Evaluation of a Submerged Remote Sensing SRS Technique
Abstract
To test and validate the Submerged Remote Sensing (SRS) technique on a large Case I optical database that has been collected by the Center for Hydro-Optics and Remote Sensing, San Diego State University since 1990. The purpose of this work is to determine the optical properties of the atmosphere and water column using the SRS technique by knowing only the absolute downwelling irradiance at two wavelengths at a known depth, for a given date, time and position. It is straight forward to calculate the total path transmittance (a single value representing the combined water and atmospheric attenuation) by knowing the extra-terrestrial solar spectral irradiance, date, time, latitude and longitude. The difficulty is determining the two component parts of attenuation separately. The SRS approach was to make measurements at two wavelengths and then use them in a set of equations, to solve for the separate attenuations. This required models describing the attenuation coefficients of sea water and the atmosphere and how they changed with wavelength for a variety of turbidities. Using the knowledge about the optical characteristics of the atmosphere and seawater it is possible to compute the transmission of light through the atmosphere, the air-water interface and through the water to a given depth under a set of environmental conditions. The pair of irradiances values is then used to perform the inverse computation to calculate the diffuse attenuation coefficient of the water, K(lambda), and the optical depth of the atmosphere for the two wavelengths. It has been shown that there exists an apparent spectral relationship between K(lambda) and the various water types found in the open ocean. The SRS was originally validated using a limited number of optical stations (54, n = 221) and fast scanning Multispectral Environmental Radiometers (MERs, Biospherical Instruments, Inc.).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2008
- Accession Number
- ADA517453
Entities
People
- Charles Trees
Organizations
- Centre for Maritime Research and Experimentation