86 research outputs found

    On the philosophy of modeling—reply to a comment by M. R. DroopX

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110088/1/lno19782320385.pd

    Bio-optical profile data report coastal transition zone program, R/V Point Sur, June 15-28, 1987

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    Twenty vertical profiles of the bio-optical properties of the ocean were made during a research cruise on the R/V Point Sur, June 15 to 28, 1987, as part of the Coastal Transition Zone Program off Point Arena, California. Extracted chlorophyll values were also measured at some stations to provide calibration data for the in situ fluorometer. This summary provides investigators with an overview of the data collected. The entire data set is available in digital form

    Bio-optical profile data report coastal transition zone program, R/V Thomas Washington, June 24 - July 21, 1988

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    Twenty-three vertical profiles of the bio-optical properties of the ocean were made during a research cruise on the R/V Thomas Washington, June 24 to July 21, 1988, as part of the Coastal Transition Zone Program off Point Arena, California. A summary is given, to provide investigators with an overview of the data collected. The entire data set is available in digital form for interested researchers

    Multiple dataset water-quality analyses in the vicinity of an ocean wastewater plume

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    The White's Point ocean outfall is the method of disposal for approximately 374 million gallons of treated wastewater per day from Los Angeles County. The photosynthetic characteristics and particle distributions have well-defined properties that can be exploited to yield information on transport of the plume, mixing dynamics, and resuspension of bottom sediments during periods of bottom current velocity in excess of ca. 0.1 m/s. This plume of particles serves as a conservative tracer, which was studied using a number of sampling platforms and strategies, including underway sawtooth, or 'tow-yo' sampling, moored arrays of instruments, stationary profiling, and now for the first time with remotely-sensed multispectral color imagery. Research in this area previously focused on examination of the plume as it relates to the local current field and transport of particles, and on the resuspension of bottom sediments during periods of increased currents. In addition, Wu et al elucidated techniques for separating the particle signal into photosynthetic and nonphotosynthetic components, based on the beam attenuation to chlorophyll fluorescence ratio. High-frequency time series measurements of the current field and bio-optical characteristics at a site close to the waste diffusers were also collected. These are being analyzed for the spectral characteristics of the longer-timescale variability, in order to predict particle transport through simple meteorological measurements. With the advent of high spectral and spatial resolution imaging spectrometers such as AVIRIS, it is now possible to construct causal relationships between particle distributions and signature of the upwelled radiance from the surface. The availability of a constant and well-characterized source of material lends itself well to models which predict upwelled radiance from the surface. The availability of a constant and well-characterized source of material lends itself well to models which predict upwelled light as a function of particle distributions, photosynthetic pigments, colored dissolved organic material, and detrital and degradation products of photosynthesis. In addition, the spatial coverage provided by the tow-yo sampling device, combined with the profile measurements of the light field, should facilitate the best inverse modeling attempts possible thus far

    Atmospheric correction of AVIRIS data of Monterey Bay contaminated by thin cirrus clouds

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    Point source measurements (e.g. sun photometer data, weather station observations) are often used to constrain radiative transfer models such as MODTRAN/LOWTRAN7 when atmospherically correcting AVIRIS imagery. The basic assumption is that the atmosphere is horizontally homogeneous throughout the entire area. If the target area of interest is isolated a distance away from the point measurement position, the calculated visibility and atmospheric profiles may not be characteristic of the atmosphere over the target. AVIRIS scenes are often rejected when cloud cover exceeds 10%. However, if the cloud cover is determined to be primarily cirrus rather than cumulus, in-water optical properties may still be extracted over open ocean. High altitude cirrus clouds are non-absorbing at 744 nm. If the optical properties of the AVIRIS scene can be determined from the 744 nm band itself, the atmospheric conditions during the overflight may be deduced

    Marine diatoms grown in chemostats under silicate or ammonium limitation. II. Transient response of Skeletonema costatum to a single addition of the limiting nutrient

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    Skeletonema costatum was grown at different steady-state growth rates in ammonium or silicate-limited chemostats. The culture was perturbed from its steady-state condition by a single addition of the limiting nutrients ammonium or silicate. The transient response was followed by measuring nutrient disappearance of the liliting perturbation experiment indicate that three distinct modes of uptake of the limiting nutrient can be distinguished; surge uptake ( V s ), internally controlled uptake ( V i ), and externally controlled uptake ( V e ). An interpretation of these three modes of uptake is given and their relation to control of uptake of the limiting nutrient is discussed. The uptake rates of the non-limiting nutrients were shown to be depressed during the surge of the uptake of the limiting nutrient. Kinetic uptake parameters, K s and V max , were obtained from data acquired during the externally controlled uptake segment, V e . The same V max value of 0. 12 h -1 , was obtained under either silicate or ammonium limitation. Estimates of K s were 0.4 μg-at NH 4 -N l -1 and 0.7 μg-at Si l -1 . Short-term 15 N uptake-rate measurements conducted on nitrogen-limited cultures appear to be a combination of V s or V i , or at lower substrate concentrations V s and V e . It is difficult to separate these different uptake modes in batch or tracer experiments, and ensuing problems in interpretation are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46629/1/227_2004_Article_BF00390940.pd

    Hyperspectral Imager for the Coastal Ocean (HICO): Overview, Operational Updates, and Coastal Ocean Applications

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    The Hyperspectral Imager for the Coastal Ocean (HICO) was built to measure inwater properties of complex coastal regions. HICO enables synoptic coverage; 100meter spatial resolution for sampling the variability and spatial irregularity of coastal waters; and high spectral resolution to untangle the signals from chlorophyll, colored dissolved organic matter, suspended sediments and varying bottom types. HICO was built by the Naval Research Laboratory, installed on the International Space Station (ISS) in September 2009, and operated for ONR for the first three years. In 2013, NASA assumed sponsorship of operations in order to leverage HICO's ability to address their Earth monitoring mission. This has opened up access of HICO data to the broad research community. Over 8000 images are now available on NASA's Ocean Color Website (http://oceancolor.gsfc.nasa.gov/cgi/browse.pl?sen=hi). Oregon State University's HICO website (http://hico.coas.oregonstate.edu) remains the portal for researchers to request new collections and access their requested data. We will present updates on HICO's calibration and improvements in geolocation and show examples of the use of HICO data to address issues in the coastal ocean and Great Lakes

    A modern coastal ocean observing system using data from advanced satellite and in situ sensors – an example

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    Report of the Ocean Observation Research Coordination Network In-situ-Satellite Observation Working GroupThis report is intended to illustrate and provide recommendations for how ocean observing systems of the next decade could focus on coastal environments using combined satellite and in situ measurements. Until recently, space-based observations have had surface footprints typically spanning hundreds of meters to kilometers. These provide excellent synoptic views for a wide variety of ocean characteristics. In situ observations are instead generally point or linear measurements. The interrelation between space-based and in-situ observations can be challenging. Both are necessary and as sensors and platforms evolve during the next decade, the trend to facilitate interfacing space and in-situ observations must continue and be expanded. In this report, we use coastal observation and analyses to illustrate an observing system concept that combines in situ and satellite observing technologies with numerical models to quantify subseasonal time scale transport of freshwater and its constituents from terrestrial water storage bodies across and along continental shelves, as well as the impacts on some key biological/biogeochemical properties of coastal waters.Ocean Research Coordination Network and the National Science Foundatio
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