冬春季格陵兰海冰变化与初夏中国气温/降水关系的初步分析   总被引：3，自引：5，他引：3  

陈明轩  管兆勇  徐海明 《高原气象》2003,22(1):7-13

采用英国Hadley中心GISST海冰面积资料，NCEP／NCAR再分析资料以及中国地面降水和气温资料，运用EOF分解，小波分析和合成分析等方法，初步探讨了格陵兰岛两侧附近冬春季海冰面积变化特征及其与初夏6月中国气温和降水的关系，结果表明，格陵兰岛东西两侧海冰面积呈显著反相变化，并且具有明显的年际和年代际周期性振荡，冬春季格陵兰－寻威海海冰与初夏6月中国长江以北气温（降水）正相关（反相关），与长江以南气温（降水）反相关（正相关），而对于戴维斯海峡－拉布拉多海海冰则具有相反的相关型，大尺度500hPa环流合成分析初步表明，冬春季格陵兰附近海冰面积变化伴随着北极极涡环流和北半球阻塞高压的持续异常，海冰变化可能是影响初夏中国气温和降水的因子之一。  相似文献   

Preliminary palaeomagnetic results of an Archaean dolerite dyke of west Greenland: geomagnetic field intensity at 2.8 Ga     

Chiyo Morimoto  Yo-ichiro Otofuji  Masako Miki  Hidefumi Tanaka  Tetsumaru Itaya 《Geophysical Journal International》1997,128(3):585-593

The geomagnetic field intensity during Archaean times is evaluated from a palaeomagnetic and chronological study of a dolerite dyke intruded into the 3000 Ma Nuuk Gneisses at Nuuk (64.2°N, 51.7°W), west Greenland. Plagioclase from the dolerite dyke yields a mean K-Ar age of 2752 Ma. Palaeomagnetic directions after thermal demagnetization of the dyke and the gneiss reveal a positive baked-contact test, indicating that the high-temperature-component magnetization of the dyke is primary. Thellier experiments on 12 dyke specimens yield a palaeointensity value of 13.5±4.4 μT. The virtual dipole moment at ca. 2.8 Ga is 1.9±0.6 × 10²² Am², which is about one-quarter of the present value. The present study and other available data imply that the Earth's magnetic field at 2.7 ∼ 2.8 Ga was characterized by a weak dipole moment and that a fairly strong geomagnetic field similar to the present intensity followed the weak field after ca. 2.6 Ga.  相似文献   

Magma flow in the East Greenland dyke swarm inferred from study of anisotropy of magnetic susceptibility: magmatic growth of a volcanic margin   总被引：2，自引：0，他引：2  

Jean-Paul Callot  Laurent Geoffroy 《Geophysical Journal International》2004,159(2):816-830

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The crustal structure of central East Greenland—I: From the Caledonian orogen to the Tertiary igneous province     

Mechita C. Schmidt-Aursch  Wilfried Jokat 《Geophysical Journal International》2005,160(2):736-752

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Re-exposed basement landforms in the Disko region, West Greenland — disregarded data for estimation of glacial erosion and uplift modelling   总被引：1，自引：1，他引：1  

Johan M. Bonow   《Geomorphology》2005,72(1-4):106-127

Classifications of large-scale landscapes in Greenland have traditionally been based on type and intensity of glacial erosion, with the general idea that present landforms are mainly the result of erosion from ice sheets and glaciers. However, on southern Disko and in areas offshore in Disko Bugt, a basement surface has preserved remnants of weathered gneiss and pre-Paleocene landforms, recently exhumed from Paleocene basalt. Isolated hills and lineaments have been mapped in a digital terrain model and aerial photographs. Offshore have hills been mapped from seismic lines. The medium size bedrock forms on southern Disko as tors, clefts and roche moutonées have been studied in the field. Remnant saprolites were inventoried, sampled and analysed according to grain size and clay mineralogy. The basement surface retains saprolites up to 8 m thick in close relation to the cover rocks. The landforms in the basement rocks belong essentially to an etched surface only slightly remodelled by glacial erosion and, below the highest coastline, also by wave action. The outline of hills is governed by two lineament directions, ENE–WSW representing the schistocity of the gneiss and NW–SE fracture zones. These structures are thus interpreted to have been exploited by the deep weathering while the frequent N–S lineaments have not and thus might be younger. Main ice-flow has been from the NE and has resulted in plucking of SW facing lee sides, however the resulting bedrock forms are mainly controlled by structures and orientation of joints. The identification of re-exposed sub-Paleocene etch forms on Disko and the hills of similar size offshore, forming a hilly relief, have implications for identification of a hilly relief south of Disko Bugt, its relation to younger planation surfaces as well as for conclusions of uplift events.  相似文献   

Significant differences in late Quaternary bedrock erosion and transport: East versus West Greenland ∼70°N – evidence from the mineralogy of offshore glacial marine sediments          下载免费PDF全文

JOHN T. ANDREWS  ANDERS A. BJORK  DENNIS D. EBERL  ANNE E. JENNINGS  EMILY P. VERPLANCK 《第四纪科学杂志》2015,30(5):452-463

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Paleoenvironments during Younger Dryas‐Early Holocene retreat of the Greenland Ice Sheet from outer Disko Trough,central west Greenland          下载免费PDF全文

ANNE E. JENNINGS  MARIAH E. WALTON  COLM Ó COFAIGH  AOIBHEANN KILFEATHER  JOHN T. ANDREWS  JOSEPH D. ORTIZ  ANNE DE VERNAL  JULIAN A. DOWDESWELL 《第四纪科学杂志》2014,29(1):27-40

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High‐Arctic climate conditions for the last 7000 years inferred from multi‐proxy analysis of the Bliss Lake record,North Greenland     

Jesper Olsen  Kurt H. Kjær  Svend Funder  Nicolaj K. Larsen  Anna Ludikova 《第四纪科学杂志》2012,27(3):318-327

The Arctic is more vulnerable to climate change than are mid latitudes. Therefore, palaeolimnological studies from the High Arctic are important in providing insights into the dynamics of the climate system. Here we present a multi‐proxy study from one of the world's northernmost lakes: Bliss Lake, Peary Land, Greenland. The early Holocene (10 850–10 480 cal. a BP) is characterized by increased erosion and gradually more marine conditions. Full marine conditions developed from 10 480 cal. a BP until the lake was isolated at 7220 cal. a BP. From its marine isolation at 7220 cal. a BP Bliss Lake becomes a lacustrine environment. Evidence from geochemical proxies (δ¹³C and total organic carbon) suggests that warmer conditions prevailed between 7220 and 6500 cal. a BP, corresponding to the Holocene thermal maximum, and from 3300 until 910 cal. a BP. From 850 to 500 cal. a BP colder climate conditions persisted. The transition from warmer to colder climate conditions taking place around 850 cal. a BP may be associated with the transition from the Medieval Warm Period to the Little Ice Age. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Establishment of modern circulation pattern at c. 6000 cal a BP in Disko Bugt,central West Greenland: opening of the Vaigat Strait     

KERSTIN PERNER  MATTHIAS MOROS  IAN SNOWBALL  JEREMY M. LLOYD  ANTOON KUIJPERS  THOMAS RICHTER 《第四纪科学杂志》2013,28(5):480-489

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Constraining Holocene 10Be production rates in Greenland     

Jason P. Briner  Nicolás E. Young  Brent M. Goehring  Joerg M. Schaefer 《第四纪科学杂志》2012,27(1):2-6

The absence of a production rate calibration experiment on Greenland has limited the ability to link ¹⁰Be exposure dating chronologies of ice‐margin change to independent records of rapid climate change. We use radiocarbon age control on Holocene glacial features near Jakobshavn Isbræ, western Greenland, to investigate ¹⁰Be production rates. The radiocarbon chronology is inconsistent with the ¹⁰Be age calculations based on the current globally averaged ¹⁰Be production rate calibration data set, but is consistent with the ¹⁰Be production rate calibration data set from north‐eastern North America, which includes a calibration site nearby on north‐eastern Baffin Island. Based on the best‐dated feature available from the Jakobshavn Isbræ forefield, we derive a ¹⁰Be production rate value of 3.98 ± 0.24 atoms g a^?1, using the ‘St’ scaling scheme, which overlaps with recently published reference ¹⁰Be production rates. We suggest that these ¹⁰Be production rate data, or the very similar data from north‐eastern North America, are used on Greenland. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献