parameters and between the lakes. The analysis of
such parameters (e.g. water depth, surrounding
landuse) in relationship to the optical lake water
properties shows also the influence on the trophic
state.
2. STUDY AREA
The Northern Brandenburg lake district is located about
80 km northwest of Berlin, Germany (see fig. 1). The
surface morphology of the northern part of Germany
was shaped by glaciers from Scandinavia. In this
context the study area was mostly influenced by the
Weichsel ice age during the Brandenburg phase
(18000BP). The area is characterized by terminal
moraines of the Frankfurter Staffel containing dead ice
kettles and lakes of different stages of silting up
(Gellert, (ed.), 1965). Soils of the area have been
formed on substrates of varying loam and sand
content. Beech stands, mixed forest, and coniferous
stands (pine) interfinger with cultivated areas
(agricultural fields and pastures). Cultivated areas are
dominated by large spatial units which are the result of
cooperative farming in East Germany. Most of the
settlements are small and the majority of people lives
on agriculture, tourism, and services.
working area
Germany
®
München
Fig. 1: Study area within the Northern Brandenburg
lake district and location of ice marginal grounds
‘Frankfurter Staffel’ determining its physiography
The lakes of the study area (see fig. 2) differ in size,
depth, catchment area, and trophic state. Many lakes
are interconnected by natural streams or by man made
canals. Some of the lakes are situated within small
closed basins without surface tributaries (e.g., Lake
Wummsee). The trophic state of the lakes ranges from
oligotrophic to hypertrophic, while the majority of the
lakes is classified as mesoptrophic lakes (MBLU 1996,
Gewasserkataster, 1996 ).
Chlorophyll-a concentration measured in the field for
selected lakes (Thiemann et al., 1998) ranges from 1-3
ug/l for lake GroBer Wummsee to 50-100 jug/l for lake
Braminsee. Lake Wummsee has a maximum depth of
36 m and its bottom is formed by sand and gravel.
These characteristics and its isolated position as a
closed basin lake led to a low nutrient content. The
largest lake of the study area GroBer Stechlinsee has a
maximum depth of 68 m and is the only one classified
as oligotrophic according to the determination of
trophic state by Hôntzsch et al. (1993). Lake
Braminsee represents the opposite side with its shallow
depth of about 2 m and its high nutrient content being
the result of an advanced stage of silting up.
Fig. 2: IRS-1C subset of study area
(lakes: 1 - Gr. Wummsee, 2 - Gr. Zechliner
See, 3 - Braminsee, 4 - Gr. Stechlinsee, 5 -
Plátlinsee) covers an area by 25 km * 20 km
3. OBJECTIVES
The goal of this study is to combine the investigation of
the spatial and seasonal variability of optical lake water
properties with an assessment of parameters
influencing the trophic state of lakes. The optical lake
water properties reflect the intensity of bioproduction of
algae which significantly influences the trophic state of
lakes.
For this purpose, multitemporal satellite data are
analyzed for describing lake behavior, spatial variability
and seasonal changes during the observed period of
time between August 1996 and September 1997.
Additionally, information about factors influencing lake
water properties are organized within a GIS for further
systematic analysis. For this purpose influencing
factors are subdivided into local lake factors and
watershed factors, which are analyzed in their
importance for the trophic state of lakes.
4. LAKE WATER ANALYSIS USING SATELLITE
REMOTE SENSING
4.1 Satellite data
Data of the Indian Remote Sensing Satellite IRS-1C
are available for Europe since spring 1996 with a
repetition cycle of 24 days. For a ‘multispectral scene
(25 m pixel size) the swath width is 140 km and for a
130 International Archives of Photogrammetry and Remote Sensing. Vol. XXXII, Part 7, Budapest, 1998
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