Algal blooms in the Southern Baltic Sea 23.7.2001
Satellite sensors operating in the visible wavelength region are now in use for the monitoring of oceanic waters.
For the first time ever, Finnish scientists have demonstrated the practical usability of satellite data for the simultaneous monitoring of water quality in large lake and coastal regions. The project was carried out by the Laboratory of Space Technology of the Helsinki University of Technology in cooperation with the Finnish Environment Institute.
The attached figures show examples of water turbidity retrieval results obtained for Finnish lake and coastal regions by applying Nasa’s MODIS spectrometer data, with more to come from the ESA Envisat MERIS-spectrometer. These sensors with nearly global daily coverage employ visible wavelength channels of observation with spectral characteristics suited for water quality monitoring of turbid lakes and coastal regions. Turbidity is one of the essential water quality indicators as it describes, in practise, the integrated amount of algae biomass and suspended matter.
Conventional discrete water quality sampling or the collection transect data with ship-borne observation systems never give a complete areal vision.
These improvements are important aspects in boreal regions where the number of lakes is large and the quality of lake water is highly variable and sensitive to external pollution and climate change. In Finland, for example, the total number of lakes exceeding the minimum area of 0.01 km2 (1 ha) is about 60,000. MODIS data enables the monitoring of about 50 percent of the total Finnish lake area (16,000 km2).
Monitoring the status of the Baltic Sea is another promising application for satellite sensors. The analysis of the data from MODIS and SeaWiFS spectrometers has shown that satellite observations are useful for the mapping of turbidity, chlorophyll concentration (algae biomass) and algae blooms. Particularly interesting results have been obtained for the Gulf of Finland using MODIS observations. The MODIS data-based turbidity maps have demonstrated the strong influence of the St. Petersburg region on the overall water quality in the Gulf of Finland.
A good spatial resolution is required to monitor Baltic coastal regions and boreal forest/sub-arctic zone with fragmented water bodies, lakes and coastal zones comprising a small-scaled labyrinth of water and land areas. The spatial resolution of MODIS and MERIS is adequate even for the monitoring of the lakes of boreal forest zone: at its best 250 m and 300 m, respectively.
Jari Kirsilä | alphagalileo
Bioinvasion on the rise
15.02.2017 | Universität Konstanz
Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung
Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...
The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.
The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...
Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...
Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".
Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...
13.02.2017 | Event News
10.02.2017 | Event News
09.02.2017 | Event News
24.02.2017 | Life Sciences
24.02.2017 | Life Sciences
24.02.2017 | Trade Fair News