地貌学与第四纪研究的新手段——陆地宇生核素研究   总被引：3，自引：1，他引：3  

徐孝彬  王建  Francoise Yiou  Grant Raisbeck 《地理科学》2002,22(5):587-591

暴露岩石表层中的宇生核素的浓度，是产生速率、衰变常数及侵蚀速率的函数。根据该原理，在宇生核素形成速率为已知的条件下，建立宇生核素浓度与时间及侵蚀速率的函数关系，根据该模式可对岩面的暴露时间及侵蚀速度进行计算，这使得该测年技术在地貌学与第四纪研究中有着极大的运用前景。在众多的宇生核素中，取自于石英的^26Al和^10Be是目前该领域中运用最广泛、最成熟的宇生核素。  相似文献   

Cosmogenic Be dating of the Salpausselkä I Moraine in southwestern Finland     

Vincent R. Rinterknecht  Peter U. Clark  Grant M. Raisbeck  Franoise Yiou  Edward J. Brook  Silvio Tschudi  Juha P. Lunkka 《Quaternary Science Reviews》2004,23(23-24):2283-2289

We determined in situ cosmogenic ¹⁰Be ages for nine boulders sampled on the Salpausselkä I (Ss I) Moraine. Previous dating of this moraine indicated that it formed during the Younger Dryas Stadial along the southern margin of the Scandinavian Ice Sheet in southern Finland. Our new exposure ages range from 10.9±1.0 to 13.5±1.2 ¹⁰Be ka, with an error-weighted mean age of 12.4±0.7 ¹⁰Be ka. Our results confirm four previous ¹⁰Be ages obtained 40 km northeast of our sample location. The combined data (n=13) indicate that retreat from the Ss I Moraine occurred at 12.5±0.7 ¹⁰Be ka, in excellent agreement with an age of 12.1 ka for retreat from the Ss I Moraine based on varve chronologies. These results identify the Ss I Moraine as among the best-dated margins associated with Late Quaternary ice sheets.  相似文献   

Simulated changes in the relationship between tropical ocean temperatures and the western African monsoon during the mid-Holocene     

Y. Zhao  P. Braconnot  S. P. Harrison  P. Yiou  O. Marti 《Climate Dynamics》2007,28(5):533-551

Results from nine coupled ocean-atmosphere simulations have been used to investigate changes in the relationship between the variability of monsoon precipitation over western Africa and tropical sea surface temperatures (SSTs) between the mid-Holocene and the present day. Although the influence of tropical SSTs on the African monsoon is generally overestimated in the control simulations, the models reproduce aspects of the observed modes of variability. Thus, most models reproduce the observed negative correlation between western Sahelian precipitation and SST anomalies in the eastern tropical Pacific, and many of them capture the positive correlation between SST anomalies in the eastern tropical Atlantic and precipitation over the Guinea coastal region. Although the response of individual model to the change in orbital forcing between 6 ka and present differs somewhat, eight of the models show that the strength of the teleconnection between SSTs in the eastern tropical Pacific and Sahelian precipitation is weaker in the mid-Holocene. Some of the models imply that this weakening was associated with a shift towards longer time periods (from 3–5 years in the control simulations toward 4–10 years in the mid-Holocene simulations). The simulated reduction in the teleconnection between eastern tropical Pacific SSTs and Sahelian precipitation appears to be primarily related to a reduction in the atmospheric circulation bridge between the Pacific and West Africa but, depending on the model, other mechanisms such as increased importance of other modes of tropical ocean variability or increased local recycling of monsoonal precipitation can also play a role.  相似文献   

Testing asynchronous coupling on simple “ocean-atmosphere” dynamic systems     

M. A. Dubois  P. Yiou 《Climate Dynamics》1999,15(1):1-7

 Simulations of long-term climatic variations require the use of coupled oceanic and atmospheric models. Given their different scales in space and time and present computing limitations, asynchronous coupling schemes are often used. Comparing the evolutions of simple dynamic systems which we couple alternatively with synchronous and asynchronous schemes, we show that the behaviour can be modified, not only in minute details, but drastically, if asynchronous coupling is used with insufficient care. We study how it happens, then suggest methods to insure that the average behaviour of more realistic models is not modified with asynchronous schemes. Other branches of physics with coupled non-linear systems could make use of these remarks. Received: 19 February 1997 / Accepted: 17 June 1998  相似文献   

技术关联性、复杂性与区域多样化——来自中国地级市的证据   总被引：1，自引：0，他引：1  

马双  曾刚  张翼鸥 《地理研究》2020,39(4):865-879

忽视现实基础,盲目追求新兴产业的现象普遍存在于当前中国的一些城市。基于国家知识产权局的专利数据,描绘1987—2016年中国地级市技术关联性和复杂性的时空演化特征,探讨两者对区域技术进入和增长的影响。结果表明：① 新技术的本地关联度越高,就越有可能进入该地区;现有技术的本地关联度越低,就越容易退出该地区;② 中国城市的技术发展总体上呈现路径依赖特点。其中,东部地区的技术关联性和复杂性变化较大,中西部地区变化较小;③ 技术关联性对新技术的进入和增长起到显著的促进作用。在引入复杂性较高的技术时,只有存在较高关联性才会促进区域的技术进步。最后提出的区域多样化发展框架,可为决策者权衡选择技术发展道路提供参考。  相似文献   

Grapevine harvest dates in Besan?on (France) between 1525 and 1847: Social outcomes or climatic evidence?     

E. Garnier  V. Daux  P. Yiou  I. Garc��a de Cort��zar-Atauri 《Climatic change》2011,104(3-4):703-727

We present a unique contextualised series of grape harvest dates (GHD) from Besançon, Eastern France, from the early sixteenth to the mid nineteenth century. The GHD series was processed to remove as far as possible health-medical and socio-political influences. It is well correlated with temperature indices determined from other documentary sources. However, we find that the relation between the GHD-series and the occurrence of meteorological processions is not convincing. At the inter-annual scale the Besançon GHD-series is highly correlated with the corresponding GHD-series from Germany, Switzerland and Burgundy (France) and to instrumental temperature series from England and the Netherlands. On the other hand, the series are not correlated to one another at the multidecadal scales. The origins of this decoupling remain to be elucidated.  相似文献   

Ensemble reconstruction of the atmospheric column from surface pressure using analogues   总被引：1，自引：1，他引：0  

Pascal Yiou  Tamara Salameh  Philippe Drobinski  Laurent Menut  Robert Vautard  Mathieu Vrac 《Climate Dynamics》2013,41(5-6):1333-1344

We present a statistical method to reconstruct continuous atmospheric fields on various pressure levels, given a constraint at the surface. The method is based on analogues of circulation and taking into consideration the time sequence of the analogues. The method is tested on the 2001–2011 period, with an emphasis on the year 2010. We base the atmospheric reconstruction on reanalysis data from 1948 to 2000, and use a constraint of sea-level pressure for 2001–2011. The pattern correlation scores appear to be significant most of the time, although score flaws are occasionally detected. Those flaws are mainly due to the time continuity constraint that is imposed on the reconstruction, which lowers the possibility of finding matching analogues. This method offers an ensemble of atmospheric reconstructions, and presents a computationally cheap alternative to data assimilation for a climate model, although with lower scores.  相似文献   

中国关于气候变化归因和责任的研究进展与展望     

张轶鸥  丑洁明  董文杰 《干旱气象》2013,(1):174-181

首先对2000～2011年中国关于气候变化归因和责任研究的相关文献进行分类统计,归纳总结了中国最近十余年的研究进展,在此基础上,对于现阶段研究及存在的问题进行了初步讨论。提出我国在气候变化归因与责任领域研究的基本框架和大体趋势已经确立,"气候变化原因"研究,应在强化多方全面研究和改进研究工具的同时,注重人为原因的探究,将人为原因的探究作为今后研究的重点方向;气候变化责任的研究,应在坚持"共同但有区别责任"立场的前提下,寻求更有力的技术支持,特别是需要构建"全球有序应对气候变化"的研究体系,开展更为全面的地球系统科学模拟研究。  相似文献   

Assessing climate change impacts on European wind energy from ENSEMBLES high-resolution climate projections     

Isabelle Tobin  Robert Vautard  Irena Balog  François-Marie Bréon  Sonia Jerez  Paolo Michele Ruti  Françoise Thais  Mathieu Vrac  Pascal Yiou 《Climatic change》2015,128(1-2):99-112

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10Be exposure age constraints on the Late Weichselian ice‐sheet geometry and dynamics in inter‐ice‐stream areas,western Svalbard     

Jon Y. Landvik  Edward J. Brook  Lyn Gualtieri  Henriette Linge  Grant Raisbeck  Otto Salvigsen  Françoise Yiou 《Boreas: An International Journal of Quaternary Research》2013,42(1):43-56

The Late Weichselian ice sheet of western Svalbard was characterized by ice streams and inter‐ice‐stream areas. To reconstruct its geometry and dynamics we investigated the glacial geology of two areas on the island of Prins Karls Forland and the Mitrahalvøya peninsula. Cosmogenic ¹⁰Be surface exposure dating of glacial erratics and bedrock was used to constrain past ice thickness, providing minimum estimates in both areas. Contrary to previous studies, we found that Prins Karls Forland experienced a westward ice flux from Spitsbergen. Ice thickness reached >470 m a.s.l., and warm‐based conditions occurred periodically. Local deglaciation took place between 16 and 13 ka. At Mitrahalvøya, glacier ice draining the Krossfjorden basin reached >300 m a.s.l., and local deglaciation occurred at c. 13 ka. We propose the following succession of events for the last deglaciation. After the maximum glacier extent, ice streams in the cross‐shelf troughs and fjords retreated, tributary ice streams formed in Forlandsundet and Krossfjorden, and, finally, local ice caps were isolated over both Prins Karls Forland and Mitrahalvøya and their adjacent shelves.  相似文献