Real Time Red Tide Detection and Monitoring

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REAL TIME RED TIDE DETECTION AND MONITORING

Outline
• History of RS application in water quality monitoring. • Current applications of RS technologies in water quality monitoring • Water quality algorithms • Research plan

History of RS in water quality
• Monitoring water quality started since the late of 1970s. • The content of suspended solids in water is the parameter that firstly been remote sensed. • Collecting water samples and analyzing the samples in a laboratory (e.g. chlorophyll, turbidity and total phosphorous • Traditional water quality monitoring techniques are costly and time consuming. • Frequent ground samplings are generally not possible.

History of RS in water quality
The application of and research of remote sensing in water quality monitoring has developed from the pure waters of the initial identification of water quality indicators to remote monitoring , mapping and forecasting.

History of RS in water quality
• One of the advantages of remote sensing is that the measurements can be performed from a great distance (several hundred or even several thousand km in the case of satellite sensors), which means that large areas on ground can be covered easily

RS in water quality
Main factors affecting water quality :
• • • • • • • Suspended solids in water (Turbidity) Algae(Chlorophyll, Carotenoids) Chemicals (nutrients, inseticide,metal) Dissolved organic matter Heat emissions Pathogens Oil substances

RS in water quality
Parameters that can be estimated with optical remote sensing methods in situ data analyzed in laboratory from water samples: • Phytoplankton (chlorophyll a) • Suspended inorganic material (e.g. sand, dust and clay) • Colored dissolved organic matter • Turbidity

Biological status related to phytoplankton and other aquatic in situ data estimated in the field: • Secchi depth • Temperature • Occurrence and extent of algal blooms

RS in water quality
•The first satellite based sensor devoted to water quality measurements was the Coastal Zone Color Scanner (CZCS) which was launched in 1978.

•In CZCS, every parameter was optimized for use over water to the exclusion of any other type of sensing. • CZCS had six spectral bands, four of which were used primarily for ocean color. These were of a 20 nanometer bandwidth centered at 443, 520, 550, and 670 nm. •Bands 1-4 were preset to view water only and saturated when the IFOV was over most types of land surfaces, or cloud

RS in water quality
The chlorophyll-a images for granules at about 40 - 50 degrees South around Southern Argentina

http://oceancolor.gsfc.nasa.gov/CZCS/czcs_processing/czcs_nav/

RS in water quality
•SeaWiFS (Sea-viewing Wide Field Sensor, launched in 1997) continued on the path started by CZCS and has also produced good results. Instrument Bands Band 1 2 3 4 5 6 7 Wavelength 402-422 nm 433-453 nm 480-500 nm 500-520 nm 545-565 nm 660-680 nm 745-785 nm

8

845-885 nm

RS in water quality
•Airborne instruments such as AISA (Airborne Imaging Spectrometer for Application) ,CASI (Compact Airborne Spectrographic Imager) and HyMap have been determined to be feasible for monitoring small areas in Scandinavia and Germany. CASI Bands :

RS in water quality
•Data from airborne sensors can also be used for developing retrieval algorithms for spaceborne sensors such as MODIS and MERIS (Medium Resolution Imaging Spectrometer) The primary objective of MERIS is to observe the color of the ocean, both in the open ocean (clear or Case I waters) and in coastal zones (turbid or Case II waters). These observations are used to derive estimates of the concentration of chlorophyll and sediments in suspension in the water, for instance .

RS in water quality
MERIS Bands :

RS in water quality
Bands 7 ,5 & 2

MERIS study : BELGIAN COASTAL WATERS

(K. Ruddick at.el ,2002)

RS in water quality
MODIS (Moderate Resolution Imaging Spectroradiometer)  Terra's orbit around the Earth is...
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