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南极和北极海域的深海钻探（DSDP）和大洋钻探（ODP）研究所取得的成就是举世瞩目的,为人类研究过去全球变化打开了新的视野。它们揭示了北大西洋高纬度海区新近纪的古海洋学和古气候的演化历史,发现了早更新世"41ka世界"千年尺度的气候波动,以及冰期表层水温与深层水的耦合颤动,说明冰期旋回中冰消期气候的不稳定性。检验了新近纪环南极洋流的形成历史,并揭示了南极新生代的气候变冷和冰盖的演变历史,以及证实了南大洋温度变化领先于全球冰量的变化。2004年北极罗蒙诺索脊的综合大洋钻探（IODP）将宣告科学探索时代的到来,其研究将重建北冰洋新生代环境变化和气候的演变历史,展示北冰洋在全球气候变化中的作用。 相似文献
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古洪水事件对中国古代文明的演变进程产生过重大影响,古洪水水文学研究是全球变化研究的前沿课题.通过野外深入考察,在汉江上游河谷阶地上,发现典型的全新世剖面中赋存古洪水滞流沉积层,记录了古洪水事件的气候水文信息.选择三个剖面系统采样,应用SAR法的Post-IR OSL技术对样品进行测年研究,获得了14个OSL年龄数据.结合样品的粒度成分和磁化率等气候替代指标测定分析,获得了全新世洪水事件与气候变化关系的记录.证明在距今9.5~8.5 ka和3.2~2.8 ka前,汉江上游经历了2个特大洪水期.该流域黄土—古土壤剖面记录了全新世早期气温回升增湿的气候,由于大气波动失稳,出现了9~8 ka前的全球降温事件;中期土壤成壤强烈,记录了温暖湿润的气候;晚期形成的现代黄土和表土层,记录了相对干旱的气候.由此揭示了在全新世早期气候波动失稳和中期向晚期过渡的气候转折时期,气候变化剧烈,降水变率增大,是导致特大古洪水事件频发的主要原因,这也是该区域气候水文事件对全球气候变化响应规律的具体表现. 相似文献
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气候变化驱动下的水循环与水资源演变规律研究是重要的科学问题, 也是国际社会普遍关注的全球性问题。以雅鲁藏布江流域为研究区, 利用线性倾向估计、多元线性回归等方法检验气象要素变化特征, 揭示下垫面演变规律;基于Budyko假设的弹性系数法, 揭示径流演变规律, 并进行归因分析。结果表明: 1961—2014年, 雅鲁藏布江流域气温呈升高趋势, 降水整体呈增加趋势, 气候向暖湿化方向发展;植被整体改善, 上游西北部和下游植被存在退化现象;年径流序列具有3~4 a、12 a、20 a和32 a左右的周期;降水变化、潜在蒸散发量变化、下垫面变化和冰川变化对径流量增加的贡献率分别为39.62%、-2.74%、32.32%和30.94%。相关结果对理解气候变化和下垫面变化下雅鲁藏布江径流演变规律, 具有重要的参考价值。 相似文献
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《矿物岩石地球化学通报》2019,(6)
重建全新世以来南海气候环境演变记录对了解我国乃至东亚地区气候环境的演变规律具有重要的意义。造礁珊瑚在热带海洋气候环境演变研究方面具有独特的优势。最近二十年来,基于珊瑚地球化学记录的全新世南海气候环境演变研究取得了大量成果。本文对在季节-年际-年代际-千年际尺度的气候变化、海水pH、生态演化和人类活动等研究方面获得的代表性成果进行了总结,提出传统的珊瑚古气候研究需要从重建气候环境记录、探讨气候变化问题上升到研究珊瑚对气候环境变化的适应性演变机制、珊瑚礁生态系统和气候环境协同演化过程,以适应地球系统科学发展的要求。 相似文献
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高分辨率古海水温度记录──珊瑚Ｓｒ／Ｃａ比值韦刚健，李献华（中国科学院广州地球化学研究所，广州５１０６４０）关键词ＳＳＴ记录Ｓｒ／Ｃａ比值，珊瑚礁１弓】言研究第四纪古气候古环境变化，了解过去的气候演变规律，对预测未来气候变化趋势有重要意义，而依据地质... 相似文献
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渭河咸阳段全新世古洪水事件光释光测年研究 总被引：3，自引：1，他引：2
古洪水水文学研究是全球气候变化研究的前沿课题,确定古洪水事件的年代是古洪水研究的重要内容之一。对渭河流域进行深入的野外考察,在中游咸阳段阶地发现全新世黄土-古土壤层里夹有古洪水滞流沉积层,表明该地层记录了古洪水事件发生的信息。在该剖面采集光释光样品,分离提取40~63 μm石英颗粒成分,应用单片再生剂量法（SAR）进行红外后蓝光(Post-IR OSL)释光测量,获得了9个OSL年龄值。结果表明由古洪水滞流沉积层记录的特大古洪水事件发生在3 200~2 800 a B.P.之间。结合沉积样品系列的磁化率和粒度成分等气候替代性指标分析,揭示了在全新世中期向晚期转折过渡时期,渭河流域处于气候向干旱化发展的转型期,气候变化剧烈,大气系统不稳定,降水变率增大等,是导致特大洪水多发的主要原因。这也是渭河流域气候水文系统对于全球性气候恶化响应的结果。 相似文献
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气候变化轨道驱动的发现,使古气候研究进入了定量探索变化机理的新阶段。然而经典版本的米兰科维奇学说只考虑北半球高纬区的辐射量变化,与新发现的地质记录和热带过程在现代气候中所起的作用相矛盾。文章简要地综述以贸易风与季风系统为主的低纬过程如何响应轨道变化,指出岁差与偏心率周期通过驱动热带过程影响全球气候的重要性,建议在古气候研究中发展新思路,重视区别高、低纬区不同过程的轨道周期,从高、低纬区相互作用的角度研究气候变化的机理。 相似文献
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Milankovitch theory posits that Earth's orbital cycles were the primary forcing of Pleistocene ice-age cycles through their strong influence on summer insolation at high latitudes. Accordingly, Milankovitch theory predicts ice volume should vary at both obliquity and precessional periods. However, early Pleistocene global ice volume varied mainly at the obliquity period with weak variability at the precessional period suggesting that Milankovitch theory is not sufficient to explain the ice-age cycles. Here we describe the results from a series of coupled ocean-atmosphere general circulation model experiments, using the Fast Ocean Atmosphere Model, that systematically investigate the influence of precession and obliquity on continental snowfall and potential ablation.Our model results identify three factors that magnify the influence of obliquity forcing on the global ice volume: First, high-latitude snowfall variability is dominated by changes in Earth's axial tilt. Second, hemispheric changes in net snowfall due to Earth's precession are out-of-phase, and largely cancel to produce a very small global snowfall change. Third, snowmelt variability over Antarctica responds greatly to changes in obliquity that intensify accumulation over obliquity cycle. We discuss the implications of these factors for existing hypotheses that account for the variability in the ice volume record. 相似文献
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地球圈层相互作用中的深海过程和深海记录（II）：气候变化的热带驱动与碳循环 总被引：1，自引：3，他引：1
地球轨道变化驱动冰期旋回的理论是气候演变研究在20世纪的最大突破。然而以65°N太阳辐射量为准的传统轨道理论，忽视了低纬区和碳循环的作用。本项目以“西太平洋暖池”为重点，通过地质资料和气候数值模拟的结合，揭示了“西太平洋暖池”和东亚季风发育的阶段性，发现了暖池海区冰消期表层水升温超前于北半球冰盖的融化。在南沙海区发现了碳同位素有40~50万年长周期，经过全球对比和对意大利上新世地层的实测与分析，证明这是世界大洋碳储库对于地球运行轨道偏心率长周期的响应，并推测是通过浮游植物群改变有机碳在海洋碳沉积中的比例所致。研究表明热带驱动和碳循环在气候演变中重要性，其正确认识是预测气候长期演变趋势的前提。是“深海973”项目总结报道之后的续篇，对上述成果作专题讨论。 相似文献
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快速气候变化与高分辨率的深海沉积记录 总被引：9，自引：5，他引：4
通过高分辨率海洋古气候序列研究快速气候变化的机制是大洋钻探ODP及相关的国际海洋古全球变化研究IMAGES的重要贡献。研究发现,千年、百年尺度的古气候事件具有全球性,不仅见于冰芯和北大西洋高纬区,也发生在热带太平洋等其它海区和地球的其它部分;不仅见于末次冰期,也发生在全新世和早、中更新世。尽管这些快速气候变化的原因和机理尚无定论,但至少说明存在有别于冰期／间冰期冰盖体积变化的因素（如热带过程、太阳活动等）在起作用,从根本上改变了学术界对地球气候环境系统历史的认识。 相似文献
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James Rose 《Proceedings of the Geologists' Association. Geologists' Association》2010,121(3):334-341
This brief review provides an Earth Science perspective on present climate change (global warming) using evidence from past ice ages with details from the Quaternary ice age. It places the present (Quaternary) ice age in the context of Earth history and outlines possible causes of ice ages and the scale and style of ice age climate. Milankovitch climate forcing is described and explained as the cause of relatively predictable climatic variations within an ice age (and at other times), and this is followed by an outline of the factors likely to be responsible for short and rapid sub-Milankovitch climate variations that are superimposed on the predictable changes. Finally the anomalous, relatively constant climate of the last 11.5 ka (Holocene) is highlighted and explained in terms of human input of greenhouse gasses into the Earth's atmosphere. 相似文献
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Widespread empirical evidence suggests that extraterrestrial forcing influences the Earth’s climate, but how this could occur remains unclear. Here we describe a new approach to this problem that unifies orbital, solar and lunar forcing based on their common control of the Earth’s latitudinal insolation gradient (LIG). The LIG influences the climate system through differential solar heating between the tropics and the poles that gives rise to the latitudinal temperature gradient (LTG), which drives the Earth’s atmospheric and (wind driven) ocean circulation. We use spectral analysis of recent changes in the Earth’s LTG to support earlier work on orbital timescales (Davis and Brewer, 2009) that suggests the climate system may be unusually sensitive to changes in the LIG. Identification of LIG forcing of the LTG is possible because the LIG varies according to seasonally specific periodicities based on obliquity in summer (41 kyr orbital and 18.6 yr lunar cycle), and precession (21 kyr orbital cycle) and total solar irradiance (11 yr solar cycle) in winter. We analyse changes in the Northern Hemisphere LTG over the last 120 years and find significant (99%) peaks in spectral frequencies corresponding to 11 years in winter and 18.6 years in summer, consistent with LIG forcing. The cross-seasonal and multi-frequency nature of the LIG signal, and the diffuse effect of the LTG driver on the climate system may account for the complexity of the response to extraterrestrial forcing as seen throughout the climatic record. This hypersensitivity of the LTG to the LIG appears poorly reproduced in climate models, but would be consistent with the controversial theory that the LTG is finely balanced to maximise entropy. 相似文献
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千百年尺度气候快速变化及其数值模拟研究进展 总被引：1，自引：0，他引：1
千百年尺度全球气候快速变化是古气候研究中的一个重要内容。研究发现，末次冰期和全新世都存在着千年、百年尺度的快速气候变化，其变化幅度可以达到典型的地质变化或天文因子所造成的冰期/间冰期的气候振荡幅度，同时这些古气候事件具有全球性。对冰期和全新世气候变化的数值模拟揭示了气候系统对地球轨道参数变化的响应以及海洋、植被、冰盖、温室气体等反馈因子的重要性,其中大洋温盐环流对北大西洋淡水注入的敏感性与末次冰期和全新世气候快速变化密切相联。利用中等复杂程度的气候模式（EMIC）CLIMBER 2模拟了末次冰期典型时段（60~20 ka BP）D/O和Heinrich事件以及东亚气候的响应过程。模拟研究揭示了全新世青藏高原冰雪环境对亚洲—非洲季风气候的显著影响。今后的古气候模拟研究将在改进模式分辨率、结合古气候代用资料确定更加符合历史时期边界条件以进一步改善气候模式的基础上,更加注重气候突变机制的研究以及加强全球变化背景下的区域气候的长期变化研究。 相似文献
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T.C. Partridge P.B. Demenocal S.A. Lorentz M.J. Paiker J.C. Vogel 《Quaternary Science Reviews》1997,16(10):1125-1133
Late Pleistocene variations in rainfall in subtropical southern African are estimated from sediments preserved in the Pretoria Saltpan, a 200000 year-old closed-basin crater lake on the interior plateau of South Africa. We show that South African summer rainfall covaried with changes in southern hemisphere summer insolation resulting from orbital precession. As predicted by orbital precession geometry (Berger, 1978), this South African record is out of phase with North African palaeomonsoon indices (Street and Grove, 1979; Rossignol-Strick, 1983; McIntyre et al., 1989); the amplitude of the rainfall response to insolation forcing agrees with climate model estimates (Prell and Kutzbach, 1987). These results document the importance of direct orbital insolation forcing on both subtropical North and South African climate as well as the predicted antiphase sensitivity to precessional insolation forcing. 相似文献
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ANDREW B. G. BUSH 《Boreas: An International Journal of Quaternary Research》2004,33(2):155-163
Through the late Quaternary, the global climate system ranged from full glacial to temperate interglacial conditions. On a smaller spatial scale, regional climates of the late Quaternary exhibited fluctuations that were at times asynchronous to these global changes. For example, glacier expansion in the Himalayas during the mid-Holocene appears to be at odds with the notion of increased global temperature. A clear understanding of the dynamical processes governing regional climate is therefore essential to the correct interpretation of proxy climate data. We summarize results from numerical simulations of the Last Glacial Maximum (LGM) and the mid-Holocene, and focus on the multiple processes that control regional climate of the Himalaya and surrounding areas, with emphasis on monsoon dynamics and variability. It is shown that changes in the south Asian monsoon (caused by fluctuations in Earth's orbital parameters, by tropical Pacific Ocean temperatures, or by exposure of the Sunda shelf) alter the hydrological balance in regions bordering the Tibetan Plateau, a balance for which there are extensive continental proxy records. Numerical results correlate with the expansion/contraction cycles of deserts near the Chinese Loess Plateau. In addition, the LGM monsoon exhibits significant snow accumulation in the eastern Himalaya, whereas the mid-Holocene monsoon exhibits increased accumulation in the northwestern Himalaya. Simulated changes are therefore in accord with field data and demonstrate that numerical simulations can be a useful tool in the interpretation of regional proxy data, particularly when those data are asynchronous to global records. 相似文献
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古气候数值模拟:进展评述 总被引：5，自引：0，他引：5
数值模拟是古气候研究的一个重要内容。过去30年来,古气候数值模拟研究在相当程度上深化了我们对古气候变化机制的理解。在轨道尺度上,数值模拟证明了冰后期气候系统变化主要是对地球轨道参数变化的响应,同时揭示了温室气体、植被、海洋、冰盖等反馈因子的重要性。针对短尺度气候变化,数值模拟揭示出大洋传送带对北大西洋淡水注入的敏感性。在构造尺度上,数值模拟揭示了气候系统对于高原抬升、海道开合、大陆漂移导致的古地理变化、大气CO2浓度变化和太阳常数变化等的响应,揭示了气候系统突变对驱动因子阈值的敏感性。目前,古气候模拟研究中还存在分辨率不高、模拟结果与记录不完全吻合、模拟的边界条件不清楚等诸多问题。今后古气候模拟研究的改进有赖于模式的改进和计算机运算速度的提高,也有赖于对变化机制的更深理解和对边界条件更精确的重建。 相似文献