Using multispectral satellite data to determine littoral water depths despite varying water turbidity

摘要

Satellite data is used to determine water depth by accounting for the changing turbidity of the water over time and without requiring calibration using SONAR measurements. Radiance values at multiple wavelengths sensed at both a first time and a second time are stored in a database. Modeled reflectance values are calculated for a defined surface area on the water based on an assumed depth, assumed water constituents and assumed bottom cover. A plurality of differences between the modeled reflectance values and the reflectances sensed at the two times are calculated. A bathymetry application module minimizes the sum of the differences between the modeled and sensed subsurface reflectances by varying the assumed depth, bottom cover and water constituents. The differences are weighted based on wavelength before being summed. The depth that results in the minimized sum of the differences is the estimated depth, which is displayed on a graphical user interface.

主权项

1. A method comprising:
storing a first light intensity value indicative of a radiance at a first wavelength emanating from a surface area of a body of water at a first time; storing a second light intensity value indicative of the radiance at the first wavelength emanating from the surface area of the body of water at a second time; calculating a plurality of modeled light intensity values at the first wavelength, wherein each of the plurality of modeled light intensity values is indicative of the radiance at the first wavelength emanating from the surface area of the body of water, and wherein each of the plurality of modeled light intensity values depends on an assumed bottom cover on a bottom below the surface area and on an assumed depth between the surface area and the bottom; determining a plurality of first differences between the first light intensity value and each of the plurality of modeled light intensity values; determining a plurality of second differences between the second light intensity value and each of the plurality of modeled light intensity values; minimizing a deviation among the plurality of first differences and the plurality of second differences by varying the assumed depth and the assumed bottom cover; and displaying an estimated depth between the surface area and the bottom, wherein the estimated depth is the assumed depth that results in the minimized deviation among the plurality of first differences and the plurality of second differences, and wherein the estimated depth is displayed on a graphical user interface.