(Images from NOAA web site).

2. (Images from NOAA web site).

3. (Images from NOAA web site).

4. How to use satellite data ?

5. River plumes modelling from Seawifs and Modis data. Florian JOSSE – August 2005

6. 1. What are Seawifs and Modis data ? • 2. What can we do with these data ? • 3. Results and applications.

7. What are Seawifs and Modis data ? Seawifs (SEA-viewing Wide Field of view Sensor). MODIS (Moderate-resolution Imaging Spectroradiometer). The purpose of these Projects is to provide earth bio-optical data (“photography”) to the scientist community. http://oceancolor.gsfc.nasa.gov/SeaWiFS/ http://modis.gsfc.nasa.gov/ • These projects are directed by NASA by the EOS program (Earth Observation System). • They are Earth reflectivity values of the sunlight. • These values are measured by a satellite sensor and transmit to a ground station . This station treat the data, correct them, and provide them on the Internet for a free access to the public. (Images from Seawifs web site).

8. What are Seawifs and Modis data ? The result is “photography” of the Earth. These photos are composed by heights different wavelengths; all together form a true colour image. (Images from Seawifs web site).

9. What are Seawifs and Modis data ? • Three types of Seawifs data are available: • The LAC Product; a Local Area Coverage with 1 km resolution. • The GAC Product; a Global Area Coverage with 4 km resolution. • Binned data product with a global coverage. (Images from Seawifs web site).

10. What are Seawifs and Modis data ? • The MODIS data available are: • 44 different types of data, to study many earth characteristics. Permit scientist to work in many field: oceanography, biology, atmosphere studies, etc… • Different spatial resolution: 250m, 500m, 1km. • Global earth coverage in two days. • Accurate and precise data, available in quantity on the Internet. (Images from MODIS web site).

11. Seawifs/Modis data access web site Images selection, location, clouds, .. • What can we do with these data? Downloading

12. What can we do with these data? • FTP process (downloading): • It consists in a connection to an ftp web server via a web adress. • Two solutions are possibles, directly with an internet navigator (Internet Explorer, Mozilla Firefox), or with an ftp client, which provide you a special interface (WS_FTP, CuteFTP). • But with an Internet security system, such as the university one, it needs specific connection parameters and authorizations. • After many tries, it was not possible to be connected to NASA servers. All the security systems (firewall, antispyware, etc.) not allow the connection or disconnect it after a few moment. • These barrers have blocked all connections and many data could not be downloaded. It must be resolved for the future, large quantities of free data are available and can be used in many different fields.

13. Seawifs/Modis data access web site • What can we do with these data? Images selection, location, clouds, .. Downloading ENVI Select one wavelenght; 555nm (green), selection of the area, georeference it Open with Microsoft Excel Exported in ASCII format And TIFF image.

14. Long Lat Value Long Lat Value Geolocatedvalue point Geolocated value point File 1 File 2 • What can we do with these data? 2 points per lines ?!

15. BDD (397,1071)553 • What can we do with these data? • GIS: Geographical Information System. • Software : ArcView 9. Database imported as X,Y,Z value points

16. Shift Data were sending back in Excel for a direct correction of the latitude coordinate. • What can we do with these data? North-South Shifting of the data ENVI bug ? TIFF Image Data

17. Merge One file File 1 File 2 • What can we do with these data?

18. What can we do with these data? After parameter the legend, a first look was done on the points. A surface must be created but without the “land point”. For that a new polygon was created by digitizing the coastline, the polygon must just cover the sea area.

19. What can we do with these data? A grid was created for surface the area from the points. This one show river plumes as expected. A TIN (Triangulated Irregular Network) was created: this one permit a better accuracy and a no-rectangular surface than a simple interpolation. After creation, the TIN was put in a 3D view with the grid as surface. Additional elements were added for a better comprehension.

20. Orange River Buffels River • Results and applications. • The results show two rivers plumes in our area: • The North one is created by the Orange river. It is important, with a large influence. • The South one is created by the Buffels river. • Plumes can be measured and monitored: activity, size, orientation can be determined. • It can be compared to precipitation, wind or current data, and see what is their influence on each others. Mai 1998

21. Buffels Orange

22. Results and applications. A useful tool who can be link to others studies: • Environmental studies with the impact of the river plumes on coastal biology. • Physical studies with their influence on upwelling or on currents. Example The West coast rock lobster Mining Waste Industries What is the influence of the Orange River plume on the local biology ?

23. Conclusion. • A method for use directly, satellite is available: a monitoring of a phenomena with bio-optical characteristics can be done (river plumes, phytoplankton bloom, algae bloom, pollution,etc.). • Data can provide high resolution in term of space (250m) but also in term of time (one image every two days can be visualized). • The method is easily reproductible and can be done from a simple pc with an Internet connection. • All these data can be link with other studies, compute with other ones and, they can complete the knowledge. • Satellite data can be use by everybody, for his own project. Many parameters can be choose, just specify your needs and download them.

24. Thank you to all the IOI team!