Intercomparison of fog water samplers     

DIETER SCHELL  HANS-WALTER GEORGII  ROLF MASER  WOLFGANG JAESCHKE  BEATE G. ARENDS  GERARD P. A. KOS  PETER WINKLER  THOMAS SCHNEIDER  AXEL BERNER  CHRISTIAN KRUISZ 《Tellus. Series B, Chemical and physical meteorology》1992,44(5):612-631

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A New Video and Digital Camera System for Studies of the Dynamics of Microtopographic Features on Tidal Flats     

LARS CHRESTEN LUND-HANSEN  EINER LARSEN  KURT THOMAS JENSEN  KIM N. MOURITSEN  CHRISTIAN CHRISTIANSEN  THORBJØRN JOEST ANDERSEN 《Marine Georesources & Geotechnology》2013,31(1-2):115-122

A newly developed video and camera system for tidal flat microtopographic studies is presented. It consists of a SONY handy cam placed in an underwater housing mounted on a frame about 70?cm above the sediment surface. A rectangular surface area of 30?×40?cm is imaged by the camera. The camera records video sequences and/or digital images at predetermined time lapses. The total number of images is about 540, and a similar number of 10-second long video sequences can be recorded. The camera is programmed with a PC before deployment, and the total deployment time depends on the time lapse between recordings. The camera is connected to an external power supply (12?volt), and a halogen projector pointing towards the sediment surface ensures that the system is operable on a 24-hours scale. The system has been tested in the Danish Wadden Sea. It has proved to be a very useful tool in studies of topographic effects of erosion and deposition sequences, and for studies of benthic organisms-sediment interactions. The test site was further equipped with sensors for water and seabed measurements, which proved to be indispensable regarding the interpretation of recorded image time-series.  相似文献   

Synthesis of a spinifex‐textured basalt as an analog to Gusev crater basalts,Mars     

Nicolas BOST  Frances WESTALL  Fabrice GAILLARD  Claire RAMBOZ  Frédéric FOUCHER 《Meteoritics & planetary science》2012,47(5):820-831

Abstract– Analyses by the Mars Exploration Rover (MER), Spirit, of Martian basalts from Gusev crater show that they are chemically very different from terrestrial basalts, being characterized in particular by high Mg‐ and Fe‐contents. To provide suitable analog basalts for the International Space Analogue Rockstore (ISAR), a collection of analog rocks and minerals for preparing in situ space missions, especially, the upcoming Mars mission MSL‐2011 and the future international Mars‐2018 mission, it is necessary to synthesize Martian basalts. The aim of this study was therefore to synthesize Martian basalt analogs to the Gusev crater basalts, based on the geochemical data from the MER rover Spirit. We present the results of two experiments, one producing a quench‐cooled basalt (<1 h) and one producing a more slowly cooled basalt (1 day). Pyroxene and olivine textures produced in the more slowly cooled basalt were surprisingly similar to spinifex textures in komatiites, a volcanic rock type very common on the early Earth. These kinds of ultramafic rocks and their associated alteration products may have important astrobiological implications when associated with aqueous environments. Such rocks could provide habitats for chemolithotrophic microorganisms, while the glass and phyllosilicate derivatives can fix organic compounds.  相似文献   

The research front in Arctic Quaternary geology     

CHRISTIAN HJORT 《Boreas: An International Journal of Quaternary Research》1986,15(3):216-216

Book reviewed in this article:
Andrews, J. T. (ed.) 1985. Quaternary Environments: Eastern Canadian Arctic, Baffin Bay and Western Greenland  相似文献   

Quaternary International     

CHRISTIAN HJORT 《Boreas: An International Journal of Quaternary Research》1990,19(2):126-126

Book reviewed in this article:
Quaternary International. Edited by N. Rutterin associationwith N. R. Catto  相似文献   

Glacial history of interior Jameson Land, East Greenland     

PER MöLLER  CHRISTIAN HJORT  LENA ADRIELSSON  OTTO SALVIGSEN 《Boreas: An International Journal of Quaternary Research》1994,23(4):320-348

The plateaus between 400 and 800 m a.s.l. around the water-divides on central and eastern Janieson Land are covered by the 'Jameson Land Drift' up to 50 m thick glacial. placiotluvial and glaciolacustrine deposits. A high content of far-travelled wcsterii rocks indicates the overriding by extensive glaciers channelled from the west through the Scoresby Sund basin. The Jameson Land Drift deposits have bccn lithostratigraphically divided into two groups. each representing the sedimentary successions from one glaciation in the wider sense of the word. sediments from the lower Lollandselv glaciation are upwards delimited by a distinct periglacial surface. TL-dates suggest a prc-Saalian (approximately isotope stages 11–9) age. The following Scoreshby Sund glaciation . when most of the studied Jameson Land Drift sediments were laid down. is of Saalian age (e. isotope stages 8 6). The deposits from the Scoresby Sund glaciation are interpreted as representing a complete glaciation deglaciation succession, including proglacial sandur and glaciolacustrine sediments. followed by till deposition, with an overlying succession of glaciolacustrinc and glaciofluvial sediments. From 200–250 m to c . 400 m a.s.l. there is a driftless area, exposing Jurassic sandstones, probably a result of intensive and long-lasting periglacial erosion. Extensive occurrences of tors and of glaciofluvially (subglacially as well as subaerially) eroded canyons and channels characterize the landscape. A similar. although less well defined. upper driftless zone is found above c 500 m a.s.l. on northern Jameson Land, north of the drift-covered plateaus. During the Wcichsclian (isotope stages 5d 2). thick glacial. fluvial and marine deposits were laid down in a coastal zone below c . 200 m a.s.l., and only cold-based local ice caps seem to have existed on the interior plateaus of Jameson Land. The now driftless areas were characterized by periglacial erosion during this period.  相似文献   

Getting to know your neighbours a little better?     

CHRISTIAN HJORT 《Boreas: An International Journal of Quaternary Research》1985,14(4):334-334

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Glacial history and shoreline displacement on Erdmannflya and Bohemanflya, Spitsbergen, Svalbard     

OTTO SALVIGSEN  ANNE ELGERSMA  CHRISTIAN HJORT  ERIK LAGERLUND  OLAV LIESTØL  NILS-OLOF SVENSSON 《Polar research》1990,8(2):261-273

Traces of former glaciation were studied on Erdmannflya and Bohemanflya. Both peninsulas were probably completely covered by glaciers during the Late Weichselian and the final dcglaciation took place around years BP. Esmarkbreen readvanced shortly after 9,500 BP, probably a local and shortlasting event. Raised beaches occur to about 60 m above sea level, and date back to about 10,000 BP. Initial land emergence was rapid, about 3m/100 years. It seems to have been followed by a marine transgression between 8,500 and 7,500 BP, which resulted in a large and distinct beach bridge and marine abrasion cliffs about 10-12 m above present sea level. Mytilus edulis lived in the area between at least 9.000 and 5,000 BP. Five thousand years ago relative sea level probably stood 3-4 m higher than today. Relative sea level has remained close to present during the last centuries. Different positions of glacier fronts in this century have also been mapped.  相似文献   

Seasonal and annual variations in the photosynthetic productivity and carbon balance of a central Siberian pine forest   总被引：9，自引：0，他引：9  

JON LLOYD  OLGA SHIBISTOVA  DANIIL ZOLOTOUKHINE  OLAF KOLLE  ALMUT ARNETH  CHRISTIAN WIRTH  JULIE M. STYLES  N. M. TCHEBAKOVA  E.-DETLEF SCHULZE 《Tellus. Series B, Chemical and physical meteorology》2002,54(5):590-610

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ATTILA: atmospheric tracer transport in a Lagrangian model   总被引：2，自引：0，他引：2  

CHRISTIAN REITHMEIER  ROBERT SAUSEN 《Tellus. Series B, Chemical and physical meteorology》2002,54(3):278-299

The model ATTILA has been developed to treat the global-scale transport of passive trace species in the atmosphere within the framework of a general circulation model (GCM). ATTILA runs online within the GCM ECHAM4 and advects the centroids of 80.000 to 190.000 constant mass air parcels. Each trace constituent is thereby represented by a mass mixing ratio in each parcel. ATTILA contains state-of-the-art parameterizations of convection, turbulent boundary layer mixing and inter-parcel transport, and provides an algorithm to map the tracer concentrations from the trajectories to the ECHAM model grid. The transport characteristics of ATTILA are evaluated against observations and the standard semi-Lagrangian transport scheme of ECHAM by two experiments. (1) We simulate the distribution of the short-lived tracer radon (²²²Rn) in order to examine fast vertical transport over continents, and long-range transport from the continents to remote areas. (2) We simulate the distribution of radiocarbon (¹⁴C) from nuclear weapon tests in order to examine upper tropospheric and stratospheric transport characteristics. Contrary to the semi-Lagrangian scheme, ATTILA shows a greatly reduced meridional transport in the upper troposphere and lower stratosphere, and a reduced downward flux from the stratosphere to the troposphere, especially in mid-latitudes. Since ATTILA is a numerically non-diffusive scheme, it is able to maintain steep gradients, which compare better to the observations than the rather smooth gradients produced by the semi-Lagrangian scheme.  相似文献