A new validation scheme for the evaluation of multiparameter fields     

FRIEDRICH-WILHELM GERSTENGARBE  MARTIN KÜCKEN  PETER C. WERNER 《地球，A辑:动力气象学与海洋学》2005,57(1):35-42

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Simulation of atmospheric CO₂ over Europe and western Siberia using the regional scale model REMO     

ANNE CHEVILLARD  UTE KARSTENS  PHILIPPE CIAIS  SÉBASTIEN LAFONT  MARTIN HEIMANN 《Tellus. Series B, Chemical and physical meteorology》2002,54(5):872-894

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Eurasian ice-sheet interaction in northwestern Russia throughout the late Quaternary     

KURT H. KJæR  EILIV LARSEN  SVEND FUNDER  IGOR N. DEMIDOV  MARIA JENSEN  LENA HAKANSSON  REW MURRAY 《Boreas: An International Journal of Quaternary Research》2006,35(3):444-475

Sediment successions from the Kanin Peninsula and Chyoshskaya Bay in northwestern Russia contain information on the marginal behaviour of all major ice sheets centred in Scandinavia, the Barents Sea and the Kara Sea during the Eemian-Weichselian. Extensive luminescence dating of regional lithostratigraphical units, supported by biostratigraphical evidence, identifies four major ice advances at 100-90, 70-65, 55-45 and 20-18 kyr ago interbedded with lacustrine, glaciolacustrine and marine sediments. The widespread occurrence of marine tidal sediments deposited c. 65-60 kyr ago allows a stratigraphical division of the Middle Weichselian Barents Sea and Kara Sea ice sheets into two shelf-based glaciations separated by almost complete deglaciation. The first ice dispersal centre was in the Barents Sea and thereafter in the Kara Sea. It is possible to extract both flow patterns from ice marginal landforms inside the southward termination. Accordingly, it is proposed that the Markhida line and its western continuation are asynchronous and originate from two separate glaciations before and after the marine transgression. The marine sedimentation occurred during a eustatic sea-level rise of up to 20 m/1000 yr, i.e. the Mezen Transgression. We speculate that the rapid eustatic sea-level rise triggered a collapse of the Barents Sea Ice Sheet at the MIS (Marine Isotope Stage) 4 to 3 transition. This is motivated by lack of an early marine highstand, the timing of events, and the marginal position of Arkhangelsk relative to open marine conditions.  相似文献   

Palaeo-ice streams and the subglacial landscape mosaic of the North American mid-continental prairies     

MARTIN ROSS  JANET E. CAMPBELL  MICHEL PARENT  ROBERTA S. ADAMS 《Boreas: An International Journal of Quaternary Research》2009,38(3):421-439

The analysis of the glacial landscape of southern Saskatchewan (Canada) through multiple data sets (e.g. digital elevation model, till compositional data) has revealed previously unrecognized subglacial sediment–landform assemblages. A southwest-trending corridor of mega-scale till lineations (Maskwa corridor) bounded on each side by hummocky terrain extends from the Canadian Shield to southwestern Saskatchewan. This landform assemblage is clearly cross-cut by a broad south to southeast trending corridor (Buffalo corridor) consisting of subparallel curvilinear till ridges. The carbonate content of the surface till is spatially consistent within these assemblages, suggesting a strong sediment–landform relationship. The two corridors are interpreted as the product of palaeo-ice streams. The Maskwa palaeo-ice stream flowed up the regional slope and across preglacial valleys, indicating it was thick and stable. Narrow dispersal trains extending across as well as down-glacier from the Athabasca Basin suggest that the Maskwa palaeo-ice stream extended far into the ice sheet across contrasting shield and platform terrains. In comparison, the Buffalo palaeo-ice stream was thinner and largely controlled by subglacial geology and topography. Its catchments were located at the Canadian Shield boundary and the system was oriented along-slope. It experienced lateral shifts and it was fed by a network of tributaries. The glacial dynamics shift from the Maskwa to the Buffalo system occurred at about 13.5 ¹⁴C kyr BP. The Buffalo system later evolved into thin outlet lobes until final deglaciation of the area. The proposed model has implications for ice-sheet reconstruction and the assessment of till properties in the prairies and in similar terrains.  相似文献   

Spatial distribution and optical properties of Saharan dust observed by airborne high spectral resolution lidar during SAMUM 2006     

By MICHAEL ESSELBORN  MARTIN WIRTH  REAS FIX  BERNADETT WEINZIERL  KATHARINA RASP  MATTHIAS TESCHE  ANDREAS PETZOLD 《Tellus. Series B, Chemical and physical meteorology》2009,61(1):131-143

Airborne measurements of pure Saharan dust extinction and backscatter coefficients, the corresponding lidar ratio and the aerosol optical thickness (AOT) have been performed during the Saharan Mineral Dust Experiment 2006, with a high spectral resolution lidar. Dust layers were found to range from ground up to 4–6 km above sea level (asl). Maximum AOT values at 532 nm, encountered within these layers during the DLR Falcon research flights were 0.50–0.55. A significant horizontal variability of the AOT south of the High Atlas mountain range was observed even in cases of a well-mixed dust layer. High vertical variations of the dust lidar ratio of 38–50 sr were observed in cases of stratified dust layers. The variability of the lidar ratio was attributed to dust advection from different source regions. The aerosol depolarization ratio was about 30% at 532 nm during all measurements and showed only marginal vertical variations.  相似文献   

Depositional environments and sea-level changes deduced from Middle Weichselian tidally influenced sediments, Arkhangelsk region, northwestern Russia     

MARIA JENSEN  EILIV LARSEN  IGOR N. DEMIDOV  SVEND FUNDER  KURT H. KJæR 《Boreas: An International Journal of Quaternary Research》2006,35(3):521-538

Deposits from a Middle Weichselian transgression, the Mezen Transgression, are found in coastal sections in the Mezen and Chyorskaya Bays, northwestern Russia. The marine event is bracketed between two ice advances from the Barents and Kara Sea shelves and dated by Optically Stimulated Luminescence (OSL) to around 60 kyr BP. The deposits represent a shallowing upward succession from offshore marine to intertidal coastal environments. Relative sea-level maximum was at least 40 m above the present owing to significant isostatic subsidence. The sedimentary record is dominated by shallow-marine, subtidal deposits bounded below by an erosion surface representing a downward shift in facies and above by subaerial exposure. The succession reflects deposition during forced regression due to isostatic uplift. A rapidly aggrading succession of subtidal deposits at one site suggests a relative sea-level rise or stillstand superimposed on the isostatically controlled sea-level fall. The rhythmic tidal deposits allow identification of semi-monthly to yearly cycles, providing an estimate of the sedimentation rate of 39 cm/year. This implies a high sediment yield and a rapid relative sea-level rise. We correlate this signal with the rapid eustatic sea-level rise at the end of OIS 4 known from deep-sea records.  相似文献   

Some Implications of the Intemationalisation of Commercial Capital for New Zealand     

MARTIN PERRY 《New Zealand geographer》1991,47(1):26-31

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Till stratigraphy and ice movements in eastern Overijssel, The Netherlands     

SJOERD J. KLUIVING  MARTIN RAPPOL  DICK VAN DER WATEREN 《Boreas: An International Journal of Quaternary Research》1991,20(3):193-205

A three–till section in eastern Overijssel, eastern Netherlands, represents the most complete till sequence of the Older Saalian glaciation presently known from The Netherlands and adjacent Germany. On the basis of structural analyses, four different glacial events within one continuous glacial cover can be distinguished: (1) deposition of till 1 (lowest till) by ice probably moving in a southerly direction, (2) glaciotectonic dislocation of till 1 under a compressive strain regime acting towards the west, (3) deposition of till 2 by ice moving in a westerly direction, and (4) deposition of till 3 by southeasterly moving ice. During deposition of tills 2 and 3, the underlying older tills were subjected to a strong extensional tectonic regimc, leading among other things to the development of characteristic sheath folds. On the basis of directional and compositional characteristics, the three tills can be correlated with the till stratigraphy of the northern Netherlands.  相似文献   

Continental/Cordilleran ice interactions: a dominant cause of westward super-elevation of the last glacial maximum continental ice limit in southwestern Alberta, Canada     

EDWARD C. LITTLE  LIONEL E. JACKSON Jr.  THOMAS S. JAMES  STEPHEN R. HICOCK  ELIZABETH R. LEBOE 《Boreas: An International Journal of Quaternary Research》2001,30(1):43-52

In southwestern Alberta, Canada, a westward-rising last-glacial-maximum continental ice limit has been identified. This limit is defined by the upper elevation of Canadian Shield erratics deposited by last-glacial-maximum continental ice along the flanks of prominent ridges and buttes within the region. The interpolation between ice-limit data points has produced two distinct slope profiles: 2.9 m/km to the east, and 4.2 m/km to the west of Mokowan Butte. Three hypotheses are proposed to explain this westward rise of the last-glacial-maximum continental ice limit: (1) regional tectonic uplift, (2) glacio-isostatic uplift, and (3) continental ice-flow convergence due to topographic obstacles and interaction with montane ice. Inferred long-term rates of tectonic uplift and glacio-isostatic modelling show that these two mechanisms account for less than 25% of the observed absolute elevation increase of the limit between the Del Bonita uplands and Cloudy Ridge in southwestern Alberta. The remaining rise in elevation of the continental ice-sheet margin in this region is thought to result from continental ice-flow convergence due to the combined effects of the regional topography and interaction with montane glaciers to the west. The steeper rise in the former continental ice surface west of Mokowan Butte can be explained by the topographic obstruction and interaction with montane glaciers in the area of the Rocky Mountain front.  相似文献   

Modelling the long-range transport of ²²²Rn to subantarctic and antarctic areas     

MARTIN HEIMANN†  PATRICK MONFRAY†‡  GEORGES POLIAN‡ 《Tellus. Series B, Chemical and physical meteorology》1990,42(1):83-99

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