Greenland: projects/activities

Mapping and monitoring of the snow cover with use of satellitte born optical instruments for (1) direct use of observations of climate change and (2) use of observations in climate modelling. Measurements of the snows spectral reflectance and other physical properties.

The submitted proposal aims to perform the monitoring of the pollen rain in the Greenland atmosphere by distinguishing the local pollen production, relatively low, from pollen grains originating from other Arctic areas. A regular monitoring of the atmospheric pollen content must be performed in order to evaluate the amount emitted and characterise the seasonality of the emission. A comparison with air mass trajectories must allow the modelling of long distance transport

-Quantify changes in ice dynamics and characteristics resulting from the switch in AO phase -Establish a climate record for the region north of Greenland through the retrieval and analysis of sediment cores -Improve an existing dynamic-thermodynamic sea ice model, focusing on the heavily deformed ice common in the region -Relate the region-specific changes which have occurred to the larger-scale Arctic variablity pattern -Place the recent ice and climate variability for this critical region into the context of long term climate record, as reconstructed from sediment cores

Projects at Zackenberg Station Relevance: Climate Change Project title: Duration: Start year: 1995 End year: Continuing Responsible institution: Relevance: Climate Change Changes in UV radiation and its effects

Analysis of the energy balance terms obtained during the measuring campaign in 1991 at Greenland. It deals with profile and turbulence measurements, RASS-SODAR observations and radiation measurments.

The project aims at reconstructing the environmental history in the interior Kangerlussuaq region since deglaciation. Focus is placed on the lacustrine and eolian sediments to decipher climate evolution in terms of temperature, evaporation- precipitation balance and phases of high- wind speed events. The overall objectives are to build a high-resolution (decadal-to-century scale) chronostratigraphic framework for past climate variability from the analysis of organic-rich lake sediments and peat filled basins using a variety of sediment analysis techniques (magnetostratigraphy, grainsize, sedimentfractionation techniques, AMS 14C dating, diatom-, pollen- and macrofossil analysis) and sedimentology. Research activities diatom analysis, pollen analysis, magnetic susceptibility, automated correlation techniques, grainsize, organic chemistry, sediment fractionation techniques, AMS radiocarbon dating, sedimentology, mapping, sediment transport and erosion measurements/monitoring, micro-meteorology, vegetation mapping, pollen rain studies, diatom salinity training sets, limnology

In the wake of topical research issues such as global change and energy resources, one can recognize two priority targets for the study of fossil plant remains: - insight into the role of land plants and phytoplankton as monitors, recorders, motors and moderators of climatic and environmental change; -insight into the predictive value of organic remains with respect to genesis, composition, occurrence, quality and quantity of fossil fuel reserves. In harmony with these targets, current research at the Laboratory of Palaeobotany and Palynology (LPP) is aimed to provide for basic contributions to the palaeoecological study and interpretation of Palaeozoic, Mesozoic and Cenozoic plant life. Four interconnected areas of scientific emphasis are currently distinguished: - biotic change: documentation and causal analysis of changes of past plant biota in terrestrial and marine environments, both at short and long time-scales; - selective preservation: identification of the biological, physical and chemical factors that determine selective preservation of organic matter during transport, sedimentation and burial; - methodology: development and introduction of new analytical methodology relevant to the study and interpretation of fossil plant remains; - systematics: generation and compilation of systematic data aimed at the accurate identification and classification of fossil plant remains. Overview of results LPP strives after a balance between the study of land plant remains and organic-walled marine phytoplankton (mainly dinoflagellates). Research objectives are related to both short (latest Pleistocene-Holocene) and long time-scales (late Palaeozoic-Cenozoic). Short time-scales Modern land plant communities can be understood only in the light of their history since the onset of the last deglaciation (15,000 yr BP). In western and southern Europe this history is governed by the climatically induced spread of forest communities and their subsequent recession as man's influence expanded. Through fine-scale analysis (temporal and spatial, as well as systematic), of assemblages of microscopic and macroscopic plant remains, research concentrates on the accurate discrimination between autogenic, climatically induced, and anthropogenic vegetational change in contrasting physiographic entities: (1) crystalline mountains in France and the Iberian peninsula; (2) landscapes characterized by Pleistocene-Holocene eolian (sand, loess) deposition in the Netherlands and Germany; (3) fluvial plains in the Netherlands; (4) littoral landscapes in Portugal, and (5) Arctic landscapes of Spitsbergen, Jan Mayen and Greenland. Following earrlier research experiences with respect to the palaeoecological analysis of pollen assemblages from the Vosges (France), in the research period special attention was given to deciphering the complex, altitude related, late Pleistocene-Holocene pollen signals from other low mountain ranges. Results have demonstrated that the spatial distribution of vegetation patterns can be followed through time by recognizing: (1) common time-proportionate trends in pollen values, and (2) local pollen components characteristic for altitudinal vegetation zones and lake/mire development. Long time-scales For the recognition and evaluation of biotic change on long time-scales, LPP concentrates on the study of land plant and phytoplankton records from sedimentary successions that contrast with respect to: (1) time of formation (selected late Palaeozoic, Mesozoic and Cenozoic intervals); (2) paleotectonic and palaeogeographic history (intracratonic; passive and active plate margins); (3) depositional environment (terrestrial to deep-marine); and (4) biogeographic provinciality. Temporal and spatial distribution patterns of plant remains are explored for proxy variables indicative of terrestrial and marine environmental change. Investigated variables include land temperature, humidity, precipitation, runoff, sea-level, sea surface temperature, salinity, nutrient supply, productivity, organic burial rate and CO2 level. In the review period particular attention has been given to the development of palaeoecological models of dinoflagellate cyst distribution in marine sediments. It has been shown that: (1) the potential of dinoflagellates in Mesozoic and Cenozoic time-resolution may frequently exceed that of planktonic foraminifera and calcareous nannoplankton, and (2) dinoflagellates can be applied in novel ways to further the environmental understanding of depositional sequences and sedimentary cycles defined by physical (seismic, sedimentological) analysis. Although research related to global change programmes is generally restricted to the Late Tertiary-Quaternary, there is one notable exception. It is recognized that a better understanding of the patterns and processes of past mass extinctions can contribute to an understanding of present and future man-induced extinction processes. Work by LPP concentrates on the profound biotic crises at the Permian/Triassic (P/Tr) and Cretaceous/Tertiary (K/T) junctions. Study of the P/Tr land plant record has now revealed ecosystem collapse in the terrestrial biosphere. At the K/T junction, it has been demon-strated that dinoflagellates have remained immune to extinction. Independent of configurations predicted by meteorite-impact or massive volcanism, therefore, palynological studies enable high-resolution reconstruction of environmental change, both during pre-crisis times and the phases of K/T ecosystem decline and recovery.

The global thermohaline circulation is driven by sinking of cold, dense surface waters in the Greenland and Norwegian Seas and its replacement by warmer surface water from lower latitudes. This global circulation system, the conveyor belt, is the main regulator of global climate. Even slight disturbances of this delicate system will cause significant climate changes, especially for NW Europe. While the current hydrographical situation and associated overflow pathways are well-documented, paleoceanographic studies of the Greenland and Faroe/Shetland (F/S) overflow pathways are still scarce. The F/S pathway is presently the subject of study of the MAST program (ENAM project). This project focusses on the late Quaternary overflow history of the important East Greenland pathway. High resolution multichannel sleevegun seismic data recently collected by the Geological Survey of Greenland and Denmark (GEUS) allowed identification of suitable box- and piston-coring sites. Results from the high-resolution cores, allowing direct correlation with regional atmospheric changes documented in the Greenland ice-cores will provide new information on causes and mechanisms of climate change. The continental slope and rise off SE-Greenland can be considered as a potential key area for paleoceanographic and paleoclimatic studies, since: 1) The area is located in the immediate vicinity of the Denmark Strait arctic gateway for water mass exchange between the Arctic and Atlantic ocean. Recent hydrographic measurements (Dickson 1994) demonstrate the important role of the area with regard to hydrographic processes contributing to the formation of NADW. 2) The seafloor morphology and information from multichannel seismic recording shows the presence of numerous large detached sediment drifts and other drift-related features, which will provide important paleoceanographic information as outlined before. 3) The distribution and architecture of the sediment drifts is also affected by down-slope processes transporting upperslope/shelf sediments of mainly glacial origin. Thus the area offers an unique opportunity to study the sediment drifts both with regard to the (paleo)oceanic flow regime and the climatically-inherited signal from the down-slope sediment input. Research activities: All research is directed towards documentation of high resolution natural climate variability during the late Quaternary. Separate topics include: 1. Seismic/sidescan sonar studies 2. High resolution quantitative micropaleontology (planktonic/benthic foraminifera, diatoms, calcareous nannoplankton, dinoflagellates) 3. High resolution stable oxygen/carbon isotope studies 4. DNA studies on planktonic foraminifera (with University of Edinburgh)

The aim of the project is to obtain more insight in the response of the Greenland ice sheet to climatic change. For this purpose we will link our surface energy-balance model to an atmospheric model, so that the model can be forced by variables characterizing the atmosphere outside the thermal influence of the ice sheet itself. The modelling is supported by the mass-balance and meteorological data that we collect along a transect in West Greenland (the Kangerlussuaq-transect or K-transect). The albedo of the ice sheet is studied by means of satellite data and measurements obtained from a helicopter. Research activities - develop numerical models of the surface energy balance and the boundary layer above the ice sheet - perform annual measurements of the mass balance and ice velocity along the K-transect - maintain two automatic weather stations along the K-transect - study the surface albedo by means of remote-sensing images - improve methods to retrieve the surface albedo from satellite data by means of measurements obtained from a helicopter