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
Invasive Insects Cost the World Billions Per Year
04.10.2016 | University of Adelaide
Malaysia's unique freshwater mussels in danger
27.09.2016 | The University of Nottingham Malaysia Campus
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
25.10.2016 | Earth Sciences
25.10.2016 | Power and Electrical Engineering
25.10.2016 | Process Engineering