Hydrological optics has a rich history, playing a significant role in physical, chemical, and biological oceanography. The success over the last 30 years has provided oceanographers with a non-invasive means to study regional and global scale physical, chemical, and biological processes (Figure 1). The ability to map the color of...
Sensor design and mission planning for satellite ocean color measurements requires careful consideration of the signal dynamic range and sensitivity (specifically here signal-to-noise ratio or SNR) so that small changes of ocean properties (e.g., surface chlorophyll-a concentrations or Chl) can be quantified while most measurements are not saturated. Past and...
Remote-sensing reflectance is easier to interpret for the open ocean than for coastal regions because the optical signals are highly coupled to the phytoplankton (e.g., chlorophyll) concentrations. For estuarine or coastal waters, variable terrigenous colored dissolved organic matter (CDOM), suspended sediments, and bottom reflectance, all factors that do not covary...
We present the results of a study of optical scattering and backscattering of particulates for three coastal sites that represent a wide range of optical properties that are found in U.S. near-shore waters. The 6000 scattering and backscattering spectra collected for this study can be well approximated by a power-law...
Macronutrients persist in the surface layer of the equatorial Pacific Ocean because the production of phytoplankton is limited; the nature of this limitation has yet to be resolved. Measurements of photosynthesis as a function of irradiance (P-I) provide information on the control of primary productivity, a question of great biogeochemical...
A drifter equipped with bio-optical sensors and an automated water sampler was deployed in the California Current as part of the coastal transition zone program to study the biological, chemical, and physical dynamics of the meandering filaments. During deployments in 1987 and 1988, measurements were made of fluorescence, downwelling irradiance,...
The Ocean Portable Hyperspectral Imager for Low-Light Spectroscopy (Ocean PHILLS) is a hyperspectral imager specifically designed for imaging the coastal ocean. It uses a thinned, backside-illuminated CCD for high sensitivity and an all-reflective spectrograph with a convex grating in an Offner configuration to produce a nearly distortion-free image. The sensor,...
As a demonstrator for technologies for the next generation of ocean color sensors,
the Hyperspectral Imager for the Coastal Ocean (HICO) provides enhanced spatial and
spectral resolution that is required to understand optically complex aquatic environments. In
this study we apply HICO, along with satellite remote sensing and in situ...
As a demonstrator for technologies for the next generation of ocean color sensors,
the Hyperspectral Imager for the Coastal Ocean (HICO) provides enhanced spatial and
spectral resolution that is required to understand optically complex aquatic environments. In
this study we apply HICO, along with satellite remote sensing and in situ...
As a demonstrator for technologies for the next generation of ocean color sensors,
the Hyperspectral Imager for the Coastal Ocean (HICO) provides enhanced spatial and
spectral resolution that is required to understand optically complex aquatic environments. In
this study we apply HICO, along with satellite remote sensing and in situ...
Current ocean color sensors, for example SeaWiFS and MODIS, are well suited for sampling the open ocean. However,
coastal environments are spatially and optically more complex and require more frequent sampling and higher spatial
resolution sensors with additional spectral channels. We have conducted experiments with data from Hyperion and
airborne...
Hyperion is a hyperspectral sensor on board NASA’s EO-1 satellite with a spatial
resolution of approximately 30 m and a swath width of about 7 km. It was originally designed
for land applications, but its unique spectral configuration (430 nm – 2400 nm with a ~10 nm
spectral resolution) and...
The physical, biological, chemical, and optical
processes of the ocean operate on a wide
variety of spatial and temporal scales, from
seconds to decades and from micrometers to
thousands of kilometers (Dickey et al., this
issue; Dickey, 1991). These processes drive
the accumulation and loss of living and nonliving
mass...
In optically shallow waters, i.e., when the bottom is visible through the water,
a tantalizing variety and level of detail about bottom characteristics are
apparent in aerial imagery (Figure 1a). Some information is relatively easy to
extract from true color, 3-band imagery (e.g., the presence and extent of submerged
vegetation),...
The Hyperspectral Imager for the Coastal Ocean (HICO) presently onboard the International Space Station (ISS) is an imaging spectrometer designed for remote sensing of coastal waters. The instrument is not equipped with any onboard spectral and radiometric calibration devices. Here we describe vicarious calibration techniques that have been used in...
This study uses derivative spectroscopy to assess qualitative and quantitative information regarding seafloor types that can be extracted from hyperspectral remote sensing reflectance signals. Carbonate sediments with variable concentrations of microbial pigments were used as a model system. Reflectance signals measured directly over sediment bottoms were compared with remotely sensed...
Existing atmospheric correction algorithms for multichannel remote sensing of ocean color from space were designed for retrieving water-leaving radiances in the visible over clear deep ocean areas and cannot easily be modified for retrievals over turbid coastal waters. We have developed an atmospheric correction algorithm for hyperspectral remote sensing of...
We evaluate the theoretical performance of a point-source integrating-cavity absorption meter (PSICAM) with Monte Carlo simulations and a sensitivity analysis. We quantify the scattering errors, verifying that they are negligible for most ocean optics applications. Although the PSICAM detector response is highly sensitive to the value of the wall reflectivity,...
A spectrum-matching and look-up-table (LUT) methodology has been developed and evaluated to extract environmental information from remotely sensed hyperspectral imagery. The LUT methodology works as follows. First, a database of remote-sensing reflectance (R[subscript]rs) spectra corresponding to various water depths, bottom reflectance spectra, and water-column inherent optical properties (IOPs) is constructed...