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Collins, Donald J.

Publications and source records attributed to Collins, Donald J..

14 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

(abstract) Satellite Physical Oceanography Data Available From an EOSDIS Archive

The Physical Oceanography Distributed Active Archive Center (PO.DAAC) at the Jet Propulsion Laboratory archives and distributes data as part of the Earth Observing System Data and Information System (EOSDIS). Products available from JPL are largely satellite derived and include sea-surface height, surface-wind speed and vectors, integrated water vapor, atmospheric liquid water, sea-surface temperature, heat flux, and in-situ data as it pertains to satellite data. Much of the data is global and spans fourteen years.There is email access, a WWW site, product catalogs, and FTP capabilities. Data is free of charge.

oceanography Earth Observing System oceans data cl↗
NASA NTRS1993

Knowledge-based assistance for science visualization and analysis using large distributed databases

Within this decade, the growth in complexity of exploratory data analysis and the sheer volume of space data require new and innovative approaches to support science investigators in achieving their research objectives. To date, there have been numerous efforts addressing the individual issues involved in inter-disciplinary, multi-instrument investigations. However, while successful in small scale, these efforts have not proven to be open and scalable. This proposal addresses four areas of significant need: scientific visualization and analysis; science data management; interactions in a distributed, heterogeneous environment; and knowledge-based assistance for these functions. The fundamental innovation embedded with this proposal is the integration of three automation technologies, namely, knowledge-based expert systems, science visualization and science data management. This integration is based on concept called the DataHub. With the DataHub concept, NASA will be able to apply a more complete solution to all nodes of a distributed system. Both computation nodes and interactive nodes will be able to effectively and efficiently use the data services (address, retrieval, update, etc.) with a distributed, interdisciplinary information system in a uniform and standard way. This will allow the science investigators to concentrate on their scientific endeavors, rather than to involve themselves in the intricate technical details of the systems and tools required to accomplish their work. Thus, science investigators need not be programmers. The emphasis will be on the definition and prototyping of system elements with sufficient detail to enable data analysis and interpretation leading to publishable scientific results. In addition, the proposed work includes all the required end-to-end components and interfaces to demonstrate the completed concept.

Handley, Thomas H., Jr.↗
NASA NTRS1993

DataHub sponsored analysis

The primary productivity of phytoplankton in the ocean is largely responsible for the assimilation of carbon into the oceanic environment, and thus in part the removal of carbon from the atmosphere. Because the ocean is thought to be a primary sink for atmospheric carbon, the basin wide and global distribution of oceanic primary productivity is of central importance in the global budget of carbon. To understand the global productivity of the oceans, the interactions between the physical and biological structures must be known. To address the broader context of the primary productivity of the sea, the physical and biological processes and their variability, including changes in water mass, incident irradiance, nutrients, and consequent formation of blooms of different species of marine phytoplankton and bacteria must be studied. In this investigation, we will use time series of the pigment distributions, taken from the Coastal Zone Color Scanner (CZCS), and of the sea-surface temperature, taken from the NOAA Advanced Very High Resolution Radiometer (AVHRR). These time series will be examined to determine the spatial and temporal statistics of productivity, including the interannual variations that occur in productivity caused by variations in the physical environment. For this task we have chosen to use monthly composite global maps created from the satellite imagery.

Tran, An Van↗
NASA NTRS1992

Knowledge-based assistance for science visualization and analysis using large distributed databases

Within this decade, the growth in complexity of exploratory data analysis and the sheer volume of space data require new and innovative approaches to support science investigators in achieving their research objectives. To date, there have been numerous efforts addressing the individual issues involved in inter-disciplinary, multi-instrument investigations. However, while successful in small scale, these efforts have not proven to be open and scaleable. This proposal addresses four areas of significant need: scientific visualization and analysis; science data management; interactions in a distributed, heterogeneous environment; and knowledge-based assistance for these functions. The fundamental innovation embedded within this proposal is the integration of three automation technologies, namely, knowledge-based expert systems, science visualization and science data management. This integration is based on the concept called the Data Hub. With the Data Hub concept, NASA will be able to apply a more complete solution to all nodes of a distributed system. Both computation nodes and interactive nodes will be able to effectively and efficiently use the data services (access, retrieval, update, etc.) with a distributed, interdisciplinary information system in a uniform and standard way. This will allow the science investigators to concentrate on their scientific endeavors, rather than to involve themselves in the intricate technical details of the systems and tools required to accomplish their work. Thus, science investigators need not be programmers. The emphasis will be on the definition and prototyping of system elements with sufficient detail to enable data analysis and interpretation leading to publishable scientific results. In addition, the proposed work includes all the required end-to-end components and interfaces to demonstrate the completed concept.

Handley, Thomas H., Jr.↗
NASA NTRS1991

The EOSDIS Version 0 Distributed Active Archive Center for physical oceanography and air-sea interaction

The Distributed Active Archive Center (DAAC) at the Jet Propulsion Laboratory will support scientists specializing in physical oceanography and air-sea interaction. As part of the NASA Earth Observing System Data and Information System Version 0 the DAAC will build on existing capabilities to provide services for data product generation, archiving, distribution and management of information about data. To meet scientist's immediate needs for data, existing data sets from missions such as Seasat, Geosat, the NOAA series of satellites and the Global Positioning Satellite system will be distributed to investigators upon request. In 1992, ocean topography, wave and surface roughness data from the Topex/Poseidon radar altimeter mission will be archived and distributed. New data products will be derived from Topex/Poseidon and other sensor systems based on recommendations of the science community. In 1995, ocean wind field measurements from the NASA Scatterometer will be supported by the DAAC.

Hilland, Jeffrey E.↗
NASA NTRS1990

Bio-optical profile data report: Southern California Bight Study (SCB2-29) R/V Robert G. Sproul, 20-25 August 1988

Time series measurements of the incident surface downwelling irradiance and vertical profiles of the bio-optical properties of the ocean were studied during the 29th cruise of the Southern California Bight Study (SCBS) during the period of August 20-25, 1988. A summary of these data is presented to permit investigators an overview of the data collected. The data are available in digital form for scientific investigators.

Collins, Donald J.↗
NASA NTRS1990

Bio-optical profile data report: Joint Global Ocean Flux Study, Hawaii Ocean Time-Series, HOT-3, R/V Moana Wave, 6-10 January 1989

Time-series measurements of the incident surface downwelling irradiance and vertical profiles of the Bio-optical properties of the ocean have been measured during the third cruise of the Hawaii Ocean Time-Series to the ALOHA site, 22 degrees 56.4 minutes N, 157 degrees 54.6 minutes W, north of the island of Oahu, Hawaii, during the period January 6 to 10, 1989. A summary of these data is presented to permit investigators an overview of the data collected. The data are available in digital form for scientific investigators.

Collins, Donald J.↗
NASA NTRS1990

Calculating Irradiance For Photosynthesis In The Ocean

Mathematical model predicts available and usable irradiances. Yields estimates of irradiance available for photosynthesis (Epar) and irradiance usable for photosynthesis (Epur) as functions of depth in ocean. Describes Epur and Epar in terms of spectral parameters measured remotely (from satellites or airplanes). These irradiances useful in studies of photosynthetic productivity of phytoplankton in euphotic layer.

Collins, Donald J.↗
NASA NTRS1990

The incident solar irradiance at the sea surface

Computations have been performed of the incident spectral irradiance at the sea surface using LOWTRAN-7 as the basis to describe the incident scalar and vector irradiance in terms of the true solar zenith angle and the nominal visibility in the atmosphere. These computations have been used to describe the contributions to the incident irradiance from the direct and the sky components of the total irradiance and the average cosine of the sky component as a measure of the radiance distribution of the sky for varying atmospheric conditions. Comparisons of the computations from LOWTRAN-7 have been made with the results from other models, and with data obtained from field measurements, and excellent agreement has been obtained for the daily profiles of the vector and scalar irradiance at the surface. These computations have been used to provide a description of the irradiance at the sea surface for use in the analysis of remotely sensed data based on information on the radiative transfer through the atmosphere above the sea surface.

Van Tran, AN↗
NASA NTRS1989

The remote sensing of oceanic primary productivity - A review

The ocean is a major sink for atmospheric carbon dioxide. This paper assesses the correctness of the present estimates of the marine primary productivity, obtained by remote sensing techniques, by modeling the physiological mechanisms of carbon assimilation by phytoplankton. The model uses, as the input, measurements of the ocean-surface pigments and data on the incident solar irradiance, and incorporates a description of the photosynthetically available and usable irradiance in the ocean, to describe the light field required for photosynthesis. A comparison of measured and estimated values of the water-column integrated primary marine productivity over large ocean regions yielded favorable results. These estimates do not appear to depend on regional or seasonal factors.

Collins, Donald J.↗
NASA NTRS1988

A model of the photosynthetically available and usable irradiance in the sea

A theoretical model describing the depth dependence of the solar irradiance available to phytoplankton for photosynthesis is developed for waters classified as Case I by Jerlov (1976). The techniques used to account for the effects of incident solar irradiance, pigment concentration, and the spectral diffuse attentuation coefficient are described; an expression for the photosynthetically usable irradiance is derived; and particular attention is given to the specific diffuse absorption coefficient for chlorophyll (Morel, 1978). The relationships among the primary model parameters are shown in graphs.

Collins, Donald J.↗
NASA NTRS1986

The interaction of light with phytoplankton in the marine environment

In many regions of the ocean, the phytoplankton population dominates both the attenuation and scattering of light. In other regions, non-phytoplankton contributions to the absorption and scattering may change the remote sensing reflectance and thus affect the ability to interpret remotely sensed ocean color. Hence, variations in the composition of both the phytoplankton population and of the non-phytoplankton material in the water can affect the optical properties of the sea. The effects of these contributions to the remote sensing reflectance and the submarine light field are modeled using scattering and absorption measurements of phytoplankton cultures obtained at the Friday Harbor Laboratory of the University of Washington. These measurements are used to develop regional chlorophyll algorithms specific to the summer waters of Puget Sound for the Coastal Zone Color Scanner, Thematic Mapper and future Ocean Color Imager, and their accuracies are compared for high chlorophyll waters with little or no Gelbstoff, but with variable detrital and suspended material.

Carder, Kendall L.↗
NASA NTRS1986

A model for the use of satellite remote sensing for the measurement of primary production in the ocean

A model of primary production based upon the responses of phytoplankton to differing light and nutrient fields is described. This model includes the effects on production of variations in surface pigment concentration, the mixed layer depth, and the dependence on the incident solar irradiance. The model has been tested using in situ data provided by the Southern California Bight Studies of Eppley, et al. (1979), the California Cooperative Fisheries Investigations, the Organization of Persistent Upwelling Structures, and other data sets. A synoptic measure of the distribution of surface pigments is derived from the West Coast Chlorophyll and Temperature Time Series. The features and behavior of the model are presented together with the results of the model verification.

Collins, Donald J.↗