机碳同位素序列进行了气候突变诊断研究。结果发现,近800kaBP来该区气候存在明显的突变,且突变开始于470kaBP。进一步的研究发现470kaBP开始的这一气候突变事件与青藏高原的构造隆升有密切的关系。 相似文献
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
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《地震工程与工程振动(英文版)》2014,(4)
正This journal is established by the Institute of Engineering Mechanics(IEM),China Earthquake Administration,to promote scientific exchange between Chinese and foreign scientists and engineers so as to improve the theory and practice of earthquake hazards mitigation,preparedness,and recovery.To accomplish this purpose,the journal aims to attract a balanced number of papers between Chinese and 相似文献
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George W. Housner 《地震工程与工程振动(英文版)》2008,7(2):I0001-I0001
Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States. 相似文献
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JianCheng Shi 《中国科学:地球科学(英文版)》2014,57(10):2281-2282
正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases 相似文献
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《国际泥沙研究》2014,(4)
正President:Giampaolo Di Silvio,Italy Vice Presidents:Ulrich C.E.Zanke,Germany Zhao-yin Wang,China The World Association for Sedimentation and Erosion Research(WASER),inaugurated on Oct.19,2004,is an independent non-governmental,non-profit organization.The mission of WASER is to promote international co-operation on the study 相似文献