Band Width Manipulation

This section covers the different types of measurements SeaWiFS and AVHRR satellites make, and how these are used to estimate lake parameters.



Click the image left for David Schneider's tutorial on the electromagnetic spectrum:

SeaWiFS and AVHRR each use a series of bandwidths to estimate lake parameters, and the difference in wavelengths between the two satellites explains the difference in data types each instrument creates:

SeaWiFS
Band Wavelength
1 402-422 nm
2 433-453 nm
3 480-500 nm
4 500-520 nm
5 545-565 nm
6 660-680 nm
7 745-785 nm
8 845-885nm


SeaWiFS operates from visible Blue (~400 nm) to Near Infrared (~900 nm). This is the range which chlorophyl absorbs light, and so SeaWiFS main parameters estimate biological qualities, such as chlorophyl content, and back scattered energy associated with sediment concentration in natural waters.







AVHRR
Band Wavelength
1 580-680
2 720-1100 nm
3 3530-3930 nm
4 10.3-11.3 microns
5 11.5-12.5 microns


AVHRR operates over a much larger spectrum, and while bands 1 and 2 allow estimation of remote sensing reflectance, AVHRR bands 3 (Mid-Infrared), 4 and 5 (Thermal Infrared) are utilized to detect thermal phenomena such as atmospheric, sea, and black body radiation. Channel 1 is used in coastal waters to estimate sediment concentration, whereas Channel 2 is used for atmospheric Raleygh Reflectance concentration. Channels 3-5 are used to estimate sea or lake surface temperature (LST or SST) as well as for cloud detection.









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