Le Sahara: géomorphologie et paléogéomorphologie éoliennes in The Sahara and the Nile. Quaternary environments and prehistoric occupation in northern Africa.
support the view that from the Red Sea to the Atlantic the Sahara operates as a dynamic unit with respect to wind action. The movement of sand is in harmony with the trade wind circulation, except where the sand flows around major topographic obstacles
At the present time wind is the most active geomorphic agent in the Sahara. In addition, fixed dunes along the margins of the desert testify to the former extent of wind action during times of even drier climate. Satellite images and air photos
Distribution of quartz in late Quaternary Atlantic sediments in relation to climate
Sahara avait une situation beaucoup plus méridionale lors de la dernière glaciation| de même la bande que l'on trouve actuellement au large du Groenland et du Labrador en relation avec le transport de sable par les glaces flottantes. Par ailleurs
Case studies of tropical atlantic surface circulation patterns during recent sub-saharan weather anomalies: 1967 and1968
L'A. cherche à mettre en relation la circulation atmosphérique à grande échelle et les conditions de surface, sur l'Atlantique tropical (30N-30S) avec les anomalies pluviométriques observées en Afrique occidentale, au sud du Sahara (10-20N). Par
Major change in Atlantic deep and bottom waters 700,000 yr ago: benthonic foraminiferal evidence from the South Atlantic
Analysis of the benthonic foraminiferal faunas in two sediment cores recovered from the Vema and Hunter Channels in the western South Atlantic shows that the level of the transition between deep and bottom waters shallowed sharply about 700,000 yr
ago. This rise indicates a sharp, sustained increase in the volume of bottom water flowing through the South Atlantic after this time. Prior to about 700,000 yr ago, the amount of Antarctic Bottom Water entering the western South Atlantic was greatly
reduced and Circumpolar Deep Water apparently accounted for the bulk of northward flow. Production of southward-flowing North Atlantic Deep Water seems not to have been affected. The timing of this change in circulation regime suggests a possible causal
Discussion of the results of the investigations of organic matter in the SW Atlantic, in the Polar Frontal Zone. The present goal was organic matter distribution at the period of its accumulation and bacterioplankton activization anomalously warm
Forms of unusual patterned ground: examples from the Falkland Islands, South Atlantic
Aeolian features ; Atlantic Ocean ; Earth surface processes ; Island ; Lacustrine sediment ; Patterned ground ; Peat ; Sand ; Sediment transport ; South Atlantic Ocean
This paper descibes the characteristics of, and outlines the most likely origins for, three forms of unusual patterned ground observed in the Falkland Islands, South Atlantic. The features here described are not products of frost-related processes
L'A. s'élève contre l'usage fréquent aux Etats-Unis des expressions Middle Atlantic Bight et South Atlantic Bight pour désigner la côte des Middle Atlantic States et celle des états du Sud-Est, de la Caroline du Nord à la Floride. Les termes
employés conduisent à des aberrations dans les indexations par ordinateur. Il propose de leur subsistuer les formules : Off the Middle Atlantic States et Coastal Waters of the Southern US Atlantic States. - (FC)
Africa ; Atlantic Ocean ; Atmospheric dynamics ; Climatic warming ; Holocene ; Meltwater ; Monsoon ; North Atlantic Ocean ; Ocean atmosphere interaction ; Palaeoclimate ; Precipitation ; South Atlantic Ocean ; Surface temperature ; Surface water
The deglacial pattern of a high-resolution alkenone-derived temperature record from the southeastern tropical Atlantic was compared with one from the northeastern subtropical Atlantic. During Termination 1b, surface waters in the eastern tropical
Atlantic (6°S) reached modern temperatures, whereas those in the subtropical northeastern Atlantic (21°N) were still considerably colder than today. This asymmetrical warming may reflect meltwater-induced reductions in the northward heat transport and helps
Linkages between atmospheric circulation, climate and streamflow in the northern North Atlantic : research prospects
Atlantic Ocean ; Atmospheric circulation ; Canada ; Climate ; Climate oscillation ; Climatic anomaly ; Iceland ; Model ; North Atlantic Ocean ; Northern Europe ; Ocean atmosphere interaction ; Precipitation ; Stream flow ; United States of America
The main focus lies with climatic and hydrologic implications of the major circulation patterns in the northern North Atlantic, namely the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO). The studies reviewed here reveal key
relationships between circulation, climate and streamflow across the northern North Atlantic, allowing the construction of a simple conceptual model for this system. To help promote a better understanding of the system, several research gaps are identified
Synchronism of Holocene East Asian monsoon variations and North Atlantic drift-ice tracers
Aeolian features ; Atlantic Ocean ; Beijing ; C 14 dating ; China ; Correlation ; Holocene ; Monsoon ; North Atlantic Ocean ; Ocean atmosphere interaction ; Palaeoclimatology ; Palaeosol ; Quaternary
. The monsoon variations correlate closely with variations in North Atlantic drift-ice tracers that represent episodic advection of drift ice and cold polar surface water southward and eastward into warmer subpolar water. The correspondence of these records over
the full span of Holocene time implies a close relationship between North Atlantic climate and the monsoon climate of central China.
Freshwater diatom influx in intertropical Atlantic : relationships with continental records from Africa
This tentative approach shows that freshwater diatoms in Atlantic cores may be a good tool for reconstructing paleoclimates and for establishing continent-ocean correlations if species analyses are made and if the continental distribution