Morphometry and Spatial Distribution of Lakes in the Lena Delta, NE Siberia (Remote Sensing and GIS Analyses)


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amorgenstern [ at ] awi-potsdam.de

Abstract

The Lena Delta in the Laptev Sea in northern Siberia is the largest delta in the Arctic covering an area of about 32.000 km². It is situated in the zone of continuous permafrost, but is also characterized by widespread thermokarst. For many years the interest of Russian and lately also German scientists (e.g. within the framework of the German-Russian research project System Laptev Sea 2000 supported by the BMBF) has been focused on the investigation of different problems concerning biology and geosciences in this area, which serves as an interface between the Siberian mainland and the Laptev Sea. The Lena Delta can be clearly divided into an active part in the East and a passive one in the West. Furthermore, a classification is made into three main terraces, which were formed during different stages since the late Pleistocene. The first and second terraces (early to late Pleistocene) were built by fluvial action of the Lena River. The third terrace consists of relicts of a late Pleistocene accumulation plain, which was enclosed by Holocene delta progression. In addition to about 800 channels, numerous lakes occur in the Lena Delta as characteristic landforms. These are not only relevant for the reconstruction of the paleoenvironment in this area, but also for todays delta geomorphology and ecology. The lakes are obviously of different genesis, e.g. thermokarst or abandoned channel lakes, which is important for balancing methane emissions in the Lena Delta as different lake types contribute different amounts of methane to the overall methane budget. Many of them have a clear orientation of their major axes tending in the same direction, most obvious on the second terrace. The phenomenon of oriented lakes described for many arctic coastal plains has not been fully explained yet despite intense research during the past decades. Different theories on the cause of orientation have been proposed, in most of which wind is seen as the main driving force. In order to generally quantify different lake types, to investigate possible ideas about their genesis, and to test tendencies of their orientation the lakes were analyzed using remote sensing methods and spatial statistics. All lakes > 20.000 m² were included in the analysis (more than 2.600 lakes). Their total area is ca. 1.865 km² which is 6% of the delta area. Investigations were made using a Geographical Information System (GIS) based on LANDSAT-7 ETM+ satellite data. This allowed for an effective processing of the vast study area. We analyzed parameters describing lake morphometry (e.g. area, perimeter, different form indices, orientation of the major axis) as well as the spatial distribution of lakes throughout the delta area. That includes both the geographical position and the lakes geologic-geomorphologic unit within the delta. Based on this, correlations between several parameters were tested to investigate potentially predetermined patterns concerning lake morphogenesis and lake orientation. In order to test the wind hypothesis, morphometric data were combined with regional climate data.



Item Type
Conference (Poster)
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Not peer-reviewed
Publication Status
Published
Event Details
22nd International Polar Meeting, September 18-24, Jena, Germany..
Eprint ID
13497
Cite as
Morgenstern, A. , Grosse, G. , Schirrmeister, L. and Asche, H. (2005): Morphometry and Spatial Distribution of Lakes in the Lena Delta, NE Siberia (Remote Sensing and GIS Analyses) , 22nd International Polar Meeting, September 18-24, Jena, Germany. .


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