Flagging optically shallow pixels for improved analysis of ocean color data

Science.gov (United States)

McKinna, L. I. W.; Werdell, J.; Knowles, D., Jr.

2016-02-01

Ocean color remote-sensing is routinely used to derive marine geophysical parameters from sensor-observed water-leaving radiances. However, in clear geometrically shallow regions, traditional ocean color algorithms can be confounded by light reflected from the seafloor. Such regions are typically referred to as "optically shallow". When performing spatiotemporal analyses of ocean color datasets, optically shallow features such as coral reefs can lead to unexpected regional biases. Benthic contamination of the water-leaving radiance is dependent on bathymetry, water clarity and seafloor albedo. Thus, a prototype ocean color processing flag called OPTSHAL has been developed that takes all three variables into account. In the method described here, the optical depth of the water column at 547 nm, ζ(547), is predicted from known bathymetry and estimated inherent optical properties. If ζ(547) is less then the pre-defined threshold, a pixel is flagged as optically shallow. Radiative transfer modeling was used to identify the appropriate threshold value of ζ(547) for a generic benthic sand albedo. OPTSHAL has been evaluated within the NASA Ocean Biology Processing Group's L2GEN code. Using MODIS Aqua imagery, OPTSHAL was tested in two regions: (i) the Pedro Bank south-west of Jamaica, and (ii) the Great Barrier Reef, Australia. It is anticipated that OPTSHAL will benefit end-users when quality controlling derived ocean color products. Further, OPTSHAL may prove useful as a mechanism for switching between optically deep and shallow algorithms during ocean color processing.

Geostationary Surface and Insolation Products (GSIP), Version 3

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Surface and Insolation Products (GSIP) Version 3 contains upwelling and downwelling shortwave (0.2-4.0 um) and visible (0.4-0.7 um) radiative...

Minimizing Gaps of Daily Ndvi Map with Geostationary Satellite Remote Sensing Data

Science.gov (United States)

Lee, S.; Ryu, Y.; Jiang, C.

2015-12-01

Satellite based remote sensing has been used to monitor plant phenology. Numerous studies have generally utilized normalized difference vegetation index (NDVI) to quantify phenological patterns and changes in regional to the global scales. Obtaining the NDVI values during summer in East Asian Monsoon regions is important because most plants grow vigorously in this season. However, satellite derived NDVI data are error prone to clouds during most of the period. Various methods have attempted to reduce the effect of cloud in temporal and spatial NDVI monitoring; the fundamental solution is to have a large data pool that includes multiple images in short period and supplements NDVI values in same period. Multiple images of geostationary satellite in a day can be a method to expand the pool. In this study, we suggest an approach that minimizes data gaps in NDVI of the day through geostationary satellite derived NDVI composition. We acquired data from Geostationary Ocean Color Imager (GOCI) which is a satellite that was launched to monitor ocean around the Korean peninsula, China, Japan and Russia. The satellite observes eight times per day (09:00 - 16:00, every hour) at 500 x 500 m resolution from 2011 to 2015. GOCI red- and near infrared radiance was converted into surface reflectance by using 6S Radiative Transfer Model (6S). We calculated NDVI tiles for each of observed eight tiles per day and made one day NDVI through maximum-value composite method. We evaluated the composite GOCI derived NDVI by comparing with daily MODIS-derived NDVI (composited from MOD09GA and MYD09GA), 16-day Landsat 8-derived NDVI, and in-situ light emitting diode (LED) NDVI measurements at a homogeneous deciduous forest and rice paddy sites. We found that GOCI-derived NDVI maps revealed little data gaps compared to MODIS and Landsat, and GOCI derived NDVI time series were smoother than MODIS derived NDVI time series in summer. GOCI-derived NDVI agreed well with in-situ observations of NDVI

Validation and Intercomparison of Ocean Color Algorithms for Estimating Particulate Organic Carbon in the Oceans

Directory of Open Access Journals (Sweden)

Hayley Evers-King

2017-08-01

Full Text Available Particulate Organic Carbon (POC plays a vital role in the ocean carbon cycle. Though relatively small compared with other carbon pools, the POC pool is responsible for large fluxes and is linked to many important ocean biogeochemical processes. The satellite ocean-color signal is influenced by particle composition, size, and concentration and provides a way to observe variability in the POC pool at a range of temporal and spatial scales. To provide accurate estimates of POC concentration from satellite ocean color data requires algorithms that are well validated, with uncertainties characterized. Here, a number of algorithms to derive POC using different optical variables are applied to merged satellite ocean color data provided by the Ocean Color Climate Change Initiative (OC-CCI and validated against the largest database of in situ POC measurements currently available. The results of this validation exercise indicate satisfactory levels of performance from several algorithms (highest performance was observed from the algorithms of Loisel et al., 2002; Stramski et al., 2008 and uncertainties that are within the requirements of the user community. Estimates of the standing stock of the POC can be made by applying these algorithms, and yield an estimated mixed-layer integrated global stock of POC between 0.77 and 1.3 Pg C of carbon. Performance of the algorithms vary regionally, suggesting that blending of region-specific algorithms may provide the best way forward for generating global POC products.

Satellite Ocean Color Sensor Design Concepts and Performance Requirements

Science.gov (United States)

McClain, Charles R.; Meister, Gerhard; Monosmith, Bryan

2014-01-01

In late 1978, the National Aeronautics and Space Administration (NASA) launched the Nimbus-7 satellite with the Coastal Zone Color Scanner (CZCS) and several other sensors, all of which provided major advances in Earth remote sensing. The inspiration for the CZCS is usually attributed to an article in Science by Clarke et al. who demonstrated that large changes in open ocean spectral reflectance are correlated to chlorophyll-a concentrations. Chlorophyll-a is the primary photosynthetic pigment in green plants (marine and terrestrial) and is used in estimating primary production, i.e., the amount of carbon fixed into organic matter during photosynthesis. Thus, accurate estimates of global and regional primary production are key to studies of the earth's carbon cycle. Because the investigators used an airborne radiometer, they were able to demonstrate the increased radiance contribution of the atmosphere with altitude that would be a major issue for spaceborne measurements. Since 1978, there has been much progress in satellite ocean color remote sensing such that the technique is well established and is used for climate change science and routine operational environmental monitoring. Also, the science objectives and accompanying methodologies have expanded and evolved through a succession of global missions, e.g., the Ocean Color and Temperature Sensor (OCTS), the Seaviewing Wide Field-of-view Sensor (SeaWiFS), the Moderate Resolution Imaging Spectroradiometer (MODIS), the Medium Resolution Imaging Spectrometer (MERIS), and the Global Imager (GLI). With each advance in science objectives, new and more stringent requirements for sensor capabilities (e.g., spectral coverage) and performance (e.g., signal-to-noise ratio, SNR) are established. The CZCS had four bands for chlorophyll and aerosol corrections. The Ocean Color Imager (OCI) recommended for the NASA Pre-Aerosol, Cloud, and Ocean Ecosystems (PACE) mission includes 5 nanometers hyperspectral coverage from 350 to

Assessment of NPP VIIRS Ocean Color Data Products: Hope and Risk

Science.gov (United States)

Turpie, Kevin R.; Meister, Gerhard; Eplee, Gene; Barnes, Robert A.; Franz, Bryan; Patt, Frederick S.; Robinson, Wayne d.; McClain, Charles R.

2010-01-01

For several years, the NASA/Goddard Space Flight Center (GSFC) NPP VIIRS Ocean Science Team (VOST) provided substantial scientific input to the NPP project regarding the use of Visible Infrared Imaging Radiometer Suite (VIIRS) to create science quality ocean color data products. This work has culminated into an assessment of the NPP project and the VIIRS instrument's capability to produce science quality Ocean Color data products. The VOST concluded that many characteristics were similar to earlier instruments, including SeaWiFS or MODIS Aqua. Though instrument performance and calibration risks do exist, it was concluded that programmatic and algorithm issues dominate concerns. Keywords: NPP, VIIRS, Ocean Color, satellite remote sensing, climate data record.

SWIM: A Semi-Analytical Ocean Color Inversion Algorithm for Optically Shallow Waters

Science.gov (United States)

McKinna, Lachlan I. W.; Werdell, P. Jeremy; Fearns, Peter R. C. S.; Weeks, Scarla J.; Reichstetter, Martina; Franz, Bryan A.; Shea, Donald M.; Feldman, Gene C.

2014-01-01

Ocean color remote sensing provides synoptic-scale, near-daily observations of marine inherent optical properties (IOPs). Whilst contemporary ocean color algorithms are known to perform well in deep oceanic waters, they have difficulty operating in optically clear, shallow marine environments where light reflected from the seafloor contributes to the water-leaving radiance. The effect of benthic reflectance in optically shallow waters is known to adversely affect algorithms developed for optically deep waters [1, 2]. Whilst adapted versions of optically deep ocean color algorithms have been applied to optically shallow regions with reasonable success [3], there is presently no approach that directly corrects for bottom reflectance using existing knowledge of bathymetry and benthic albedo.To address the issue of optically shallow waters, we have developed a semi-analytical ocean color inversion algorithm: the Shallow Water Inversion Model (SWIM). SWIM uses existing bathymetry and a derived benthic albedo map to correct for bottom reflectance using the semi-analytical model of Lee et al [4]. The algorithm was incorporated into the NASA Ocean Biology Processing Groups L2GEN program and tested in optically shallow waters of the Great Barrier Reef, Australia. In-lieu of readily available in situ matchup data, we present a comparison between SWIM and two contemporary ocean color algorithms, the Generalized Inherent Optical Property Algorithm (GIOP) and the Quasi-Analytical Algorithm (QAA).

Dazzled by ice and snow: improving medium ocean color images in Arctic waters

Science.gov (United States)

Babin, M.; Goyens, C.; Belanger, S.

2016-02-01

The importance of phytoplankton blooms for the Arctic marine ecosystem is well recognized but studies disagree as the consequences of sea ice melt on the phytoplankton distribution and growth. This limited understanding in actual and future Arctic phytoplankton dynamics mostly results from a lack of accurate data at the receding ice-edges where phytoplankton blooms are known to occur. Ocean color sensors on-board satellites represent therefore a crucial tool providing a synoptic view of the ocean systems over broad spatio-temporal scales. However, today the use of ocean color data in Arctic environments remains strongly compromised due to, among others, sea ice contamination. Indeed, medium ocean color data along the receding ice edge are "dazzled" by nearby and/or sub-pixel highly reflective ice floes. Standard ocean color data methods ignore ice-contamination during data processing which deteriorates the quality of the radiometric data and subsequent satellite derived bio-geochemical products. Moreover, since Arctic phytoplankton spring blooms typically develop along the receding ice-edges, ignoring ice-contaminated pixels may lead to wrong interpretation of satellite data. The present study shows how adjacent and sub-pixel sea-ice floes affect the retrieved ocean color data. A correction approach is also suggested to improve the "dazzled" ocean color pixels along the receding ice edge in the aim to provide additional support to better understand current and future trends in phytoplankton dynamics.

Validation of ocean color sensors using a profiling hyperspectral radiometer

Science.gov (United States)

Ondrusek, M. E.; Stengel, E.; Rella, M. A.; Goode, W.; Ladner, S.; Feinholz, M.

2014-05-01

Validation measurements of satellite ocean color sensors require in situ measurements that are accurate, repeatable and traceable enough to distinguish variability between in situ measurements and variability in the signal being observed on orbit. The utility of using a Satlantic Profiler II equipped with HyperOCR radiometers (Hyperpro) for validating ocean color sensors is tested by assessing the stability of the calibration coefficients and by comparing Hyperpro in situ measurements to other instruments and between different Hyperpros in a variety of water types. Calibration and characterization of the NOAA Satlantic Hyperpro instrument is described and concurrent measurements of water-leaving radiances conducted during cruises are presented between this profiling instrument and other profiling, above-water and moored instruments. The moored optical instruments are the US operated Marine Optical BuoY (MOBY) and the French operated Boussole Buoy. In addition, Satlantic processing versions are described in terms of accuracy and consistency. A new multi-cast approach is compared to the most commonly used single cast method. Analysis comparisons are conducted in turbid and blue water conditions. Examples of validation matchups with VIIRS ocean color data are presented. With careful data collection and analysis, the Satlantic Hyperpro profiling radiometer has proven to be a reliable and consistent tool for satellite ocean color validation.

Seahawk: An Advanced Cubesat Mission for Sustained Ocean Color Monitoring

Science.gov (United States)

Morrison, John M.; Jeffrey, Hazel; Gorter, Hessel; Anderson, Pamela; Clark, Craig; Holmes, Alan; Feldman, Gene C.; Pratt, Frederick S.

2016-01-01

Sustained ocean color monitoring is vital to understanding the marine ecosystem. It has been identified as an Essential Climate Variable (ECV) and is a vital parameter in understanding long-term climate change. Furthermore, observations can be beneficial in observing oil spills, harmful algal blooms and the health of fisheries. Space-based remote sensing, through MERIS, SeaWiFS and MODIS instruments, have provided a means of observing the vast area covered by the ocean which would otherwise be impossible using ships alone. However, the large pixel size makes measurements of lakes, rivers, estuaries and coastal zones difficult. Furthermore, retirement of a number of widely used and relied upon ocean observation instruments, particularly MERIS and SeaWiFS, leaves a significant gap in ocean color observation opportunities. This paper presents an overview of the SeaHawk mission, a collaborative effort between Clyde Space Ltd., the University of North Carolina Wilmington, Cloudland Instruments, and Goddard Spaceflight Center, funded by the Gordon and Betty Moore Foundation. The goal of the project is to enhance the ability to observe ocean color in high temporal and spatial resolution through use of a low-cost, next-generation ocean color sensor flown aboard a CubeSat. The final product will be 530 times smaller (0.0034 vs 1.81cu m) and 115 time less massive (3.4 vs 390.0 kg) but with a ground resolution 10 times better whilst maintaining a signal/noise ratio 50 that of SeaWiFs. This paper will describe the objectives of the mission, outline the payload specification and the spacecraft platform to support it.

Use of Multiangle Satellite Observations to Retrieve Aerosol Properties and Ocean Color

Science.gov (United States)

Martonchik, John V.; Diner, David; Khan, Ralph

2005-01-01

A new technique is described for retrieving aerosol over ocean water and the associated ocean color using multiangle satellite observations. Unlike current satellite aerosol retrieval algorithms which only utilize observations at red wavelengths and longer, with the assumption that these wavelengths have a negligible ocean (water-leaving radiance), this new algorithm uses all available spectral bands and simultaneously retrieves both aerosol properties and the spectral ocean color. We show some results of case studies using MISR data, performed over different water conditions (coastal water, blooms, and open water).

Ocean Color and Earth Science Data Records

Science.gov (United States)

Maritorena, S.

2014-12-01

The development of consistent, high quality time series of biogeochemical products from a single ocean color sensor is a difficult task that involves many aspects related to pre- and post-launch instrument calibration and characterization, stability monitoring and the removal of the contribution of the atmosphere which represents most of the signal measured at the sensor. It is even more challenging to build Climate Data Records (CDRs) or Earth Science Data Records (ESDRs) from multiple sensors as design, technology and methodologies (bands, spectral/spatial resolution, Cal/Val, algorithms) differ from sensor to sensor. NASA MEaSUREs, ESA Climate Change Initiative (CCI) and IOCCG Virtual Constellation are some of the underway efforts that investigate or produce ocean color CDRs or ESDRs from the recent and current global missions (SeaWiFS, MODIS, MERIS). These studies look at key aspects of the development of unified data records from multiple sensors, e.g. the concatenation of the "best" individual records vs. the merging of multiple records or band homogenization vs. spectral diversity. The pros and cons of the different approaches are closely dependent upon the overall science purpose of the data record and its temporal resolution. While monthly data are generally adequate for biogeochemical modeling or to assess decadal trends, higher temporal resolution data records are required to look into changes in phenology or the dynamics of phytoplankton blooms. Similarly, short temporal resolution (daily to weekly) time series may benefit more from being built through the merging of data from multiple sensors while a simple concatenation of data from individual sensors might be better suited for longer temporal resolution (e.g. monthly time series). Several Ocean Color ESDRs were developed as part of the NASA MEaSUREs project. Some of these time series are built by merging the reflectance data from SeaWiFS, MODIS-Aqua and Envisat-MERIS in a semi-analytical ocean color

Trace Gas Measurements from the GeoTASO and GCAS Airborne Instruments: An Instrument and Algorithm Test-Bed for Air Quality Observations from Geostationary Orbit

Science.gov (United States)

Nowlan, C. R.; Liu, X.; Janz, S. J.; Leitch, J. W.; Al-Saadi, J. A.; Chance, K.; Cole, J.; Delker, T.; Follette-Cook, M. B.; Gonzalez Abad, G.; Good, W. S.; Kowalewski, M. G.; Loughner, C.; Pickering, K. E.; Ruppert, L.; Soo, D.; Szykman, J.; Valin, L.; Zoogman, P.

2016-12-01

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) and the GEO-CAPE Airborne Simulator (GCAS) instruments are pushbroom sensors capable of making remote sensing measurements of air quality and ocean color. Originally developed as test-bed instruments for the Geostationary Coastal and Air Pollution Events (GEO-CAPE) decadal survey, these instruments are now also part of risk reduction for the upcoming Tropospheric Emissions: Monitoring of Pollution (TEMPO) and Geostationary Environment Monitoring Spectrometer (GEMS) geostationary satellite missions, and will provide validation capabilities after the satellite instruments are in orbit. GeoTASO and GCAS flew on two different aircraft in their first intensive air quality field campaigns during the DISCOVER-AQ missions over Texas in 2013 and Colorado in 2014. GeoTASO was also deployed in 2016 during the KORUS-AQ field campaign to make measurements of trace gases and aerosols over Korea. GeoTASO and GCAS collect spectra of backscattered solar radiation in the UV and visible that can be used to derive 2-D maps of trace gas columns below the aircraft at spatial resolutions on the order of 250 x 500 m. We present spatially resolved maps of trace gas retrievals of ozone, nitrogen dioxide, formaldehyde and sulfur dioxide over urban areas and power plants from flights during the field campaigns, and comparisons with data from ground-based spectrometers, in situ monitoring instruments, and satellites.

Regional impacts of ocean color on tropical Pacific variability

OpenAIRE

W. Anderson; A. Gnanadesikan; A. Wittenberg

2009-01-01

The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly se...

Evaluating VIIRS ocean color products for west coast and Hawaiian waters

KAUST Repository

Davis, Curtiss O.; Tufillaro, Nicholas; Nahorniak, Jasmine; Jones, Burton; Arnone, Robert

2013-01-01

Automated match ups allow us to maintain and improve the ocean color products of current satellite instruments MODIS, and since February 2012 the Visible Infrared Imaging Radiometer Suite (VIIRS). As part of the VIIRS mission Ocean Calibration

Use of satellite ocean color observations to refine understanding of global geochemical cycles

Science.gov (United States)

Walsh, J. J.; Dieterle, D. A.

1985-01-01

In October 1978, the first satellite-borne color sensor, the Coastal Zone Color Scanner (CZCS), was launched aboard Nimbus-7 with four visible and two infrared bands, permitting a sensitivity about 60 times that of the Landsat-1 multispectral scanner. The CZCS radiance data can be utilized to estimate ocean chlorophyll concentrations by detecting shifts in sea color, particularly in oceanic waters. The obtained data can be used in studies regarding problems of overfishing, and, in addition, in investigations concerning the consequences of man's accelerated extraction of nitrogen from the atmosphere and addition of carbon to the atmosphere. The satellite data base is considered along with a simulation analysis, and ships providing ground-truth chlorophyll measurements in the ocean.

Ocean Color Measurements from Landsat-8 OLI using SeaDAS

Science.gov (United States)

Franz, Bryan Alden; Bailey, Sean W.; Kuring, Norman; Werdell, P. Jeremy

2014-01-01

The Operational Land Imager (OLI) is a multi-spectral radiometer hosted on the recently launched Landsat-8 satellite. OLI includes a suite of relatively narrow spectral bands at 30-meter spatial resolution in the visible to shortwave infrared that make it a potential tool for ocean color radiometry: measurement of the reflected spectral radiance upwelling from beneath the ocean surface that carries information on the biogeochemical constituents of the upper ocean euphotic zone. To evaluate the potential of OLI to measure ocean color, processing support was implemented in SeaDAS, which is an open-source software package distributed by NASA for processing, analysis, and display of ocean remote sensing measurements from a variety of satellite-based multi-spectral radiometers. Here we describe the implementation of OLI processing capabilities within SeaDAS, including support for various methods of atmospheric correction to remove the effects of atmospheric scattering and absorption and retrieve the spectral remote-sensing reflectance (Rrs; sr exp 1). The quality of the retrieved Rrs imagery will be assessed, as will the derived water column constituents such as the concentration of the phytoplankton pigment chlorophyll a.

Intercomparison of Ocean Color Algorithms for Picophytoplankton Carbon in the Ocean

Directory of Open Access Journals (Sweden)

Víctor Martínez-Vicente

2017-12-01

Full Text Available The differences among phytoplankton carbon (Cphy predictions from six ocean color algorithms are investigated by comparison with in situ estimates of phytoplankton carbon. The common satellite data used as input for the algorithms is the Ocean Color Climate Change Initiative merged product. The matching in situ data are derived from flow cytometric cell counts and per-cell carbon estimates for different types of pico-phytoplankton. This combination of satellite and in situ data provides a relatively large matching dataset (N > 500, which is independent from most of the algorithms tested and spans almost two orders of magnitude in Cphy. Results show that not a single algorithm outperforms any of the other when using all matching data. Concentrating on the oligotrophic regions (Chlorophyll-a concentration, B, less than 0.15 mg Chl m−3, where flow cytometric analysis captures most of the phytoplankton biomass, reveals significant differences in algorithm performance. The bias ranges from −35 to +150% and unbiased root mean squared difference from 5 to 10 mg C m−3 among algorithms, with chlorophyll-based algorithms performing better than the rest. The backscattering-based algorithms produce different results at the clearest waters and these differences are discussed in terms of the different algorithms used for optical particle backscattering coefficient (bbp retrieval.

In-Orbit Vicarious Calibration for Ocean Color and Aerosol Products

National Research Council Canada - National Science Library

Wang, Menghua

2005-01-01

It is well known that, to accurately retrieve the spectrum of the water-leaving radiance and derive the ocean color products from satellite sensors, a vicarious calibration procedure, which performs...

SWIM: A Semi-Analytical Ocean Color Inversion Algorithm for Optically Shallow Waters

Science.gov (United States)

McKinna, Lachlan I. W.; Werdell, P. Jeremy; Fearns, Peter R. C. S.; Weeks, Scarla J.; Reichstetter, Martina; Franz, Bryan A.; Bailey, Sean W.; Shea, Donald M.; Feldman, Gene C.

2014-01-01

In clear shallow waters, light that is transmitted downward through the water column can reflect off the sea floor and thereby influence the water-leaving radiance signal. This effect can confound contemporary ocean color algorithms designed for deep waters where the seafloor has little or no effect on the water-leaving radiance. Thus, inappropriate use of deep water ocean color algorithms in optically shallow regions can lead to inaccurate retrievals of inherent optical properties (IOPs) and therefore have a detrimental impact on IOP-based estimates of marine parameters, including chlorophyll-a and the diffuse attenuation coefficient. In order to improve IOP retrievals in optically shallow regions, a semi-analytical inversion algorithm, the Shallow Water Inversion Model (SWIM), has been developed. Unlike established ocean color algorithms, SWIM considers both the water column depth and the benthic albedo. A radiative transfer study was conducted that demonstrated how SWIM and two contemporary ocean color algorithms, the Generalized Inherent Optical Properties algorithm (GIOP) and Quasi-Analytical Algorithm (QAA), performed in optically deep and shallow scenarios. The results showed that SWIM performed well, whilst both GIOP and QAA showed distinct positive bias in IOP retrievals in optically shallow waters. The SWIM algorithm was also applied to a test region: the Great Barrier Reef, Australia. Using a single test scene and time series data collected by NASA's MODIS-Aqua sensor (2002-2013), a comparison of IOPs retrieved by SWIM, GIOP and QAA was conducted.

Retrospective satellite ocean color analysis of purposeful and natural ocean iron fertilization

Science.gov (United States)

Westberry, Toby K.; Behrenfeld, Michael J.; Milligan, Allen J.; Doney, Scott C.

2013-03-01

Significant effort has been invested in understanding the role of iron in marine ecosystems over the past few decades. What began as shipboard amendment experiments quickly grew into a succession of in situ, mesoscale ocean iron fertilization (OIF) experiments carried out in all three high nutrient low chlorophyll (HNLC) regions of the world ocean. Dedicated process studies have also looked at regions of the ocean that are seasonally exposed to iron-replete conditions as natural OIF experiments. However, one problem common to many OIF experiments is determination of biological response beyond the duration of the experiment (typicallyfloristic shifts in the phytoplankton community. Further, a consistent pattern of decreased satellite fluorescence efficiency (FLH:Chl or ϕf) following OIF is observed that is in agreement with current understanding of phytoplankton physiological responses to relief from iron stress. The current study extends our ability to retrieve phytoplankton physiology from space-based sensors, strengthens the link between satellite fluorescence and iron availability, and shows that satellite ocean color analyses provide a unique tool for monitoring OIF experiments.

Calibration Uncertainty in Ocean Color Satellite Sensors and Trends in Long-term Environmental Records

Science.gov (United States)

Turpie, Kevin R.; Eplee, Robert E., Jr.; Franz, Bryan A.; Del Castillo, Carlos

2014-01-01

Launched in late 2011, the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (NPP) spacecraft is being evaluated by NASA to determine whether this sensor can continue the ocean color data record established through the Sea-Viewing Wide Field-of-view Sensor (SeaWiFS) and the MODerate resolution Imaging Spectroradiometer (MODIS). To this end, Goddard Space Flight Center generated evaluation ocean color data products using calibration techniques and algorithms established by NASA during the SeaWiFS and MODIS missions. The calibration trending was subjected to some initial sensitivity and uncertainty analyses. Here we present an introductory assessment of how the NASA-produced time series of ocean color is influenced by uncertainty in trending instrument response over time. The results help quantify the uncertainty in measuring regional and global biospheric trends in the ocean using satellite remote sensing, which better define the roles of such records in climate research.

Suspended sediment concentration and optical property observations of mixed-turbidity, coastal waters through multispectral ocean color inversion

Science.gov (United States)

Multispectral satellite ocean color data from high-turbidity areas of the coastal ocean contain information about the surface concentrations and optical properties of suspended sediments and colored dissolved organic matter (CDOM). Empirical and semi-analytical inversion algorit...

Assimilation of Ocean-Color Plankton Functional Types to Improve Marine Ecosystem Simulations

Science.gov (United States)

Ciavatta, S.; Brewin, R. J. W.; Skákala, J.; Polimene, L.; de Mora, L.; Artioli, Y.; Allen, J. I.

2018-02-01

We assimilated phytoplankton functional types (PFTs) derived from ocean color into a marine ecosystem model, to improve the simulation of biogeochemical indicators and emerging properties in a shelf sea. Error-characterized chlorophyll concentrations of four PFTs (diatoms, dinoflagellates, nanoplankton, and picoplankton), as well as total chlorophyll for comparison, were assimilated into a physical-biogeochemical model of the North East Atlantic, applying a localized Ensemble Kalman filter. The reanalysis simulations spanned the years 1998-2003. The skill of the reference and reanalysis simulations in estimating ocean color and in situ biogeochemical data were compared by using robust statistics. The reanalysis outperformed both the reference and the assimilation of total chlorophyll in estimating the ocean-color PFTs (except nanoplankton), as well as the not-assimilated total chlorophyll, leading the model to simulate better the plankton community structure. Crucially, the reanalysis improved the estimates of not-assimilated in situ data of PFTs, as well as of phosphate and pCO2, impacting the simulation of the air-sea carbon flux. However, the reanalysis increased further the model overestimation of nitrate, in spite of increases in plankton nitrate uptake. The method proposed here is easily adaptable for use with other ecosystem models that simulate PFTs, for, e.g., reanalysis of carbon fluxes in the global ocean and for operational forecasts of biogeochemical indicators in shelf-sea ecosystems.

Geostationary satellites collocation

CERN Document Server

Li, Hengnian

2014-01-01

Geostationary Satellites Collocation aims to find solutions for deploying a safe and reliable collocation control. Focusing on the orbital perturbation analysis, the mathematical foundations for orbit and control of the geostationary satellite are summarized. The mathematical and physical principle of orbital maneuver and collocation strategies for multi geostationary satellites sharing with the same dead band is also stressed. Moreover, the book presents some applications using the above algorithms and mathematical models to help readers master the corrective method for planning station keeping maneuvers. Engineers and scientists in the fields of aerospace technology and space science can benefit from this book. Hengnian Li is the Deputy Director of State Key Laboratory of Astronautic Dynamics, China.

Uncertainties in Coastal Ocean Color Products: Impacts of Spatial Sampling

Science.gov (United States)

Pahlevan, Nima; Sarkar, Sudipta; Franz, Bryan A.

2016-01-01

With increasing demands for ocean color (OC) products with improved accuracy and well characterized, per-retrieval uncertainty budgets, it is vital to decompose overall estimated errors into their primary components. Amongst various contributing elements (e.g., instrument calibration, atmospheric correction, inversion algorithms) in the uncertainty of an OC observation, less attention has been paid to uncertainties associated with spatial sampling. In this paper, we simulate MODIS (aboard both Aqua and Terra) and VIIRS OC products using 30 m resolution OC products derived from the Operational Land Imager (OLI) aboard Landsat-8, to examine impacts of spatial sampling on both cross-sensor product intercomparisons and in-situ validations of R(sub rs) products in coastal waters. Various OLI OC products representing different productivity levels and in-water spatial features were scanned for one full orbital-repeat cycle of each ocean color satellite. While some view-angle dependent differences in simulated Aqua-MODIS and VIIRS were observed, the average uncertainties (absolute) in product intercomparisons (due to differences in spatial sampling) at regional scales are found to be 1.8%, 1.9%, 2.4%, 4.3%, 2.7%, 1.8%, and 4% for the R(sub rs)(443), R(sub rs)(482), R(sub rs)(561), R(sub rs)(655), Chla, K(sub d)(482), and b(sub bp)(655) products, respectively. It is also found that, depending on in-water spatial variability and the sensor's footprint size, the errors for an in-situ validation station in coastal areas can reach as high as +/- 18%. We conclude that a) expected biases induced by the spatial sampling in product intercomparisons are mitigated when products are averaged over at least 7 km × 7 km areas, b) VIIRS observations, with improved consistency in cross-track spatial sampling, yield more precise calibration/validation statistics than that of MODIS, and c) use of a single pixel centered on in-situ coastal stations provides an optimal sampling size for

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4, Volume IV: Inherent Optical Properties: Instruments, Characterizations, Field Measurements and Data Analysis Protocols

Science.gov (United States)

Mueller, J. L.; Fargion, G. S.; McClain, C. R. (Editor); Pegau, S.; Zanefeld, J. R. V.; Mitchell, B. G.; Kahru, M.; Wieland, J.; Stramska, M.

2003-01-01

This document stipulates protocols for measuring bio-optical and radiometric data for the Sensor Intercomparision and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities and algorithm development. The document is organized into 6 separate volumes as Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 4. Volume I: Introduction, Background, and Conventions; Volume II: Instrument Specifications, Characterization and Calibration; Volume III: Radiometric Measurements and Data Analysis Methods; Volume IV: Inherent Optical Properties: Instruments, Characterization, Field Measurements and Data Analysis Protocols; Volume V: Biogeochemical and Bio-Optical Measurements and Data Analysis Methods; Volume VI: Special Topics in Ocean Optics Protocols and Appendices. The earlier version of Ocean Optics Protocols for Satellite Ocean Color Sensor Validation, Revision 3 is entirely superseded by the six volumes of Revision 4 listed above.

Polarization-based enhancement of ocean color signal for estimating suspended particulate matter: radiative transfer simulations and laboratory measurements.

Science.gov (United States)

Liu, Jia; He, Xianqiang; Liu, Jiahang; Bai, Yan; Wang, Difeng; Chen, Tieqiao; Wang, Yihao; Zhu, Feng

2017-04-17

Absorption and scattering by molecules, aerosols and hydrosols, and the reflection and transmission over the sea surface can modify the original polarization state of sunlight. However, water-leaving radiance polarization, containing embedded water constituent information, has largely been neglected. Here, the efficiency of the parallel polarization radiance (PPR) for enhancing ocean color signal of suspended particulate matter is examined via vector radiative transfer simulations and laboratory experiments. The simulation results demonstrate that the PPR has a slightly higher ocean color signal at the top-of-atmosphere as compared with that of the total radiance. Moreover, both the simulations and laboratory measurements reveal that, compared with total radiance, PPR can effectively enhance the normalized ocean color signal for a large range of observation geometries, wavelengths, and suspended particle concentrations. Thus, PPR has great potential for improving the ocean color signal detection from satellite.

Near Real Time Operational Satellite Ocean Color Products From NOAA OSPO CoastWatch Okeanos System:: Status and Challenges

Science.gov (United States)

Banghua Yan, B.

2016-02-01

Near real-time (NRT) ocean color (OC) satellite operation products are generated and distributed in NOAA Okeanos Operational Product System, by using the CWAPS including the Multi-Sensor Level (MSL) 12 and the chlorophyll-a frontal algorithms. Current OC operational products include daily chlorophyll concentration (anomaly), water turbidity, remote sensing reflectance and chlorophyll frontal products from Moderate-resolution Imaging Spectroradiometer (MODIS)/Aqua. The products have been widely applied to USA local and state ecosystem research, ecosystem observations, and fisheries managements for coastal and regional forecasting of ocean water quality, phytoplankton concentrations, and primary production. Users of the products have the National Ocean Service, National Marine Fisheries Service, National Weather Service, and Oceanic and Atmospheric Research. Recently, the OC products are being extended to S-NPP VIIRS to provide global NRT ocean color products to user community suh as National Weatrher Service for application for Global Data Assimilation System and Real-Time Ocean Forecast System. However, there remain some challenges in application of the products due to certain product quality and coverage issues. Recent efforts were made to provide a comprehensive web-based Quality Assurance (QA) tool for monitoring OC products quality in near real time mode, referring to http://www.ospo.noaa.gov/Products/ocean/color_new/color.htm. The new QA monitoring tool includes but not limited to the following advanced features applicable for MODIS/Aqua and NPP/VIIRS OC products: 1) Monitoring product quality in NRT mode; 2) Monitoring the availability and quality of OC products with time; 3) Detecting anomalous OC products due to low valid pixels and other quality issues. As an example, potential application and challenges of the ocean color products to oceanic oil spill detection are investigated. It is thus expected that the Okeanos ocean color operational system in

Use of ocean color scanner data in water quality mapping

Science.gov (United States)

Khorram, S.

1981-01-01

Remotely sensed data, in combination with in situ data, are used in assessing water quality parameters within the San Francisco Bay-Delta. The parameters include suspended solids, chlorophyll, and turbidity. Regression models are developed between each of the water quality parameter measurements and the Ocean Color Scanner (OCS) data. The models are then extended to the entire study area for mapping water quality parameters. The results include a series of color-coded maps, each pertaining to one of the water quality parameters, and the statistical analysis of the OCS data and regression models. It is found that concurrently collected OCS data and surface truth measurements are highly useful in mapping the selected water quality parameters and locating areas having relatively high biological activity. In addition, it is found to be virtually impossible, at least within this test site, to locate such areas on U-2 color and color-infrared photography.

GOCI Level-2 Processing Improvements and Cloud Motion Analysis

Science.gov (United States)

Robinson, Wayne D.

2015-01-01

The Ocean Biology Processing Group has been working with the Korean Institute of Ocean Science and Technology (KIOST) to process geosynchronous ocean color data from the GOCI (Geostationary Ocean Color Instrument) aboard the COMS (Communications, Ocean and Meteorological Satellite). The level-2 processing program, l2gen has GOCI processing as an option. Improvements made to that processing are discussed here as well as a discussion about cloud motion effects.

GHRSST Level 2P West Atlantic Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-12 satellite (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

GHRSST Level 2P Eastern Pacific Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-11 satellite (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

Calibration Improvements in the Detector-to-Detector Differences for the MODIS Ocean Color Bands

Science.gov (United States)

Li, Yonghong; Angal, Amit; Wu, Aisheng; Geng, Xu; Link, Daniel; Xiong, Xiaoxiong

2016-01-01

The Moderate Resolution Imaging Spectroradiometer (MODIS), a major instrument within NASAs Earth Observation System missions, has operated for over 16 and 14 years onboard the Terra and Aqua satellites, respectively. Its reflective solar bands (RSB) covering a spectral range from 0.4 to 2.1 micrometers are primarily calibrated using the on-board solar diffuser(SD), with its on-orbit degradation monitored using the Solar Diffuser Stability Monitor. RSB calibrations are supplemented by near-monthly lunar measurements acquired from the instruments space-view port. Nine bands (bands 8-16) in the visible to near infrared spectral range from 0.412 to 0.866 micrometers are primarily used for ocean color observations.During a recent reprocessing of ocean color products, performed by the NASA Ocean Biology Processing Group, detector-to-detector differences of up to 1.5% were observed in bands 13-16 of Terra MODIS. This paper provides an overview of the current approach to characterize the MODIS detector-to-detector differences. An alternative methodology was developed to mitigate the observed impacts for bands 13-16. The results indicated an improvement in the detector residuals and in turn are expected to improve the MODIS ocean color products. This paper also discusses the limitations,subsequent enhancements, and the improvements planned for future MODIS calibration collections.

Evaluating VIIRS ocean color products for west coast and Hawaiian waters

KAUST Repository

Davis, Curtiss O.

2013-06-03

Automated match ups allow us to maintain and improve the ocean color products of current satellite instruments MODIS, and since February 2012 the Visible Infrared Imaging Radiometer Suite (VIIRS). As part of the VIIRS mission Ocean Calibration and Validation Team, we have created a web-based automated match up tool that provides access to searchable fields for date, site, and products, and creates matchups between satellites (MODIS, VIIRS), and in-situ measurements (HyperPRO and SeaPRISM). The goal is to evaluate the standard VIIRS ocean color products produced by the IDPS and available through NOAA’s CLASS data system. Comparisons are made with MODIS data for the same location, and VIIRS data processed using the NRL Automated Processing System (APS) used to produce operational products for the Navy. Results are shown for the first year of VIIRS data matching the satellite data with the data from Platform Eureka SeaPRISM off L. A. Harbor in the Southern California Bight, and HyperPRO data from Station ALOHA near Hawaii. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Regional impacts of ocean color on tropical Pacific variability

Science.gov (United States)

Anderson, W.; Gnanadesikan, A.; Wittenberg, A.

2009-08-01

The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly sensitive to the concentration and distribution of ocean chlorophyll. Setting the near-oligotrophic regions to contain optically pure water warms the mean state and suppresses variability in the western tropical Pacific. Doing the same above the shadow zones of the tropical Pacific also warms the mean state but enhances the variability. It is shown that increasing penetration can both deepen the pycnocline (which tends to damp El Niño) while shifting the mean circulation so that the wind response to temperature changes is altered. Depending on what region is involved this change in the wind stress can either strengthen or weaken ENSO variability.

GHRSST Level 2P Western Atlantic Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-13 satellite (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

GHRSST Level 2P Central Pacific Regional Skin Sea Surface Temperature from the Geostationary Operational Environmental Satellites (GOES) Imager on the GOES-15 satellite (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Geostationary Operational Environmental Satellites (GOES) operated by the United States National Oceanic and Atmospheric Administration (NOAA) support weather...

A design study for an advanced ocean color scanner system. [spaceborne equipment

Science.gov (United States)

Kim, H. H.; Fraser, R. S.; Thompson, L. L.; Bahethi, O.

1980-01-01

Along with a colorimetric data analysis scheme, the instrumental parameters which need to be optimized in future spaceborne ocean color scanner systems are outlined. With regard to assessing atmospheric effects from ocean colorimetry, attention is given to computing size parameters of the aerosols in the atmosphere, total optical depth measurement, and the aerosol optical thickness. It is suggested that sensors based on the use of linear array technology will meet hardware objectives.

47 CFR 25.278 - Additional coordination obligation for non-geostationary and geostationary satellite systems in...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Additional coordination obligation for non-geostationary and geostationary satellite systems in frequencies allocated to the fixed-satellite service. 25.278 Section 25.278 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER...

An overview of approaches and challenges for retrieving marine inherent optical properties from ocean color remote sensing

Science.gov (United States)

Werdell, P. Jeremy; McKinna, Lachlan I. W.; Boss, Emmanuel; Ackleson, Steven G.; Craig, Susanne E.; Gregg, Watson W.; Lee, Zhongping; Maritorena, Stéphane; Roesler, Collin S.; Rousseaux, Cécile S.; Stramski, Dariusz; Sullivan, James M.; Twardowski, Michael S.; Tzortziou, Maria; Zhang, Xiaodong

2018-01-01

Ocean color measured from satellites provides daily global, synoptic views of spectral water-leaving reflectances that can be used to generate estimates of marine inherent optical properties (IOPs). These reflectances, namely the ratio of spectral upwelled radiances to spectral downwelled irradiances, describe the light exiting a water mass that defines its color. IOPs are the spectral absorption and scattering characteristics of ocean water and its dissolved and particulate constituents. Because of their dependence on the concentration and composition of marine constituents, IOPs can be used to describe the contents of the upper ocean mixed layer. This information is critical to further our scientific understanding of biogeochemical oceanic processes, such as organic carbon production and export, phytoplankton dynamics, and responses to climatic disturbances. Given their importance, the international ocean color community has invested significant effort in improving the quality of satellite-derived IOP products, both regionally and globally. Recognizing the current influx of data products into the community and the need to improve current algorithms in anticipation of new satellite instruments (e.g., the global, hyperspectral spectroradiometer of the NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission), we present a synopsis of the current state of the art in the retrieval of these core optical properties. Contemporary approaches for obtaining IOPs from satellite ocean color are reviewed and, for clarity, separated based their inversion methodology or the type of IOPs sought. Summaries of known uncertainties associated with each approach are provided, as well as common performance metrics used to evaluate them. We discuss current knowledge gaps and make recommendations for future investment for upcoming missions whose instrument characteristics diverge sufficiently from heritage and existing sensors to warrant reassessing current approaches.

Regional impacts of ocean color on tropical Pacific variability

Directory of Open Access Journals (Sweden)

W. Anderson

2009-08-01

Full Text Available The role of the penetration length scale of shortwave radiation into the surface ocean and its impact on tropical Pacific variability is investigated with a fully coupled ocean, atmosphere, land and ice model. Previous work has shown that removal of all ocean color results in a system that tends strongly towards an El Niño state. Results from a suite of surface chlorophyll perturbation experiments show that the mean state and variability of the tropical Pacific is highly sensitive to the concentration and distribution of ocean chlorophyll. Setting the near-oligotrophic regions to contain optically pure water warms the mean state and suppresses variability in the western tropical Pacific. Doing the same above the shadow zones of the tropical Pacific also warms the mean state but enhances the variability. It is shown that increasing penetration can both deepen the pycnocline (which tends to damp El Niño while shifting the mean circulation so that the wind response to temperature changes is altered. Depending on what region is involved this change in the wind stress can either strengthen or weaken ENSO variability.

Variability of the reflectance coefficient of skylight from the ocean surface and its implications to ocean color.

Science.gov (United States)

Gilerson, Alexander; Carrizo, Carlos; Foster, Robert; Harmel, Tristan

2018-04-16

The value and spectral dependence of the reflectance coefficient (ρ) of skylight from wind-roughened ocean surfaces is critical for determining accurate water leaving radiance and remote sensing reflectances from shipborne, AERONET-Ocean Color and satellite observations. Using a vector radiative transfer code, spectra of the reflectance coefficient and corresponding radiances near the ocean surface and at the top of the atmosphere (TOA) are simulated for a broad range of parameters including flat and windy ocean surfaces with wind speeds up to 15 m/s, aerosol optical thicknesses of 0-1 at 440nm, wavelengths of 400-900 nm, and variable Sun and viewing zenith angles. Results revealed a profound impact of the aerosol load and type on the spectral values of ρ. Such impacts, not included yet in standard processing, may produce significant inaccuracies in the reflectance spectra retrieved from above-water radiometry and satellite observations. Implications for satellite cal/val activities as well as potential changes in measurement and data processing schemes are discussed.

How ocean color can steer Pacific tropical cyclones

Science.gov (United States)

Gnanadesikan, Anand; Emanuel, Kerry; Vecchi, Gabriel A.; Anderson, Whit G.; Hallberg, Robert

2010-09-01

Because ocean color alters the absorption of sunlight, it can produce changes in sea surface temperatures with further impacts on atmospheric circulation. These changes can project onto fields previously recognized to alter the distribution of tropical cyclones. If the North Pacific subtropical gyre contained no absorbing and scattering materials, the result would be to reduce subtropical cyclone activity in the subtropical Northwest Pacific by 2/3, while concentrating cyclone tracks along the equator. Predicting tropical cyclone activity using coupled models may thus require consideration of the details of how heat moves into the upper thermocline as well as biogeochemical cycling.

Use of Real Time Satellite Infrared and Ocean Color to Produce Ocean Products

Science.gov (United States)

Roffer, M. A.; Muller-Karger, F. E.; Westhaver, D.; Gawlikowski, G.; Upton, M.; Hall, C.

2014-12-01

Real-time data products derived from infrared and ocean color satellites are useful for several types of users around the world. Highly relevant applications include recreational and commercial fisheries, commercial towing vessel and other maritime and navigation operations, and other scientific and applied marine research. Uses of the data include developing sampling strategies for research programs, tracking of water masses and ocean fronts, optimizing ship routes, evaluating water quality conditions (coastal, estuarine, oceanic), and developing fisheries and essential fish habitat indices. Important considerations for users are data access and delivery mechanisms, and data formats. At this time, the data are being generated in formats increasingly available on mobile computing platforms, and are delivered through popular interfaces including social media (Facebook, Linkedin, Twitter and others), Google Earth and other online Geographical Information Systems, or are simply distributed via subscription by email. We review 30 years of applications and describe how we develop customized products and delivery mechanisms working directly with users. We review benefits and issues of access to government databases (NOAA, NASA, ESA), standard data products, and the conversion to tailored products for our users. We discuss advantages of different product formats and of the platforms used to display and to manipulate the data.

Validation of Ocean Color Sensors Using a Profiling Hyperspectral Radiometer

Science.gov (United States)

2014-01-01

Chesapeake Bay, South Florida, Hawaii, and the Gulf of Mexico . Typical data collected for each station include Hyperpro in-water measurements, ASD above...K., Demer, K., Fishe,r K.M., Davis, E., Urizar, C, and Merlini, R., "Assessment of the Eastern Gulf of Mexico Harmful Algal Bloom Operational...conducted in turbid and blue water conditions. Examples of validation matchups with VIIRS ocean color data are presented. With careful data collection

NOAA JPSS Visible Infrared Imaging Radiometer Suite (VIIRS) Ocean Color/Chlorophyll (OCC) Environmental Data Record (EDR) from IDPS

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a high quality operational Environmental Data Record (EDR) of Ocean Color/Chlorophyll (OCC) from the Visible Infrared Imaging Radiometer Suite...

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation. Volume 2; Revised

Science.gov (United States)

Mueller, James L. (Editor); Fargion, Giulietta S. (Editor); Trees, C.; Austin, R. W.; Pietras, C. (Editor); Hooker, S.; Holben, B.; McClain, Charles R.; Clark, D. K.; Yuen, M.

2002-01-01

This document stipulates protocols for measuring bio-optical and radiometric data for the SIMBIOS Project. It supersedes the earlier version, and is organized into four parts: Introductory Background, Instrument Characteristics, Field Measurements and Data Analysis, Data Reporting and Archival. Changes in this revision include the addition of three new chapters: (1) Fundamental Definitions, Relationships and Conventions; (2) MOBY, A Radiometric Buoy for Performance Monitoring and Vicarious Calibration of Satellite Ocean Color Sensors: Measurement and Data Analysis Protocols; and (3) Normalized Water-Leaving Radiance and Remote Sensing Reflectance: Bidirectional Reflectance and Other Factors. Although the present document represents another significant, incremental improvement in the ocean optics protocols, there are several protocols that have either been overtaken by recent technological progress, or have been otherwise identified as inadequate. Revision 4 is scheduled for completion sometime in 2003. This technical report is not meant as a substitute for scientific literature. Instead, it will provide a ready and responsive vehicle for the multitude of technical reports issued by an operational Project. The contributions are published as submitted, after only minor editing to correct obvious grammatical or clerical errors.

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation. Volume 1; Revised

Science.gov (United States)

Mueller, James L. (Editor); Fargion, Giulietta (Editor); Mueller, J. L.; Trees, C.; Austin, R. W.; Pietras, C.; Hooker, S.; Holben, B.; McClain, Charles R.; Clark, D. K.;

Penetration of UV-visible solar radiation in the global oceans: Insights from ocean color remote sensing

Science.gov (United States)

Lee, Zhongping; Hu, Chuanmin; Shang, Shaoling; Du, Keping; Lewis, Marlon; Arnone, Robert; Brewin, Robert

2013-09-01

Penetration of solar radiation in the ocean is determined by the attenuation coefficient (Kd(λ)). Following radiative transfer theory, Kd is a function of angular distribution of incident light and water's absorption and backscattering coefficients. Because these optical products are now generated routinely from satellite measurements, it is logical to evolve the empirical Kd to a semianalytical Kd that is not only spectrally flexible, but also the sun-angle effect is accounted for explicitly. Here, the semianalytical model developed in Lee et al. (2005b) is revised to account for the shift of phase function between molecular and particulate scattering from the short to long wavelengths. Further, using field data collected independently from oligotrophic ocean to coastal waters covering >99% of the Kd range for the global oceans, the semianalytically derived Kd was evaluated and found to agree with measured data within ˜7-26%. The updated processing system was applied to MODIS measurements to reveal the penetration of UVA-visible radiation in the global oceans, where an empirical procedure to correct Raman effect was also included. The results indicated that the penetration of the blue-green radiation for most oceanic waters is ˜30-40% deeper than the commonly used euphotic zone depth; and confirmed that at a depth of 50-70 m there is still ˜10% of the surface UVA radiation (at 360 nm) in most oligotrophic waters. The results suggest a necessity to modify or expand the light attenuation product from satellite ocean-color measurements in order to be more applicable for studies of ocean physics and biogeochemistry.

Applications of Geostationary Satellite Data to Aviation

Science.gov (United States)

Ellrod, Gary P.; Pryor, Kenneth

2018-03-01

Weather is by far the most important factor in air traffic delays in the United States' National Airspace System (NAS) according to the Federal Aviation Administration (FAA). Geostationary satellites have been an effective tool for the monitoring of meteorological conditions that affect aviation operations since the launch of the first Synchronous Meteorological Satellite (SMS) in the United States in 1974. This paper will review the global use of geostationary satellites in support of aviation weather since their inception, with an emphasis on the latest generation of satellites, such as Geostationary Operational Environmental Satellite (GOES)-R (16) with its Advanced Baseline Imager (ABI) and Geostationary Lightning Mapper (GLM). Specific applications discussed in this paper include monitoring of convective storms and their associated hazards, fog and low stratus, turbulence, volcanic hazards, and aircraft icing.

Sea Surface Temperature and Ocean Color Variability in the South China Sea

Science.gov (United States)

Conaty, A. P.

2001-12-01

The South China Sea is a marginal sea in the Southeast Asian region whose surface circulation is driven by monsoons and whose surface currents have complex seasonal patterns. Its rich natural resources and strategic location have made its small islands areas of political dispute among the neighboring nations. This study aims to show the seasonal and interannual variability of sea surface temperature and ocean color in South China Sea. It makes use of NOAA's Advanced Very High Resolution Radiometer (AVHRR) satellite data sets on sea surface temperature for the period 1981-2000 and NASA's Nimbus-7 Coastal Zone Color Scanner (CZCS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite data sets on pigment concentration (ocean color) for the period 1981-1996 and 1997-2000, respectively. Transect lines were drawn along several potential hotspot areas to show the variability in sea surface temperature and pigment concentration through time. In-situ data on sea surface temperature along South China Sea were likewise plotted to see the variability with time. Higher seasonal variability in sea surface temperature was seen at higher latitudes. Interannual variability was within 1-3 Kelvin. In most areas, pigment concentration was higher during northern hemisphere winter and autumn, after the monsoon rains, with a maximum of 30 milligrams per cubic meter.

Perspectives on empirical approaches for ocean color remote sensing of chlorophyll in a changing climate.

Science.gov (United States)

Dierssen, Heidi M

2010-10-05

Phytoplankton biomass and productivity have been continuously monitored from ocean color satellites for over a decade. Yet, the most widely used empirical approach for estimating chlorophyll a (Chl) from satellites can be in error by a factor of 5 or more. Such variability is due to differences in absorption and backscattering properties of phytoplankton and related concentrations of colored-dissolved organic matter (CDOM) and minerals. The empirical algorithms have built-in assumptions that follow the basic precept of biological oceanography--namely, oligotrophic regions with low phytoplankton biomass are populated with small phytoplankton, whereas more productive regions contain larger bloom-forming phytoplankton. With a changing world ocean, phytoplankton composition may shift in response to altered environmental forcing, and CDOM and mineral concentrations may become uncoupled from phytoplankton stocks, creating further uncertainty and error in the empirical approaches. Hence, caution is warranted when using empirically derived Chl to infer climate-related changes in ocean biology. The Southern Ocean is already experiencing climatic shifts and shows substantial errors in satellite-derived Chl for different phytoplankton assemblages. Accurate global assessments of phytoplankton will require improved technology and modeling, enhanced field observations, and ongoing validation of our "eyes in space."

VIIRS Ocean Color Reprocessed Science Quality Environmental Data Record (EDR) Level 3 products from 2012-01 to the present

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains VIIRS Ocean Color Reprocessed Environmental Data Record (EDR) Level 3 products produced by the NESDIS Center for Satellite Applications and...

VIIRS Ocean Color Reprocessed Science Quality Environmental Data Record (EDR) Level 2 products from 2012-01 to the present

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains VIIRS Ocean Color Reprocessed Environmental Data Record (EDR) Level 2 products produced by the NESDIS Center for Satellite Applications and...

Marine mammal distribution in the open ocean: a comparison of ocean color data products and levant time scales

Science.gov (United States)

Ohern, J.

2016-02-01

Marine mammals are generally located in areas of enhanced surface primary productivity, though they may forage much deeper within the water column and higher on the food chain. Numerous studies over the past several decades have utilized ocean color data from remote sensing instruments (CZCS, MODIS, and others) to asses both the quantity and time scales over which surface primary productivity relates to marine mammal distribution. In areas of sustained upwelling, primary productivity may essentially grow in the secondary levels of productivity (the zooplankton and nektonic species on which marine mammals forage). However, in many open ocean habitats a simple trophic cascade does not explain relatively short time lags between enhanced surface productivity and marine mammal presence. Other dynamic features that entrain prey or attract marine mammals may be responsible for the correlations between marine mammals and ocean color. In order to investigate these features, two MODIS (moderate imaging spectroradiometer) data products, the concentration as well as the standard deviation of surface chlorophyll were used in conjunction with marine mammal sightings collected within Ecuadorian waters. Time lags between enhanced surface chlorophyll and marine mammal presence were on the order of 2-4 weeks, however correlations were much stronger when the standard deviation of spatially binned images was used, rather than the chlorophyll concentrations. Time lags also varied between Balaenopterid and Odontocete cetaceans. Overall, the standard deviation of surface chlorophyll proved a useful tool for assessing potential relationships between marine mammal sightings and surface chlorophyll.

Performance metrics for the assessment of satellite data products: an ocean color case study

Science.gov (United States)

Performance assessment of ocean color satellite data has generally relied on statistical metrics chosen for their common usage and the rationale for selecting certain metrics is infrequently explained. Commonly reported statistics based on mean squared errors, such as the coeffic...

Classification of Hyperspectral or Trichromatic Measurements of Ocean Color Data into Spectral Classes

Directory of Open Access Journals (Sweden)

Dilip K. Prasad

2016-03-01

Full Text Available We propose a method for classifying radiometric oceanic color data measured by hyperspectral satellite sensors into known spectral classes, irrespective of the downwelling irradiance of the particular day, i.e., the illumination conditions. The focus is not on retrieving the inherent optical properties but to classify the pixels according to the known spectral classes of the reflectances from the ocean. The method compensates for the unknown downwelling irradiance by white balancing the radiometric data at the ocean pixels using the radiometric data of bright pixels (typically from clouds. The white-balanced data is compared with the entries in a pre-calibrated lookup table in which each entry represents the spectral properties of one class. The proposed approach is tested on two datasets of in situ measurements and 26 different daylight illumination spectra for medium resolution imaging spectrometer (MERIS, moderate-resolution imaging spectroradiometer (MODIS, sea-viewing wide field-of-view sensor (SeaWiFS, coastal zone color scanner (CZCS, ocean and land colour instrument (OLCI, and visible infrared imaging radiometer suite (VIIRS sensors. Results are also shown for CIMEL’s SeaPRISM sun photometer sensor used on-board field trips. Accuracy of more than 92% is observed on the validation dataset and more than 86% is observed on the other dataset for all satellite sensors. The potential of applying the algorithms to non-satellite and non-multi-spectral sensors mountable on airborne systems is demonstrated by showing classification results for two consumer cameras. Classification on actual MERIS data is also shown. Additional results comparing the spectra of remote sensing reflectance with level 2 MERIS data and chlorophyll concentration estimates of the data are included.

Predicting minimum uncertainties in the inversion of ocean color geophysical parameters based on Cramer-Rao bounds.

Science.gov (United States)

Jay, Sylvain; Guillaume, Mireille; Chami, Malik; Minghelli, Audrey; Deville, Yannick; Lafrance, Bruno; Serfaty, Véronique

2018-01-22

We present an analytical approach based on Cramer-Rao Bounds (CRBs) to investigate the uncertainties in estimated ocean color parameters resulting from the propagation of uncertainties in the bio-optical reflectance modeling through the inversion process. Based on given bio-optical and noise probabilistic models, CRBs can be computed efficiently for any set of ocean color parameters and any sensor configuration, directly providing the minimum estimation variance that can be possibly attained by any unbiased estimator of any targeted parameter. Here, CRBs are explicitly developed using (1) two water reflectance models corresponding to deep and shallow waters, resp., and (2) four probabilistic models describing the environmental noises observed within four Sentinel-2 MSI, HICO, Sentinel-3 OLCI and MODIS images, resp. For both deep and shallow waters, CRBs are shown to be consistent with the experimental estimation variances obtained using two published remote-sensing methods, while not requiring one to perform any inversion. CRBs are also used to investigate to what extent perfect a priori knowledge on one or several geophysical parameters can improve the estimation of remaining unknown parameters. For example, using pre-existing knowledge of bathymetry (e.g., derived from LiDAR) within the inversion is shown to greatly improve the retrieval of bottom cover for shallow waters. Finally, CRBs are shown to provide valuable information on the best estimation performances that may be achieved with the MSI, HICO, OLCI and MODIS configurations for a variety of oceanic, coastal and inland waters. CRBs are thus demonstrated to be an informative and efficient tool to characterize minimum uncertainties in inverted ocean color geophysical parameters.

North American pollution measurements from geostationary orbit with Tropospheric Emissions: Monitoring of Pollution (TEMPO)

Science.gov (United States)

Chance, K.

2017-12-01

TEMPO is the first NASA Earth Venture Instrument. It launches between 2019 and 2021 to measure atmospheric pollution from Mexico City and Cuba to the Canadian oil sands, and from the Atlantic to the Pacific, hourly at high spatial resolution, 10 km2. Geostationary daytime measurements capture the variability in the diurnal cycle of emissions and chemistry at sub-urban scale to improve emission inventories, monitor population exposure, and enable emission-control strategies.TEMPO measures UV/visible Earth reflectance spectra to retrieve O3, NO2, SO2, H2CO, C2H2O2, H2O, BrO, OClO, IO, aerosols, cloud parameters, and UVB radiation. It tracks aerosol loading. It provides near-real-time air quality products. TEMPO is the North American component of the upcoming the global geostationary constellation for pollution monitoring, together with the European Sentinel-4 and the Korean Geostationary Environmental Monitoring Spectrometer (GEMS).TEMPO science studies include: Intercontinental pollution transport; Solar-induced fluorescence from chlorophyll over land and in the ocean to study tropical dynamics, primary productivity and carbon uptake, to detect red tides, and to study phytoplankton; measurements of stratospheric intrusions that cause air quality exceedances; measurements at peaks in vehicle travel to capture the variability in emissions from mobile sources; measurements of thunderstorm activity, including outflow regions to better quantify lightning NOx and O3 production; cropland measurements to follow the temporal evolution of emissions after fertilizer application and from rain-induced emissions from semi-arid soils; investigating the chemical processing of primary fire emissions and the secondary formation of VOCs and ozone; examining ocean halogen emissions and their impact on the oxidizing capacity of coastal environments; measuring spectra of nighttime lights as markers for human activity, energy conservation, and compliance with outdoor lighting standards

Spatially Resolving Ocean Color and Sediment Dispersion in River Plumes, Coastal Systems, and Continental Shelf Waters

Science.gov (United States)

Aurin, Dirk Alexander; Mannino, Antonio; Franz, Bryan

2013-01-01

Satellite remote sensing of ocean color in dynamic coastal, inland, and nearshorewaters is impeded by high variability in optical constituents, demands specialized atmospheric correction, and is limited by instrument sensitivity. To accurately detect dispersion of bio-optical properties, remote sensors require ample signal-to-noise ratio (SNR) to sense small variations in ocean color without saturating over bright pixels, an atmospheric correction that can accommodate significantwater-leaving radiance in the near infrared (NIR), and spatial and temporal resolution that coincides with the scales of variability in the environment. Several current and historic space-borne sensors have met these requirements with success in the open ocean, but are not optimized for highly red-reflective and heterogeneous waters such as those found near river outflows or in the presence of sediment resuspension. Here we apply analytical approaches for determining optimal spatial resolution, dominant spatial scales of variability ("patches"), and proportions of patch variability that can be resolved from four river plumes around the world between 2008 and 2011. An offshore region in the Sargasso Sea is analyzed for comparison. A method is presented for processing Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua and Terra imagery including cloud detection, stray lightmasking, faulty detector avoidance, and dynamic aerosol correction using short-wave- and near-infrared wavebands in extremely turbid regions which pose distinct optical and technical challenges. Results showthat a pixel size of approx. 520 mor smaller is generally required to resolve spatial heterogeneity in ocean color and total suspended materials in river plumes. Optimal pixel size increases with distance from shore to approx. 630 m in nearshore regions, approx 750 m on the continental shelf, and approx. 1350 m in the open ocean. Greater than 90% of the optical variability within plume regions is resolvable with

Phytoplankton phenology indices in coral reef ecosystems: Application to ocean-color observations in the Red Sea

KAUST Repository

Racault, Marie-Fanny; Raitsos, Dionysios E.; Berumen, Michael L.; Brewin, Robert J.W.; Platt, Trevor; Sathyendranath, Shubha; Hoteit, Ibrahim

2015-01-01

Initiative project (OC-CCI) in the entire Red Sea basin. The OC-CCI product, comprising merged and bias-corrected observations from three independent ocean-color sensors (SeaWiFS, MODIS and MERIS), and processed using the POLYMER algorithm (MERIS period

Characteristic vector analysis of inflection ratio spectra: New technique for analysis of ocean color data

Science.gov (United States)

Grew, G. W.

1985-01-01

Characteristic vector analysis applied to inflection ratio spectra is a new approach to analyzing spectral data. The technique applied to remote data collected with the multichannel ocean color sensor (MOCS), a passive sensor, simultaneously maps the distribution of two different phytopigments, chlorophyll alpha and phycoerythrin, the ocean. The data set presented is from a series of warm core ring missions conducted during 1982. The data compare favorably with a theoretical model and with data collected on the same mission by an active sensor, the airborne oceanographic lidar (AOL).

Coastal Zone Color Scanner

Science.gov (United States)

Johnson, B.

1988-01-01

The Coastal Zone Color Scanner (CZCS) spacecraft ocean color instrument is capable of measuring and mapping global ocean surface chlorophyll concentration. It is a scanning radiometer with multiband capability. With new electronics and some mechanical, and optical re-work, it probably can be made flight worthy. Some additional components of a second flight model are also available. An engineering study and further tests are necessary to determine exactly what effort is required to properly prepare the instrument for spaceflight and the nature of interfaces to prospective spacecraft. The CZCS provides operational instrument capability for monitoring of ocean productivity and currents. It could be a simple, low cost alternative to developing new instruments for ocean color imaging. Researchers have determined that with global ocean color data they can: specify quantitatively the role of oceans in the global carbon cycle and other major biogeochemical cycles; determine the magnitude and variability of annual primary production by marine phytoplankton on a global scale; understand the fate of fluvial nutrients and their possible affect on carbon budgets; elucidate the coupling mechanism between upwelling and large scale patterns in ocean basins; answer questions concerning the large scale distribution and timing of spring blooms in the global ocean; acquire a better understanding of the processes associated with mixing along the edge of eddies, coastal currents, western boundary currents, etc., and acquire global data on marine optical properties.

Ocean color remote sensing using polarization properties of reflected sunlight

Science.gov (United States)

Frouin, R.; Pouliquen, E.; Breon, F.-M.

1994-01-01

The effects of the atmosphere and surface on sunlight backscattered to space by the ocean may be substantially reduced by using the unpolarized component of reflectance instead of total reflectance. At 450 nm, a wavelength of interest in ocean color remote sensing, and for typical conditions, 45% of the unpolarized reflectance may originate from the water body instead of 20% of the total reflectance, which represents a gain of a factor 2.2 in useful signal for water composition retrieval. The best viewing geometries are adjacent to the glitter region; they correspond to scattering angles around 100 deg, but they may change slightly depending on the polarization characteristics of the aerosols. As aerosol optical thickness increases, the atmosphere becomes less efficient at polarizing sunlight, and the enhancement of the water body contribution to unpolarized reflectance is reduced. Since the perturbing effects are smaller on unpolarized reflectance, at least for some viewing geometries, they may be more easily corrected, leading to a more accurate water-leaving signal and, therefore, more accurate estimates of phytoplankton pigment concentration.

CDOM-DOC relationship in contrasted coastal waters : implication for DOC retrieval from ocean color remote sensing observation

OpenAIRE

Vantrepotte, V.; Danhiez, F. P.; Loisel, Hubert; Ouillon, Sylvain; Meriaux, X.; Cauvin, A.; Dessailly, D.

2015-01-01

Increasing our knowledge on dissolved organic carbon (DOC) spatio-temporal distribution in the coastal ocean represents a crucial challenge for better understanding the role of these ecosystems in the global oceanic carbon cycle. The assessment of DOC concentration from the absorption properties of the colored part of the dissolved organic matter (a(cdom)) was investigated from an extensive data set covering a variety of coastal environments. Our results confirmed that variation in the acdom(...

HIMAWARI-8 Geostationary Satellite Observation of the Internal Solitary Waves in the South China Sea

Science.gov (United States)

Gao, Q.; Dong, D.; Yang, X.; Husi, L.; Shang, H.

2018-04-01

The new generation geostationary meteorological satellite, Himawari-8 (H-8), was launched in 2015. Its main payload, the Advanced Himawari Imager (AHI), can observe the earth with 10-minute interval and as high as 500-m spatial resolution. This makes the H-8 satellite an ideal data source for marine and atmospheric phenomena monitoring. In this study, the propagation of internal solitary waves (ISWs) in the South China Sea is investigated using AHI imagery time series for the first time. Three ISWs cases were studied at 3:30-8:00 UTC on 30 May, 2016. In all, 28 ISWs were detected and tracked between the time series image pairs. The propagation direction and phase speeds of these ISWs are calculated and analyzed. The observation results show that the properties of ISW propagation not stable and maintains nonlinear during its lifetime. The resultant ISW speeds agree well with the theoretical values estimated from the Taylor-Goldstein equation using Argo dataset. This study has demonstrated that the new generation geostationary satellite can be a useful tool to monitor and investigate the oceanic internal waves.

Post launch calibration and testing of the Geostationary Lightning Mapper on GOES-R satellite

Science.gov (United States)

Rafal, Marc; Clarke, Jared T.; Cholvibul, Ruth W.

2016-05-01

The Geostationary Operational Environmental Satellite R (GOES-R) series is the planned next generation of operational weather satellites for the United States National Oceanic and Atmospheric Administration (NOAA). The National Aeronautics and Space Administration (NASA) is procuring the GOES-R spacecraft and instruments with the first launch of the GOES-R series planned for October 2016. Included in the GOES-R Instrument suite is the Geostationary Lightning Mapper (GLM). GLM is a single-channel, near-infrared optical detector that can sense extremely brief (800 μs) transient changes in the atmosphere, indicating the presence of lightning. GLM will measure total lightning activity continuously over the Americas and adjacent ocean regions with near-uniform spatial resolution of approximately 10 km. Due to its large CCD (1372x1300 pixels), high frame rate, sensitivity and onboard event filtering, GLM will require extensive post launch characterization and calibration. Daytime and nighttime images will be used to characterize both image quality criteria inherent to GLM as a space-based optic system (focus, stray light, crosstalk, solar glint) and programmable image processing criteria (dark offsets, gain, noise, linearity, dynamic range). In addition ground data filtering will be adjusted based on lightning-specific phenomenology (coherence) to isolate real from false transients with their own characteristics. These parameters will be updated, as needed, on orbit in an iterative process guided by pre-launch testing. This paper discusses the planned tests to be performed on GLM over the six-month Post Launch Test period to optimize and demonstrate GLM performance.

Coastal Ocean Ecosystem Dynamics Imager Pointing Line-of-Sight Solution Development and Testing

Data.gov (United States)

National Aeronautics and Space Administration — A stable pointing line of sight solution is developed and tested in support of the Coastal Ocean Ecosystem Dynamics Imager for the GEOstationary Coastal and Air...

Coastal Zone Color Scanner (CZCS): Imagery of near-surface phytoplankton pigment concentrations from the first coastal ocean dynamics experiment (CODE-1), March - July 1981

Science.gov (United States)

Abbott, M. R.; Zion, P. M.

1984-01-01

As part of the first Coastal Ocean Dynamics Experiment, images of ocean color were collected from late March until late July, 1981, by the Coastal Zone Color Scanner aboard Nimbus-7. Images that had sufficient cloud-free area to be of interest were processed to yield near-surface phytoplankton pigment concentrations. These images were then remapped to a fixed equal-area grid. This report contains photographs of the digital images and a brief description of the processing methods.

Estimation of the Potential Detection of Diatom Assemblages Based on Ocean Color Radiance Anomalies in the North Sea

Directory of Open Access Journals (Sweden)

Anne-Hélène Rêve-Lamarche

2017-12-01

Full Text Available Over the past years, a large number of new approaches in the domain of ocean-color have been developed, leading to a variety of innovative descriptors for phytoplankton communities. One of these methods, named PHYSAT, currently allows for the qualitative detection of five main phytoplankton groups from ocean-color measurements. Even though PHYSAT products are widely used in various applications and projects, the approach is limited by the fact it identifies only dominant phytoplankton groups. This current limitation is due to the use of biomarker pigment ratios for establishing empirical relationships between in-situ information and specific ocean-color radiance anomalies in open ocean waters. However, theoretical explanations of PHYSAT suggests that it could be possible to detect more than dominance cases but move more toward phytoplanktonic assemblage detection. Thus, to evaluate the potential of PHYSAT for the detection of phytoplankton assemblages, we took advantage of the Continuous Plankton Recorder (CPR survey, collected in both the English Channel and the North Sea. The available CPR dataset contains information on diatom abundance in two large areas of the North Sea for the period 1998-2010. Using this unique dataset, recurrent diatom assemblages were retrieved based on classification of CPR samples. Six diatom assemblages were identified in-situ, each having indicators taxa or species. Once this first step was completed, the in-situ analysis was used to empirically associate the diatom assemblages with specific PHYSAT spectral anomalies. This step was facilitated by the use of previous classifications of regional radiance anomalies in terms of shape and amplitude, coupled with phenological tools. Through a matchup exercise, three CPR assemblages were associated with specific radiance anomalies. The maps of detection of these specific radiances anomalies are in close agreement with current in-situ ecological knowledge.

INFRARED GLOBAL GEOSTATIONARY COMPOSITE V1

Data.gov (United States)

National Aeronautics and Space Administration — The National Center for Environmental Prediction/Aviation Weather Center Infrared Global Geostationary Composite data set contains global composite images from the...

Improved ocean-color remote sensing in the Arctic using the POLYMER algorithm

Science.gov (United States)

Frouin, Robert; Deschamps, Pierre-Yves; Ramon, Didier; Steinmetz, François

2012-10-01

Atmospheric correction of ocean-color imagery in the Arctic brings some specific challenges that the standard atmospheric correction algorithm does not address, namely low solar elevation, high cloud frequency, multi-layered polar clouds, presence of ice in the field-of-view, and adjacency effects from highly reflecting surfaces covered by snow and ice and from clouds. The challenges may be addressed using a flexible atmospheric correction algorithm, referred to as POLYMER (Steinmetz and al., 2011). This algorithm does not use a specific aerosol model, but fits the atmospheric reflectance by a polynomial with a non spectral term that accounts for any non spectral scattering (clouds, coarse aerosol mode) or reflection (glitter, whitecaps, small ice surfaces within the instrument field of view), a spectral term with a law in wavelength to the power -1 (fine aerosol mode), and a spectral term with a law in wavelength to the power -4 (molecular scattering, adjacency effects from clouds and white surfaces). Tests are performed on selected MERIS imagery acquired over Arctic Seas. The derived ocean properties, i.e., marine reflectance and chlorophyll concentration, are compared with those obtained with the standard MEGS algorithm. The POLYMER estimates are more realistic in regions affected by the ice environment, e.g., chlorophyll concentration is higher near the ice edge, and spatial coverage is substantially increased. Good retrievals are obtained in the presence of thin clouds, with ocean-color features exhibiting spatial continuity from clear to cloudy regions. The POLYMER estimates of marine reflectance agree better with in situ measurements than the MEGS estimates. Biases are 0.001 or less in magnitude, except at 412 and 443 nm, where they reach 0.005 and 0.002, respectively, and root-mean-squared difference decreases from 0.006 at 412 nm to less than 0.001 at 620 and 665 nm. A first application to MODIS imagery is presented, revealing that the POLYMER algorithm is

Estimating Advective Near-surface Currents from Ocean Color Satellite Images

Science.gov (United States)

2015-01-01

on the SuomiNational Polar-Orbiting Partner- ship (S- NPP ) satellite. The GOCI is the world’s first geostationary orbit satellite sensor over the...radiance Lwn at several wave - lengths. These spectral Lwn channels are used to derive several in- water bio-optical properties (Lee, Carder, & Arnone...the same surface flow, it is the inter-product similarities, instead of the differences, that are more likely to stand for the surface advection. If

The Geostationary Fourier Transform Spectrometer

Science.gov (United States)

Key, Richard; Sander, Stanley; Eldering, Annmarie; Blavier, Jean-Francois; Bekker, Dmitriy; Manatt, Ken; Rider, David; Wu, Yen-Hung

2012-01-01

The Geostationary Fourier Transform Spectrometer (GeoFTS) is an imaging spectrometer designed for a geostationary orbit (GEO) earth science mission to measure key atmospheric trace gases and process tracers related to climate change and human activity. GEO allows GeoFTS to continuously stare at a region of the earth for frequent sampling to capture the variability of biogenic fluxes and anthropogenic emissions from city to continental spatial scales and temporal scales from diurnal, synoptic, seasonal to interannual. The measurement strategy provides a process based understanding of the carbon cycle from contiguous maps of carbon dioxide (CO2), methane (CH4), carbon monoxide (CO), and chlorophyll fluorescence (CF) collected many times per day at high spatial resolution (2.7kmx2.7km at nadir). The CO2/CH4/CO/CF measurement suite in the near infrared spectral region provides the information needed to disentangle natural and anthropogenic contributions to atmospheric carbon concentrations and to minimize uncertainties in the flow of carbon between the atmosphere and surface. The half meter cube size GeoFTS instrument is based on a Michelson interferometer design that uses all high TRL components in a modular configuration to reduce complexity and cost. It is self-contained and as independent of the spacecraft as possible with simple spacecraft interfaces, making it ideal to be a "hosted" payload on a commercial communications satellite mission. The hosted payload approach for measuring the major carbon-containing gases in the atmosphere from the geostationary vantage point will affordably advance the scientific understating of carbon cycle processes and climate change.

Intersatellite comparisons and evaluations of three ocean color products along the Zhejiang coast, eastern China

Science.gov (United States)

Cui, Qiyuan; Wang, Difeng; Gong, Fang; Pan, Delu; Hao, Zengzhou; Wang, Tianyu; Zhu, Qiankun

2017-10-01

With its broad spatial coverage and fine temporal resolution, ocean color remote sensing data represents an effective tool for monitoring large areas of ocean, and has the potential to provide crucial information in coastal waters where routine monitoring is either lacking or unsatisfactory. The semi-analytical or empirical algorithms that work well in Case 1 waters encounter many problems in offshore areas where the water is often optically complex and presents difficulties for atmospheric correction. Zhejiang is one of the most developed provinces in eastern China, and its adjacent seas have been greatly affected by recent rapid economic development. Various islands and semi-closed bays along the Zhejiang coast promote the formation of muddy tidal flats. Moreover, large quantities of terrestrial substances coming down with the Yangtze River and other local rivers also have a great impact on the coastal waters of the province. MODIS, VIIRS and GOCI are three commonly used ocean color sensors covering the East China Sea. Several ocean color products such as remote-sensing reflectance (Rrs) and the concentrations of chlorophyll a (Chl-a) and total suspended matter (TSM) of the above three sensors on the Zhejiang coast have been evaluated. Cloud-free satellite images with synchronous field measurements taken between 2012 and 2015 were used for comparison. It is shown that there is a good correlation between the MODIS and GOCI spectral data, while some outliers were found in the VIIRS images. The low signal-to-noise ratio at short wavelengths in highly turbid waters also reduced the correlation between different sensors. In addition, it was possible to obtain more valid data with GOCI in shallow waters because of the use of an appropriate atmospheric correction algorithm. The standard Chl-a and TSM products of the three satellites were also evaluated, and it was found that the Chl-a and TSM concentrations calculated by the OC3G and Case 2 algorithms, respectively

Locating center of mass of earth and geostationary satellites

International Nuclear Information System (INIS)

Qureshi, A.; Marvi, M.

2014-01-01

CoM (Center of Mass) of earth is a very important factor which can play a major role in satellite communication and related earth sciences. The CoM of earth is assumed to be around equator due to geometrical shape of earth. However, no technical method is available in the literature which can justify the presence of CoM of earth around equator. Therefore, in this research work the CoM of earth has been located theoretically with the help of mathematical relations. It also presents the mathematical justification against the assumption that equator is the CoM of earth. The effect of calculated CoM of earth on geostationary satellites has also been discussed. The CoM of earth has been found mathematically by using land to ocean ratios and the data is collected from the Google earth software. The final results are accurate with an approximate error of 1%. (author)

A novel method for destriping of OCM-2 data and radiometric performance analysis for improved ocean color data products

Science.gov (United States)

Singh, Rakesh Kumar; Shanmugam, Palanisamy

2018-06-01

Despite the capability of Ocean Color Monitor aboard Oceansat-2 satellite to provide frequent, high-spatial resolution, visible and near-infrared images for scientific research on coastal zones and climate data records over the global ocean, the generation of science quality ocean color products from OCM-2 data has been hampered by serious vertical striping artifacts and poor calibration of detectors. These along-track stripes are the results of variations in the relative response of the individual detectors of the OCM-2 CCD array. The random unsystematic stripes and bandings on the scene edges affect both visual interpretation and radiometric integrity of remotely sensed data, contribute to confusion in the aerosol correction process, and multiply and propagate into higher level ocean color products generated by atmospheric correction and bio-optical algorithms. Despite a number of destriping algorithms reported in the literature, complete removal of stripes without residual effects and signal distortion in both low- and high-level products is still challenging. Here, a new operational algorithm has been developed that employs an inverted gaussian function to estimate error fraction parameters, which are uncorrelated and vary in spatial, spectral and temporal domains. The algorithm is tested on a large number of OCM-2 scenes from Arabian Sea and Bay of Bengal waters contaminated with severe stripes. The destriping effectiveness of this approach is then evaluated by means of various qualitative and quantitative analyses, and by comparison with the results of the previously reported method. Clearly, the present method is more effective in terms of removing the stripe noise while preserving the radiometric integrity of the destriped OCM-2 data. Furthermore, a preliminary time-dependent calibration of the OCM-2 sensor is performed with several match-up in-situ data to evaluate its radiometric performance for ocean color applications. OCM-2 derived water

Optimization of Instrument Requirements for NASAs GEO-CAPE Coastal Mission Concept Based On Sensor Capability And Cost Studies

Science.gov (United States)

Mannino, Antonio

2015-01-01

NASA's GEOstationary Coastal and Air Pollution Events (GEOCAPE) mission concept recommended by the U.S. National Research Council (2007) focuses on measurements of atmospheric trace gases and aerosols and aquatic coastal ecology and biogeochemistry from geostationary orbit (35,786 km altitude). GEO-CAPE is currently in pre-formulation (pre- Phase) A with no established launch date. NASA continues to support science and engineering studies to reduce mission risk. Instrument design lab (IDL) studies were commissioned in 2014 to design and cost two implementations for geostationary ocean color instruments (1) Wide-Angle Spectrometer (WAS) and (2) Filter Radiometer (FR) and (3) a cost scaling study to compare the costs for implementing different science performance requirements.

Assimilation of satellite color observations in a coupled ocean GCM-ecosystem model

Science.gov (United States)

Sarmiento, Jorge L.

1992-01-01

Monthly average coastal zone color scanner (CZCS) estimates of chlorophyll concentration were assimilated into an ocean global circulation model(GCM) containing a simple model of the pelagic ecosystem. The assimilation was performed in the simplest possible manner, to allow the assessment of whether there were major problems with the ecosystem model or with the assimilation procedure. The current ecosystem model performed well in some regions, but failed in others to assimilate chlorophyll estimates without disrupting important ecosystem properties. This experiment gave insight into those properties of the ecosystem model that must be changed to allow data assimilation to be generally successful, while raising other important issues about the assimilation procedure.

Specificity of Atmospheric Correction of Satellite Data on Ocean Color in the Far East

Science.gov (United States)

Aleksanin, A. I.; Kachur, V. A.

2017-12-01

Calculation errors in ocean-brightness coefficients in the Far Eastern are analyzed for two atmospheric correction algorithms (NIR and MUMM). The daylight measurements in different water types show that the main error component is systematic and has a simple dependence on the magnitudes of the coefficients. The causes of the error behavior are considered. The most probable explanation for the large errors in ocean-color parameters in the Far East is a high concentration of continental aerosol absorbing light. A comparison between satellite and in situ measurements at AERONET stations in the United States and South Korea has been made. It is shown the errors in these two regions differ by up to 10 times upon close water turbidity and relatively high aerosol optical-depth computation precision in the case of using the NIR correction of the atmospheric effect.

Automated ocean color product validation for the Southern California Bight

Science.gov (United States)

Davis, Curtiss O.; Tufillaro, Nicholas; Jones, Burt; Arnone, Robert

2012-06-01

Automated match ups allow us to maintain and improve the products of current satellite ocean color sensors (MODIS, MERIS), and new sensors (VIIRS). As part of the VIIRS mission preparation, we have created a web based automated match up tool that provides access to searchable fields for date, site, and products, and creates match-ups between satellite (MODIS, MERIS, VIIRS), and in-situ measurements (HyperPRO and SeaPRISM). The back end of the system is a 'mySQL' database, and the front end is a `php' web portal with pull down menus for searchable fields. Based on selections, graphics are generated showing match-ups and statistics, and ascii files are created for downloads for the matchup data. Examples are shown for matching the satellite data with the data from Platform Eureka SeaPRISM off L.A. Harbor in the Southern California Bight.

A Semianalytical Ocean Color Inversion Algorithm with Explicit Water Column Depth and Substrate Reflectance Parameterization

Science.gov (United States)

Mckinna, Lachlan I. W.; Werdell, P. Jeremy; Fearns, Peter R. C.; Weeks, Scarla J.; Reichstetter, Martina; Franz, Bryan A.; Shea, Donald M.; Feldman, Gene C.

2015-01-01

A semianalytical ocean color inversion algorithm was developed for improving retrievals of inherent optical properties (IOPs) in optically shallow waters. In clear, geometrically shallow waters, light reflected off the seafloor can contribute to the water-leaving radiance signal. This can have a confounding effect on ocean color algorithms developed for optically deep waters, leading to an overestimation of IOPs. The algorithm described here, the Shallow Water Inversion Model (SWIM), uses pre-existing knowledge of bathymetry and benthic substrate brightness to account for optically shallow effects. SWIM was incorporated into the NASA Ocean Biology Processing Group's L2GEN code and tested in waters of the Great Barrier Reef, Australia, using the Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua time series (2002-2013). SWIM-derived values of the total non-water absorption coefficient at 443 nm, at(443), the particulate backscattering coefficient at 443 nm, bbp(443), and the diffuse attenuation coefficient at 488 nm, Kd(488), were compared with values derived using the Generalized Inherent Optical Properties algorithm (GIOP) and the Quasi-Analytical Algorithm (QAA). The results indicated that in clear, optically shallow waters SWIM-derived values of at(443), bbp(443), and Kd(443) were realistically lower than values derived using GIOP and QAA, in agreement with radiative transfer modeling. This signified that the benthic reflectance correction was performing as expected. However, in more optically complex waters, SWIM had difficulty converging to a solution, a likely consequence of internal IOP parameterizations. Whilst a comprehensive study of the SWIM algorithm's behavior was conducted, further work is needed to validate the algorithm using in situ data.

Arctic-COLORS (Coastal Land Ocean Interactions in the Arctic) - a NASA field campaign scoping study to examine land-ocean interactions in the Arctic

Science.gov (United States)

Hernes, P.; Tzortziou, M.; Salisbury, J.; Mannino, A.; Matrai, P.; Friedrichs, M. A.; Del Castillo, C. E.

2014-12-01

The Arctic region is warming faster than anywhere else on the planet, triggering rapid social and economic changes and impacting both terrestrial and marine ecosystems. Yet our understanding of critical processes and interactions along the Arctic land-ocean interface is limited. Arctic-COLORS is a Field Campaign Scoping Study funded by NASA's Ocean Biology and Biogeochemistry Program that aims to improve understanding and prediction of land-ocean interactions in a rapidly changing Arctic coastal zone, and assess vulnerability, response, feedbacks and resilience of coastal ecosystems, communities and natural resources to current and future pressures. Specific science objectives include: - Quantify lateral fluxes to the arctic inner shelf from (i) rivers and (ii) the outer shelf/basin that affect biology, biodiversity, biogeochemistry (i.e. organic matter, nutrients, suspended sediment), and the processing rates of these constituents in coastal waters. - Evaluate the impact of the thawing of Arctic permafrost within the river basins on coastal biology, biodiversity and biogeochemistry, including various rates of community production and the role these may play in the health of regional economies. - Assess the impact of changing Arctic landfast ice and coastal sea ice dynamics. - Establish a baseline for comparison to future change, and use state-of-the-art models to assess impacts of environmental change on coastal biology, biodiversity and biogeochemistry. A key component of Arctic-COLORS will be the integration of satellite and field observations with coupled physical-biogeochemical models for predicting impacts of future pressures on Arctic, coastal ocean, biological processes and biogeochemical cycles. Through interagency and international collaborations, and through the organization of dedicated workshops, town hall meetings and presentations at international conferences, the scoping study engages the broader scientific community and invites participation of

Global Ocean Phytoplankton

Science.gov (United States)

Franz, B. A.; Behrenfeld, M. J.; Siegel, D. A.; Werdell, P. J.

2014-01-01

Marine phytoplankton are responsible for roughly half the net primary production (NPP) on Earth, fixing atmospheric CO2 into food that fuels global ocean ecosystems and drives the ocean's biogeochemical cycles. Phytoplankton growth is highly sensitive to variations in ocean physical properties, such as upper ocean stratification and light availability within this mixed layer. Satellite ocean color sensors, such as the Sea-viewing Wide Field-of-view Sensor (SeaWiFS; McClain 2009) and Moderate Resolution Imaging Spectroradiometer (MODIS; Esaias 1998), provide observations of sufficient frequency and geographic coverage to globally monitor physically-driven changes in phytoplankton distributions. In practice, ocean color sensors retrieve the spectral distribution of visible solar radiation reflected upward from beneath the ocean surface, which can then be related to changes in the photosynthetic phytoplankton pigment, chlorophyll- a (Chla; measured in mg m-3). Here, global Chla data for 2013 are evaluated within the context of the 16-year continuous record provided through the combined observations of SeaWiFS (1997-2010) and MODIS on Aqua (MODISA; 2002-present). Ocean color measurements from the recently launched Visible and Infrared Imaging Radiometer Suite (VIIRS; 2011-present) are also considered, but results suggest that the temporal calibration of the VIIRS sensor is not yet sufficiently stable for quantitative global change studies. All MODISA (version 2013.1), SeaWiFS (version 2010.0), and VIIRS (version 2013.1) data presented here were produced by NASA using consistent Chla algorithms.

Validation of MERIS Ocean Color Algorithms in the Mediterranean Sea

Science.gov (United States)

Marullo, S.; D'Ortenzio, F.; Ribera D'Alcalà, M.; Ragni, M.; Santoleri, R.; Vellucci, V.; Luttazzi, C.

2004-05-01

Satellite ocean color measurements can contribute, better than any other source of data, to quantify the spatial and time variability of ocean productivity and, tanks to the success of several satellite missions starting with CZCS up to SeaWiFS, MODIS and MERIS, it is now possible to start doing the investigation of interannual variations and compare level of production during different decades ([1],[2]). The interannual variability of the ocean productivity at global and regional scale can be correctly measured providing that chlorophyll estimate are based on well calibrated algorithms in order to avoid regional biases and instrumental time shifts. The calibration and validation of Ocean Color data is then one of the most important tasks of several research projects worldwide ([3], [4]). Algorithms developed to retrieve chlorophyll concentration need a specific effort to define the error ranges associated to the estimates. In particular, the empirical algorithms, calculated on regression with in situ data, require independent records to verify the degree of uncertainties associated. In addition several evidences demonstrated that regional algorithms can improve the accuracy of the satellite chlorophyll estimates [5]. In 2002, Santoleri et al. (SIMBIOS) first showed a significant overestimation of the SeaWiFS derived chlorophyll concentration in Mediterranean Sea when the standard global NASA algorithms (OC4v2 and OC4v4) are used. The same authors [6] proposed two preliminary new algorithms for the Mediterranean Sea (L-DORMA and NL-DORMA) on a basis of a bio-optical data set collected in the basin from 1998 to 2000. In 2002 Bricaud et al., [7] analyzing other bio-optical data collected in the Mediterranean, confirmed the overestimation of the chlorophyll concentration in oligotrophic conditions and proposed a new regional algorithm to be used in case of low concentrations. Recently, the number of in situ observations in the basin was increased, permitting a first

Improved Chlorophyll-a Algorithm for the Satellite Ocean Color Data in the Northern Bering Sea and Southern Chukchi Sea

Science.gov (United States)

Lee, Sang Heon; Ryu, Jongseong; Park, Jung-woo; Lee, Dabin; Kwon, Jae-Il; Zhao, Jingping; Son, SeungHyun

2018-03-01

The Bering and Chukchi seas are an important conduit to the Arctic Ocean and are reported to be one of the most productive regions in the world's oceans in terms of high primary productivity that sustains large numbers of fishes, marine mammals, and sea birds as well as benthic animals. Climate-induced changes in primary production and production at higher trophic levels also have been observed in the northern Bering and Chukchi seas. Satellite ocean color observations could enable the monitoring of relatively long term patterns in chlorophyll-a (Chl-a) concentrations that would serve as an indicator of phytoplankton biomass. The performance of existing global and regional Chl-a algorithms for satellite ocean color data was investigated in the northeastern Bering Sea and southern Chukchi Sea using in situ optical measurements from the Healy 2007 cruise. The model-derived Chl-a data using the previous Chl-a algorithms present striking uncertainties regarding Chl-a concentrations-for example, overestimation in lower Chl-a concentrations or systematic overestimation in the northeastern Bering Sea and southern Chukchi Sea. Accordingly, a simple two band ratio (R rs(443)/R rs(555)) algorithm of Chl-a for the satellite ocean color data was devised for the northeastern Bering Sea and southern Chukchi Sea. The MODIS-derived Chl-a data from July 2002 to December 2014 were produced using the new Chl-a algorithm to investigate the seasonal and interannual variations of Chl-a in the northern Bering Sea and the southern Chukchi Sea. The seasonal distribution of Chl-a shows that the highest (spring bloom) Chl-a concentrations are in May and the lowest are in July in the overall area. Chl-a concentrations relatively decreased in June, particularly in the open ocean waters of the Bering Sea. The Chl-a concentrations start to increase again in August and become quite high in September. In October, Chl-a concentrations decreased in the western area of the Study area and the Alaskan

Interferometric Imaging of Geostationary Satellites: Signal-to-Noise Considerations

Science.gov (United States)

Jorgensen, A.; Schmitt, H.; Mozurkewich, D.; Armstrong, J.; Restaino, S.; Hindsley, R.

2011-09-01

Geostationary satellites are generally too small to image at high resolution with conventional single-dish telescopes. Obtaining many resolution elements across a typical geostationary satellite body requires a single-dish telescope with a diameter of 10’s of m or more, with a good adaptive optics system. An alternative is to use an optical/infrared interferometer consisting of multiple smaller telescopes in an array configuration. In this paper and companion papers1, 2 we discuss the performance of a common-mount 30-element interferometer. The instrument design is presented by Mozurkewich et al.,1 and imaging performance is presented by Schmitt et al.2 In this paper we discuss signal-to-noise ratio for both fringe-tracking and imaging. We conclude that the common-mount interferometer is sufficiently sensitive to track fringes on the majority of geostationary satellites. We also find that high-fidelity images can be obtained after a short integration time of a few minutes to a few tens of minutes.

Diurnal variability in carbon and nitrogen pools within Chesapeake Bay and northern Gulf of Mexico: implications for future ocean color satellite sensors

Science.gov (United States)

Mannino, A.; Novak, M. G.; Tzortziou, M.; Salisbury, J.

2016-02-01

Relative to their areal extent, estuaries and coastal ocean ecosystems contribute disproportionately more to global biogeochemical cycling of carbon, nitrogen and other elements compared to the open ocean. Applying ocean color satellite data to study biological and biogeochemical processes within coastal ecosystems is challenging due to the complex mixtures of aquatic constituents derived from terrestrial, anthropogenic, and marine sources, human-impacted atmospheric properties, presence of clouds during satellite overpass, fine-scale spatial gradients, and time-varying processes on diurnal scales that cannot be resolved with current sensors. On diurnal scales, biological, photochemical, and biogeochemical processes are regulated by the variation in solar radiation. Other physical factors, such as tides, river discharge, estuarine and coastal ocean circulation, wind-driven mixing, etc., impart further variability on biological and biogeochemical processes on diurnal to multi-day time scales. Efforts to determine the temporal frequency required from a NASA GEO-CAPE ocean color satellite sensor to discern diurnal variability C and N stocks, fluxes and productivity culminated in field campaigns in the Chesapeake Bay and northern Gulf of Mexico. Near-surface drogues were released and tracked in quasi-lagrangian space to monitor hourly changes in community production, C and N stocks, and optical properties. While only small diurnal changes were observed in dissolved organic carbon (DOC) and colored dissolved organic matter (CDOM) absorption in Chesapeake Bay, substantial variation in particulate organic carbon (POC) and nitrogen (PN), chlorophyll-a, and inorganic nitrogen (DIN) were measured. Similar or greater diurnal changes in POC, PN, chlorophyll-a and DIN were found in Gulf of Mexico nearshore and offshore sites. These results suggest that satellite observations at hourly frequency are desirable to capture diurnal variability in carbon and nitrogen stocks, fluxes

Infuence of Averaging Method on the Evaluation of a Coastal Ocean Color Event on the U.S. Northeast Coast

Science.gov (United States)

Acker, James G.; Uz, Stephanie Schollaert; Shen, Suhung; Leptoukh, Gregory G.

2010-01-01

Application of appropriate spatial averaging techniques is crucial to correct evaluation of ocean color radiometric data, due to the common log-normal or mixed log-normal distribution of these data. Averaging method is particularly crucial for data acquired in coastal regions. The effect of averaging method was markedly demonstrated for a precipitation-driven event on the U.S. Northeast coast in October-November 2005, which resulted in export of high concentrations of riverine colored dissolved organic matter (CDOM) to New York and New Jersey coastal waters over a period of several days. Use of the arithmetic mean averaging method created an inaccurate representation of the magnitude of this event in SeaWiFS global mapped chl a data, causing it to be visualized as a very large chl a anomaly. The apparent chl a anomaly was enhanced by the known incomplete discrimination of CDOM and phytoplankton chlorophyll in SeaWiFS data; other data sources enable an improved characterization. Analysis using the geometric mean averaging method did not indicate this event to be statistically anomalous. Our results predicate the necessity of providing the geometric mean averaging method for ocean color radiometric data in the Goddard Earth Sciences DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni).

Bio-optical profiling floats as new observational tools for biogeochemical and ecosystem studies: Potential synergies with ocean color remote sensing

Energy Technology Data Exchange (ETDEWEB)

Claustre, H.; Bishop, J.; Boss, E.; Bernard, S.; Berthon, J.-F.; Coatanoan, C.; Johnson, K.; Lotiker, A.; Ulloa, O.; Perry, M.J.; D' Ortenzio, F.; D' andon, O.H.F.; Uitz, J.

2009-10-01

Profiling floats now represent a mature technology. In parallel with their emergence, the field of miniature, low power bio-optical and biogeochemical sensors is rapidly evolving. Over recent years, the bio-geochemical and bio-optical community has begun to benefit from the increase in observational capacities by developing profiling floats that allow the measurement of key biooptical variables and subsequent products of biogeochemical and ecosystem relevance like Chlorophyll a (Chla), optical backscattering or attenuation coefficients which are proxies of Particulate Organic Carbon (POC), Colored Dissolved Organic Matter (CDOM). Thanks to recent algorithmic improvements, new bio-optical variables such as backscattering coefficient or absorption by CDOM, at present can also be extracted from space observations of ocean color. In the future, an intensification of in situ measurements by bio-optical profiling floats would permit the elaboration of unique 3D/4D bio-optical climatologies, linking surface (remotely detected) properties to their vertical distribution (measured by autonomous platforms), with which key questions in the role of the ocean in climate could be addressed. In this context, the objective of the IOCCG (International Ocean Color Coordinating Group) BIO-Argo working group is to elaborate recommendations in view of a future use of bio-optical profiling floats as part of a network that would include a global array that could be 'Argo-relevant', and specific arrays that would have more focused objectives or regional targets. The overall network, realizing true multi-scale sustained observations of global marine biogeochemistry and biooptics, should satisfy the requirements for validation of ocean color remote sensing as well as the needs of a wider community investigating the impact of global change on biogeochemical cycles and ecosystems. Regarding the global profiling float array, the recommendation is that Chla as well as POC should be the

Air Quality Science and Regulatory Efforts Require Geostationary Satellite Measurements

Science.gov (United States)

Pickering, Kenneth E.; Allen, D. J.; Stehr, J. W.

2006-01-01

Air quality scientists and regulatory agencies would benefit from the high spatial and temporal resolution trace gas and aerosol data that could be provided by instruments on a geostationary platform. More detailed time-resolved data from a geostationary platform could be used in tracking regional transport and in evaluating mesoscale air quality model performance in terms of photochemical evolution throughout the day. The diurnal cycle of photochemical pollutants is currently missing from the data provided by the current generation of atmospheric chemistry satellites which provide only one measurement per day. Often peak surface ozone mixing ratios are reached much earlier in the day during major regional pollution episodes than during local episodes due to downward mixing of ozone that had been transported above the boundary layer overnight. The regional air quality models often do not simulate this downward mixing well enough and underestimate surface ozone in regional episodes. Having high time-resolution geostationary data will make it possible to determine the magnitude of this lower-and mid-tropospheric transport that contributes to peak eight-hour average ozone and 24-hour average PM2.5 concentrations. We will show ozone and PM(sub 2.5) episodes from the CMAQ model and suggest ways in which geostationary satellite data would improve air quality forecasting. Current regulatory modeling is typically being performed at 12 km horizontal resolution. State and regional air quality regulators in regions with complex topography and/or land-sea breezes are anxious to move to 4-km or finer resolution simulations. Geostationary data at these or finer resolutions will be useful in evaluating such models.

Seasonal estimates of DOC standing stocks in Apalachicola Bay estuary: Towards a better understanding using field, ocean color and model data

Science.gov (United States)

D'Sa, E. J.; Joshi, I.; Osburn, C. L.; Bianchi, T. S.; Ko, D. S.; Oviedo-Vargas, D.; Arellano, A.; Ward, N.

2016-12-01

Apalachicola Bay, a semi-enclosed estuary located in Florida's panhandle, is well known for its water quality and oyster yields. We present the use of combined field and ocean color satellite observations and the outputs of a high-resolution hydrodynamic model to study the influence of physical processes on the distribution and the transport of terrestrially derived CDOM and DOC to shelf waters during the spring and fall of 2015. Determination of DOC stocks were based on the development of a CDOM algorithm (R2 = 0.87, N = 9) for the VIIRS ocean color sensor, and the assessment of CDOM - DOC relationships (R2 = 0.88, N = 13 in March; R2 = 0.83, N = 24 in November) for the Apalachicola Bay. Satellite-derived CDOM and DOC maps together with model-based salinity distributions revealed their spatial extent, sources and transport to the shelf water. Furthermore, strong seasonal influence on DOM distribution in the bay was associated with inputs from Apalachicola and Carrabelle Rivers and the surrounding marshes. Estimates of DOC standing stocks in the bay obtained using ocean color data and high-resolution bathymetry showed relatively higher stocks in November ( 3.71 × 106 kg C, 560 km2) than in March ( 4.07 × 106 kg C, 560 km2) despite lower river discharge in dry season. Results of DOC flux estimates from the bay to coastal waters will also be presented.

Microradiometers Reveal Ocean Health, Climate Change

Science.gov (United States)

2013-01-01

When NASA researcher Stanford Hooker is in the field, he pays close attention to color. For Hooker, being in the field means being at sea. On one such research trip to the frigid waters of the Arctic, with a Coast Guard icebreaker looming nearby and the snow-crusted ice shelf a few feet away, Hooker leaned over the edge of his small boat and lowered a tethered device into the bright turquoise water, a new product devised by a NASA partner and enabled by a promising technology for oceanographers and atmospheric scientists alike. Color is a function of light. Pure water is clear, but the variation in color observed during a visit to the beach or a flight along a coastline depends on the water s depth and the constituents in it, how far down the light penetrates and how it is absorbed and scattered by dissolved and suspended material. Hooker cares about ocean color because of what it can reveal about the health of the ocean, and in turn, the health of our planet. "The main thing we are interested in is the productivity of the water," Hooker says. The seawater contains phytoplankton, microscopic plants, which are the food base for the ocean s ecosystems. Changes in the water s properties, whether due to natural seasonal effects or human influence, can lead to problems for delicate ecosystems such as coral reefs. Ocean color can inform researchers about the quantities and distribution of phytoplankton and other materials, providing clues as to how the world ocean is changing. NASA s Coastal Zone Color Scanner, launched in 1978, was the first ocean color instrument flown on a spacecraft. Since then, the Agency s ocean color research capabilities have become increasingly sophisticated with the launch of the SeaWiFS instrument in 1997 and the twin MODIS instruments carried into orbit on NASA s Terra (1999) and Aqua (2002) satellites. The technology provides sweeping, global information on ocean color on a scale unattainable by any other means. One issue that arises from

The Global Geostationary Wildfire ABBA: Current Implementation and Future Plans

Science.gov (United States)

Prins, E.; Schmidt, C. C.; Hoffman, J.; Brunner, J.; Hyer, E. J.; Reid, J. S.

2012-12-01

The Wild Fire Automated Biomass Burning Algorithm (WF_ABBA), developed at the Cooperative Institute for Meteorological Satellite Studies (CIMSS), has a long legacy of operational near real-time wildfire detection and characterization in the Western Hemisphere. The first phase of the global geostationary WF_ABBA was made operational at NOAA NESDIS in 2009 and currently includes diurnal active fire monitoring from GOES-East, GOES-South America, GOES-West, Meteosat-9 and MTSAT-1R/-2. This allows for near global active fire monitoring with coverage of Europe, Africa, Southeast Asia and the Western Pacific utilizing distinct geostationary sensors and a consistent algorithm. Version 6.5.006 of the WF_ABBA was specifically designed to address the capabilities and limitations of diverse geostationary sensors and requests from the global fire monitoring and user community. This presentation will provide an overview of version 6.5.006 of the global WF_ABBA fire product including the new fire and opaque cloud mask and associated metadata. We will demonstrate the WF_ABBA showing examples from around the globe with a focus on the capabilities and plans for integrating new geostationary platforms with coverage of Eastern Europe and Asia (INSAT-3D, Korean COMS, Russian GOMS Elektro-L MSU-GS). We are also preparing for future fire monitoring in the Western Hemisphere, Europe, and Africa utilizing the next generation GOES-R Imager and Meteosat Third Generation Flexible Combined Imager (MTG - FCI). The goal is to create a globally consistent long-term fire product utilizing the capabilities of each of these unique operational systems and a common fire detection algorithm. On an international level, development of a global geostationary fire monitoring system is supported by the IGOS GOFC/GOLD Fire Implementation Team. This work also generally supports Committee on Earth Observation Satellites (CEOS) activities and the Group on Earth Observations (GEO).

CDOM-DOC relationship in contrasted coastal waters: implication for DOC retrieval from ocean color remote sensing observation.

Science.gov (United States)

Vantrepotte, Vincent; Danhiez, François-Pierre; Loisel, Hubert; Ouillon, Sylvain; Mériaux, Xavier; Cauvin, Arnaud; Dessailly, David

2015-01-12

Increasing our knowledge on dissolved organic carbon (DOC) spatio-temporal distribution in the coastal ocean represents a crucial challenge for better understanding the role of these ecosystems in the global oceanic carbon cycle. The assessment of DOC concentration from the absorption properties of the colored part of the dissolved organic matter (a(cdom)) was investigated from an extensive data set covering a variety of coastal environments. Our results confirmed that variation in the a(cdom)(412) to DOC ratio (a*(cdom)(412)) can be depicted from the CDOM spectral slope in the UV domain (S(275-295)). They also evidenced that regional first order variation in both a*(cdom)(412) and S(275-295) are highly correlated to variation in a(cdom)(412). From these observations, generalized relationships for estimating a*(cdom)(412) from S(275-295) or a(cdom)(412) were parameterized from our development sites (N = 158; English Channel, French Guiana, Hai Phong Bay) and tested against an independent data set covering others coastal regions (N = 223; French Polynesia, Rhone River estuary, Gulf of Maine, Chesapeake Bay, Southern Middle Atlantic Bight) demonstrating the possibility to derive DOC estimates from in situ CDOM optical properties with an average accuracy of ~16% over very contrasted coastal environments (with DOC ranging from 50 to 250 µmol.L(-1)). The applicability of these generalized approaches was evaluated in the context of ocean color remote sensing observation emphasizing the limits of S(275-295)-based formulations and the potential for a(cdom)-based approaches to represent a compelling alternative for assessing synoptic DOC distribution.

47 CFR 25.135 - Licensing provisions for earth station networks in the non-voice, non-geostationary mobile...

Science.gov (United States)

2010-10-01

... in the non-voice, non-geostationary mobile-satellite service. 25.135 Section 25.135 Telecommunication...-voice, non-geostationary mobile-satellite service. (a) Each applicant for a blanket earth station license in the non-voice, non-geostationary mobile-satellite service shall demonstrate that transceiver...

Application of Geostationary GNSS and SBAS Satellites for Studying Ionospheric TEC Disturbances of Geomagnetic and Meteorological Origin

Science.gov (United States)

Padokhin, A. M.; Kurbatov, G. A.; Yasyukevich, Y.; Yasyukevich, A.

2017-12-01

With the development of GNSS and SBAS constellations, the coherent multi-frequency L band transmissions are now available from a number of geostationary satellites. These signals can be used for ionospheric TEC estimations in the same way as widely used GPS/GLONASS signals. In this work, we compare noise patterns in TEC estimations based on different geostationary satellites data: augmentation systems (Indian GAGAN, European EGNOS and American WAAS), and Chinese COMPASS/Beidou navigation system. We show that noise level in geostationary COMPASS/Beidou TEC estimations is times smaller than noise in SBAS TEC estimation and corresponds to those of GPS/GLONASS at the same elevation angles. We discuss the capabilities of geostationary TEC data for studying ionospheric variability driven by space weather and meteorological sources at different time scales. Analyzing data from IGS/MGEX receivers we present geostationary TEC response on X-class Solar flares of current cycle, moderate and strong geomagnetic storms, including G4 St. Patrick's day Storm 2015 and recent G3 storm of the end of May 2017. We also discuss geostationary TEC disturbances in near equatorial ionosphere caused by two SSW events (minor and major final warming of 2015-2016 winter season) as well as geostationary TEC response on typhoons activity near Taiwan in autumn 2016. Our results show large potential of geostationary TEC estimations with GNSS and SBAS signals for continuous ionospheric monitoring.

Sensor-centric calibration and characterization of the VIIRS Ocean Color bands using Suomi NPP operational data

Science.gov (United States)

Pratt, P.

2012-12-01

Ocean color bands on VIIRS span the visible spectrum and include two NIR bands. There are sixteen detectors per band and two HAM (Half-angle mirror) sides giving a total of thirty two independent systems. For each scan, thirty two hundred pixels are collected and each has a fixed specific optical path and a dynamic position relative to the earth geoid. For a given calibration target where scene variation is minimized, sensor characteristics can be observed. This gives insight into the performance and calibration of the instrument from a sensor-centric perspective. Calibration of the blue bands is especially challenging since there are few blue targets on land. An ocean region called the South Pacific Gyre (SPG) was chosen for its known stability and large area to serve as a calibration target for this investigation. Thousands of pixels from every granule that views the SPG are collected daily through an automated system and tabulated along with the detector, HAM and scan position. These are then collated and organized in a sensor-centric set of tables. The data are then analyzed by slicing by each variable and then plotted in a number of ways over time. Trends in the data show that the VIIRS sensor is largely behaving as expected according to heritage data and also reveals weaknesses where additional characterization of the sensor is possible. This work by Northrop Grumman NPP CalVal Team is supporting the VIIRS on-orbit calibration and validation teams for the sensor and ocean color as well as providing scientists interested in performing ground truth with results that show which detectors and scan angles are the most reliable over time. This novel approach offers a comprehensive sensor-centric on-orbit characterization of the VIIRS instrument on the NASA Suomi NPP mission.

Some Insights of Spectral Optimization in Ocean Color Inversion

Science.gov (United States)

Lee, Zhongping; Franz, Bryan; Shang, Shaoling; Dong, Qiang; Arnone, Robert

2011-01-01

In the past decades various algorithms have been developed for the retrieval of water constituents from the measurement of ocean color radiometry, and one of the approaches is spectral optimization. This approach defines an error target (or error function) between the input remote sensing reflectance and the output remote sensing reflectance, with the latter modeled with a few variables that represent the optically active properties (such as the absorption coefficient of phytoplankton and the backscattering coefficient of particles). The values of the variables when the error reach a minimum (optimization is achieved) are considered the properties that form the input remote sensing reflectance; or in other words, the equations are solved numerically. The applications of this approach implicitly assume that the error is a monotonic function of the various variables. Here, with data from numerical simulation and field measurements, we show the shape of the error surface, in a way to justify the possibility of finding a solution of the various variables. In addition, because the spectral properties could be modeled differently, impacts of such differences on the error surface as well as on the retrievals are also presented.

Study on the cloud detection of GOCI by using the simulated surface reflectance from BRDF-model for the land application and meteorological utilization

Science.gov (United States)

Kim, Hye-Won; Yeom, Jong-Min; Woo, Sun-Hee; Chae, Tae-Byeong

2016-04-01

COMS (Communication, Ocean, and Meteorological Satellite) was launched at French Guiana Kourou space center on 27 June 2010. Geostationary Ocean Color Imager (GOCI), which is the first ocean color geostationary satellite in the world for observing the ocean phenomena, is able to obtain the scientific data per an hour from 00UTC to 07UTC. Moreover, the spectral channels of GOCI would enable not only monitoring for the ocean, but for extracting the information of the land surface over the Korean Peninsula, Japan, and Eastern China. Since it is extremely important to utilize GOCI data accurately for the land application, cloud pixels over the surface have to be removed. Unfortunately, infra-red (IR) channels that can easily detect the water vapor with the cloud top temperature, are not included in the GOCI sensor. In this paper, the advanced cloud masking algorithm will be proposed with visible and near-IR (NIR) bands that are within GOCI bands. The main obstacle of cloud masking with GOCI is how to handle the high variable surface reflectance, which is mainly depending on the solar zenith angle. In this study, we use semi-empirical BRDF model to simulate the surface reflectance by using 16 day composite cloudy free image. When estimating the simulated surface reflectance, same geometry for GOCI observation was applied. The simulated surface reflectance is used to discriminate cloud areas especially for the thin cloud and shows more reasonable result than original threshold methods.

Generalized Ocean Color Inversion Model for Retrieving Marine Inherent Optical Properties

Science.gov (United States)

Werdell, P. Jeremy; Franz, Bryan A.; Bailey, Sean W.; Feldman, Gene C.; Boss, Emmanuel; Brando, Vittorio E.; Dowell, Mark; Hirata, Takafumi; Lavender, Samantha J.; Lee, ZhongPing;

Static and kinematic positioning using WADGPS from geostationary satellites

Science.gov (United States)

Cefalo, R.; Gatti, M.

2003-04-01

STATIC AND KINEMATIC POSITIONING USING WADGPS CORRECTIONS FROM GEOSTATIONARY SATELLITES Cefalo R. (1), Gatti M (2) (1) Department of Civil Engineering, University of Trieste, P.le Europa 1, 34127 Trieste, Italy, cefalo@dic.univ.trieste.it, (2) Department of Engineering, University of Ferrara, via Saragat 1, 44100 Ferrara, Italy, mgatti@ing.unife.it ABSTRACT. Starting from February 2000, static and kinematic experiments have been performed at the Department of Civil Engineering of University of Trieste, Italy and the Department of Engineering of University of Ferrara, Italy, using the WADGPS (Wide Area Differential GPS) corrections up linked by Geostationary Satellites belonging to the American WAAS and European EGNOS. Recently, a prototypal service by ESA (European Space Agency) named SISNet (Signal In Space through Internet), has been introduced using Internet to diffuse the messages up linked through AOR-E and IOR Geostationary Satellites. This service will overcome the problems relative to the availability of the corrections in urban areas. This system is currently under tests by the authors in order to verify the latency of the message and the applicability and accuracies obtainable in particular in dynamic applications.

The 2017 Hurricane Season: A Revolution in Geostationary Weather Satellite Imaging and Data Processing

Science.gov (United States)

Weiner, A. M.; Gundy, J.; Brown-Bertold, B.; Yates, H.; Dobler, J. T.

2017-12-01

Since their introduction, geostationary weather satellites have enabled us to track hurricane life-cycle movement from development to dissipation. During the 2017 hurricane season, the new GOES-16 geostationary satellite demonstrated just how far we have progressed technologically in geostationary satellite imaging, with hurricane imagery showing never-before-seen detail of the hurricane eye and eyewall structure and life cycle. In addition, new ground system technology, leveraging high-performance computing, delivered imagery and data to forecasters with unprecedented speed—and with updates as often as every 30 seconds. As additional satellites and new products become operational, forecasters will be able to track hurricanes with even greater accuracy and assist in aftermath evaluations. This presentation will present glimpses into the past, a look at the present, and a prediction for the future utilization of geostationary satellites with respect to all facets of hurricane support.

Bayesian model for matching the radiometric measurements of aerospace and field ocean color sensors.

Science.gov (United States)

Salama, Mhd Suhyb; Su, Zhongbo

2010-01-01

A Bayesian model is developed to match aerospace ocean color observation to field measurements and derive the spatial variability of match-up sites. The performance of the model is tested against populations of synthesized spectra and full and reduced resolutions of MERIS data. The model derived the scale difference between synthesized satellite pixel and point measurements with R(2) > 0.88 and relative error < 21% in the spectral range from 400 nm to 695 nm. The sub-pixel variabilities of reduced resolution MERIS image are derived with less than 12% of relative errors in heterogeneous region. The method is generic and applicable to different sensors.

Bayesian Model for Matching the Radiometric Measurements of Aerospace and Field Ocean Color Sensors

Directory of Open Access Journals (Sweden)

Mhd. Suhyb Salama

2010-08-01

Full Text Available A Bayesian model is developed to match aerospace ocean color observation tofield measurements and derive the spatial variability of match-up sites. The performance of the model is tested against populations of synthesized spectra and full and reduced resolutions of MERIS data. The model derived the scale difference between synthesized satellite pixel and point measurements with R2 > 0.88 and relative error < 21% in the spectral range from 400 nm to 695 nm. The sub-pixel variabilities of reduced resolution MERIS image are derived with less than 12% of relative errors in heterogeneous region. The method is generic and applicable to different sensors.

Spectral interdependence of remote-sensing reflectance and its implications on the design of ocean color satellite sensors.

Science.gov (United States)

Lee, Zhongping; Shang, Shaoling; Hu, Chuanmin; Zibordi, Giuseppe

2014-05-20

Using 901 remote-sensing reflectance spectra (R(rs)(λ), sr⁻¹, λ from 400 to 700 nm with a 5 nm resolution), we evaluated the correlations of R(rs)(λ) between neighboring spectral bands in order to characterize (1) the spectral interdependence of R(rs)(λ) at different bands and (2) to what extent hyperspectral R(rs)(λ) can be reconstructed from multiband measurements. The 901 R(rs) spectra were measured over a wide variety of aquatic environments in which water color varied from oceanic blue to coastal green or brown, with chlorophyll-a concentrations ranging from ~0.02 to >100  mg  m⁻³, bottom depths from ~1  m to >1000  m, and bottom substrates including sand, coral reef, and seagrass. The correlation coefficient of R(rs)(λ) between neighboring bands at center wavelengths λ(k) and λ(l), r(Δλ)(λ(k), λ(l)), was evaluated systematically, with the spectral gap (Δλ=λ(l)-λ(k)) changing between 5, 10, 15, 20, 25, and 30 nm, respectively. It was found that r(Δλ) decreased with increasing Δλ, but remained >0.97 for Δλ≤20  nm for all spectral bands. Further, using 15 spectral bands between 400 and 710 nm, we reconstructed, via multivariant linear regression, hyperspectral R(rs)(λ) (from 400 to 700 nm with a 5 nm resolution). The percentage difference between measured and reconstructed R(rs) for each band in the 400-700 nm range was generally less than 1%, with a correlation coefficient close to 1.0. The mean absolute error between measured and reconstructed R(rs) was about 0.00002  sr⁻¹ for each band, which is significantly smaller than the R(rs) uncertainties from all past and current ocean color satellite radiometric products. These results echo findings of earlier studies that R(rs) measurements at ~15 spectral bands in the visible domain can provide nearly identical spectral information as with hyperspectral (contiguous bands at 5 nm spectral resolution) measurements. Such results provide insights for data

ESA personal communications and digital audio broadcasting systems based on non-geostationary satellites

Science.gov (United States)

Logalbo, P.; Benedicto, J.; Viola, R.

1993-01-01

Personal Communications and Digital Audio Broadcasting are two new services that the European Space Agency (ESA) is investigating for future European and Global Mobile Satellite systems. ESA is active in promoting these services in their various mission options including non-geostationary and geostationary satellite systems. A Medium Altitude Global Satellite System (MAGSS) for global personal communications at L and S-band, and a Multiregional Highly inclined Elliptical Orbit (M-HEO) system for multiregional digital audio broadcasting at L-band are described. Both systems are being investigated by ESA in the context of future programs, such as Archimedes, which are intended to demonstrate the new services and to develop the technology for future non-geostationary mobile communication and broadcasting satellites.

Using Remote Sensing and Field Observations of Colored Dissolved Organic Material (CDOM) to Improve Understanding of Carbon Dynamics at the Land-Ocean Interface

Science.gov (United States)

Lai, L.; Tzortziou, M.; Gilerson, A.; Foster, R.

2013-12-01

Dissolved Organic Matter (DOM) and its colored component, (CDOM) are sensitive indicators of environmental pollution, nutrient enrichment, water quality and plays a key role in a broad range of processes and climate-related biogeochemical cycles in estuarine and coastal ecosystems. Because of its strong influence on how ocean color is viewed, CDOM can provide an invaluable optical tool for coastal zone environmental assessment and from space. There is a continuous cycle of sources and sinks of CDOM from terrestrial sources to the wetlands to the estuaries and to the ocean waters. Terrestrial inputs from natural processes, anthropogenic activities, exchanges with the atmosphere, rich biodiversity and high primary productivity, physical, photochemical and microbial processes affect not only the amount but also the quality and optical signature of CDOM in near-shore waters. In this study, new measurements are presented of the optical characteristics of CDOM collected from the Chesapeake Bay estuarine environment. Measured parameters include absorption spectra, estimated spectral slopes, slope ratios, DOC-specific CDOM absorption as well as 3D CDOM fluorescence emission-excitation matrices. Such results will provide insight of the measured CDOM in this complex environment and the complex process that affect CDOM quality and amount during transport to the estuary and coastal ocean. New field campaigns will be conducted in August and September in the Chesapeake Bay estuary and the coast of the Gulf of Mexico to collect more samples for analysis of CDOM dynamics and link field observations and measurements to satellite ocean color retrievals of estuarine biogeochemical processes. In addition, advanced satellite CDOM data distribution and usage is discussed as it has considerable operational value and practical application beyond the scientific community and research. Keywords: CDOM, carbon dynamics, estuaries, coastal ecosystems, optical properties, satellite applications

Retrieval of Oceanic Constituents from Ocean Color Using Simulated Annealing

National Research Council Canada - National Science Library

Kempeneers, Pieter; Sterckx, Sindy; Debruyn, Walter; De Backer, Steve; Scheunders, Paul; Park, Youngje; Ruddick, Kevin

2005-01-01

...), phytoplankton pigments such as chlorophyll (CHL) and colored dissolved organic matter (CDOM). Reversely, optical sensors that measure the water-leaving reflectance spectra allow us to calculate the desired concentration products...

Estimating the marine signal in the near infrared for atmospheric correction of satellite ocean-color imagery over turbid waters

Science.gov (United States)

Bourdet, Alice; Frouin, Robert J.

2014-11-01

The classic atmospheric correction algorithm, routinely applied to second-generation ocean-color sensors such as SeaWiFS, MODIS, and MERIS, consists of (i) estimating the aerosol reflectance in the red and near infrared (NIR) where the ocean is considered black (i.e., totally absorbing), and (ii) extrapolating the estimated aerosol reflectance to shorter wavelengths. The marine reflectance is then retrieved by subtraction. Variants and improvements have been made over the years to deal with non-null reflectance in the red and near infrared, a general situation in estuaries and the coastal zone, but the solutions proposed so far still suffer some limitations, due to uncertainties in marine reflectance modeling in the near infrared or difficulty to extrapolate the aerosol signal to the blue when using observations in the shortwave infrared (SWIR), a spectral range far from the ocean-color wavelengths. To estimate the marine signal (i.e., the product of marine reflectance and atmospheric transmittance) in the near infrared, the proposed approach is to decompose the aerosol reflectance in the near infrared to shortwave infrared into principal components. Since aerosol scattering is smooth spectrally, a few components are generally sufficient to represent the perturbing signal, i.e., the aerosol reflectance in the near infrared can be determined from measurements in the shortwave infrared where the ocean is black. This gives access to the marine signal in the near infrared, which can then be used in the classic atmospheric correction algorithm. The methodology is evaluated theoretically from simulations of the top-of-atmosphere reflectance for a wide range of geophysical conditions and angular geometries and applied to actual MODIS imagery acquired over the Gulf of Mexico. The number of discarded pixels is reduced by over 80% using the PC modeling to determine the marine signal in the near infrared prior to applying the classic atmospheric correction algorithm.

Near-real-time global biomass burning emissions product from geostationary satellite constellation

Science.gov (United States)

Zhang, Xiaoyang; Kondragunta, Shobha; Ram, Jessica; Schmidt, Christopher; Huang, Ho-Chun

2012-07-01

Near-real-time estimates of biomass burning emissions are crucial for air quality monitoring and forecasting. We present here the first near-real-time global biomass burning emission product from geostationary satellites (GBBEP-Geo) produced from satellite-derived fire radiative power (FRP) for individual fire pixels. Specifically, the FRP is retrieved using WF_ABBA V65 (wildfire automated biomass burning algorithm) from a network of multiple geostationary satellites. The network consists of two Geostationary Operational Environmental Satellites (GOES) which are operated by the National Oceanic and Atmospheric Administration, the Meteosat second-generation satellites (Meteosat-09) operated by the European Organisation for the Exploitation of Meteorological Satellites, and the Multifunctional Transport Satellite (MTSAT) operated by the Japan Meteorological Agency. These satellites observe wildfires at an interval of 15-30 min. Because of the impacts from sensor saturation, cloud cover, and background surface, the FRP values are generally not continuously observed. The missing observations are simulated by combining the available instantaneous FRP observations within a day and a set of representative climatological diurnal patterns of FRP for various ecosystems. Finally, the simulated diurnal variation in FRP is applied to quantify biomass combustion and emissions in individual fire pixels with a latency of 1 day. By analyzing global patterns in hourly biomass burning emissions in 2010, we find that peak fire season varied greatly and that annual wildfires burned 1.33 × 1012 kg dry mass, released 1.27 × 1010 kg of PM2.5 (particulate mass for particles with diameter forest and savanna fires in Africa, South America, and North America. Evaluation of emission result reveals that the GBBEP-Geo estimates are comparable with other FRP-derived estimates in Africa, while the results are generally smaller than most of the other global products that were derived from burned

Improved Vegetation Profiles with GOCI Imagery Using Optimized BRDF Composite

Directory of Open Access Journals (Sweden)

Sang-il Kim

2016-01-01

Full Text Available The purpose of this study was to optimize a composite method for the Geostationary Ocean Color Imager (GOCI, which is the first geostationary ocean color sensor in the world. Before interpreting the sensitivity of each composite with ground measurements, we evaluated the accuracy of bidirectional reflectance distribution function (BRDF performance by comparing modeled surface reflectance from BRDF simulation with GOCI-measured surface reflectance according to composite period. The root mean square error values for modeled and measured surface reflectance showed reasonable accuracy for all of composite days since each BRDF composite period includes at least seven cloud-free angular sampling for all BRDF performances. Also, GOCI-BRDF-adjusted NDVIs with four different composite periods were compared with field-observation NDVI and we interpreted the sensitivity of temporal crop dynamics of GOCI-BRDF-adjusted NDVIs. The results showed that vegetation index seasonal profiles appeared similar to vegetation growth curves in both field observations from crop scans and GOCI normalized difference vegetation index (NDVI data. Finally, we showed that a 12-day composite period was optimal in terms of BRDF simulation accuracy, surface coverage, and real-time sensitivity.

Improving Coastal Ocean Color Validation Capabilities through Application of Inherent Optical Properties (IOPs)

Science.gov (United States)

Mannino, Antonio

2008-01-01

Understanding how the different components of seawater alter the path of incident sunlight through scattering and absorption is essential to using remotely sensed ocean color observations effectively. This is particularly apropos in coastal waters where the different optically significant components (phytoplankton, detrital material, inorganic minerals, etc.) vary widely in concentration, often independently from one another. Inherent Optical Properties (IOPs) form the link between these biogeochemical constituents and the Apparent Optical Properties (AOPs). understanding this interrelationship is at the heart of successfully carrying out inversions of satellite-measured radiance to biogeochemical properties. While sufficient covariation of seawater constituents in case I waters typically allows empirical algorithms connecting AOPs and biogeochemical parameters to behave well, these empirical algorithms normally do not hold for case I1 regimes (Carder et al. 2003). Validation in the context of ocean color remote sensing refers to in-situ measurements used to verify or characterize algorithm products or any assumption used as input to an algorithm. In this project, validation capabilities are considered those measurement capabilities, techniques, methods, models, etc. that allow effective validation. Enhancing current validation capabilities by incorporating state-of-the-art IOP measurements and optical models is the purpose of this work. Involved in this pursuit is improving core IOP measurement capabilities (spectral, angular, spatio-temporal resolutions), improving our understanding of the behavior of analytical AOP-IOP approximations in complex coastal waters, and improving the spatial and temporal resolution of biogeochemical data for validation by applying biogeochemical-IOP inversion models so that these parameters can be computed from real-time IOP sensors with high sampling rates. Research cruises supported by this project provides for collection and

Astrometry and Geostationary Satellites in Venezuela

Science.gov (United States)

Lacruz, E.; Abad, C.

2015-10-01

We present the current status and the first results of the astrometric project CIDA - ABAE for tracking geo-stationary satellites. This project aims to determine a preliminary orbit for the Venezuelan satellite VENESAT-1, using astrometric positions obtained from an optical telescope. The results presented here are based on observations from the Luepa space tracking ground station in Venezuela, which were processed using astrometric procedures.

Icing Detection over East Asia from Geostationary Satellite Data Using Machine Learning Approaches

Directory of Open Access Journals (Sweden)

Seongmun Sim

2018-04-01

Full Text Available Even though deicing or airframe coating technologies continue to develop, aircraft icing is still one of the critical threats to aviation. While the detection of potential icing clouds has been conducted using geostationary satellite data in the US and Europe, there is not yet a robust model that detects potential icing areas in East Asia. In this study, we proposed machine-learning-based icing detection models using data from two geostationary satellites—the Communication, Ocean, and Meteorological Satellite (COMS Meteorological Imager (MI and the Himawari-8 Advanced Himawari Imager (AHI—over Northeast Asia. Two machine learning techniques—random forest (RF and multinomial log-linear (MLL models—were evaluated with quality-controlled pilot reports (PIREPs as the reference data. The machine-learning-based models were compared to the existing models through five-fold cross-validation. The RF model for COMS MI produced the best performance, resulting in a mean probability of detection (POD of 81.8%, a mean overall accuracy (OA of 82.1%, and mean true skill statistics (TSS of 64.0%. One of the existing models, flight icing threat (FIT, produced relatively poor performance, providing a mean POD of 36.4%, a mean OA of 61.0, and a mean TSS of 9.7%. The Himawari-8 based models also produced performance comparable to the COMS models. However, it should be noted that very limited PIREP reference data were available especially for the Himawari-8 models, which requires further evaluation in the future with more reference data. The spatio-temporal patterns of the icing areas detected using the developed models were also visually examined using time-series satellite data.

Ocean Color and the Equatorial Annual Cycle in the Pacific

Science.gov (United States)

Hammann, A. C.; Gnanadesikan, A.

2012-12-01

The presence of chlorophyll, colored dissolved organic matter (CDOM) and other scatterers in ocean surface waters affect the flux divergence of solar radiation and thus the vertical distribution of radiant heating of the ocean. While this may directly alter the local mixed-layer depth and temperature (Martin 1985; Strutton & Chavez 2004), non-local changes are propagated through advection (Manizza et al. 2005; Murtugudde et al. 2002; Nakamoto et al. 2001; Sweeny et al. 2005). In and coupled feedbacks (Lengaigne et al. 2007; Marzeion & Timmermann 2005). Anderson et al. (2007), Anderson et al. (2009) and Gnanadesikan & Anderson (2009) have performed a series of experiments with a fully coupled climate model which parameterizes the e-folding depth of solar irradiance in terms of surface chlorophyll-a concentration. The results have so far been discussed with respect to the climatic mean state and ENSO variability in the tropical Pacific. We extend the discussion here to the Pacific equatorial annual cycle. The focus of the coupled experiments has been the sensitivity of the coupled system to regional differences in chlorophyll concentration. While runs have been completed with realistic SeaWiFS-derived monthly composite chlorophyll ('green') and with a globally chlorophyll-free ocean ('blue'), the concentrations in two additional runs have been selectively set to zero in specific regions: the oligotrophic subtropical gyres ('gyre') in one case and the mesotrophic gyre margins ('margin') in the other. The annual cycle of ocean temperatures exhibits distinctly reduced amplitudes in the 'blue' and 'margin' experiments, and a slight reduction in 'gyre' (while ENSO variability almost vanishes in 'blue' and 'gyre', but amplifies in 'margin' - thus the frequently quoted inverse correlation between ENSO and annual amplitudes holds only for the 'green' / 'margin' comparison). It is well-known that on annual time scales, the anomalous divergence of surface currents and vertical

Spectroscopic Observations of Geo-Stationary Satellites Over the Korean Peninsula

Directory of Open Access Journals (Sweden)

D. K. Lee

2001-11-01

Full Text Available Low resolution spectroscopic observations of geo-stationary satellites over the Korean peninsula have been carried out at the KyungHee Optical Satellite Observing Facility (KOSOF with a 40cm telescope. We have observed 9 telecommunication satellites and 1 weather satellite of 6 countries. The obtained spectral data showed that satellites could be classified and grouped with similar basic spectral feature. We divided the 10 satellites into 4 groups based on spectral slop and reflectance. It is suggested that the material types of the satellites can be determined through spectral comparisons with the ground laboratory data. We will continuously observe additional geo-stationary satellites for the accurate classification of spectral features.

Enhance field water-color measurements with a Secchi disk and its implication for fusion of active and passive ocean-color remote sensing.

Science.gov (United States)

Lee, Zhongping; Shang, Shaoling; Du, Keping; Liu, Bingyi; Lin, Gong; Wei, Jianwei; Li, Xiaolong

2018-05-01

Inversion of the total absorption (a) and backscattering coefficients of bulk water through a fusion of remote sensing reflectance (R rs ) and Secchi disk depth (Z SD ) is developed. An application of such a system to a synthesized wide-range dataset shows a reduction of ∼3 folds in the uncertainties of inverted a(λ) (in a range of ∼0.01-6.8  m -1 ) from R rs (λ) for the 350-560 nm range. Such a fusion is further proposed to process concurrent active (ocean LiDAR) and passive (ocean-color) measurements, which can lead to nearly "exact" analytical inversion of an R rs spectrum. With such a fusion, it is found that the uncertainty in the inverted total a in the 350-560 nm range could be reduced to ∼2% for the synthesized data, which can thus significantly improve the derivation of a coefficients of other varying components. Although the inclusion of Z SD places an extra constraint in the inversion of R rs , no apparent improvement over the quasi-analytical algorithm (QAA) was found when the fusion of Z SD and R rs was applied to a field dataset, which calls for more accurate determination of the absorption coefficients from water samples.

Underway Sampling of Marine Inherent Optical Properties on the Tara Oceans Expedition as a Novel Resource for Ocean Color Satellite Data Product Validation

Science.gov (United States)

Werdell, P. Jeremy; Proctor, Christopher W.; Boss, Emmanuel; Leeuw, Thomas; Ouhssain, Mustapha

2013-01-01

Developing and validating data records from operational ocean color satellite instruments requires substantial volumes of high quality in situ data. In the absence of broad, institutionally supported field programs, organizations such as the NASA Ocean Biology Processing Group seek opportunistic datasets for use in their operational satellite calibration and validation activities. The publicly available, global biogeochemical dataset collected as part of the two and a half year Tara Oceans expedition provides one such opportunity. We showed how the inline measurements of hyperspectral absorption and attenuation coefficients collected onboard the R/V Tara can be used to evaluate near-surface estimates of chlorophyll-a, spectral particulate backscattering coefficients, particulate organic carbon, and particle size classes derived from the NASA Moderate Resolution Imaging Spectroradiometer onboard Aqua (MODISA). The predominant strength of such flow-through measurements is their sampling rate-the 375 days of measurements resulted in 165 viable MODISA-to-in situ match-ups, compared to 13 from discrete water sampling. While the need to apply bio-optical models to estimate biogeochemical quantities of interest from spectroscopy remains a weakness, we demonstrated how discrete samples can be used in combination with flow-through measurements to create data records of sufficient quality to conduct first order evaluations of satellite-derived data products. Given an emerging agency desire to rapidly evaluate new satellite missions, our results have significant implications on how calibration and validation teams for these missions will be constructed.

Development of a numerical system to improve particulate matter forecasts in South Korea using geostationary satellite-retrieved aerosol optical data over Northeast Asia

Science.gov (United States)

Lee, Sojin; Song, Chul-han; Park, Rae Seol; Park, Mi Eun; Han, Kyung man; Kim, Jhoon; Choi, Myungje; Ghim, Young Sung; Woo, Jung-Hun

2016-04-01

To improve short-term particulate matter (PM) forecasts in South Korea, the initial distribution of PM composition, particularly over the upwind regions, is primarily important. To prepare the initial PM composition, the aerosol optical depth (AOD) data retrieved from a geostationary equatorial orbit (GEO) satellite sensor, GOCI (Geostationary Ocean Color Imager) which covers a part of Northeast Asia (113-146° E; 25-47° N), were used. Although GOCI can provide a higher number of AOD data in a semicontinuous manner than low Earth orbit (LEO) satellite sensors, it still has a serious limitation in that the AOD data are not available at cloud pixels and over high-reflectance areas, such as desert and snow-covered regions. To overcome this limitation, a spatiotemporal-kriging (STK) method was used to better prepare the initial AOD distributions that were converted into the PM composition over Northeast Asia. One of the largest advantages in using the STK method in this study is that more observed AOD data can be used to prepare the best initial AOD fields compared with other methods that use single frame of observation data around the time of initialization. It is demonstrated in this study that the short-term PM forecast system developed with the application of the STK method can greatly improve PM10 predictions in the Seoul metropolitan area (SMA) when evaluated with ground-based observations. For example, errors and biases of PM10 predictions decreased by ˜ 60 and ˜ 70{%}, respectively, during the first 6 h of short-term PM forecasting, compared with those without the initial PM composition. In addition, the influences of several factors on the performances of the short-term PM forecast were explored in this study. The influences of the choices of the control variables on the PM chemical composition were also investigated with the composition data measured via PILS-IC (particle-into-liquid sampler coupled with ion chromatography) and low air-volume sample

Characterization of geostationary particle signatures based on the 'injection boundary' model

International Nuclear Information System (INIS)

Mauk, B.H.; Meng, C.

1983-01-01

To lend further support to the 'injection boundary' concept, this paper characterizes the details of geostationary particle signatures using a very simple-minded analysis procedure. The signatures are generated using the time of flight effects which evolve from an initial sharply defined, double-spiraled boundary configuration. By using only the most fundamental characteristics of standard convection configurations, the very complex and highly variable dispersion patterns frequently observed by geostationary satellites are successfully reproduced. In particular, seven distinctly different ion-electron paired dispersion patterns on energy versus time spectrograms (1 eV to 100 KeV) are predicted, and all seven of these are observed on a regular basis by both the SCATHA satellite (in the near geostationary orbit) and the ATS-6 satellite. Many of the details of the patterns have not been previously presented. It is concluded that most dynamical dispersion features (including energetic ion and electron echoes) can be mapped to the double-spiral boundary without further ad hoc assumptions. It is shown further that the predicted and observed dispersion patterns have symmetries which are distinct from the symmetries generally associated with the quasistationary particle convection patterns

Comparison of Cloud Properties from CALIPSO-CloudSat and Geostationary Satellite Data

Science.gov (United States)

Nguyen, L.; Minnis, P.; Chang, F.; Winker, D.; Sun-Mack, S.; Spangenberg, D.; Austin, R.

2007-01-01

Cloud properties are being derived in near-real time from geostationary satellite imager data for a variety of weather and climate applications and research. Assessment of the uncertainties in each of the derived cloud parameters is essential for confident use of the products. Determination of cloud amount, cloud top height, and cloud layering is especially important for using these real -time products for applications such as aircraft icing condition diagnosis and numerical weather prediction model assimilation. Furthermore, the distribution of clouds as a function of altitude has become a central component of efforts to evaluate climate model cloud simulations. Validation of those parameters has been difficult except over limited areas where ground-based active sensors, such as cloud radars or lidars, have been available on a regular basis. Retrievals of cloud properties are sensitive to the surface background, time of day, and the clouds themselves. Thus, it is essential to assess the geostationary satellite retrievals over a variety of locations. The availability of cloud radar data from CloudSat and lidar data from CALIPSO make it possible to perform those assessments over each geostationary domain at 0130 and 1330 LT. In this paper, CloudSat and CALIPSO data are matched with contemporaneous Geostationary Operational Environmental Satellite (GOES), Multi-functional Transport Satellite (MTSAT), and Meteosat-8 data. Unlike comparisons with cloud products derived from A-Train imagers, this study considers comparisons of nadir active sensor data with off-nadir retrievals. These matched data are used to determine the uncertainties in cloud-top heights and cloud amounts derived from the geostationary satellite data using the Clouds and the Earth s Radiant Energy System (CERES) cloud retrieval algorithms. The CERES multi-layer cloud detection method is also evaluated to determine its accuracy and limitations in the off-nadir mode. The results will be useful for

Generating Land Surface Reflectance for the New Generation of Geostationary Satellite Sensors with the MAIAC Algorithm

Science.gov (United States)

Wang, W.; Wang, Y.; Hashimoto, H.; Li, S.; Takenaka, H.; Higuchi, A.; Lyapustin, A.; Nemani, R. R.

2017-12-01

The latest generation of geostationary satellite sensors, including the GOES-16/ABI and the Himawari 8/AHI, provide exciting capability to monitor land surface at very high temporal resolutions (5-15 minute intervals) and with spatial and spectral characteristics that mimic the Earth Observing System flagship MODIS. However, geostationary data feature changing sun angles at constant view geometry, which is almost reciprocal to sun-synchronous observations. Such a challenge needs to be carefully addressed before one can exploit the full potential of the new sources of data. Here we take on this challenge with Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm, recently developed for accurate and globally robust applications like the MODIS Collection 6 re-processing. MAIAC first grids the top-of-atmosphere measurements to a fixed grid so that the spectral and physical signatures of each grid cell are stacked ("remembered") over time and used to dramatically improve cloud/shadow/snow detection, which is by far the dominant error source in the remote sensing. It also exploits the changing sun-view geometry of the geostationary sensor to characterize surface BRDF with augmented angular resolution for accurate aerosol retrievals and atmospheric correction. The high temporal resolutions of the geostationary data indeed make the BRDF retrieval much simpler and more robust as compared with sun-synchronous sensors such as MODIS. As a prototype test for the geostationary-data processing pipeline on NASA Earth Exchange (GEONEX), we apply MAIAC to process 18 months of data from Himawari 8/AHI over Australia. We generate a suite of test results, including the input TOA reflectance and the output cloud mask, aerosol optical depth (AOD), and the atmospherically-corrected surface reflectance for a variety of geographic locations, terrain, and land cover types. Comparison with MODIS data indicates a general agreement between the retrieved surface reflectance

How Ocean Color Influences the Interplay Between Annual and Interannual Tropical Pacific Variability

Science.gov (United States)

Hammann, A. C.; Gnanadesikan, A.

2010-12-01

While the basic mechanisms responsible for ENSO have long been known, many details still evade our understanding. Since the behavior of the real climate system appears to be highly sensitive to such details, however, our ability to model, let alone predict it with any confidence has so far been rather restricted. Not only can small perturbations in many state variables lead to strongly amplified responses, but also do spatial and temporal scales of variability rarely occur in isolation from each other. Both points are born out in the study by Anderson et al. (2009), who removed surface chlorophyll in different regions of the tropical (but mostly off-equatorial) Pacific in a coupled ocean-atmosphere-land-ice model. Different removal patterns lead to large differences in the amplitudes of both ENSO and the equatorial annual cycle. Anderson et al.’s analysis focuses on ENSO and reveals that the transmission of off-equatorial perturbations to the equator happens mainly through a changed atmospheric response to SST anomalies. Here, we analyze the same data with respect to the annual cycle and how it interacts with ENSO. Guilyardi (2006) reports that observations and models alike show a zero-sum-type behavior of annual and ENSO-scale variability; increased spectral power in the annual band means decreased power in the ENSO band and vice versa. This is not the case for the different patterns of chlorophyll removal in our model, and hence it appears that this removal changes a fundamental part of its mean state. The dynamics of the annual cycle are likely influenced by oceanic meridional temperature advection, which provides another possible route for off-to-equatorial signal propagation. A common aspect of the tropical annual cycle in most coupled climate models is the presence of a double ITCZ instead of a single north-shifted one. Even though this appears to be unrelated to (albeit influenced by) the changes in ocean color, our model exhibits a much improved

Influence of CDOM and particle composition on ocean color of the Eastern New Caledonia Lagoon during the CALIOPE cruises

Science.gov (United States)

Dupouy, Cécile; Röttgers, Rüdiger; Tedetti, Marc; Martias, Chloe; Murakami, Hiroshi; Doxaran, David; Lantoine, Francois; Rodier, Martine; Favareto, Luciane; Kampel, Milton; Goutx, Madeleine; Frouin, Robert J.

2014-11-01

Ocean color of tropical lagoons is dependent on bathymetry and bottom type, as well as input of coastal living and mineral particles and chromophoric dissolved organic matter (CDOM). The New Caledonia lagoon lies in the Southwestern Tropical Pacific around 21° 30'S and 166° 30'E, with a great marine biodiversity in UNESCO Heritage coral reefs, benthic sea grass, and benthic communities. They are largely connected to the open ocean in the southern and eastern parts, but only by narrow passes in the southwest part. The trophic state is linked to spatial variations in flushing times. High run offs due to rain carrying abundant chromophoric dissolved organic matter (CDOM) and particle loads may greatly impact the functioning of ecosystems while rivers and sewage effluents may induce localized impacts. Two oceanographic cruises (CALIOPE 1 in 2011 and CALIOPE 2 in 2014) were carried out off the Eastern Coast of New Caledonia during a calm dry period and during high winds, respectively. Multi- and hyper-spectral marine reflectance was measured with a SIMBADA instrument and a TRIOS radiometer system, together with inherent optical properties (total and CDOM absorption coefficients with a PSICAM, in situ absorption and scattering with an AC9, backscattering with a Hydroscat-6). Fluorescence of CDOM (EEM/PARAFAC) was measured on collected 0.2 μm filtered samples. In 2014, Satlantic and FieldSpec hyper-spectral radiometers were available for in-water profiling of upwelling radiance and downwelling irradiance and above-water reflectance measurements, respectively. Inherent and apparent optical data from the two cruises are compared and used to estimate ocean color algorithms performance and evaluate a Linear Matrix Inversion method, providing tools for remote sensing on this highly under-sampled coastal region of New Caledonia.

Surface roughness considerations for atmospheric correction of ocean color sensors. I - The Rayleigh-scattering component. II - Error in the retrieved water-leaving radiance

Science.gov (United States)

Gordon, Howard R.; Wang, Menghua

1992-01-01

The first step in the Coastal Zone Color Scanner (CZCS) atmospheric-correction algorithm is the computation of the Rayleigh-scattering (RS) contribution, L sub r, to the radiance leaving the top of the atmosphere over the ocean. In the present algorithm, L sub r is computed by assuming that the ocean surface is flat. Calculations of the radiance leaving an RS atmosphere overlying a rough Fresnel-reflecting ocean are presented to evaluate the radiance error caused by the flat-ocean assumption. Simulations are carried out to evaluate the error incurred when the CZCS-type algorithm is applied to a realistic ocean in which the surface is roughened by the wind. In situations where there is no direct sun glitter, it is concluded that the error induced by ignoring the Rayleigh-aerosol interaction is usually larger than that caused by ignoring the surface roughness. This suggests that, in refining algorithms for future sensors, more effort should be focused on dealing with the Rayleigh-aerosol interaction than on the roughness of the sea surface.

Interpretation of Spectrometric Measurements of Active Geostationary Satellites

Science.gov (United States)

Bedard, D.; Wade, G.

2014-09-01

Over 5000 visible near-infrared (VNIR) spectrometric measurements of active geostationary satellites have been collected with the National Research Council (NRC) 1.8m Plaskett telescope located at the Dominion Astrophysical Observatory (DAO) in Victoria, Canada. The objective of this ongoing experiment is to study how reflectance spectroscopy can be used to reliably identify specific material types on the surface of artificial Earth-orbiting objects. Active geostationary satellites were selected as the main subjects for this experiment since their orientation is stable and can be estimated to a high-level of confidence throughout a night of observation. Furthermore, for most geostationary satellites, there is a wide variety of sources that can provide some level of information as to their external surface composition. Notwithstanding the high number of measurements that have been collected to date, it was assumed that the experimenters would have a much greater success rate in material identification given the choice experimental subjects. To date, only the presence of aluminum has been confidently identified in some of the reflectance spectra that have been collected. Two additional material types, namely photovoltaic cells and polyimide film, the first layer of multi-layer insulation (MLI), have also been possibly identified. However uncertainties in the reduced spectral measurements prevent any definitive conclusion with respect to these materials at this time. The surprising lack of results with respect to material identification have forced the experimenters to use other data interpretation methods to characterize the spectral scattering characteristics of the studied satellites. The results from this study have already led to improvements in the ways that reflectance spectra from spacecraft are collected and analysed. Equally important, the data interpretation techniques elaborated over the course of this experiment will also serve to increase the body of

Prediction Model for Relativistic Electrons at Geostationary Orbit

Science.gov (United States)

Khazanov, George V.; Lyatsky, Wladislaw

2008-01-01

We developed a new prediction model for forecasting relativistic (greater than 2MeV) electrons, which provides a VERY HIGH correlation between predicted and actually measured electron fluxes at geostationary orbit. This model implies the multi-step particle acceleration and is based on numerical integrating two linked continuity equations for primarily accelerated particles and relativistic electrons. The model includes a source and losses, and used solar wind data as only input parameters. We used the coupling function which is a best-fit combination of solar wind/interplanetary magnetic field parameters, responsible for the generation of geomagnetic activity, as a source. The loss function was derived from experimental data. We tested the model for four year period 2004-2007. The correlation coefficient between predicted and actual values of the electron fluxes for whole four year period as well as for each of these years is stable and incredibly high (about 0.9). The high and stable correlation between the computed and actual electron fluxes shows that the reliable forecasting these electrons at geostationary orbit is possible.

COLORS OF A SECOND EARTH: ESTIMATING THE FRACTIONAL AREAS OF OCEAN, LAND, AND VEGETATION OF EARTH-LIKE EXOPLANETS

International Nuclear Information System (INIS)

Fujii, Yuka; Kawahara, Hajime; Suto, Yasushi; Taruya, Atsushi; Fukuda, Satoru; Nakajima, Teruyuki; Turner, Edwin L.

2010-01-01

Characterizing the surfaces of rocky exoplanets via their scattered light will be an essential challenge in investigating their habitability and the possible existence of life on their surfaces. We present a reconstruction method for fractional areas of different surface types from the colors of an Earth-like exoplanet. We create mock light curves for Earth without clouds using empirical data. These light curves are fitted to an isotropic scattering model consisting of four surface types: ocean, soil, snow, and vegetation. In an idealized situation where the photometric errors are only photon shot noise, we are able to reproduce the fractional areas of those components fairly well. The results offer some hope for detection of vegetation via the distinct spectral feature of photosynthesis on Earth, known as the red edge. In our reconstruction method, Rayleigh scattering due to the atmosphere plays an important role, and for terrestrial exoplanets with an atmosphere similar to our Earth, it is possible to estimate the presence of oceans and an atmosphere simultaneously.

Electron Flux Models for Different Energies at Geostationary Orbit

Science.gov (United States)

Boynton, R. J.; Balikhin, M. A.; Sibeck, D. G.; Walker, S. N.; Billings, S. A.; Ganushkina, N.

2016-01-01

Forecast models were derived for energetic electrons at all energy ranges sampled by the third-generation Geostationary Operational Environmental Satellites (GOES). These models were based on Multi-Input Single-Output Nonlinear Autoregressive Moving Average with Exogenous inputs methodologies. The model inputs include the solar wind velocity, density and pressure, the fraction of time that the interplanetary magnetic field (IMF) was southward, the IMF contribution of a solar wind-magnetosphere coupling function proposed by Boynton et al. (2011b), and the Dst index. As such, this study has deduced five new 1 h resolution models for the low-energy electrons measured by GOES (30-50 keV, 50-100 keV, 100-200 keV, 200-350 keV, and 350-600 keV) and extended the existing >800 keV and >2 MeV Geostationary Earth Orbit electron fluxes models to forecast at a 1 h resolution. All of these models were shown to provide accurate forecasts, with prediction efficiencies ranging between 66.9% and 82.3%.

Los Alamos energetic particle sensor systems at geostationary orbit

International Nuclear Information System (INIS)

Baker, D.N.; Aiello, W.; Asbridge, J.R.; Belian, R.D.; Higbie, P.R.; Klebesadel, R.W.; Laros, J.G.; Tech, E.R.

1985-01-01

The Los Alamos National Laboratory has provided energetic particle sensors for a variety of spacecraft at the geostationary orbit (36,000 km altitude). The sensor system called the Charged Particle Analyzer (CPA) consists of four separate subsystems. The LoE and HiE subsystems measure electrons in the energy ranges 30 to 300 keV and 200 to 2000 keV, respectively. The LoP and HiP subsystems measure ions in the ranges 100 to 600 keV and 0.40 to 150 MeV, respectively. A separate sensor system called the spectrometer for energetic electrons (SEE) measures very high-energy electrons (2 to 15 MeV) using advanced scintillator design. In this paper we describe the relationship of operational anomalies and spacecraft upsets to the directly measured energetic particle environments at 6.6 R/sub E/. We also compare and contrast the CPA and SEE instrument design characteristics with the next generation of Los Alamos instruments to be flown at geostationary altitudes

Computational Ocean Acoustics

CERN Document Server

Jensen, Finn B; Porter, Michael B; Schmidt, Henrik

2011-01-01

Since the mid-1970s, the computer has played an increasingly pivotal role in the field of ocean acoustics. Faster and less expensive than actual ocean experiments, and capable of accommodating the full complexity of the acoustic problem, numerical models are now standard research tools in ocean laboratories. The progress made in computational ocean acoustics over the last thirty years is summed up in this authoritative and innovatively illustrated new text. Written by some of the field's pioneers, all Fellows of the Acoustical Society of America, Computational Ocean Acoustics presents the latest numerical techniques for solving the wave equation in heterogeneous fluid–solid media. The authors discuss various computational schemes in detail, emphasizing the importance of theoretical foundations that lead directly to numerical implementations for real ocean environments. To further clarify the presentation, the fundamental propagation features of the techniques are illustrated in color. Computational Ocean A...

An algorithm for estimating aerosol optical depth from HIMAWARI-8 data over Ocean

Science.gov (United States)

Lee, Kwon Ho

2016-04-01

The paper presents currently developing algorithm for aerosol detection and retrieval over ocean for the next generation geostationary satellite, HIMAWARI-8. Enhanced geostationary remote sensing observations are now enables for aerosol retrieval of dust, smoke, and ash, which began a new era of geostationary aerosol observations. Sixteen channels of the Advanced HIMAWARI Imager (AHI) onboard HIMAWARI-8 offer capabilities for aerosol remote sensing similar to those currently provided by the Moderate Resolution Imaging Spectroradiometer (MODIS). Aerosols were estimated in detection processing from visible and infrared channel radiances, and in retrieval processing using the inversion-optimization of satellite-observed radiances with those calculated from radiative transfer model. The retrievals are performed operationally every ten minutes for pixel sizes of ~8 km. The algorithm currently under development uses a multichannel approach to estimate the effective radius, aerosol optical depth (AOD) simultaneously. The instantaneous retrieved AOD is evaluated by the MODIS level 2 operational aerosol products (C006), and the daily retrieved AOD was compared with ground-based measurements from the AERONET databases. The results show that the detection of aerosol and estimated AOD are in good agreement with the MODIS data and ground measurements with a correlation coefficient of ˜0.90 and a bias of 4%. These results suggest that the proposed method applied to the HIMAWARI-8 satellite data can accurately estimate continuous AOD. Acknowledgments This work was supported by "Development of Geostationary Meteorological Satellite Ground Segment(NMSC-2014-01)" program funded by National Meteorological Satellite Centre(NMSC) of Korea Meteorological Administration(KMA).

Biodiversity of Pigmented Fungi Isolated from Marine Environment in La Réunion Island, Indian Ocean: New Resources for Colored Metabolites

Directory of Open Access Journals (Sweden)

Mireille Fouillaud

2017-07-01

Full Text Available Marine ecosystems cover about 70% of the planet surface and are still an underexploited source of useful metabolites. Among microbes, filamentous fungi are captivating organisms used for the production of many chemical classes of secondary metabolites bound to be used in various fields of industrial application. The present study was focused on the collection, isolation, screening and genotyping of pigmented filamentous fungi isolated from tropical marine environments around La Réunion Island, Indian Ocean. About 150 micromycetes were revived and isolated from 14 marine samples (sediments, living corals, coral rubble, sea water and hard substrates collected in four different locations. Forty-two colored fungal isolates belonging to 16 families, 25 genera and 31 species were further studied depending on their ability to produce pigments and thus subjected to molecular identification. From gene sequence analysis, the most frequently identified colored fungi belong to the widespread Penicillium, Talaromyces and Aspergillus genera in the family Trichocomaceae (11 species, then followed by the family Hypocreaceae (three species. This study demonstrates that marine biotopes in La Réunion Island, Indian Ocean, from coral reefs to underwater slopes of this volcanic island, shelter numerous species of micromycetes, from common or uncommon genera. This unstudied biodiversity comes along with the ability for some fungal marine inhabitants, to produce a range of pigments and hues.

The Geostationary Earth Radiation Budget Project.

Science.gov (United States)

Harries, J. E.; Russell, J. E.; Hanafin, J. A.; Brindley, H.; Futyan, J.; Rufus, J.; Kellock, S.; Matthews, G.; Wrigley, R.; Last, A.; Mueller, J.; Mossavati, R.; Ashmall, J.; Sawyer, E.; Parker, D.; Caldwell, M.; Allan, P. M.; Smith, A.; Bates, M. J.; Coan, B.; Stewart, B. C.; Lepine, D. R.; Cornwall, L. A.; Corney, D. R.; Ricketts, M. J.; Drummond, D.; Smart, D.; Cutler, R.; Dewitte, S.; Clerbaux, N.; Gonzalez, L.; Ipe, A.; Bertrand, C.; Joukoff, A.; Crommelynck, D.; Nelms, N.; Llewellyn-Jones, D. T.; Butcher, G.; Smith, G. L.; Szewczyk, Z. P.; Mlynczak, P. E.; Slingo, A.; Allan, R. P.; Ringer, M. A.

2005-07-01

This paper reports on a new satellite sensor, the Geostationary Earth Radiation Budget (GERB) experiment. GERB is designed to make the first measurements of the Earth's radiation budget from geostationary orbit. Measurements at high absolute accuracy of the reflected sunlight from the Earth, and the thermal radiation emitted by the Earth are made every 15 min, with a spatial resolution at the subsatellite point of 44.6 km (north south) by 39.3 km (east west). With knowledge of the incoming solar constant, this gives the primary forcing and response components of the top-of-atmosphere radiation. The first GERB instrument is an instrument of opportunity on Meteosat-8, a new spin-stabilized spacecraft platform also carrying the Spinning Enhanced Visible and Infrared (SEVIRI) sensor, which is currently positioned over the equator at 3.5°W. This overview of the project includes a description of the instrument design and its preflight and in-flight calibration. An evaluation of the instrument performance after its first year in orbit, including comparisons with data from the Clouds and the Earth's Radiant Energy System (CERES) satellite sensors and with output from numerical models, are also presented. After a brief summary of the data processing system and data products, some of the scientific studies that are being undertaken using these early data are described. This marks the beginning of a decade or more of observations from GERB, as subsequent models will fly on each of the four Meteosat Second Generation satellites.

Spectral slopes of the absorption coefficient of colored dissolved and detrital material inverted from UV-visible remote sensing reflectance.

Science.gov (United States)

Wei, Jianwei; Lee, Zhongping; Ondrusek, Michael; Mannino, Antonio; Tzortziou, Maria; Armstrong, Roy

2016-03-01

The spectral slope of the absorption coefficient of colored dissolved and detrital material (CDM), S cdm (units: nm -1 ), is an important optical parameter for characterizing the absorption spectral shape of CDM. Although highly variable in natural waters, in most remote sensing algorithms, this slope is either kept as a constant or empirically modeled with multiband ocean color in the visible domain. In this study, we explore the potential of semianalytically retrieving S cdm with added ocean color information in the ultraviolet (UV) range between 360 and 400 nm. Unique features of hyperspectral remote sensing reflectance in the UV-visible wavelengths (360-500 nm) have been observed in various waters across a range of coastal and open ocean environments. Our data and analyses indicate that ocean color in the UV domain is particularly sensitive to the variation of the CDM spectral slope. Here, we used a synthesized data set to show that adding UV wavelengths to the ocean color measurements will improve the retrieval of S cdm from remote sensing reflectance considerably, while the spectral band settings of past and current satellite ocean color sensors cannot fully account for the spectral variation of remote sensing reflectance. Results of this effort support the concept to include UV wavelengths in the next generation of satellite ocean color sensors.

Revisiting Short-Wave-Infrared (SWIR) Bands for Atmospheric Correction in Coastal Waters

Science.gov (United States)

Pahlevan, Nima; Roger, Jean-Claude; Ahmad, Ziauddin

2017-01-01

The shortwave infrared (SWIR) bands on the existing Earth Observing missions like MODIS have been designed to meet land and atmospheric science requirements. The future geostationary and polar-orbiting ocean color missions, however, require highly sensitive SWIR bands (greater than 1550nm) to allow for a precise removal of aerosol contributions. This will allow for reasonable retrievals of the remote sensing reflectance (R(sub rs)) using standard NASA atmospheric corrections over turbid coastal waters. Design, fabrication, and maintaining high-performance SWIR bands at very low signal levels bear significant costs on dedicated ocean color missions. This study aims at providing a full analysis of the utility of alternative SWIR bands within the 1600nm atmospheric window if the bands within the 2200nm window were to be excluded due to engineering/cost constraints. Following a series of sensitivity analyses for various spectral band configurations as a function of water vapor amount, we chose spectral bands centered at 1565 and 1675nm as suitable alternative bands within the 1600nm window for a future geostationary imager. The sensitivity of this band combination to different aerosol conditions, calibration uncertainties, and extreme water turbidity were studied and compared with that of all band combinations available on existing polar-orbiting missions. The combination of the alternative channels was shown to be as sensitive to test aerosol models as existing near-infrared (NIR) band combinations (e.g., 748 and 869nm) over clear open ocean waters. It was further demonstrated that while in extremely turbid waters the 1565/1675 band pair yields R(sub rs) retrievals as good as those derived from all other existing SWIR band pairs (greater than 1550nm), their total calibration uncertainties must be less than 1% to meet current science requirements for ocean color retrievals (i.e., delta R(sub rs) (443) less than 5%). We further show that the aerosol removal using the

VIIRS Product Evaluation at the Ocean PEATE

Science.gov (United States)

Patt, Frederick S.; Feldman, Gene C.

2010-01-01

The National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) mission will support the continuation of climate records generated from NASA missions. The NASA Science Data Segment (SDS) relies upon discipline-specific centers of expertise to evaluate the NPP data products for suitability as climate data records, The Ocean Product Evaluation and Analysis Tool Element (PEATE) will build upon Well established NASA capabilities within the Ocean Color program in order to evaluate the NPP Visible and Infrared Imager/Radiometer Suite (VIIRS) Ocean Color and Chlorophyll data products. The specific evaluation methods will support not only the evaluation of product quality but also the sources of differences with existing data records.

A new parameterization for surface ocean light attenuation in Earth System Models: assessing the impact of light absorption by colored detrital material

OpenAIRE

G. E. Kim; M.-A. Pradal; A. Gnanadesikan

2015-01-01

Light limitation can affect the distribution of biota and nutrients in the ocean. Light absorption by colored detrital material (CDM) was included in a fully coupled Earth System Model using a new parameterization for shortwave attenuation. Two model runs were conducted, with and without light attenuation by CDM. In a global average sense, greater light limitation associated with CDM increased surface chlorophyll, biomass and nutrients together. These changes can be attribut...

Phytoplankton phenology indices in coral reef ecosystems: Application to ocean-color observations in the Red Sea

KAUST Repository

Racault, Marie-Fanny

2015-02-18

Phytoplankton, at the base of the marine food web, represent a fundamental food source in coral reef ecosystems. The timing (phenology) and magnitude of the phytoplankton biomass are major determinants of trophic interactions. The Red Sea is one of the warmest and most saline basins in the world, characterized by an arid tropical climate regulated by the monsoon. These extreme conditions are particularly challenging for marine life. Phytoplankton phenological indices provide objective and quantitative metrics to characterize phytoplankton seasonality. The indices i.e. timings of initiation, peak, termination and duration are estimated here using 15 years (1997–2012) of remote sensing ocean-color data from the European Space Agency (ESA) Climate Change Initiative project (OC-CCI) in the entire Red Sea basin. The OC-CCI product, comprising merged and bias-corrected observations from three independent ocean-color sensors (SeaWiFS, MODIS and MERIS), and processed using the POLYMER algorithm (MERIS period), shows a significant increase in chlorophyll data coverage, especially in the southern Red Sea during the months of summer NW monsoon. In open and reef-bound coastal waters, the performance of OC-CCI chlorophyll data is shown to be comparable with the performance of other standard chlorophyll products for the global oceans. These features have permitted us to investigate phytoplankton phenology in the entire Red Sea basin, and during both winter SE monsoon and summer NW monsoon periods. The phenological indices are estimated in the four open water provinces of the basin, and further examined at six coral reef complexes of particular socio-economic importance in the Red Sea, including Siyal Islands, Sharm El Sheikh, Al Wajh bank, Thuwal reefs, Al Lith reefs and Farasan Islands. Most of the open and deeper waters of the basin show an apparent higher chlorophyll concentration and longer duration of phytoplankton growth during the winter period (relative to the summer

GEONEX: Land Monitoring From a New Generation of Geostationary Satellite Sensors

Science.gov (United States)

Nemani, Ramakrishna; Lyapustin, Alexei; Wang, Weile; Wang, Yujie; Hashimoto, Hirofumi; Li, Shuang; Ganguly, Sangram; Michaelis, Andrew; Higuchi, Atsushi; Takaneka, Hideaki;

GEONEX: Land monitoring from a new generation of geostationary satellite sensors

Science.gov (United States)

Nemani, R. R.; Lyapustin, A.; Wang, W.; Ganguly, S.; Wang, Y.; Michaelis, A.; Hashimoto, H.; Li, S.; Higuchi, A.; Huete, A. R.; Yeom, J. M.; camacho De Coca, F.; Lee, T. J.; Takenaka, H.

2017-12-01

The latest generation of geostationary satellites carry sensors such as ABI (Advanced Baseline Imager on GOES-16) and the AHI (Advanced Himawari Imager on Himawari) that closely mimic the spatial and spectral characteristics of Earth Observing System flagship MODIS for monitoring land surface conditions. More importantly they provide observations at 5-15 minute intervals. Such high frequency data offer exciting possibilities for producing robust estimates of land surface conditions by overcoming cloud cover, enabling studies of diurnally varying local-to-regional biosphere-atmosphere interactions, and operational decision-making in agriculture, forestry and disaster management. But the data come with challenges that need special attention. For instance, geostationary data feature changing sun angle at constant view for each pixel, which is reciprocal to sun-synchronous observations, and thus require careful adaptation of EOS algorithms. Our goal is to produce a set of land surface products from geostationary sensors by leveraging NASA's investments in EOS algorithms and in the data/compute facility NEX. The land surface variables of interest include atmospherically corrected surface reflectances, snow cover, vegetation indices and leaf area index (LAI)/fraction of photosynthetically absorbed radiation (FPAR), as well as land surface temperature and fires. In order to get ready to produce operational products over the US from GOES-16 starting 2018, we have utilized 18 months of data from Himawari AHI over Australia to test the production pipeline and the performance of various algorithms for our initial tests. The end-to-end processing pipeline consists of a suite of modules to (a) perform calibration and automatic georeference correction of the AHI L1b data, (b) adopt the Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm to produce surface spectral reflectances along with compositing schemes and QA, and (c) modify relevant EOS retrieval

Small Aperture Telescope Observations of Co-located Geostationary Satellites

Science.gov (United States)

Scott, R.; Wallace, B.

As geostationary orbit (GEO) continues to be populated, satellite operators are increasing usage of co-location techniques to maximize usage of fewer GEO longitude slots. Co-location is an orbital formation strategy where two or more geostationary satellites reside within one GEO stationkeeping box. The separation strategy used to prevent collision between the co-located satellites generally uses eccentricity (radial separation) and inclination (latitude separation) vector offsets. This causes the satellites to move in relative motion ellipses about each other as the relative longitude drift between the satellites is near zero. Typical separations between the satellites varies from 1 to 100 kilometers. When co-located satellites are observed by optical ground based space surveillance sensors the participants appear to be separated by a few minutes of arc or less in angular extent. Under certain viewing geometries, these satellites appear to visually conjunct even though the satellites are, in fact, well separated spatially. In situations where one of the co-located satellites is more optically reflective than the other, the reflected sunglint from the more reflective satellite can overwhelm the other. This less frequently encountered issue causes the less reflective satellite to be glint masked in the glare of the other. This paper focuses on space surveillance observations on co-located Canadian satellites using a small optical telescope operated by Defence R&D Canada - Ottawa. The two above mentioned problems (cross tagging and glint masking) are investigated and we quantify the results for Canadian operated geostationary satellites. The performance of two line element sets when making in-frame CCD image correlation between the co-located satellites is also examined. Relative visual magnitudes between the co-located members are also inspected and quantified to determine the susceptibility of automated telescopes to glint masking of co-located satellite members.

Mapping daily evapotranspiration at field to continental scales using geostationary and polar orbiting satellite imagery

Directory of Open Access Journals (Sweden)

M. C. Anderson

2011-01-01

Full Text Available Thermal infrared (TIR remote sensing of land-surface temperature (LST provides valuable information about the sub-surface moisture status required for estimating evapotranspiration (ET and detecting the onset and severity of drought. While empirical indices measuring anomalies in LST and vegetation amount (e.g., as quantified by the Normalized Difference Vegetation Index; NDVI have demonstrated utility in monitoring ET and drought conditions over large areas, they may provide ambiguous results when other factors (e.g., air temperature, advection are affecting plant functioning. A more physically based interpretation of LST and NDVI and their relationship to sub-surface moisture conditions can be obtained with a surface energy balance model driven by TIR remote sensing. The Atmosphere-Land Exchange Inverse (ALEXI model is a multi-sensor TIR approach to ET mapping, coupling a two-source (soil + canopy land-surface model with an atmospheric boundary layer model in time-differencing mode to routinely and robustly map daily fluxes at continental scales and 5 to 10-km resolution using thermal band imagery and insolation estimates from geostationary satellites. A related algorithm (DisALEXI spatially disaggregates ALEXI fluxes down to finer spatial scales using moderate resolution TIR imagery from polar orbiting satellites. An overview of this modeling approach is presented, along with strategies for fusing information from multiple satellite platforms and wavebands to map daily ET down to resolutions on the order of 10 m. The ALEXI/DisALEXI model has potential for global applications by integrating data from multiple geostationary meteorological satellite systems, such as the US Geostationary Operational Environmental Satellites, the European Meteosat satellites, the Chinese Fen-yung 2B series, and the Japanese Geostationary Meteorological Satellites. Work is underway to further evaluate multi-scale ALEXI implementations over the US, Europe, Africa

Detection of Coccolithophore Blooms in Ocean Color Satellite Imagery: a Generalized Approach for Use with Multiple Sensors

Science.gov (United States)

Moore, Timothy; Dowell, Mark; Franz, Bryan A.

2012-01-01

A generalized coccolithophore bloom classifier has been developed for use with ocean color imagery. The bloom classifier was developed using extracted satellite reflectance data from SeaWiFS images screened by the default bloom detection mask. In the current application, we extend the optical water type (OWT) classification scheme by adding a new coccolithophore bloom class formed from these extracted reflectances. Based on an in situ coccolithophore data set from the North Atlantic, the detection levels with the new scheme were between 1,500 and 1,800 coccolithophore cellsmL and 43,000 and 78,000 lithsmL. The detected bloom area using the OWT method was an average of 1.75 times greater than the default bloom detector based on a collection of SeaWiFS 1 km imagery. The versatility of the scheme is shown with SeaWiFS, MODIS Aqua, CZCS and MERIS imagery at the 1 km scale. The OWT scheme was applied to the daily global SeaWiFS imagery mission data set (years 19972010). Based on our results, average annual coccolithophore bloom area was more than two times greater in the southern hemisphere compared to the northern hemi- sphere with values of 2.00 106 km2 and 0.75 106 km2, respectively. The new algorithm detects larger bloom areas in the Southern Ocean compared to the default algorithm, and our revised global annual average of 2.75106 km2 is dominated by contributions from the Southern Ocean.

Prospects for Geostationary Doppler Weather Radar

Science.gov (United States)

Tanelli, Simone; Fang, Houfei; Durden, Stephen L.; Im, Eastwood; Rhamat-Samii, Yahya

2009-01-01

A novel mission concept, namely NEXRAD in Space (NIS), was developed for detailed monitoring of hurricanes, cyclones, and severe storms from a geostationary orbit. This mission concept requires a space deployable 35-m diameter reflector that operates at 35-GHz with a surface figure accuracy requirement of 0.21 mm RMS. This reflector is well beyond the current state-of-the-art. To implement this mission concept, several potential technologies associated with large, lightweight, spaceborne reflectors have been investigated by this study. These spaceborne reflector technologies include mesh reflector technology, inflatable membrane reflector technology and Shape Memory Polymer reflector technology.

Investigating Rhône River plume (Gulf of Lions, France) dynamics using metrics analysis from the MERIS 300m Ocean Color archive (2002-2012)

Science.gov (United States)

Gangloff, Aurélien; Verney, Romaric; Doxaran, David; Ody, Anouck; Estournel, Claude

2017-07-01

In coastal environments, river plumes are major transport mechanisms for particulate matter, nutriments and pollutants. Ocean color satellite imagery is a valuable tool to explore river turbid plume characteristics, providing observations at high temporal and spatial resolutions of suspended particulate matter (SPM) concentration over a long time period, covering a wide range of hydro-meteorological conditions. We propose here to use the MERIS-FR (300m) Ocean Color archive (2002-2012) in order to investigate Rhône River turbid plume patterns generated by the two main forcings acting on the north-eastern part of the Gulf of Lions (France): wind and river freshwater discharge. Results are exposed considering plume metrics (area of extension, south-east-westernmost points, shape, centroid, SPM concentrations) extracted from satellite data using an automated image-processing tool. Rhône River turbid plume SPM concentrations and area of extension are shown to be mainly driven by the river outflow while wind direction acts on its shape and orientation. This paper also presents the region of influence of the Rhône River turbid plume over monthly and annual periods, and highlights its interannual variability.

INVESTIGATION THE BEHAVIOR OF MODIS OCEAN COLOR PRODUCTS UNDER THE 2008 RED TIDE IN THE EASTERN PERSIAN GULF

Directory of Open Access Journals (Sweden)

M. Ghanea

2015-12-01

Full Text Available Biophysical properties of water undergo serious variations under red tide (RT outbreak. During RT conditions, algal blooms spread out in the estuarine, marine and fresh waters due to different triggering factors such as nutrient loading, marine currents, and monsoonal winds. The Persian Gulf (PG was a talent region subjected to different RTs in recent decade. A massive RT started from the Strait of Hormuz in October 2008 and extended towards the northern parts of the PG covering more than 1200 km of coastlines. The bloom of microorganism C. Polykrikoides was the main specie that generated large fish mortalities, and hampered marine industries, and water desalination appliances. Ocean color satellite data have many advantages to monitor and alarm RT occurrences, such as wide and continuous extent, short time of imagery, high accessibility, and appropriate estimation of ocean color parameters. Since 1999, MODerate Resolution Imaging Spectroradiometer (MODIS satellite sensor has estimated satellite derived chlorophyll-a (Chl-a, normalized fluorescence line height (nFLH, and diffuse attenuation coefficient at 490nm (kd490. It provides a capability to study the behavior of these parameters during RT and normal conditions. This study monitors variations in satellite derived Chl-a, nFLH, and kd490 under both RT and normal conditions of the PG between 2002 and 2008. Up to now, daily and monthly variations in these products were no synchronously investigated under RT conditions in the PG. In doing so, the MODIS L1B products were provided from NASA data archive. They were corrected for Rayleigh scattering and gaseous absorption, and atmospheric interference in turbid coastal waters, and then converted to level 2 data. In addition, Enhanced Red Green Blue (ERGB image was used to illustrate better water variations. ERGB image was built with three normalized leaving water radiance between 443 to 560nm. All the above data processes were applied by SeaDAS 7

Advancing Atmosphere-Ocean Remote Sensing with Spaceborne High Spectral Resolution Lidar

Science.gov (United States)

Hostetler, C. A.; Behrenfeld, M. J.; Chepfer, H.; Hu, Y.; Hair, J. W.; Trepte, C. R.; Winker, D. M.; Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Powell, K. A.; Michaud, J.

2016-12-01

More than 1600 publications employing observations from the CALIOP lidar on CALIPSO testify to the value of spaceborne lidar for aerosol and cloud remote sensing. Recent publications have shown the value of CALIOP data for retrievals of key ocean carbon cycle stocks. In this presentation we focus on the advantages of a more advanced technique, High Spectral Resolution Lidar (HSRL), for aerosol, cloud, and ocean remote sensing. An atmosphere-ocean optimized HSRL achieves greater accuracy over the standard backscatter lidar technique for retrievals of aerosol and cloud extinction and backscatter profiles, provides additional capability to retrieve aerosol and cloud microphysical parameters, and enables vertically-resolved characterization of scattering and absorption properties of suspended and dissolved materials in the ocean. Numerous publications highlight the synergy of coincident CALIOP and passive A-train observations for studies of aerosol-cloud radiative effects and cloud-climate feedback. Less appreciated is the complementarity that would exist between an optimized spaceborne lidar and passive ocean color. An optimized HSRL flown in formation with the Plankton, Aerosol, and ocean Ecosystem (PACE) mission would provide phytoplankton vertical distribution, which is needed for accurately estimating net primary productivity but absent in the PACE ocean color data. The HSRL would also provide data needed to improve atmospheric correction schemes in ocean color retrievals. Because lidar provides measurements both night and day, through tenuous clouds and aerosol layers, and in holes between clouds, the sampling achieved is highly complementary to passive radiometry, providing data in important high latitude regions where ocean color data are sparse or nonexistent. In this presentation we will discuss 1) relevant aerosol, cloud, and ocean retrievals from airborne HSRL field missions; 2) the advantages of an optimized spaceborne HSRL for aerosol, cloud, and ocean

Empirical ocean color algorithms and bio-optical properties of the western coastal waters of Svalbard, Arctic

Science.gov (United States)

Son, Young-Sun; Kim, Hyun-cheol

2018-05-01

Chlorophyll (Chl) concentration is one of the key indicators identifying changes in the Arctic marine ecosystem. However, current Chl algorithms are not accurate in the Arctic Ocean due to different bio-optical properties from those in the lower latitude oceans. In this study, we evaluated the current Chl algorithms and analyzed the cause of the error in the western coastal waters of Svalbard, which are known to be sensitive to climate change. The NASA standard algorithms showed to overestimate the Chl concentration in the region. This was due to the high non-algal particles (NAP) absorption and colored dissolved organic matter (CDOM) variability at the blue wavelength. In addition, at lower Chl concentrations (0.1-0.3 mg m-3), chlorophyll-specific absorption coefficients were ∼2.3 times higher than those of other Arctic oceans. This was another reason for the overestimation of Chl concentration. OC4 algorithm-based regionally tuned-Svalbard Chl (SC4) algorithm for retrieving more accurate Chl estimates reduced the mean absolute percentage difference (APD) error from 215% to 49%, the mean relative percentage difference (RPD) error from 212% to 16%, and the normalized root mean square (RMS) error from 211% to 68%. This region has abundant suspended matter due to the melting of tidal glaciers. We evaluated the performance of total suspended matter (TSM) algorithms. Previous published TSM algorithms generally overestimated the TSM concentration in this region. The Svalbard TSM-single band algorithm for low TSM range (ST-SB-L) decreased the APD and RPD errors by 52% and 14%, respectively, but the RMS error still remained high (105%).

Specialized Finite Set Statistics (FISST)-Based Estimation Methods to Enhance Space Situational Awareness in Medium Earth Orbit (MEO) and Geostationary Earth Orbit (GEO)

Science.gov (United States)

2016-08-17

Specialized Finite Set Statistics (FISST)-based Estimation Methods to Enhance Space Situational Awareness in Medium Earth Orbit (MEO) and Geostationary...terms of specialized Geostationary Earth Orbit (GEO) elements to estimate the state of resident space objects in the geostationary regime. Justification...AFRL-RV-PS- AFRL-RV-PS- TR-2016-0114 TR-2016-0114 SPECIALIZED FINITE SET STATISTICS (FISST)- BASED ESTIMATION METHODS TO ENHANCE SPACE SITUATIONAL

Southern Ocean Predicted Seafloor Topography Poster - MGG9

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This 36 by 48 inch full color poster is MGG Report 9. In many areas of the global ocean, the depth of the seafloor is not well known because survey lines by ships...

Simultaneous polarimeter retrievals of microphysical aerosol and ocean color parameters from the "MAPP" algorithm with comparison to high-spectral-resolution lidar aerosol and ocean products.

Science.gov (United States)

Stamnes, S; Hostetler, C; Ferrare, R; Burton, S; Liu, X; Hair, J; Hu, Y; Wasilewski, A; Martin, W; van Diedenhoven, B; Chowdhary, J; Cetinić, I; Berg, L K; Stamnes, K; Cairns, B

2018-04-01

We present an optimal-estimation-based retrieval framework, the microphysical aerosol properties from polarimetry (MAPP) algorithm, designed for simultaneous retrieval of aerosol microphysical properties and ocean color bio-optical parameters using multi-angular total and polarized radiances. Polarimetric measurements from the airborne NASA Research Scanning Polarimeter (RSP) were inverted by MAPP to produce atmosphere and ocean products. The RSP MAPP results are compared with co-incident lidar measurements made by the NASA High-Spectral-Resolution Lidar HSRL-1 and HSRL-2 instruments. Comparisons are made of the aerosol optical depth (AOD) at 355 and 532 nm, lidar column-averaged measurements of the aerosol lidar ratio and Ångstrøm exponent, and lidar ocean measurements of the particulate hemispherical backscatter coefficient and the diffuse attenuation coefficient. The measurements were collected during the 2012 Two-Column Aerosol Project (TCAP) campaign and the 2014 Ship-Aircraft Bio-Optical Research (SABOR) campaign. For the SABOR campaign, 73% RSP MAPP retrievals fall within ±0.04 AOD at 532 nm as measured by HSRL-1, with an R value of 0.933 and root-mean-square deviation of 0.0372. For the TCAP campaign, 53% of RSP MAPP retrievals are within 0.04 AOD as measured by HSRL-2, with an R value of 0.927 and root-mean-square deviation of 0.0673. Comparisons with HSRL-2 AOD at 355 nm during TCAP result in an R value of 0.959 and a root-mean-square deviation of 0.0694. The RSP retrievals using the MAPP optimal estimation framework represent a key milestone on the path to a combined lidar + polarimeter retrieval using both HSRL and RSP measurements.

Geostationary satellite observations of the april 1979 soufriere eruptions.

Science.gov (United States)

Krueger, A F

1982-06-04

Infrared images from the geostationary satellite SMS-1 were used to study the growth of the eight major eruptions of Soufriere, St. Vincent, during April 1979. These eruptions differed considerably in growth and intensity, the most intense being that of 17 April which formed an ash cloud of 96,000 square kilometers in 4 hours. The weakest eruption formed a cloud of only 16,000 square kilometers.

Theory of geostationary satellites

CERN Document Server

Zee, Chong-Hung

1989-01-01

Geostationary or equatorial synchronous satellites are a daily reminder of our space efforts during the past two decades. The nightly television satellite weather picture, the intercontinental telecommunications of television transmissions and telephone conversations, and the establishrnent of educational programs in remote regions on Earth are constant reminders of the presence of these satellites. As used here, the term 'geo­ stationary' must be taken loosely because, in the long run, the satellites will not remain 'stationary' with respect to an Earth-fixed reference frame. This results from the fact that these satellites, as is true for all satellites, are incessantly subject to perturbations other than the central-body attraction of the Earth. Among the more predominant pertur­ bations are: the ellipticity of the Earth's equator, the Sun and Moon, and solar radiation pressure. Higher harmonics of the Earth's potential and tidal effects also influence satellite motion, but they are of second­ order whe...

Monitoring of Siberian biomass burning smoke from AHI on board geostationary satellite Himawari-8

Science.gov (United States)

Sano, I.; Mukai, S.; Yoshida, A.; Nakata, M.; Minoura, H.; Holben, B. N.

2016-12-01

High frequency aerosol measurements are demanded for evaluation of the model simulations, monitoring the atmospheric qualities such as Particulate Matter (PM2.5), and so on. Geostationary satellite provides us with the high frequency information of the atmosphere. Japanese Meteorological Agency (JMA) launched the Himawari-8 geostationary satellite in 2014 and has prepared Himawari-9 for launching in 2016. Both satellites carry new generation imagers named Advanced Himawari Imager (AHI). They have 16 multi-channels from short visible to thermal infrared wavelengths with 1 km IFOV for visible and 2 km for infrared. Each observation is done within 10 minutes for the Earth full disk. Then high frequency Earth observations are realized. AHI has frequently observed biomass burning plume around East Siberia and its transportation according to weather system. This work retrieves aerosol properties due to the Siberian smoke plume and its movements based on the measurements with AHI. The results are compared with ground based measurements which have newly deployed at an AERONET/Niigata site in Japan. It is shown here that continuous measurements of aerosols from geostationary satellite combination with the polar orbiting satellite provide us with much detail information of aerosol.

Laser experiments in light cloudiness with the geostationary satellite ARTEMIS

Science.gov (United States)

Kuzkov, V.; Kuzkov, S.; Sodnik, Z.

2016-08-01

The geostationary satellite ARTEMIS was launched in July 2001. The satellite is equipped with a laser communication terminal, which was used for the world's first inter-satellite laser communication link between ARTEMIS and the low earth orbit satellite SPOT-4. Ground-to-space laser communication experiments were also conducted under various atmospheric conditions involving ESA's optical ground station. With a rapidly increasing volume of information transferred by geostationary satellites, there is a rising demand for high-speed data links between ground stations and satellites. For ground-to-space laser communications there are a number of important design parameters that need to be addressed, among them, the influence of atmospheric turbulence in different atmospheric conditions and link geometries. The Main Astronomical Observatory of NAS of Ukraine developed a precise computer tracking system for its 0.7 m AZT-2 telescope and a compact laser communication package LACES (Laser Atmosphere and Communication experiments with Satellites) for laser communication experiments with geostationary satellites. The specially developed software allows computerized tracking of the satellites using their orbital data. A number of laser experiments between MAO and ARTEMIS were conducted in partial cloudiness with some amount of laser light observed through clouds. Such conditions caused high break-up (splitting) of images from the laser beacon of ARTEMIS. One possible explanation is Raman scattering of photons on molecules of a water vapor in the atmosphere. Raman scattering causes a shift in a wavelength of the photons.In addition, a different value for the refraction index appears in the direction of the meridian for the wavelength-shifted photons. This is similar to the anomalous atmospheric refraction that appears at low angular altitudes above the horizon. We have also estimated the atmospheric attenuation and the influence of atmospheric turbulence on observed results

A Numerical Testbed for Remote Sensing of Aerosols, and its Demonstration for Evaluating Retrieval Synergy from a Geostationary Satellite Constellation of GEO-CAPE and GOES-R

Science.gov (United States)

Wang, Jun; Xu, Xiaoguang; Ding, Shouguo; Zeng, Jing; Spurr, Robert; Liu, Xiong; Chance, Kelly; Mishchenko, Michael I.

2014-01-01

We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a geostationary satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASA's Decadal Survey Mission GEOCAPE (GEOstationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O2 A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the

The solar wind control of electron fluxes in geostationary orbit during magnetic storms

International Nuclear Information System (INIS)

Popov, G.V.; Degtyarev, V.I.; Sheshukov, S.S.; Chudnenko, S.E.

1999-01-01

The dynamics of electron fluxes (with energies from 30 to 1360 keV) in geostationary orbit during magnetic storms was investigated on the basis of LANL spacecraft 1976-059 and 1977-007 data. Thirty-seven magnetic storms with distinct onsets from the time interval July 1976-December 1978 were used in the analysis. A treatment of experimental data involved the moving averaging and the overlapping epoch method. The smoothed component of electron fluxes represents mainly trapped electrons and shows their strong dependence on the solar wind velocity. The time lag between a smoothed electron flux and the solar wind velocity increases with electron energy reflecting dynamics of the inner magnetosphere filling with trapped energetic electrons originating from substorm injection regions located not far outside geostationary orbit

Geostationary Coastal and Air Pollution Events (GEO-CAPE) Sensitivity Analysis Experiment

Science.gov (United States)

Lee, Meemong; Bowman, Kevin

2014-01-01

Geostationary Coastal and Air pollution Events (GEO-CAPE) is a NASA decadal survey mission to be designed to provide surface reflectance at high spectral, spatial, and temporal resolutions from a geostationary orbit necessary for studying regional-scale air quality issues and their impact on global atmospheric composition processes. GEO-CAPE's Atmospheric Science Questions explore the influence of both gases and particles on air quality, atmospheric composition, and climate. The objective of the GEO-CAPE Observing System Simulation Experiment (OSSE) is to analyze the sensitivity of ozone to the global and regional NOx emissions and improve the science impact of GEO-CAPE with respect to the global air quality. The GEO-CAPE OSSE team at Jet propulsion Laboratory has developed a comprehensive OSSE framework that can perform adjoint-sensitivity analysis for a wide range of observation scenarios and measurement qualities. This report discusses the OSSE framework and presents the sensitivity analysis results obtained from the GEO-CAPE OSSE framework for seven observation scenarios and three instrument systems.

A Geostationary Earth Orbit Satellite Model Using Easy Java Simulation

Science.gov (United States)

Wee, Loo Kang; Goh, Giam Hwee

2013-01-01

We develop an Easy Java Simulation (EJS) model for students to visualize geostationary orbits near Earth, modelled using a Java 3D implementation of the EJS 3D library. The simplified physics model is described and simulated using a simple constant angular velocity equation. We discuss four computer model design ideas: (1) a simple and realistic…

Plasma propulsion for geostationary satellites for telecommunication and interplanetary missions

International Nuclear Information System (INIS)

Dudeck, M; Doveil, F; Arcis, N; Zurbach, S

2012-01-01

The advantages of electric propulsion for the orbit maintenance of geostationary satellites for telecommunications are described. Different types of plasma sources for space propulsion are presented. Due to its large performances, one of them, named Hall effect thruster is described in detail and two recent missions in space (Stentor and Smart1) using French Hall thrusters are briefly presented.

Global-scale Observations of the Limb and Disk (GOLD) Mission: Science from Geostationary Orbit on-board a Commercial Communications Satellite

Science.gov (United States)

Eastes, R.; Deaver, T.; Krywonos, A.; Lankton, M. R.; McClintock, W. E.; Pang, R.

2011-12-01

Geostationary orbits are ideal for many science investigations of the Earth system on global scales. These orbits allow continuous observations of the same geographic region, enabling spatial and temporal changes to be distinguished and eliminating the ambiguity inherent to observations from low Earth orbit (LEO). Just as observations from geostationary orbit have revolutionized our understanding of changes in the troposphere, they will dramatically improve our understanding of the space environment at higher altitudes. However, geostationary orbits are infrequently used for science missions because of high costs. Geostationary satellites are large, typically weighing tons. Consequently, devoting an entire satellite to a science mission requires a large financial commitment, both for the spacecraft itself and for sufficient science instrumentation to justify a dedicated spacecraft. Furthermore, the small number of geostationary satellites produced for scientific missions increases the costs of each satellite. For these reasons, it is attractive to consider flying scientific instruments on satellites operated by commercial companies, some of whom have fleets of ~40 satellites. However, scientists' lack of understanding of the capabilities of commercial spacecraft as well as commercial companies' concerns about risks to their primary mission have impeded the cooperation necessary for the shared use of a spacecraft. Working with a commercial partner, the GOLD mission has successfully overcome these issues. Our experience indicates that there are numerous benefits to flying on commercial communications satellites (e.g., it is possible to downlink large amounts of data) and the costs are low if the experimental requirements adequately match the capabilities and available resources of the host spacecraft. Consequently, affordable access to geostationary orbit aboard a communications satellite now appears possible for science payloads.

GOCI Yonsei Aerosol Retrieval (YAER) Algorithm and Validation During the DRAGON-NE Asia 2012 Campaign

Science.gov (United States)

Choi, Myungje; Kim, Jhoon; Lee, Jaehwa; Kim, Mijin; Park, Young-Je; Jeong, Ukkyo; Kim, Woogyung; Hong, Hyunkee; Holben, Brent; Eck, Thomas F.;

GOCI Yonsei Aerosol Retrieval (YAER) algorithm and validation during the DRAGON-NE Asia 2012 campaign

Science.gov (United States)

Choi, Myungje; Kim, Jhoon; Lee, Jaehwa; Kim, Mijin; Park, Young-Je; Jeong, Ukkyo; Kim, Woogyung; Hong, Hyunkee; Holben, Brent; Eck, Thomas F.; Song, Chul H.; Lim, Jae-Hyun; Song, Chang-Keun

2016-04-01

The Geostationary Ocean Color Imager (GOCI) onboard the Communication, Ocean, and Meteorological Satellite (COMS) is the first multi-channel ocean color imager in geostationary orbit. Hourly GOCI top-of-atmosphere radiance has been available for the retrieval of aerosol optical properties over East Asia since March 2011. This study presents improvements made to the GOCI Yonsei Aerosol Retrieval (YAER) algorithm together with validation results during the Distributed Regional Aerosol Gridded Observation Networks - Northeast Asia 2012 campaign (DRAGON-NE Asia 2012 campaign). The evaluation during the spring season over East Asia is important because of high aerosol concentrations and diverse types of Asian dust and haze. Optical properties of aerosol are retrieved from the GOCI YAER algorithm including aerosol optical depth (AOD) at 550 nm, fine-mode fraction (FMF) at 550 nm, single-scattering albedo (SSA) at 440 nm, Ångström exponent (AE) between 440 and 860 nm, and aerosol type. The aerosol models are created based on a global analysis of the Aerosol Robotic Networks (AERONET) inversion data, and covers a broad range of size distribution and absorptivity, including nonspherical dust properties. The Cox-Munk ocean bidirectional reflectance distribution function (BRDF) model is used over ocean, and an improved minimum reflectance technique is used over land. Because turbid water is persistent over the Yellow Sea, the land algorithm is used for such cases. The aerosol products are evaluated against AERONET observations and MODIS Collection 6 aerosol products retrieved from Dark Target (DT) and Deep Blue (DB) algorithms during the DRAGON-NE Asia 2012 campaign conducted from March to May 2012. Comparison of AOD from GOCI and AERONET resulted in a Pearson correlation coefficient of 0.881 and a linear regression equation with GOCI AOD = 1.083 × AERONET AOD - 0.042. The correlation between GOCI and MODIS AODs is higher over ocean than land. GOCI AOD shows better

Airborne Ocean Color Imager Experiment Data 1988 - 1991

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Oceanographic and fisheries data were collected during 1988 through 1991 through a multiagency research project to develop a remote sensing system to provide near...

Gravity Field Over the S.Ocean - Poster, MGG-6

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This is a full color 24 by 36 inch poster. In many areas of the global ocean, the depth of the seafloor is not well known because survey lines by ships are hundreds...

The study of the ocean from space

Energy Technology Data Exchange (ETDEWEB)

Novogrudskii, B V; Skliarov, V E; Fedorov, K N; Shifrin, K S

1978-01-01

The application of earth satellites and manned spacecraft to the study of the world's oceans is reviewed. Attention is given to the atmospheric transfer function in the visible, near-IR, middle-IR and microwave regions and the use of satellites in ocean data acquisition and transmission systems. The measurement of sea level and the topography of the ocean surface by means of orbital radar altimeters is discussed, together with IR and microwave measurements of ocean surface temperature and the study of surface roughness, surface evidence of internal waves, oil pollution and ice fields. Consideration is also given to the determination of ocean chlorophyll content and color distribution, coastal region characteristics, ocean salinity and other biological parameters from space.

Geostationary platform systems concepts definition study. Volume 2A: Appendixes, book 2

Science.gov (United States)

1980-01-01

Various investigations and support data concerning geostationary platform feasibility are presented. Servicing flight analyses, platform cost model runs, and funding spread analyses are included. In addition, investigations of the radiation environment at synchronous altitude and its effects on satellite communication are reported.

New Approach to Monitor Transboundary Particulate Pollution over Northeast Asia

Science.gov (United States)

Park, M. E.; Song, C. H.; Park, R. S.; Lee, Jaehwa; Kim, J.; Lee, S.; Woo, J. H.; Carmichael, G. R.; Eck, Thomas F.; Holben, Brent N.;

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

Science.gov (United States)

Davis, Curtiss O.; Kappus, Mary E.; Bowles, Jeffrey H.; Evans, Cynthia A.; Stefanov, William L.

2014-01-01

The Hyperspectral Imager for the Coastal Ocean (HICO) was built to measure in-water properties of complex coastal regions. HICO enables synoptic coverage; 100-meter 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.

The Hyperspectral Imager for the Coastal Ocean (HICO): Sensor and Data Processing Overview

Science.gov (United States)

2010-01-20

backscattering coefficients, and others. Several of these software modules will be developed within the Automated Processing System (APS), a data... Automated Processing System (APS) NRL developed APS, which processes satellite data into ocean color data products. APS is a collection of methods...used for ocean color processing which provide the tools for the automated processing of satellite imagery [1]. These tools are in the process of

Ocean Bottom Pressure Seasonal Cycles and Decadal Trends from GRACE Release-05: Ocean Circulation Implications

Science.gov (United States)

Johnson, G. C.; Chambers, D. P.

2013-12-01

Ocean mass variations are important for diagnosing sea level budgets, the hydrological cycle and global energy budget, as well as ocean circulation variability. Here seasonal cycles and decadal trends of ocean mass from January 2003 to December 2012, both global and regional, are analyzed using GRACE Release 05 data. The trend of global flux of mass into the ocean approaches 2 cm decade-1 in equivalent sea level rise. Regional trends are of similar magnitude, with the North Pacific, South Atlantic, and South Indian oceans generally gaining mass and other regions losing mass. These trends suggest a spin-down of the North Pacific western boundary current extension and the Antarctic Circumpolar Current in the South Atlantic and South Indian oceans. The global average seasonal cycle of ocean mass is about 1 cm in amplitude, with a maximum in early October and volume fluxes in and out of the ocean reaching 0.5 Sv (1 Sv = 1 × 106 m3 s-1) when integrated over the area analyzed here. Regional patterns of seasonal ocean mass change have typical amplitudes of 1-4 cm, and include maxima in the subtropics and minima in the subpolar regions in hemispheric winters. The subtropical mass gains and subpolar mass losses in the winter spin up both subtropical and subpolar gyres, hence the western boundary current extensions. Seasonal variations in these currents are order 10 Sv, but since the associated depth-averaged current variations are only order 0.1 cm s-1, they would be difficult to detect using in situ oceanographic instruments. a) Amplitude (colors, in cm) and b) phase (colors, in months of the year) of an annual harmonic fit to monthly GRACE Release 05 CSR 500 km smoothed maps (concurrently with a trend and the semiannual harmonic). The 97.5% confidence interval for difference from zero is also indicated (solid black line). Data within 300 km of coastlines are not considered.

The geostationary Earth radiation budget (GERB) instrument on EUMETSAT's MSG satellite

Science.gov (United States)

Sandford, M. C. W.; Allan, P. M.; Caldwell, M. E.; Delderfield, J.; Oliver, M. B.; Sawyer, E.; Harries, J. E.; Ashmall, J.; Brindley, H.; Kellock, S.; Mossavati, R.; Wrigley, R.; Llewellyn-Jones, D.; Blake, O.; Butcher, G.; Cole, R.; Nelms, N.; DeWitte, S.; Gloesener, P.; Fabbrizzi, F.

2003-12-01

Geostationary Earth radiation budget (GERB) is an Announcement of Opportunity Instrument for EUMETSAT's Meteosat Second Generation (MSG) satellite. GERB will make accurate measurements of the Earth Radiation Budget from geostationary orbit, provide an absolute reference calibration for LEO Earth radiation budget instruments and allow studies of the energetics of atmospheric processes. By operating from geostationary orbit, measurements may be made many times a day, thereby providing essentially perfect diurnal sampling of the radiation balance between reflected and emitted radiance for that area of the globe within the field of view. GERB will thus complement other instruments which operate in low orbit and give complete global coverage, but with poor and biased time resolution. GERB measures infrared radiation in two wavelength bands: 0.32-4.0 and 0.32- 30 μm, with a pixel element size of 44 km at sub-satellite point. This paper gives an overview of the project and concentrates on the design and development of the instrument and ground testing and calibration, and lessons learnt from a short time scale low-budget project. The instrument was delivered for integration on the MSG platform in April 1999 ready for the proposed launch in October 2000, which has now been delayed probably to early 2002. The ground segment is being undertaken by RAL and RMIB and produces near real-time data for meteorological applications in conjunction with the main MSG imager—SEVERI. Climate research and other applications which are being developed under a EU Framework IV pilot project will be served by fully processed data. Because of the relevance of the observations to climate change, it is planned to maintain an operating instrument in orbit for at least 3.5 years. Two further GERB instruments are being built for subsequent launches of MSG.

Ionic ring current during magnetic disturbances according to observations at a geostationary orbit

International Nuclear Information System (INIS)

Vlasova, N.A.; Kovtyuk, A.S.; Panasyuk, M.I.

1987-01-01

Experimental data on the measurements of H + and group (C, N, O) ion fluxes with different charges obtained using the ''Gorizont'' geostationary satellite (1985 - 07A) during three moderate magnetic disturbances with the amplitudes of D st -variations of several tens nT, have been analyzed. It is shown that during magnetic storms with clearly pronounced main phases a powerful injection of H + and (N, O) 2+ ion fluxes in the absence of noticeable increases in multicharge (C, N, O) ion fluxes with the energies of tens keV/e takes place. The resuts testify in favour of ionospheric plasma as the main source of ring current particles in the energy range. Indications that the filling of geostationary orbit with solar origin ions takes place at the recovery phase of a storm in nighttime hours are obtained

SeaHawk: an advanced CubeSat mission for sustained ocean colour monitoring

Science.gov (United States)

Morrison, John M.; Jeffrey, Hazel; Gorter, Hessel; Anderson, Pamela; Clark, Craig; Holmes, Alan; Feldman, Gene C.; Patt, Frederick S.

2016-10-01

Sustained ocean color monitoring is vital to understanding the marine ecosystem. It has been identified as an Essential Climate Variable (ECV) and is a vital parameter in understanding long-term climate change. Furthermore, observations can be beneficial in observing oil spills, harmful algal blooms and the health of fisheries. Space-based remote sensing, through MERIS, SeaWiFS and MODIS instruments, have provided a means of observing the vast area covered by the ocean which would otherwise be impossible using ships alone. However, the large pixel size makes measurements of lakes, rivers, estuaries and coastal zones difficult. Furthermore, retirement of a number of widely used and relied upon ocean observation instruments, particularly MERIS and SeaWiFS, leaves a significant gap in ocean color observation opportunities This paper presents an overview of the SeaHawk mission, a collaborative effort between Clyde Space Ltd., the University of North Carolina Wilmington, Cloudland Instruments, and Goddard Spaceflight Center, funded by the Gordon and Betty Moore Foundation. The goal of the project is to enhance the ability to observe ocean color in high temporal and spatial resolution through use of a low-cost, next-generation ocean color sensor flown aboard a CubeSat. The final product will be 530 times smaller (0.0034 vs 1.81m3) and 115 time less massive (3.4 vs 390.0kg) but with a ground resolution 10 times better whilst maintaining a signal/noise ratio 50% that of SeaWiFs. This paper will describe the objectives of the mission, outline the payload specification and the spacecraft platform to support it.

Proposed satellite position determination systems and techniques for Geostationary Synthetic Aperture Radar

OpenAIRE

Martin Fuster, Roger; Fernández Usón, Marc; Casado Blanco, David; Broquetas Ibars, Antoni

2016-01-01

This paper proposes two different calibration techniques for Geostationary Synthetic Aperture Radar (GEOSAR) missions requiring a high precision positioning, based on Active Radar Calibrators and Ground Based Interferometry. The research is enclosed in the preparation studies of a future GEOSAR mission providing continuous monitoring at continental scale. Peer Reviewed

Dynamics of the transition zone in coastal zone color scanner-sensed ocean color in the North Pacific during oceanographic spring

Science.gov (United States)

Glover, David M.; Wroblewski, J. S.; Mcclain, Charles R.

1994-01-01

A transition zone in phytoplankton concentration running across the North Pacific basin at 30 deg to 40 deg north latitude corresponds to a basin-wide front in surface chlorophyll observed in a composite of coastal zone color scanner (CZCS) images for May, June, and July 1979-1986. This transition zone with low chlorophyll to the south and higher chlorophyll to the north can be simulated by a simple model of the concentration of phytoplankton, zooplankton, and dissolved nutrient (nitrate) in the surface mixed layer of the ocean applied to the North Pacific basin for the climatological conditions during oceanographic springtime (May, June, and July). The model is initialized with a 1 deg x 1 deg gridded estimate of wintertime (February, March, and April) mixed layer nitrate concentrations calculated from an extensive nutrient database and a similarly gridded mixed layer depth data set. Comparison of model predictions with CZCS data provides a means of evaluating the dynamics of the transition zone. We conclude that in the North Pacific, away from major boundary currents and coastal upwelling zones, wintertime vertical mixing determines the total nutrient available to the plankton ecosystem in the spring. The transition zone seen in basin-scale CZCS images is a reflection of the geographic variation in the wintertime mixed layer depth and the nitracline, leading to a latitudinal gradient in phytoplankton chlorophyll.

Development of the European Small Geostationary Satellite SGEO

Science.gov (United States)

Lübberstedt, H.; Schneider, A.; Schuff, H.; Miesner, Th.; Winkler, A.

2008-08-01

The SGEO product portfolio, ranging from Satellite platform delivery up to in-orbit delivery of a turnkey system including satellite and ground control station, is designed for applications ranging from TV Broadcast to multimedia applications, Internet access, mobile or fixed services in a wide range of frequency bands. Furthermore, Data Relay missions such as the European Data Relay Satellite (EDRS) as well as other institutional missions are targeted. Key design features of the SGEO platform are high flexibility and modularity in order to accommodate a very wide range of future missions, a short development time below two years and the objective to build the system based on ITAR free subsystems and components. The system will provide a long lifetime of up to 15 years in orbit operations with high reliability. SGEO is the first European satellite to perform all orbit control tasks solely by electrical propulsion (EP). This design provides high mass efficiency and the capability for direct injection into geostationary orbit without chemical propulsion (CP). Optionally, an Apogee Engine Module based on CP will provide the perigee raising manoeuvres in case of a launch into geostationary transfer orbit (GTO). This approach allows an ideal choice out of a wide range of launcher candidates in dependence of the required payload capacity. SGEO will offer to the market a versatile and high performance satellite system with low investment risk for the customer and a short development time. This paper provides an overview of the SGEO system key features and the current status of the SGEO programme.

Airborne mapping of Seoul's atmosphere: Trace gas measurements from GeoTASO during KORUS-AQ

Science.gov (United States)

Nowlan, C. R.; Al-Saadi, J. A.; Castellanos, P.; Chance, K.; Gonzalez Abad, G.; Janz, S. J.; Judd, L.; Kowalewski, M. G.; Liu, X.

2017-12-01

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) instrument is a pushbroom airborne remote sensing instrument capable of making measurements of air quality and ocean color using backscattered UV and visible light. GeoTASO is an airborne test-bed for the upcoming Tropospheric Emissions: Monitoring of Pollution (TEMPO) and Geostationary Environment Monitoring Spectrometer (GEMS) geostationary satellite missions, which will measure air quality over North America and Asia, respectively. GeoTASO also acts as a satellite analogue during field campaigns. GeoTASO flew on the NASA Langley Research Center UC-12 aircraft during the Korea-United States Air Quality Study in May-June 2016, collecting spectra over South Korea during 30 flights over 19 flight days. These observations can be used to derive 2-D maps of tropospheric trace gases including ozone, nitrogen dioxide, sulfur dioxide, formaldehyde, nitrous acid and glyoxal below the aircraft at spatial resolutions between 250 m x 250 m and 1 km x 1 km, depending on the gas. We present spatially resolved trace gas retrievals over Seoul and its surrounding industrial regions, and comparisons with correlative satellite and campaign data.

SeaWinds - Oceans, Land, Polar Regions

Science.gov (United States)

1999-01-01

The SeaWinds scatterometer on the QuikScat satellite makes global radar measurements -- day and night, in clear sky and through clouds. The radar data over the oceans provide scientists and weather forecasters with information on surface wind speed and direction. Scientists also use the radar measurements directly to learn about changes in vegetation and ice extent over land and polar regions.This false-color image is based entirely on SeaWinds measurements obtained over oceans, land, and polar regions. Over the ocean, colors indicate wind speed with orange as the fastest wind speeds and blue as the slowest. White streamlines indicate the wind direction. The ocean winds in this image were measured by SeaWinds on September 20, 1999. The large storm in the Atlantic off the coast of Florida is Hurricane Gert. Tropical storm Harvey is evident as a high wind region in the Gulf of Mexico, while farther west in the Pacific is tropical storm Hilary. An extensive storm is also present in the South Atlantic Ocean near Antarctica.The land image was made from four days of SeaWinds data with the aid of a resolution enhancement algorithm developed by Dr. David Long at Brigham Young University. The lightest green areas correspond to the highest radar backscatter. Note the bright Amazon and Congo rainforests compared to the dark Sahara desert. The Amazon River is visible as a dark line running horizontally though the bright South American rain forest. Cities appear as bright spots on the images, especially in the U.S. and Europe.The image of Greenland and the north polar ice cap was generated from data acquired by SeaWinds on a single day. In the polar region portion of the image, white corresponds to the largest radar return, while purple is the lowest. The variations in color in Greenland and the polar ice cap reveal information about the ice and snow conditions present.NASA's Earth Science Enterprise is a long-term research and technology program designed to examine Earth

Efficient medium access control protocol for geostationary satellite systems

Institute of Scientific and Technical Information of China (English)

王丽娜; 顾学迈

2004-01-01

This paper proposes an efficient medium access control (MAC) protocol based on multifrequency-time division multiple access (MF-TDMA) for geostationary satellite systems deploying multiple spot-beams and onboard processing,which uses a method of random reservation access with movable boundaries to dynamically request the transmission slots and can transmit different types of traffic. The simulation results have shown that our designed MAC protocol can achieve a high bandwidth utilization, while providing the required quality of service (QoS) for each class of service.

Evaluation of Land Surface Temperature Operationally Retrieved from Korean Geostationary Satellite (COMS Data

Directory of Open Access Journals (Sweden)

A-Ra Cho

2013-08-01

Full Text Available We evaluated the precision of land surface temperature (LST operationally retrieved from the Korean multipurpose geostationary satellite, Communication, Ocean and Meteorological Satellite (COMS. The split-window (SW-type retrieval algorithm was developed through radiative transfer model simulations under various atmospheric profiles, satellite zenith angles, surface emissivity values and surface lapse rate conditions using Moderate Resolution Atmospheric Transmission version 4 (MODTRAN4. The estimation capabilities of the COMS SW (CSW LST algorithm were evaluated for various impacting factors, and the retrieval accuracy of COMS LST data was evaluated with collocated Moderate Resolution Imaging Spectroradiometer (MODIS LST data. The surface emissivity values for two SW channels were generated using a vegetation cover method. The CSW algorithm estimated the LST distribution reasonably well (averaged bias = 0.00 K, Root Mean Square Error (RMSE = 1.41 K, correlation coefficient = 0.99; however, the estimation capabilities of the CSW algorithm were significantly impacted by large brightness temperature differences and surface lapse rates. The CSW algorithm reproduced spatiotemporal variations of LST comparing well to MODIS LST data, irrespective of what month or time of day the data were collected from. The one-year evaluation results with MODIS LST data showed that the annual mean bias, RMSE and correlation coefficient for the CSW algorithm were −1.009 K, 2.613 K and 0.988, respectively.

Modelling Angular Dependencies in Land Surface Temperatures From the SEVIRI Instrument onboard the Geostationary Meteosat Second Generation Satellites

DEFF Research Database (Denmark)

Rasmussen, Mads Olander; Pinheiro, AC; Proud, Simon Richard

2010-01-01

on vegetation structure and viewing and illumination geometry. Despite this, these effects are not considered in current operational LST products from neither polar-orbiting nor geostationary satellites. In this paper, we simulate the angular dependence that can be expected when estimating LST with the viewing...... geometry of the geostationary Meteosat Second Generation Spinning Enhanced Visible and Infrared Imager sensor across the African continent and compare it to a normalized view geometry. We use the modified geometric projection model that estimates the scene thermal infrared radiance from a surface covered...

Bio-Optical Properties of the Inner Continental Shelf off Santos Estuarine System, Southeastern Brazil, and their Implications for Ocean Color Algorithm Performance

Directory of Open Access Journals (Sweden)

Melissa Carvalho

2014-07-01

Full Text Available Optical characterizations of coastal water masses are important tools for a better understanding of physical and biochemical processes and aid the optimization of ocean color algorithms. In this study we present three optical classes of water observed during October/2005 and March/2006 on the inner continental shelf adjacent to Santos Bay (Brazil, based on remote sensing reflectance. ANOVA indicated a crescent estuarine influence in classes 1 to 3. Class 3 presented the highest chlorophyll-a and nutrient concentration and highest light absorption coefficients. Colored dissolved organic matter (CDOM dominated the light absorption in all classes and was strongly correlated to salinity in October/2005 due to the influence of the La Plata plume. The results indicated that CDOM dynamics in the Santos inner shelf are very complex. The performance of global chlorophyll algorithms was significantly smaller for October/2005 than for March/2006. As inconsistent changes in light absorption spectra by phytoplankton were detected between samplings, the results show that future bio-optical algorithms for this region must be optimized preferentially considering CDOM optical parameters.

Factors challenging our ability to detect long-term trends in ocean chlorophyll

Directory of Open Access Journals (Sweden)

C. Beaulieu

2013-04-01

Full Text Available Global climate change is expected to affect the ocean's biological productivity. The most comprehensive information available about the global distribution of contemporary ocean primary productivity is derived from satellite data. Large spatial patchiness and interannual to multidecadal variability in chlorophyll a concentration challenges efforts to distinguish a global, secular trend given satellite records which are limited in duration and continuity. The longest ocean color satellite record comes from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS, which failed in December 2010. The Moderate Resolution Imaging Spectroradiometer (MODIS ocean color sensors are beyond their originally planned operational lifetime. Successful retrieval of a quality signal from the current Visible Infrared Imager Radiometer Suite (VIIRS instrument, or successful launch of the Ocean and Land Colour Instrument (OLCI expected in 2014 will hopefully extend the ocean color time series and increase the potential for detecting trends in ocean productivity in the future. Alternatively, a potential discontinuity in the time series of ocean chlorophyll a, introduced by a change of instrument without overlap and opportunity for cross-calibration, would make trend detection even more challenging. In this paper, we demonstrate that there are a few regions with statistically significant trends over the ten years of SeaWiFS data, but at a global scale the trend is not large enough to be distinguished from noise. We quantify the degree to which red noise (autocorrelation especially challenges trend detection in these observational time series. We further demonstrate how discontinuities in the time series at various points would affect our ability to detect trends in ocean chlorophyll a. We highlight the importance of maintaining continuous, climate-quality satellite data records for climate-change detection and attribution studies.

Accurately Measuring the Color of the Ocean on Earth and from Space: Uncertainties Revisited and A Report from the Community-Led Spectral Absorption Workshop to Update and Revise the NASA Inherent Optical Properties Protocol

Science.gov (United States)

Neeley, Aimee Renee

2014-01-01

The color of the ocean (apparent optical properties or AOPs) is determined by the spectral scattering and absorption of light by its dissolved and particulate constituents.The absorption and scattering properties of the water column are the so-called inherent optical properties.

Design challenges of a tunable laser interrogator for geo-stationary communication satellites

Science.gov (United States)

Ibrahim, Selwan K.; Honniball, Arthur; McCue, Raymond; Todd, Michael; O'Dowd, John A.; Sheils, David; Voudouris, Liberis; Farnan, Martin; Hurni, Andreas; Putzer, Philipp; Lemke, Norbert; Roner, Markus

2017-09-01

Recently optical sensing solutions based on fiber Bragg grating (FBG) technology have been proposed for temperature monitoring in telecommunication satellite platforms with an operational life time beyond 15 years in geo-stationary orbit. Developing radiation hardened optical interrogators designed to be used with FBG sensors inscribed in radiation tolerant fibers offer the capabilities of multiplexing multiple sensors on the same fiber and reducing the overall weight by removing the copper wiring harnesses associated with electrical sensors. Here we propose the use of a tunable laser based optical interrogator that uses a semiconductor MG-Y type laser that has no moving parts and sweeps across the C-band wavelength range providing optical power to FBG sensors and optical wavelength references such as athermal Etalons and Gas Cells to guarantee stable operation of the interrogator over its targeted life time in radiation exposed environments. The MG-Y laser was calibrated so it remains in a stable operation mode which ensures that no mode hops occur due to aging of the laser, and/or thermal or radiation effects. The key optical components including tunable laser, references and FBGs were tested for radiation tolerances by emulating the conditions on a geo-stationary satellite including a Total Ionizing Dose (TID) radiation level of up to 100 krad for interrogator components and 25 Mrad for FBGs. Different tunable laser control, and signal processing algorithms have been designed and developed to fit within specific available radiation hardened FPGAs to guarantee operation of a single interrogator module providing at least 1 sample per second measurement capability across engineering model system developed in the frame of an ESA-ARTES program and is planned to be deployed as a flight demonstrator on-board the German Heinrich Hertz geo-stationary satellite.

Specificity of Atmosphere Correction of Satellite Ocean Color Data in Far-Eastern Region

Science.gov (United States)

Trusenkova, O.; Kachur, V.; Aleksanin, A. I.

2016-02-01

It was carried out an error analysis of satellite reflectance coefficients (Rrs) of MODIS/AQUA colour data for two atmospheric correction algorithms (NIR, MUMM) in the Far-Eastern region. Some sets of unique data of in situ and satellite measurements have been analysed. A set has some measurements with ASD spectroradiometer for each satellite pass. The measurement allocations were selected so the Chlorophyll-a concentration has high variability. Analysis of arbitrary set demonstrated that the main error component is systematic error, and it has simple relations on Rrs values. The reasons of such error behavior are considered. The most probable explanation of the large errors of oceanic color parameters in the Far-Eastern region is the ability of high concentrations of continental aerosol. A comparison of satellite and in situ measurements at AERONET stations of USA and South Korea regions has been made. It was shown that for NIR-correction of the atmosphere influence the error values in these two regions have differences up to 10 times for almost the same water turbidity and relatively good accuracy of computation of aerosol optical thickness. The study was supported by grant Russian Scientific Foundation No. 14-50-00034, by grant of Russian Foundation of Basic Research No.15-35-21032-mol-a-ved, and by Program of Basic Research "Far East" of Far Eastern Branch of Russian Academy of Sciences.

Cloud Motion in the GOCI COMS Ocean Colour Data

Science.gov (United States)

Robinson, Wayne D.; Franz, Bryan A.; Mannino, Antonio; Ahn, Jae-Hyun

2016-01-01

The Geostationary Ocean Colour Imager (GOCI) instrument, on Koreas Communications, Oceans, and Meteorological Satellite (COMS), can produce a spectral artefact arising from the motion of clouds the cloud is spatially shifted and the amount of shift varies by spectral band. The length of time it takes to acquire all eight GOCI bands for a given slot (portion of a scene) is sucient to require that cloud motion be taken into account to fully mask or correct the eects of clouds in all bands. Inter-band correlations can be used to measure the amount of cloud shift, which can then be used to adjust the cloud mask so that the union of all shifted masks can act as a mask for all bands. This approach reduces the amount of masking required versus a simple expansion of the mask in all directions away from clouds. Cloud motion can also aect regions with unidentied clouds thin or fractional clouds that evade the cloud identication process yielding degraded quality in retrieved ocean colour parameters. Areas with moving and unidentied clouds require more elaborate masking algo-rithms to remove these degraded retrievals. Correction for the eects of moving fractional clouds may also be possible. The cloud shift information can be used to determine cloud motion and thus wind at the cloud levels on sub-minute timescales. The benecial and negative eects of moving clouds should be con-sidered for any ocean colour instrument design and associated data processing plans.

Is Ocean Reflectance Acquired by Citizen Scientists Robust for Science Applications?

Directory of Open Access Journals (Sweden)

Yuyan Yang

2018-05-01

Full Text Available Monitoring the dynamics of the productivity of ocean water and how it affects fisheries is essential for management. It requires data on proper spatial and temporal scales, which can be provided by operational ocean colour satellites. However, accurate productivity data from ocean colour imagery is only possible with proper validation of, for instance, the atmospheric correction applied to the images. In situ water reflectance data are of great value due to the requirements for validation and reflectance is traditionally measured with the Surface Acquisition System (SAS solar tracker system. Recently, an application for mobile devices, “HydroColor”, was developed to acquire water reflectance data. We examined the accuracy of the water reflectance measures acquired by HydroColor with the help of both trained and untrained citizens, under different environmental conditions. We used water reflectance data acquired by SAS solar tracker and by HydroColor onboard the BC ferry Queen of Oak Bay from July to September 2016. Monte Carlo permutation F tests were used to assess whether the differences between measurements collected by SAS solar tracker and HydroColor with citizens were significant. Results showed that citizen HydroColor measurements were accurate in red, green, and blue bands, as well as red/green and red/blue ratios under different environmental conditions. In addition, we found that a trained citizen obtained higher quality HydroColor data especially under clear skies at noon.

Retrieving SW fluxes from geostationary narrowband radiances for the NASA-CERES SYN1deg product

Science.gov (United States)

Wrenn, F. J., IV; Doelling, D. R.; Liang, L.

2017-12-01

The CERES mission was designed to measure the natural variability of the net TOA flux over long time scales relevant to climate monitoring. To achieve this goal, CERES provides the level-3 SSF1deg, SYN1deg, and EBAF monthly 1° by 1° regional TOA flux. The single satellite (Terra or Aqua) SSF1deg 24-hour shortwave flux is based on one daytime measurements and assumes constant meteorology to model the diurnal change in albedo. To accurately describe regions with a prominent diurnal signal, the SYN1deg Edition4 dataset employs hourly geostationary (GEO) measurements. This improves upon Edition3, which used 3-hourly GEO measurements and with temporal interpolation. The EBAF product combines the temporal stability of the SSF1deg product with the diurnal information from SYN1deg and removes the CERES instrument calibration bias by constraining the net flux balance to the ocean heat storage term. The SYN-1deg product retrieves hourly SW fluxes from GEO measurements. Over regions with large diurnal cycles, such as maritime stratus and land afternoon convective locations, the GEO derived SW fluxes will capture the diurnal flux not observed with Terra or Aqua sun-synchronous satellites. Obtaining fluxes from geostationary satellite radiance is a multistep process. First, most GEO visible imagers lack calibration and must be calibrated to MODIS and VIIRS. Second, the GEO imager visible channel radiances are converted to broadband radiances using empirical and theoretical models. The lack of coincident, collocated, and co-angled GEO and CERES measurements makes building an empirical model difficult. The narrowband to broadband models are a function of surface and cloud conditions, which are difficult to identify due to the inconsistent cloud retrievals between the 16 GEO imagers used in the CERES record. Third, the GEO derived broadband radiances are passed through the CERES angular distribution model (ADM) to convert the radiances to fluxes. Lastly, the GEO derived

Spectroscopic Observations of Geo-Stationary Satellites Over the Korean Peninsula

OpenAIRE

D. K. Lee; S. J. Kim; W. Y. Han; J. S. Park; S. W. Min

2001-01-01

Low resolution spectroscopic observations of geo-stationary satellites over the Korean peninsula have been carried out at the KyungHee Optical Satellite Observing Facility (KOSOF) with a 40cm telescope. We have observed 9 telecommunication satellites and 1 weather satellite of 6 countries. The obtained spectral data showed that satellites could be classified and grouped with similar basic spectral feature. We divided the 10 satellites into 4 groups based on spectral slop and reflectance. It i...

Nitrogen dioxide observations from the Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument: Retrieval algorithm and measurements during DISCOVER-AQ Texas 2013

Science.gov (United States)

The Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument is a test bed for upcoming air quality satellite instruments that will measure backscattered ultraviolet, visible and near-infrared light from geostationary orbit. GeoTASO flew on the NASA F...

Coordinated Field Campaigns in Chesapeake Bay and Gulf of Mexico

Science.gov (United States)

Mannino, Antonio; Novak, Michael; Tzortziou, Maria A.

2015-01-01

NASA's GEOstationary Coastal and Air Pollution Events (GEO-CAPE) mission concept recommended by the U.S. National Research Council (2007) focuses on measurements of atmospheric trace gases and aerosols and aquatic coastal ecology and biogeochemistry from geostationary orbit (35,786 km altitude). Two GEO-CAPE-sponsored multi-investigator ship-based field campaigns were conducted to coincide with the NASA Earth Venture Suborbital project DISCOVER-AQ (Deriving Information on Surface conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaigns: (1) Chesapeake Bay in July 2011 and (2) northwestern Gulf of Mexico in September 2013. Goal: to evaluate whether GEO-CAPE coastal mission measurement and instrument requirements are optimized to address science objectives while minimizing ocean color satellite sensor complexity, size and cost - critical mission risk reduction activities. NASA continues to support science studies related to the analysis of data collected as part of these coordinated field campaigns and smaller efforts.

The Hyperspectral Imager for the Coastal Ocean (HICO (trademark)) Provides a New View of the Coastal Ocean

Science.gov (United States)

2012-02-09

The calibrated data are then sent to NRL Stennis Space Center (NRL-SSC) for further processing using the NRL SSC Automated Processing System (APS...hyperspectral sensor in space we have not previously developed automated processing for hyperspectral ocean color data. The hyperspectral processing branch

Determination of Primary Bands for Global Ocean-Color Remote Sensing

National Research Council Canada - National Science Library

Lee, ZhongPing; Arnone, Robert; Carder, Kendall; He, MingXia

2007-01-01

...) from remote sensing of its color, a sensor with roughly 17 spectral bands in the 400 - 800 nm range can provide acceptable results compared to a sensor with 81 consecutive bands (in a 5-nm step...

Prediction of the Sun-Glint Locations for the Communication, Ocean and Meteorological Satellite

Directory of Open Access Journals (Sweden)

Jae-Ik Park

2005-09-01

Full Text Available For the Communication, Ocean and Meteorological Satellite (COMS which will be launched in 2008, an algorithm for finding the precise location of the sun-glint point on the ocean surface is studied. The precise locations of the sun-glint are estimated by considering azimuth and elevation angles of Sun-satellite-Earth geometric position and the law of reflection. The obtained nonlinear equations are solved by using the Newton-Raphson method. As a result, when COMS is located at 116.2°E or 128.2°E longitude, the sun-glint covers region of ±10° (N-S latitude and 80-150° (E-W longitude. The diurnal path of the sun-glint in the southern hemisphere is curved towards the North Pole, and the path in the northern hemisphere is forwards the south pole. The algorithm presented in this paper can be applied to predict the precise location of sun-glint region in any other geostationary satellites.

A simple and efficient algorithm to estimate daily global solar radiation from geostationary satellite data

International Nuclear Information System (INIS)

Lu, Ning; Qin, Jun; Yang, Kun; Sun, Jiulin

2011-01-01

Surface global solar radiation (GSR) is the primary renewable energy in nature. Geostationary satellite data are used to map GSR in many inversion algorithms in which ground GSR measurements merely serve to validate the satellite retrievals. In this study, a simple algorithm with artificial neural network (ANN) modeling is proposed to explore the non-linear physical relationship between ground daily GSR measurements and Multi-functional Transport Satellite (MTSAT) all-channel observations in an effort to fully exploit information contained in both data sets. Singular value decomposition is implemented to extract the principal signals from satellite data and a novel method is applied to enhance ANN performance at high altitude. A three-layer feed-forward ANN model is trained with one year of daily GSR measurements at ten ground sites. This trained ANN is then used to map continuous daily GSR for two years, and its performance is validated at all 83 ground sites in China. The evaluation result demonstrates that this algorithm can quickly and efficiently build the ANN model that estimates daily GSR from geostationary satellite data with good accuracy in both space and time. -- Highlights: → A simple and efficient algorithm to estimate GSR from geostationary satellite data. → ANN model fully exploits both the information from satellite and ground measurements. → Good performance of the ANN model is comparable to that of the classical models. → Surface elevation and infrared information enhance GSR inversion.

A numerical testbed for remote sensing of aerosols, and its demonstration for evaluating retrieval synergy from a geostationary satellite constellation of GEO-CAPE and GOES-R

International Nuclear Information System (INIS)

Wang, Jun; Xu, Xiaoguang; Ding, Shouguo; Zeng, Jing; Spurr, Robert; Liu, Xiong; Chance, Kelly; Mishchenko, Michael

2014-01-01

We present a numerical testbed for remote sensing of aerosols, together with a demonstration for evaluating retrieval synergy from a geostationary satellite constellation. The testbed combines inverse (optimal-estimation) software with a forward model containing linearized code for computing particle scattering (for both spherical and non-spherical particles), a kernel-based (land and ocean) surface bi-directional reflectance facility, and a linearized radiative transfer model for polarized radiance. Calculation of gas absorption spectra uses the HITRAN (HIgh-resolution TRANsmission molecular absorption) database of spectroscopic line parameters and other trace species cross-sections. The outputs of the testbed include not only the Stokes 4-vector elements and their sensitivities (Jacobians) with respect to the aerosol single scattering and physical parameters (such as size and shape parameters, refractive index, and plume height), but also DFS (Degree of Freedom for Signal) values for retrieval of these parameters. This testbed can be used as a tool to provide an objective assessment of aerosol information content that can be retrieved for any constellation of (planned or real) satellite sensors and for any combination of algorithm design factors (in terms of wavelengths, viewing angles, radiance and/or polarization to be measured or used). We summarize the components of the testbed, including the derivation and validation of analytical formulae for Jacobian calculations. Benchmark calculations from the forward model are documented. In the context of NASA's Decadal Survey Mission GEO-CAPE (GEOstationary Coastal and Air Pollution Events), we demonstrate the use of the testbed to conduct a feasibility study of using polarization measurements in and around the O 2 A band for the retrieval of aerosol height information from space, as well as an to assess potential improvement in the retrieval of aerosol fine and coarse mode aerosol optical depth (AOD) through the

Seagrass ecophysiological performance under ocean warming and acidification.

Science.gov (United States)

Repolho, Tiago; Duarte, Bernardo; Dionísio, Gisela; Paula, José Ricardo; Lopes, Ana R; Rosa, Inês C; Grilo, Tiago F; Caçador, Isabel; Calado, Ricardo; Rosa, Rui

2017-02-01

Seagrasses play an essential ecological role within coastal habitats and their worldwide population decline has been linked to different types of anthropogenic forces. We investigated, for the first time, the combined effects of future ocean warming and acidification on fundamental biological processes of Zostera noltii, including shoot density, leaf coloration, photophysiology (electron transport rate, ETR; maximum PSII quantum yield, F v /F m ) and photosynthetic pigments. Shoot density was severely affected under warming conditions, with a concomitant increase in the frequency of brownish colored leaves (seagrass die-off). Warming was responsible for a significant decrease in ETR and F v /F m (particularly under control pH conditions), while promoting the highest ETR variability (among experimental treatments). Warming also elicited a significant increase in pheophytin and carotenoid levels, alongside an increase in carotenoid/chlorophyll ratio and De-Epoxidation State (DES). Acidification significantly affected photosynthetic pigments content (antheraxanthin, β-carotene, violaxanthin and zeaxanthin), with a significant decrease being recorded under the warming scenario. No significant interaction between ocean acidification and warming was observed. Our findings suggest that future ocean warming will be a foremost determinant stressor influencing Z. noltii survival and physiological performance. Additionally, acidification conditions to occur in the future will be unable to counteract deleterious effects posed by ocean warming.

A vector radiative transfer model for coupled atmosphere and ocean systems with a rough interface

International Nuclear Information System (INIS)

Zhai Pengwang; Hu Yongxiang; Chowdhary, Jacek; Trepte, Charles R.; Lucker, Patricia L.; Josset, Damien B.

2010-01-01

We report on an exact vector (polarized) radiative transfer (VRT) model for coupled atmosphere and ocean systems. This VRT model is based on the successive order of scattering (SOS) method, which virtually takes all the multiple scattering processes into account, including atmospheric scattering, oceanic scattering, reflection and transmission through the rough ocean surface. The isotropic Cox-Munk wave model is used to derive the ref and transmission matrices for the rough ocean surface. Shadowing effects are included by the shadowing function. We validated the SOS results by comparing them with those calculated by two independent codes based on the doubling/adding and Monte Carlo methods. Two error analyses related to the ocean color remote sensing are performed in the coupled atmosphere and ocean systems. One is the scalar error caused by ignoring the polarization in the whole system. The other is the error introduced by ignoring the polarization of the light transmitted through the ocean interface. Both errors are significant for the cases studied. This code fits for the next generation of ocean color study because it converges fast for absorbing medium as, for instance, ocean.

78 FR 19172 - Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit...

Science.gov (United States)

2013-03-29

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Parts 2 and 25 [IB Docket No. 12-376; FCC 12-161] Earth Stations Aboard Aircraft Communicating with Fixed-Satellite Service Geostationary-Orbit Space Stations... the Federal Register of March 8, 2013. The document proposed rules for Earth Stations Aboard Aircraft...

Recommendations on Future Science and Engineering Studies for Ocean Color

Science.gov (United States)

Mannino, Antonio

2015-01-01

The Ocean Health Index measured Ecological Integrity as the relative condition of assessed species in a given location. This was calculated as the weighted sum of the International Union for Conservation of Natures (IUCN) assessments of species. Weights used were based on the level of extinction risk following Butchart et al.2007: EX (extinct) 0.0, CR (critically endangered) 0.2, EN (endangered) 0.5, VU (vulnerable) 0.7, NT (not threatened) 0.9, and LC (least concern) 0.99. For primarily coastal goals, the spatial average of these per pixel scores was based on a 3nmi buffer; for goals derived from all ocean waters, the spatial average was computed for the entire EEZ.

Normalization and calibration of geostationary satellite radiances for the International Satellite Cloud Climatology Project

Science.gov (United States)

Desormeaux, Yves; Rossow, William B.; Brest, Christopher L.; Campbell, G. G.

1993-01-01

Procedures are described for normalizing the radiometric calibration of image radiances obtained from geostationary weather satellites that contributed data to the International Satellite Cloud Climatology Project. The key step is comparison of coincident and collocated measurements made by each satellite and the concurrent AVHRR on the 'afternoon' NOAA polar-orbiting weather satellite at the same viewing geometry. The results of this comparison allow transfer of the AVHRR absolute calibration, which has been established over the whole series, to the radiometers on the geostationary satellites. Results are given for Meteosat-2, 3, and 4, for GOES-5, 6, and 7, for GMS-2, 3, and 4 and for Insat-1B. The relative stability of the calibrations of these radiance data is estimated to be within +/- 3 percent; the uncertainty of the absolute calibrations is estimated to be less than 10 percent. The remaining uncertainties are at least two times smaller than for the original radiance data.

An Innovative Concept for Spacebased Lidar Measurement of Ocean Carbon Biomass

Science.gov (United States)

Hu, Yongxiang; Behrenfeld, Michael; Hostetler, Chris; Pelon, Jacques; Trepte, Charles; Hair, John; Slade, Wayne; Cetinic, Ivona; Vaughan, Mark; Lu, Xiaomei;

On the feasibility of monitoring carbon monoxide in the lower troposphere from a constellation of Northern Hemisphere geostationary satellites. (Part 1)

Science.gov (United States)

Barré, Jérôme; Edwards, David; Worden, Helen; Da Silva, Arlindo; Lahoz, William

2015-07-01

By the end of the current decade, there are plans to deploy several geostationary Earth orbit (GEO) satellite missions for atmospheric composition over North America, East Asia and Europe with additional missions proposed. Together, these present the possibility of a constellation of geostationary platforms to achieve continuous time-resolved high-density observations over continental domains for mapping pollutant sources and variability at diurnal and local scales. In this paper, we use a novel approach to sample a very high global resolution model (GEOS-5 at 7 km horizontal resolution) to produce a dataset of synthetic carbon monoxide pollution observations representative of those potentially obtainable from a GEO satellite constellation with predicted measurement sensitivities based on current remote sensing capabilities. Part 1 of this study focuses on the production of simulated synthetic measurements for air quality OSSEs (Observing System Simulation Experiments). We simulate carbon monoxide nadir retrievals using a technique that provides realistic measurements with very low computational cost. We discuss the sampling methodology: the projection of footprints and areas of regard for geostationary geometries over each of the North America, East Asia and Europe regions; the regression method to simulate measurement sensitivity; and the measurement error simulation. A detailed analysis of the simulated observation sensitivity is performed, and limitations of the method are discussed. We also describe impacts from clouds, showing that the efficiency of an instrument making atmospheric composition measurements on a geostationary platform is dependent on the dominant weather regime over a given region and the pixel size resolution. These results demonstrate the viability of the ;instrument simulator; step for an OSSE to assess the performance of a constellation of geostationary satellites for air quality measurements. We describe the OSSE results in a follow up

Oceanic eddies in synthetic aperture radar images

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

2000) can be carried out in two different ways. The first one is ..... mushroom-like currents forming composite multi- .... eddies. Combination of SAR, IR and color data will ... Fu L-L and Holt B 1982 Seasat views oceans and sea ice with.

47 CFR 25.142 - Licensing provisions for the non-voice, non-geostationary mobile-satellite service.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Licensing provisions for the non-voice, non-geostationary mobile-satellite service. 25.142 Section 25.142 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES SATELLITE COMMUNICATIONS Applications and Licenses Space...

Ocean bio-geophysical modeling using mixed layer-isopycnal general circulation model coupled with photosynthesis process

Digital Repository Service at National Institute of Oceanography (India)

Nakamoto, S.; Saito, H.; Muneyama, K.; Sato, T.; PrasannaKumar, S.; Kumar, A.; Frouin, R.

-chemical system that supports steady carbon circulation in geological time scale in the world ocean using Mixed Layer-Isopycnal ocean General Circulation model with remotely sensed Coastal Zone Color Scanner (CZCS) chlorophyll pigment concentration....

Assessing Sahelian vegetation and stress from seasonal time series of polar orbiting and geostationary satellite imagery

DEFF Research Database (Denmark)

Olsen, Jørgen Lundegaard

that short term variations in anomalies from seasonally detrended time series of indices could carry information on vegetation stress was examined and confirmed. However, it was not found sufficiently robust on pixel level to be implemented for monitoring vegetation water stress on a per-pixel basis...... provide good sensitivity to canopy water content, which can make vegetation stress detection possible. Furthermore, the high frequency observations in the optical spectrum now available from geostationary instruments have the potential for detection of changes in vegetation related surface properties...... on short timescales, which are challenging from polar orbiting instruments. Geostationary NDVI and the NIR and SWIR based Shortwave Infrared Water Stress Index (SIWSI) indices are compared with extensive field data from the Dahra site, supplemented by data from the Agoufou and Demokeya sites. The indices...

Effect of algae and water on water color shift

Science.gov (United States)

Yang, Shengguang; Xia, Daying; Yang, Xiaolong; Zhao, Jun

1991-03-01

This study showed that the combined effect of absorption of planktonic algae and water on water color shift can be simulated approximately by the exponential function: Log( E {100cm/ W }+ E {100cm/ Xch1})=0.002λ-2.5 where E {100/cm W }, E {100cm/ Xchl} are, respectively, extinction coefficients of seawater and chlorophyll—a (concentration is equal to X mg/m3), and λ (nm) is wavelength. This empirical regression equation is very useful for forecasting the relation between water color and biomass in water not affected by terrigenous material. The main factor affecting water color shift in the ocean should be the absorption of blue light by planktonic algae.

An interferometer for high-resolution optical surveillance from geostationary orbit

Science.gov (United States)

Bonino, L.; Bresciani, F.; Piasini, G.; Flebus, C.; Lecat, J.-H.; Roose, S.; Pisani, M.; Cabral, A.; Rebordão, J.; Proença, C.; Costal, J.; Lima, P. U.; Loix, N.; Musso, F.

2017-11-01

The activities described in this paper have been developed in the frame of the EUCLID CEPA 9 RTP 9.9 "High Resolution Optical Satellite Sensor" project of the WEAO Research Cell. They have been focused on the definition of an interferometric instrument optimised for the high-resolution optical surveillance from geostationary orbit (GEO) by means of the synthetic aperture technique, and on the definition and development of the related enabling technologies. In this paper we describe the industrial team, the selected mission specifications and overview of the whole design and manufacturing activities performed.

An Overview of Recent Geostationary Fire Monitoring Activities and Applications in the Western Hemisphere

Science.gov (United States)

McRae, D. J.; Conard, S. G.; Ivanova, G. A.; Sukhinin, A. I.; Hao, W. M.; Koutzenogii, K. P.; Prins, E. M.; Schmidt, C. C.; Feltz, J. M.

2002-05-01

-ESE Fire Locating And Mapping of Burning Emissions (FLAMBE) project. Furthermore, the dissemination and use of geostationary imagery and derived fire products in the Western Hemisphere provide a glimpse of future global geostationary fire monitoring capabilities. Global geostationary active fire monitoring will be possible with the launch of the European METEOSAT (METEOrological SATellite) Second Generation (MSG) and the replacement Japanese Multi-functional Transport Satellite (MTSAT-1R) over the next two years. This global network of geostationary satellites will complement the U.S. and international suite of environmental polar-orbiting satellites.

78 FR 14920 - Earth Stations Aboard Aircraft Communicating With Fixed-Satellite Service Geostationary-Orbit...

Science.gov (United States)

2013-03-08

... Consumer and Governmental Affairs Bureau, Reference Information Center shall send a copy of this Report and... ground, ESAAs shall not be authorized for transmission at angles less than 5[deg] measured from the plane..., in the plane of the geostationary satellite orbit (GSO) as it appears at the particular earth station...

North/south Station Keeping of Geostationary Satellite Using Mft

Directory of Open Access Journals (Sweden)

Woong-Young Ahn

1997-06-01

Full Text Available A precise determination of the fuel efficiency is important because North/South station keeping ,which controls the inclination of the geostationary orbit, consumes most of the satellite fuel. We estimate the amount of fuel required during the lifetime of the KOREASAT when MFT(Minimum Fuel Target technique is adopted, and the result is compared to those when MCT(Maximum Compensation Target and TBCT(Track-Back Chord Target technique are applied. From this computation, we find that if MFT technique is adopted, the lifetime of the satellite can be extended at least 45 and 15 days, respectively, compared to those consumed with MCT and TBCT technique.

NIMBUS-7 CZCS. Coastal Zone Color Scanner Imagery for Selected Coastal Regions. North America - Europe. South America - Africa - Antarctica. Level 2 Photographic Product

Science.gov (United States)

1984-01-01

The Nimbus-7 Coastal Zone Color Scanner (CZCS) is the first spacecraft instrument devoted to the measurement of ocean color. Although instruments on other satellites have sensed ocean color, their spectral bands, spatial resolution, and dynamic range were optimized for geographical or meteorological use. In the CZCS, every parameter is optimized for use over water to the exclusion of any other type of sensing. The signal-to-noise ratios in the spectral channels sensing reflected solar radiance are higher than those required in the past. These ratios need to be high because the ocean is such a poor reflecting surface that the majority of the signal seen by the reflected energy channels at spacecraft altitudes is backscattered solar radiation from the atmosphere rather than reflected solar energy from the ocean. The CZCS is a conventional multichannel scanning radiometer utilizing a rotating plane mirror at a 45 deg angle to the optic axis of a Cassegrain telescope. The mirror scans 360 deg; however, only 80 deg of data centered on the spacecraft nadir is collected for ocean color measurements. Spatial resolution at spacecraft nadir is 825x825 m with some degradation at the edges of the scan swath. The useful swath width from a spacecraft altitude of 955 km is 1600 km.

The Chinese FY-1 Meteorological Satellite Application in Observation on Oceanic Environment

Science.gov (United States)

Weimin, S.

meteorological satellite is stated in this paper. exploration of the ocean resources has been a very important question of global strategy in the world. The exploration of the ocean resources includes following items: Making full use of oceanic resources and space, protecting oceanic environment. to observe the ocean is by using of satellite. In 1978, US successfully launched the first ocean observation satellite in the world --- Sea Satellite. It develops ancient oceanography in to advanced space-oceanography. FY-1 B and FY- IC respectively. High quality data were acquired at home and abroad. FY-1 is Chinese meteorological satellite, but with 0.43 ~ 0.48 μm ,0.48 ~ 0.53 μm and 0.53 ~ 0.58 μm three ocean color channels, actually it is a multipurpose remote sensing satellite of meteorology and oceanography. FY-1 satellite's capability of observation on ocean partly, thus the application field is expanded and the value is increased. With the addition of oceanic channels on FY-1, the design of the satellite is changed from the original with meteorological observation as its main purpose into remote sensing satellite possessing capability of observing meteorology and ocean as well. Thus, the social and economic benefit of FY-1 is increased. the social and economic benefit of the development of the satellite is the key technique in the system design of the satellite. technically feasible but also save the funds in researching and manufacturing of the satellite, quicken the tempo of researching and manufacturing satellite. the scanning radiometer for FY-1 is conducted an aviation experiment over Chinese ocean. This experiment was of vital importance to the addition of oceanic observation channel on FY-1. FY-1 oceanic channels design to be correct. detecting ocean color. This is the unique character of Chinese FY-1 meteorological satellite. meteorological remote sensing channel on FY-1 to form detecting capability of three visible channels: red, yellow and blue

Airborne Mission Concept for Coastal Ocean Color and Ecosystems Research

Science.gov (United States)

Guild, Liane S.; Hooker, Stanford B.; Morrow, John H.; Kudela, Raphael M.; Palacios, Sherry L.; Torres Perez, Juan L.; Hayashi, Kendra; Dunagan, Stephen E.

2016-01-01

NASA airborne missions in 2011 and 2013 over Monterey Bay, CA, demonstrated novel above- and in-water calibration and validation measurements supporting a combined airborne sensor approach (imaging spectrometer, microradiometers, and a sun photometer). The resultant airborne data characterize contemporaneous coastal atmospheric and aquatic properties plus sea-truth observations from state-of-the-art instrument systems spanning a next-generation spectral domain (320-875 nm). This airborne instrument suite for calibration, validation, and research flew at the lowest safe altitude (ca. 100 ft or 30 m) as well as higher altitudes (e.g., 6,000 ft or 1,800 m) above the sea surface covering a larger area in a single synoptic sortie than ship-based measurements at a few stations during the same sampling period. Data collection of coincident atmospheric and aquatic properties near the sea surface and at altitude allows the input of relevant variables into atmospheric correction schemes to improve the output of corrected imaging spectrometer data. Specific channels support legacy and next-generation satellite capabilities, and flights are planned to within 30 min of satellite overpass. This concept supports calibration and validation activities of ocean color phenomena (e.g., river plumes, algal blooms) and studies of water quality and coastal ecosystems. The 2011 COAST mission flew at 100 and 6,000 ft on a Twin Otter platform with flight plans accommodating the competing requirements of the sensor suite, which included the Coastal-Airborne In-situ Radiometers (C-AIR) for the first time. C-AIR (Biospherical Instruments Inc.) also flew in the 2013 OCEANIA mission at 100 and 1,000 ft on the Twin Otter below the California airborne simulation of the proposed NASA HyspIRI satellite system comprised of an imaging spectrometer and thermal infrared multispectral imager on the ER-2 at 65,000 ft (20,000 m). For both missions, the Compact-Optical Profiling System (Biospherical

STUDY ON HIGH RESOLUTION MEMBRANE-BASED DIFFRACTIVE OPTICAL IMAGING ON GEOSTATIONARY ORBIT

Directory of Open Access Journals (Sweden)

J. Jiao

2017-05-01

Full Text Available Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the “6+1” petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

Study on High Resolution Membrane-Based Diffractive Optical Imaging on Geostationary Orbit

Science.gov (United States)

Jiao, J.; Wang, B.; Wang, C.; Zhang, Y.; Jin, J.; Liu, Z.; Su, Y.; Ruan, N.

2017-05-01

Diffractive optical imaging technology provides a new way to realize high resolution earth observation on geostationary orbit. There are a lot of benefits to use the membrane-based diffractive optical element in ultra-large aperture optical imaging system, including loose tolerance, light weight, easy folding and unfolding, which make it easy to realize high resolution earth observation on geostationary orbit. The implementation of this technology also faces some challenges, including the configuration of the diffractive primary lens, the development of high diffraction efficiency membrane-based diffractive optical elements, and the correction of the chromatic aberration of the diffractive optical elements. Aiming at the configuration of the diffractive primary lens, the "6+1" petal-type unfold scheme is proposed, which consider the compression ratio, the blocking rate and the development complexity. For high diffraction efficiency membrane-based diffractive optical element, a self-collimating method is proposed. The diffraction efficiency is more than 90 % of the theoretical value. For the chromatic aberration correction problem, an optimization method based on schupmann is proposed to make the imaging spectral bandwidth in visible light band reach 100 nm. The above conclusions have reference significance for the development of ultra-large aperture diffractive optical imaging system.

A Study on Fuel Estimation Algorithms for a Geostationary Communication & Broadcasting Satellite

OpenAIRE

Jong Won Eun

2000-01-01

It has been developed to calculate fuel budget for a geostationary communication and broadcasting satellite. It is quite essential that the pre-launch fuel budget estimation must account for the deterministic transfer and drift orbit maneuver requirements. After on-station, the calculation of satellite lifetime should be based on the estimation of remaining fuel and assessment of actual performance. These estimations step from the proper algorithms to produce the prediction of satellite lifet...

Ocean Optics Protocols for Satellite Ocean Color Sensor Validation. Revised

Science.gov (United States)

Fargion, Giulietta S.; Mueller, James L.

2000-01-01

The document stipulates protocols for measuring bio-optical and radiometric data for the Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project activities and algorithm development. This document supersedes the earlier version (Mueller and Austin 1995) published as Volume 25 in the SeaWiFS Technical Report Series. This document marks a significant departure from, and improvement on, theformat and content of Mueller and Austin (1995). The authorship of the protocols has been greatly broadened to include experts specializing in some key areas. New chapters have been added to provide detailed and comprehensive protocols for stability monitoring of radiometers using portable sources, abovewater measurements of remote-sensing reflectance, spectral absorption measurements for discrete water samples, HPLC pigment analysis and fluorometric pigment analysis. Protocols were included in Mueller and Austin (1995) for each of these areas, but the new treatment makes significant advances in each topic area. There are also new chapters prescribing protocols for calibration of sun photometers and sky radiance sensors, sun photometer and sky radiance measurements and analysis, and data archival. These topic areas were barely mentioned in Mueller and Austin (1995).

Solar power satellite - A geostationary channel tunnel

Energy Technology Data Exchange (ETDEWEB)

Bulloch, C

1981-12-01

The concept-development status of solar power satellite (SPS) systems is considered, with attention to Heavy-Lift Launch Vehicles (HLLVs), the construction methods to be used in either geostationary or low earth orbit, and the configuration of the solar array. By comparison with the 30-ton payload of the Space Shuttle, HLLV designs under consideration have payloads of 114 to 425 tons. The unit cost for 5-GW satellites, in 1977 dollars, is estimated at five billion dollars. Consideration is given to the possible deleterious environmental effects of both the 400 or more launches required for each SPS and such results of radio frequency energy transfer beam operation as the suppression of blood platelet production in human beings and ionospheric heating. The uncertainty that still surrounds the relative advantages of competing designs and the need for long-range, billion-dollar funding appear to be insuperable obstacles to the construction of SPSs.

Nimbus 7 Coastal Zone Color Scanner (CZCS). Level 1 data product users' guide

Science.gov (United States)

Williams, S. P.; Szajna, E. F.; Hovis, W. A.

1985-01-01

The coastal zone color scanner (CZCS) is a scanning multispectral radiometer designed specifically for the remote sensing of Ocean Color parameters from an Earth orbiting space platform. A technical manual which is intended for users of NIMBUS 7 CZCS Level 1 data products is presented. It contains information needed by investigators and data processing personnel to operate on the data using digital computers and related equipment.

Remote sensing estimation of terrestrially derived colored dissolved organic matterinput to the Arctic Ocean

Science.gov (United States)

Li, J.; Yu, Q.; Tian, Y. Q.

2017-12-01

The DOC flux from land to the Arctic Ocean has remarkable implication on the carbon cycle, biogeochemical & ecological processes in the Arctic. This lateral carbon flux is required to be monitored with high spatial & temporal resolution. However, the current studies in the Arctic regions were obstructed by the factors of the low spatial coverages. The remote sensing could provide an alternative bio-optical approach to field sampling for DOC dynamics monitoring through the observation of the colored dissolved organic matter (CDOM). The DOC and CDOM were found highly correlated based on the analysis of the field sampling data from the Arctic-GRO. These provide the solid foundation of the remote sensing observation. In this study, six major Arctic Rivers (Yukon, Kolyma, Lena, Mackenzie, Ob', Yenisey) were selected to derive the CDOM dynamics along four years. Our newly developed SBOP algorithm was applied to the large Landsat-8 OLI image data (nearly 100 images) for getting the high spatial resolution results. The SBOP algorithm is the first approach developing for the Shallow Water Bio-optical properties estimation. The CDOM absorption derived from the satellite images were verified with the field sampling results with high accuracy (R2 = 0.87). The distinct CDOM dynamics were found in different Rivers. The CDOM absorptions were found highly related to the hydrological activities and the terrestrially environmental dynamics. Our study helps to build the reliable system for studying the carbon cycle at Arctic regions.

Assessment of Satellite Ocean Colour Radiometry and Derived Geophysical Products. Chapter 6.1

Science.gov (United States)

Melin, Frederic; Franz, Bryan A.

2014-01-01

Standardization of methods to assess and assign quality metrics to satellite ocean color radiometry and derived geophysical products has become paramount with the inclusion of the marine reflectance and chlorophyll-a concentration (Chla) as essential climate variables (ECV; [1]) and the recognition that optical remote sensing of the oceans can only contribute to climate research if and when a continuous succession of satellite missions can be shown to collectively provide a consistent, long-term record with known uncertainties. In 20 years, the community has made significant advancements toward that objective, but providing a complete uncertainty budget for all products and for all conditions remains a daunting task. In the retrieval of marine water-leaving radiance from observed top-of-atmosphere radiance, the sources of uncertainties include those associated with propagation of sensor noise and radiometric calibration and characterization errors, as well as a multitude of uncertainties associated with the modeling and removal of effects from the atmosphere and sea surface. This chapter describes some common approaches used to assess quality and consistency of ocean color satellite products and reviews the current status of uncertainty quantification in the field. Its focus is on the primary ocean color product, the spectrum of marine reflectance Rrs, but uncertainties in some derived products such as the Chla or inherent optical properties (IOPs) will also be considered.

Simultaneous Measurements of Chlorophyll Concentration by Lidar, Fluorometry, above-Water Radiometry, and Ocean Color MODIS Images in the Southwestern Atlantic.

Science.gov (United States)

Kampel, Milton; Lorenzzetti, João A; Bentz, Cristina M; Nunes, Raul A; Paranhos, Rodolfo; Rudorff, Frederico M; Politano, Alexandre T

2009-01-01

Comparisons between in situ measurements of surface chlorophyll-a concentration (CHL) and ocean color remote sensing estimates were conducted during an oceanographic cruise on the Brazilian Southeastern continental shelf and slope, Southwestern South Atlantic. In situ values were based on fluorometry, above-water radiometry and lidar fluorosensor. Three empirical algorithms were used to estimate CHL from radiometric measurements: Ocean Chlorophyll 3 bands (OC3M(RAD)), Ocean Chlorophyll 4 bands (OC4v4(RAD)), and Ocean Chlorophyll 2 bands (OC2v4(RAD)). The satellite estimates of CHL were derived from data collected by the MODerate-resolution Imaging Spectroradiometer (MODIS) with a nominal 1.1 km resolution at nadir. Three algorithms were used to estimate chlorophyll concentrations from MODIS data: one empirical - OC3M(SAT), and two semi-analytical - Garver, Siegel, Maritorena version 01 (GSM01(SAT)), and Carder(SAT). In the present work, MODIS, lidar and in situ above-water radiometry and fluorometry are briefly described and the estimated values of chlorophyll retrieved by these techniques are compared. The chlorophyll concentration in the study area was in the range 0.01 to 0.2 mg/m(3). In general, the empirical algorithms applied to the in situ radiometric and satellite data showed a tendency to overestimate CHL with a mean difference between estimated and measured values of as much as 0.17 mg/m(3) (OC2v4(RAD)). The semi-analytical GSM01 algorithm applied to MODIS data performed better (rmse 0.28, rmse-L 0.08, mean diff. -0.01 mg/m(3)) than the Carder and the empirical OC3M algorithms (rmse 1.14 and 0.36, rmse-L 0.34 and 0.11, mean diff. 0.17 and 0.02 mg/m(3), respectively). We find that rmsd values between MODIS relative to the in situ radiometric measurements are MODIS for the stations considered in this work. Other authors have already reported over and under estimation of MODIS remotely sensed reflectance due to several errors in the bio-optical algorithm

Simultaneous Measurements of Chlorophyll Concentration by Lidar, Fluorometry, above-Water Radiometry, and Ocean Color MODIS Images in the Southwestern Atlantic

Directory of Open Access Journals (Sweden)

Cristina M. Bentz

2009-01-01

Full Text Available Comparisons between in situ measurements of surface chlorophyll-a concentration (CHL and ocean color remote sensing estimates were conducted during an oceanographic cruise on the Brazilian Southeastern continental shelf and slope, Southwestern South Atlantic. In situ values were based on fluorometry, above-water radiometry and lidar fluorosensor. Three empirical algorithms were used to estimate CHL from radiometric measurements: Ocean Chlorophyll 3 bands (OC3MRAD, Ocean Chlorophyll 4 bands (OC4v4RAD, and Ocean Chlorophyll 2 bands (OC2v4RAD. The satellite estimates of CHL were derived from data collected by the MODerate-resolution Imaging Spectroradiometer (MODIS with a nominal 1.1 km resolution at nadir. Three algorithms were used to estimate chlorophyll concentrations from MODIS data: one empirical - OC3MSAT, and two semi-analytical - Garver, Siegel, Maritorena version 01 (GSM01SAT, and CarderSAT. In the present work, MODIS, lidar and in situ above-water radiometry and fluorometry are briefly described and the estimated values of chlorophyll retrieved by these techniques are compared. The chlorophyll concentration in the study area was in the range 0.01 to 0.2 mg·m-3. In general, the empirical algorithms applied to the in situ radiometric and satellite data showed a tendency to overestimate CHL with a mean difference between estimated and measured values of as much as 0.17 mg/m3 (OC2v4RAD. The semi-analytical GSM01 algorithm applied to MODIS data performed better (rmse 0.28, rmse-L 0.08, mean diff. -0.01 mg/m3 than the Carder and the empirical OC3M algorithms (rmse 1.14 and 0.36, rmse-L 0.34 and 0.11, mean diff. 0.17 and 0.02 mg/m3, respectively. We find that rmsd values between MODIS relative to the in situ radiometric measurements are < 26%, i.e., there is a trend towards overestimation of RRS by MODIS for the stations considered in this work. Other authors have already reported over and under estimation of MODIS remotely sensed

Modeling human color categorization: Color discrimination and color memory

OpenAIRE

Heskes, T.; van den Broek, Egon; Lucas, P.; Hendriks, Maria A.; Vuurpijl, L.G.; Puts, M.J.H.; Wiegerinck, W.

2003-01-01

Color matching in Content-Based Image Retrieval is done using a color space and measuring distances between colors. Such an approach yields non-intuitive results for the user. We introduce color categories (or focal colors), determine that they are valid, and use them in two experiments. The experiments conducted prove the difference between color categorization by the cognitive processes color discrimination and color memory. In addition, they yield a Color Look-Up Table, which can improve c...

Geostatistical Analysis of Mesoscale Spatial Variability and Error in SeaWiFS and MODIS/Aqua Global Ocean Color Data

Science.gov (United States)

Glover, David M.; Doney, Scott C.; Oestreich, William K.; Tullo, Alisdair W.

2018-01-01

Mesoscale (10-300 km, weeks to months) physical variability strongly modulates the structure and dynamics of planktonic marine ecosystems via both turbulent advection and environmental impacts upon biological rates. Using structure function analysis (geostatistics), we quantify the mesoscale biological signals within global 13 year SeaWiFS (1998-2010) and 8 year MODIS/Aqua (2003-2010) chlorophyll a ocean color data (Level-3, 9 km resolution). We present geographical distributions, seasonality, and interannual variability of key geostatistical parameters: unresolved variability or noise, resolved variability, and spatial range. Resolved variability is nearly identical for both instruments, indicating that geostatistical techniques isolate a robust measure of biophysical mesoscale variability largely independent of measurement platform. In contrast, unresolved variability in MODIS/Aqua is substantially lower than in SeaWiFS, especially in oligotrophic waters where previous analysis identified a problem for the SeaWiFS instrument likely due to sensor noise characteristics. Both records exhibit a statistically significant relationship between resolved mesoscale variability and the low-pass filtered chlorophyll field horizontal gradient magnitude, consistent with physical stirring acting on large-scale gradient as an important factor supporting observed mesoscale variability. Comparable horizontal length scales for variability are found from tracer-based scaling arguments and geostatistical decorrelation. Regional variations between these length scales may reflect scale dependence of biological mechanisms that also create variability directly at the mesoscale, for example, enhanced net phytoplankton growth in coastal and frontal upwelling and convective mixing regions. Global estimates of mesoscale biophysical variability provide an improved basis for evaluating higher resolution, coupled ecosystem-ocean general circulation models, and data assimilation.

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

OpenAIRE

A. Morel; H. Claustre; B. Gentili

2010-01-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") account ...

The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

OpenAIRE

Morel, A.; Claustre, H.; Gentili, B.

2010-01-01

The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") acc...

Coastal Zone Color Scanner studies

Science.gov (United States)

Elrod, J.

1988-01-01

Activities over the past year have included cooperative work with a summer faculty fellow using the Coastal Zone Color Scanner (CZCS) imagery to study the effects of gradients in trophic resources on coral reefs in the Caribbean. Other research included characterization of ocean radiances specific to an acid-waste plume. Other activities include involvement in the quality control of imagery produced in the processing of the global CZCS data set, the collection of various other data global sets, and the subsequent data comparison and analysis.

A new parameterization for surface ocean light attenuation in Earth System Models: assessing the impact of light absorption by colored detrital material

Science.gov (United States)

Kim, G. E.; Pradal, M.-A.; Gnanadesikan, A.

2015-03-01

Light limitation can affect the distribution of biota and nutrients in the ocean. Light absorption by colored detrital material (CDM) was included in a fully coupled Earth System Model using a new parameterization for shortwave attenuation. Two model runs were conducted, with and without light attenuation by CDM. In a global average sense, greater light limitation associated with CDM increased surface chlorophyll, biomass and nutrients together. These changes can be attributed to the movement of biological productivity higher up the water column, which increased surface chlorophyll and biomass while simultaneously decreasing total biomass. Meanwhile, the reduction in biomass resulted in greater nutrient availability throughout the water column. Similar results were found on a regional scale in an analysis of the oceans by biome. In coastal regions, surface chlorophyll increased by 35% while total integrated phytoplankton biomass diminished by 18%. The largest relative increases in modeled surface chlorophyll and biomass in the open ocean were found in the equatorial biomes, while largest decreases in depth-integrated biomass and chlorophyll were found in the subpolar and polar biomes. This mismatch of surface and subsurface trends and their regional dependence was analyzed by comparing the competing factors of diminished light availability and increased nutrient availability on phytoplankton growth in the upper 200 m. Overall, increases in surface biomass were expected to accompany greater nutrient uptake and therefore diminish surface nutrients, but changes in light limitation decoupled trends between these two variables. Understanding changes in biological productivity requires both surface and depth-resolved information. Surface trends may be minimal or of the opposite sign to depth-integrated amounts, depending on the vertical structure of phytoplankton abundance.

A synthesis of light absorption properties of the Arctic Ocean: application to semianalytical estimates of dissolved organic carbon concentrations from space

Science.gov (United States)

Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Bélanger, S.; Bricaud, A.

2014-06-01

In addition to scattering coefficients, the light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the data sets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database of the Arctic Ocean by pooling the majority of published data sets and merging new data sets. Our results show that the total nonwater absorption coefficients measured in the eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (aϕ(λ)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semianalytical CDOM absorption algorithm is based on chl a-specific aϕ(λ) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Based on statistics, derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semianalytical algorithm for estimating DOC concentrations for river-influenced coastal waters of the Arctic Ocean is presented and applied to satellite

The GOES-R Geostationary Lightning Mapper (GLM) and the Global Observing System for Total Lightning

Science.gov (United States)

Goodman, Steven J.; Blakeslee, R. J.; Koshak, W.; Buechler, D.; Carey, L.; Chronis, T.; Mach, D.; Bateman, M.; Peterson, H.; McCaul, E. W., Jr.;

Passive correlation ranging of a geostationary satellite using DVB-S payload signals.

Science.gov (United States)

Shakun, Leonid; Shulga, Alexandr; Sybiryakova, Yevgeniya; Bushuev, Felix; Kaliuzhnyi, Mykola; Bezrukovs, Vladislavs; Moskalenko, Sergiy; Kulishenko, Vladislav; Balagura, Oleg

2016-07-01

Passive correlation ranging (PaCoRa) for geostationary satellites is now considered as an alternate to tone-ranging (https://artes.esa.int/search/node/PaCoRa). The PaCoRa method has been employed in the Research Institute "Nikolaev astronomical observatory" since the first experiment in August 2011 with two stations spatially separated on 150 km. The PaCoRa has been considered as an independent method for tracking the future Ukrainian geostationary satellite "Lybid'. Now a radio engineering complex (RC) for passive ranging consists of five spatially separated stations of receiving digital satellite television and a data processing center located in Mykolaiv. The stations are located in Kyiv, Kharkiv, Mukacheve, Mykolaiv (Ukraine) and in Ventspils (Latvia). Each station has identical equipment. The equipment allows making synchronous recording of fragments of the DVB-S signal from the quadrature detector output of a satellite television receiver. The fragments are recorded every second. Synchronization of the stations is performed using GPS receivers. Samples of the complex signal obtained in this way are archived and are sent to the data processing center over the Internet. Here the time differences of arrival (TDOA) for pairs of the stations are determined as a result of correlation processing of received signals. The values of the TDOA that measured every second are used for orbit determination (OD) of the satellite. The results of orbit determination of the geostationary telecommunication satellite "Eutelsat-13B" (13º East) obtained during about four months of observations in 2015 are presented in the report. The TDOA and OD accuracies are also given. Single-measurement error (1 sigma) of the TDOA is equal about 8.7 ns for all pairs of the stations. Standard deviations and average values of the residuals between the observed TDOA and the TDOA computed using the orbit elements obtained from optical measurements are estimated for the pairs Kharkiv-Mykolaiv and

Nimbus 7 Coastal Zone Color Scanner (CZCS). Level 2 data product users' guide

Science.gov (United States)

Williams, S. P.; Szajna, E. F.; Hovis, W. A.

1985-01-01

The coastal zone color scanner (CZCS) is a scanning multispectral radiometer designed for the remote sensing of ocean color parameters from an earth orbiting space platform. A Technical Manual was designed for users of NIMBUS 7 CZCS Level 2 data products. It contains information which describes how the Level 1 data was process to obtain the Level 2 (derived) product. It contains information needed to operate on the data using digital computers and related equipment.

47 CFR 25.261 - Procedures for avoidance of in-line interference events for Non Geostationary Satellite Orbit...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Procedures for avoidance of in-line interference events for Non Geostationary Satellite Orbit (NGSO) Satellite Network Operations in the Fixed Satellite Service (FSS) Bands. 25.261 Section 25.261 Telecommunication FEDERAL COMMUNICATIONS COMMISSION...

Sensitivity of Ocean Reflectance Inversion Models for Identifying and Discriminating Between Phytoplankton Functional Groups

Science.gov (United States)

Werdell, P. Jeremy; Ooesler, Collin S.

2012-01-01

The daily, synoptic images provided by satellite ocean color instruments provide viable data streams for observing changes in the biogeochemistrY of marine ecosystems. Ocean reflectance inversion models (ORMs) provide a common mechanism for inverting the "color" of the water observed a satellite into marine inherent optical properties (lOPs) through a combination of empiricism and radiative transfer theory. lOPs, namely the spectral absorption and scattering characteristics of ocean water and its dissolved and particulate constituents, describe the contents of the upper ocean, information critical for furthering scientific understanding of biogeochemical oceanic processes. Many recent studies inferred marine particle sizes and discriminated between phytoplankton functional groups using remotely-sensed lOPs. While all demonstrated the viability of their approaches, few described the vertical distributions of the water column constituents under consideration and, thus, failed to report the biophysical conditions under which their model performed (e.g., the depth and thickness of the phytoplankton bloom(s)). We developed an ORM to remotely identifY Noctiluca miliaris and other phytoplankton functional types using satellite ocean color data records collected in the northern Arabian Sea. Here, we present results from analyses designed to evaluate the applicability and sensitivity of the ORM to varied biophysical conditions. Specifically, we: (1) synthesized a series of vertical profiles of spectral inherent optical properties that represent a wide variety of bio-optical conditions for the northern Arabian Sea under aN Miliaris bloom; (2) generated spectral remote-sensing reflectances from these profiles using Hydrolight; and, (3) applied the ORM to the synthesized reflectances to estimate the relative concentrations of diatoms and N Miliaris for each example. By comparing the estimates from the inversion model to those from synthesized vertical profiles, we were able to

Integrating biogeochemistry and ecology into ocean data assimilation systems

DEFF Research Database (Denmark)

Brasseur, Pierre; Gruber, Nicolas; Barciela, Rosa

2009-01-01

that are not yet considered essential, such as upper-ocean vertical fluxes that are critically important to biological activity. Further, the observing systems will need to be expanded in terms of in situ platforms (with intensified deployments of sensors for O-2 and chlorophyll, and inclusion of new sensors...... for nutrients, zooplankton, micronekton biomass, and others), satellite missions (e.g., hyperspectral instruments for ocean color, lidar systems for mixed-layer depths, and wide-swath altimeters for coastal sea level), and improved methods to assimilate these new measurements....

How Two Sides of the Atlantic Contributed to Understanding of the Global Oceans: Charles Yentsch and Andre Morel

Science.gov (United States)

Acker, James G.

2013-01-01

In a few short days in September of this year, the ocean color/ocean optics community lost two of the founding members of its Hall of FameCharles Yentsch and Andre Morel. Yentsch passed away at the age of 85 on September 19, and Morel passed away on September 23 at the age of 79. It might sound clich to say that someone was instrumental to the advance of science in a particular field, but in the case of Yentsch and Morel and ocean color instrumentation, such an assessment would likely be accurate. Each mans career complimented that of the other Yentsch was one of the first to make measurements of the light field of the ocean from altitude and to advocate an instrument in space that could observe the spectrum of ocean radiance Morels theoretical underpinnings established a firm foundation for the measurements such an instrument could make, allowing their successful interpretation.

Modeling human color categorization: Color discrimination and color memory

NARCIS (Netherlands)

Heskes, T.; van den Broek, Egon; Lucas, P.; Hendriks, Maria A.; Vuurpijl, L.G.; Puts, M.J.H.; Wiegerinck, W.

2003-01-01

Color matching in Content-Based Image Retrieval is done using a color space and measuring distances between colors. Such an approach yields non-intuitive results for the user. We introduce color categories (or focal colors), determine that they are valid, and use them in two experiments. The

47 CFR 25.260 - Time sharing between DoD meteorological satellite systems and non-voice, non-geostationary...

Science.gov (United States)

2010-10-01

... 47 Telecommunication 2 2010-10-01 2010-10-01 false Time sharing between DoD meteorological satellite systems and non-voice, non-geostationary satellite systems in the 400.15-401 MHz band. 25.260 Section 25.260 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) COMMON CARRIER SERVICES...

Evolution of pygmy angelfishes: Recent divergences, introgression, and the usefulness of color in taxonomy

KAUST Repository

Gaither, Michelle R.; Schultz, Jennifer K.; Bellwood, David R.; Pyle, Richard L.; DiBattista, Joseph; Rocha, Luiz A.; Bowen, Brian W.

2014-01-01

The pygmy angelfishes (genus Centropyge, family Pomacanthidae) are brightly colored species that occupy reef habitats in every tropical ocean. Some species are rarely observed because they occur below conventional scuba depths. Their striking

Image color reduction method for color-defective observers using a color palette composed of 20 particular colors

Science.gov (United States)

Sakamoto, Takashi

2015-01-01

This study describes a color enhancement method that uses a color palette especially designed for protan and deutan defects, commonly known as red-green color blindness. The proposed color reduction method is based on a simple color mapping. Complicated computation and image processing are not required by using the proposed method, and the method can replace protan and deutan confusion (p/d-confusion) colors with protan and deutan safe (p/d-safe) colors. Color palettes for protan and deutan defects proposed by previous studies are composed of few p/d-safe colors. Thus, the colors contained in these palettes are insufficient for replacing colors in photographs. Recently, Ito et al. proposed a p/dsafe color palette composed of 20 particular colors. The author demonstrated that their p/d-safe color palette could be applied to image color reduction in photographs as a means to replace p/d-confusion colors. This study describes the results of the proposed color reduction in photographs that include typical p/d-confusion colors, which can be replaced. After the reduction process is completed, color-defective observers can distinguish these confusion colors.

Image navigation and registration for the geostationary lightning mapper (GLM)

Science.gov (United States)

van Bezooijen, Roel W. H.; Demroff, Howard; Burton, Gregory; Chu, Donald; Yang, Shu S.

2016-10-01

The Geostationary Lightning Mappers (GLM) for the Geostationary Operational Environmental Satellite (GOES) GOES-R series will, for the first time, provide hemispherical lightning information 24 hours a day from longitudes of 75 and 137 degrees west. The first GLM of a series of four is planned for launch in November, 2016. Observation of lightning patterns by GLM holds promise to improve tornado warning lead times to greater than 20 minutes while halving the present false alarm rates. In addition, GLM will improve airline traffic flow management, and provide climatology data allowing us to understand the Earth's evolving climate. The paper describes the method used for translating the pixel position of a lightning event to its corresponding geodetic longitude and latitude, using the J2000 attitude of the GLM mount frame reported by the spacecraft, the position of the spacecraft, and the alignment of the GLM coordinate frame relative to its mount frame. Because the latter alignment will experience seasonal variation, this alignment is determined daily using GLM background images collected over the previous 7 days. The process involves identification of coastlines in the background images and determination of the alignment change necessary to match the detected coastline with the coastline predicted using the GSHHS database. Registration is achieved using a variation of the Lucas-Kanade algorithm where we added a dither and average technique to improve performance significantly. An innovative water mask technique was conceived to enable self-contained detection of clear coastline sections usable for registration. Extensive simulations using accurate visible images from GOES13 and GOES15 have been used to demonstrate the performance of the coastline registration method, the results of which are presented in the paper.

Ocean Science for Decision-Making: Current Activities of the National Research Council's Ocean Studies Board

Science.gov (United States)

Roberts, S.; Glickson, D.; Mengelt, C.; Forrest, S.; Waddell, K.

2012-12-01

The National Research Council is a private, nonprofit organization chartered by Congress in 1916 as an expansion of the U.S. National Academy of Sciences. Its mission is to improve the use of science in government decision making and public policy, increase public understanding, and promote the acquisition and dissemination of knowledge in matters involving science, engineering, technology, and health. Within the National Research Council, the Ocean Studies Board (OSB) mission is to explore the science, policies, and infrastructure needed to understand, manage, and conserve coastal and marine environments and resources. OSB undertakes studies and workshops on emerging scientific and policy issues at the request of federal agencies, Congress, and others; provides program reviews and guidance; and facilitates communication on oceanographic issues among different sectors. OSB also serves as the U.S. National Committee to the international, nongovernmental Scientific Committee on Oceanic Research (SCOR). OSB has produced reports on a wide range of topics of interest to researchers and educators, the federal government, the non-profit sector, and industry. Recent reports have focused on ecosystem services in the Gulf of Mexico after the Deepwater Horizon oil spill, sea level rise on the U.S. west coast, scientific ocean drilling needs and accomplishments, requirements for sustained ocean color measurements, critical infrastructure for ocean research, tsunami warning and preparedness, ocean acidification, and marine and hydrokinetic power resource assessments. Studies that are currently underway include responding to oil spills in the Arctic, evaluating the effectiveness of fishery stock rebuilding plans, and reviewing the National Ocean Acidification Research Plan. OSB plays an important role in helping create policy decisions and disseminating important information regarding various aspects of ocean science.

Optical Moorings-of-Opportunity for Validation of Ocean Color Satellites

Science.gov (United States)

2008-01-01

at the midpoint of the two depths is given by: K , z d dz lnE , z , , d dλ λ λ λ ( ) = − ( )[ ] ( ) = − ( ) ( ) ( ) 4a 1 z ln E , z E , z 4bd 2 d 1...Biological Oceanography Program ( TD : OCE-9627281, OCE-9730471, OCE-9819477), NASA ( TD : NAS5-97127), the ONR Ocean Engineering and Marine Systems Program

Thinking Outside of the Blue Marble: Novel Ocean Applications Using the VIIRS Sensor

Science.gov (United States)

Vandermeulen, Ryan A.; Arnone, Robert

2016-01-01

While planning for future space-borne sensors will increase the quality, quantity, and duration of ocean observations in the years to come, efforts to extend the limits of sensors currently in orbit can help shed light on future scientific gains as well as associated uncertainties. Here, we present several applications that are unique to the polar orbiting Visual Infrared Imaging Radiometer Suite (VIIRS), each of which challenge the threshold capabilities of the sensor and provide lessons for future missions. For instance, while moderate resolution polar orbiters typically have a one day revisit time, we are able to obtain multiple looks of the same area by focusing on the extreme zenith angles where orbital views overlap, and pair these observations with those from other sensors to create pseudo-geostationary data sets. Or, by exploiting high spatial resolution (imaging) channels and analyzing patterns of synoptic covariance across the visible spectrum, we can obtain higher spatial resolution bio-optical products. Alternatively, non-traditional products can illuminate important biological interactions in the ocean, such as the use of the Day-Night-Band to provide some quantification of phototactic behavior of marine life along light polluted beaches, as well as track the location of marine fishing vessel fleets along ocean fronts. In this talk, we explore ways to take full advantage of the capabilities of existing sensors in order to maximize insights for future missions.

Influence of Surrounding Colors in the Illuminant-Color Mode on Color Constancy

Directory of Open Access Journals (Sweden)

Kazuho Fukuda

2011-05-01

Full Text Available On color constancy, we showed that brighter surrounding colors had greater influence than dim colors (Uchikawa, Kitazawa, MacLeod, Fukuda, 2010 APCV. Increasing luminance of a stimulus causes the change in appearance from the surface-color to the illuminant-color mode. However it is unknown whether the visual system considers such color appearance mode of surrounding colors to achieve color constancy. We investigated the influence of surrounding colors that appeared illuminant on color constancy. The stimulus was composed of a central test stimulus and surrounding six colors: bright and dim red, green and blue. The observers adjusted the chromaticity of the test stimulus to be appeared as an achromatic surface. The luminance balance of three bright surrounding colors was equalized with that of the optimal colors in three illuminant conditions, then, the luminance of one of the three bright colors was varied in the range beyond the critical luminance of color appearance mode transition. The results showed that increasing luminance of a bright surrounding color shifted the observers' achromatic setting toward its chromaticity, but this effect diminished for the surrounding color in the illuminant-color mode. These results suggest that the visual system considers color appearance mode of surrounding colors to accomplish color constancy.

The colors of icebergs

Science.gov (United States)

Warren, S. G.

2017-12-01

Ordinary icebergs of meteoric glacier ice appear bluish-white, i.e. intermediate in color between the white of snow and the blue of pure ice, depending on the bubble content. However, clear dark bubble-free icebergs are occasionally seen in the Antarctic Ocean; they originate from freezing of seawater to the base of ice shelves. On parts of the Amery Ice Shelf, frozen seawater contributes up to one-third of the ice-shelf thickness. Many of the icebergs produced by the Amery are therefore composite icebergs; the upper part consists of meteoric glacier ice from snowfall, but the lower part is frozen seawater ("marine ice"). When these icebergs capsize, the marine ice is exposed to view; it can be accessed for study in springtime when the icebergs are embedded in shorefast sea ice. The marine ice varies in color from blue to green depending on the content of dissolved organic matter. The color is therefore an indicator of biological productivity in the seawater from which the ice froze. To infer processes at the ice-shelf base, these icebergs may be examined and cored for spectral reflectance, hydrogen and oxygen isotopes, organic matter, particles, and distribution of cracks and stripes. Seasonal and interannual variations may be quantified from samples collected along the marine ice-growth trajectory at the meteoric/marine-ice interface. The scale of small turbulent eddies at the ice-shelf base, which govern the transfer of heat between ocean and ice, can be inferred from the size of scallops in the iceberg surface (typically a few centimeters). Dark stripes within meteoric ice result from tension-cracks at the grounding line, forming basal crevasses that fill suddenly with seawater; their width, spacing, and salinity can give clues to processes at the grounding line. Results will be shown from icebergs sampled on Australian expeditions near Davis and Mawson stations. Marine ice is more readily accessed by sampling an iceberg than by drilling through an ice shelf

Discover the Atlantic Ocean: An Exciting Coloring Book of Fish and Shellfish.

Science.gov (United States)

Flick, George J.

This coloring book contains pictures of more than 79 fish and shellfish found on the Atlantic Coast. Captions give information on habitats, behavior, or commercial uses of the species pictured. Indexes of both common and scientific names are given. (BB)

VLBI Observations of Geostationary Satellites

Science.gov (United States)

Artz, T.; Nothnagel, A.; La Porta, L.

2013-08-01

For a consistent realization of a Global Geodetic Observing System (GGOS), a proper tie between the individual global reference systems used in the analysis of space-geodetic observations is a prerequisite. For instance, the link between the terrestrial, the celestial and the dynamic reference system of artificial Earth orbiters may be realized by Very Long O Baseline Interferometry (VLBI) observations of one or several satellites. In the preparation phase for a dedicated satellite mission, one option to realize this is using a geostationary (GEO) satellite emitting a radio signal in X-Band and/or S-Band and, thus, imitating a quasar. In this way, the GEO satellite can be observed by VLBI together with nearby quasars and the GEO orbit can, thus, be determined in a celestial reference frame. If the GEO satellite is, e.g., also equipped with a GNSS-type transmitter, a further tie between GNSS and VLBI may be realized. In this paper, a concept for the generation of a radio signal is shown. Furthermore, simulation studies for estimating the GEO position are presented with a GEO satellite included in the VLBI schedule. VLBI group delay observations are then simulated for the quasars as well as for the GEO satellite. The analysis of the simulated observations shows that constant orbit changes are adequately absorbed by estimated orbit parameters. Furthermore, the post-fit residuals are comparable to those from real VLBI sessions.

On the Use of Ocean Color Remote Sensing to Measure the Transport of Dissolved Organic Carbon by the Mississippi River Plume

Science.gov (United States)

DelCastillo, Carlos E.; Miller, Richard L.

2007-01-01

We investigated the use of ocean color remote sensing to measure transport of dissolved organic carbon (DOC) by the Mississippi River to the Gulf of Mexico. From 2000 to 2005 we recorded surface measurements of DOC, colored dissolved organic matter (CDOM), salinity, and water-leaving radiances during five cruises to the Mississippi River Plume. These measurements were used to develop empirical relationships to derive CDOM, DOC, and salinity from monthly composites of SeaWiFS imagery collected from 1998 through 2005. We used river flow data and a two-end-member mixing model to derive DOC concentrations in the river end-member, river flow, and DOC transport using remote sensing data. We compared our remote sensing estimates of river flow and DOC transport with data collected by the United States Geological Survey (USGS) from 1998 through 2005. Our remote sensing estimates of river flow and DOC transport correlated well (r2 0.70) with the USGS data. Our remote sensing estimates and USGS field data showed low variability in DOC concentrations in the river end-member (7-11%), and high seasonal variability in river flow (50%). Therefore, changes in river flow control the variability in DOC transport, indicating that the remote sensing estimate of river flow is the most critical element of our DOC transport measurement. We concluded that it is possible to use this method to estimate DOC transport by other large rivers if there are data on the relationship between CDOM, DOC, and salinity in the river plume.

The CAFE model: A net production model for global ocean phytoplankton

Science.gov (United States)

Silsbe, Greg M.; Behrenfeld, Michael J.; Halsey, Kimberly H.; Milligan, Allen J.; Westberry, Toby K.

2016-12-01

The Carbon, Absorption, and Fluorescence Euphotic-resolving (CAFE) net primary production model is an adaptable framework for advancing global ocean productivity assessments by exploiting state-of-the-art satellite ocean color analyses and addressing key physiological and ecological attributes of phytoplankton. Here we present the first implementation of the CAFE model that incorporates inherent optical properties derived from ocean color measurements into a mechanistic and accurate model of phytoplankton growth rates (μ) and net phytoplankton production (NPP). The CAFE model calculates NPP as the product of energy absorption (QPAR), and the efficiency (ϕμ) by which absorbed energy is converted into carbon biomass (CPhyto), while μ is calculated as NPP normalized to CPhyto. The CAFE model performance is evaluated alongside 21 other NPP models against a spatially robust and globally representative set of direct NPP measurements. This analysis demonstrates that the CAFE model explains the greatest amount of variance and has the lowest model bias relative to other NPP models analyzed with this data set. Global oceanic NPP from the CAFE model (52 Pg C m-2 yr-1) and mean division rates (0.34 day-1) are derived from climatological satellite data (2002-2014). This manuscript discusses and validates individual CAFE model parameters (e.g., QPAR and ϕμ), provides detailed sensitivity analyses, and compares the CAFE model results and parameterization to other widely cited models.

Quantifying the biological impact of surface ocean light attenuation by colored detrital matter in an ESM using a new optical parameterization

Science.gov (United States)

Kim, G. E.; Pradal, M.-A.; Gnanadesikan, A.

2015-08-01

Light attenuation by colored detrital material (CDM) was included in a fully coupled Earth system model (ESM). This study presents a modified parameterization for shortwave attenuation, which is an empirical relationship between 244 concurrent measurements of the diffuse attenuation coefficient for downwelling irradiance, chlorophyll concentration and light absorption by CDM. Two ESM model runs using this parameterization were conducted, with and without light absorption by CDM. The light absorption coefficient for CDM was prescribed as the average of annual composite MODIS Aqua satellite data from 2002 to 2013. Comparing results from the two model runs shows that changes in light limitation associated with the inclusion of CDM decoupled trends between surface biomass and nutrients. Increases in surface biomass were expected to accompany greater nutrient uptake and therefore diminish surface nutrients. Instead, surface chlorophyll, biomass and nutrients increased together. These changes can be attributed to the different impact of light limitation on surface productivity versus total productivity. Chlorophyll and biomass increased near the surface but decreased at greater depths when CDM was included. The net effect over the euphotic zone was less total biomass leading to higher nutrient concentrations. Similar results were found in a regional analysis of the oceans by biome, investigating the spatial variability of response to changes in light limitation using a single parameterization for the surface ocean. In coastal regions, surface chlorophyll increased by 35 % while total integrated phytoplankton biomass diminished by 18 %. The largest relative increases in modeled surface chlorophyll and biomass in the open ocean were found in the equatorial biomes, while the largest decreases in depth-integrated biomass and chlorophyll were found in the subpolar and polar biomes. This mismatch of surface and subsurface trends and their regional dependence was analyzed by

The attitude inversion method of geostationary satellites based on unscented particle filter

Science.gov (United States)

Du, Xiaoping; Wang, Yang; Hu, Heng; Gou, Ruixin; Liu, Hao

2018-04-01

The attitude information of geostationary satellites is difficult to be obtained since they are presented in non-resolved images on the ground observation equipment in space object surveillance. In this paper, an attitude inversion method for geostationary satellite based on Unscented Particle Filter (UPF) and ground photometric data is presented. The inversion algorithm based on UPF is proposed aiming at the strong non-linear feature in the photometric data inversion for satellite attitude, which combines the advantage of Unscented Kalman Filter (UKF) and Particle Filter (PF). This update method improves the particle selection based on the idea of UKF to redesign the importance density function. Moreover, it uses the RMS-UKF to partially correct the prediction covariance matrix, which improves the applicability of the attitude inversion method in view of UKF and the particle degradation and dilution of the attitude inversion method based on PF. This paper describes the main principles and steps of algorithm in detail, correctness, accuracy, stability and applicability of the method are verified by simulation experiment and scaling experiment in the end. The results show that the proposed method can effectively solve the problem of particle degradation and depletion in the attitude inversion method on account of PF, and the problem that UKF is not suitable for the strong non-linear attitude inversion. However, the inversion accuracy is obviously superior to UKF and PF, in addition, in the case of the inversion with large attitude error that can inverse the attitude with small particles and high precision.

Processing of Color Words Activates Color Representations

Science.gov (United States)

Richter, Tobias; Zwaan, Rolf A.

2009-01-01

Two experiments were conducted to investigate whether color representations are routinely activated when color words are processed. Congruency effects of colors and color words were observed in both directions. Lexical decisions on color words were faster when preceding colors matched the color named by the word. Color-discrimination responses…

Color categories and color appearance

Science.gov (United States)

Webster, Michael A.; Kay, Paul

2011-01-01

We examined categorical effects in color appearance in two tasks, which in part differed in the extent to which color naming was explicitly required for the response. In one, we measured the effects of color differences on perceptual grouping for hues that spanned the blue–green boundary, to test whether chromatic differences across the boundary were perceptually exaggerated. This task did not require overt judgments of the perceived colors, and the tendency to group showed only a weak and inconsistent categorical bias. In a second case, we analyzed results from two prior studies of hue scaling of chromatic stimuli (De Valois, De Valois, Switkes, & Mahon, 1997; Malkoc, Kay, & Webster, 2005), to test whether color appearance changed more rapidly around the blue–green boundary. In this task observers directly judge the perceived color of the stimuli and these judgments tended to show much stronger categorical effects. The differences between these tasks could arise either because different signals mediate color grouping and color appearance, or because linguistic categories might differentially intrude on the response to color and/or on the perception of color. Our results suggest that the interaction between language and color processing may be highly dependent on the specific task and cognitive demands and strategies of the observer, and also highlight pronounced individual differences in the tendency to exhibit categorical responses. PMID:22176751

Preferred skin color enhancement for photographic color reproduction

Science.gov (United States)

Zeng, Huanzhao; Luo, Ronnier

2011-01-01

Skin tones are the most important colors among the memory color category. Reproducing skin colors pleasingly is an important factor in photographic color reproduction. Moving skin colors toward their preferred skin color center improves the color preference of skin color reproduction. Several methods to morph skin colors to a smaller preferred skin color region has been reported in the past. In this paper, a new approach is proposed to further improve the result of skin color enhancement. An ellipsoid skin color model is applied to compute skin color probabilities for skin color detection and to determine a weight for skin color adjustment. Preferred skin color centers determined through psychophysical experiments were applied for color adjustment. Preferred skin color centers for dark, medium, and light skin colors are applied to adjust skin colors differently. Skin colors are morphed toward their preferred color centers. A special processing is applied to avoid contrast loss in highlight. A 3-D interpolation method is applied to fix a potential contouring problem and to improve color processing efficiency. An psychophysical experiment validates that the method of preferred skin color enhancement effectively identifies skin colors, improves the skin color preference, and does not objectionably affect preferred skin colors in original images.

A Synthesis of Light Absorption Properties of the Arctic Ocean: Application to Semi-analytical Estimates of Dissolved Organic Carbon Concentrations from Space

Science.gov (United States)

Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Belanger, S.; Bricaud, A.

2014-01-01

The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean [e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012], the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher 74 than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained 75 by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian 76 side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off 77 North America. In contrast, the relationship between the phytoplankton absorption (a()) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific a() values [Matsuoka et al., 2013], this result indirectly suggests that CDOM absorption can be appropriately erived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC versus CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

Do focal colors look particularly "colorful"?

Science.gov (United States)

Witzel, Christoph; Franklin, Anna

2014-04-01

If the most typical red, yellow, green, and blue were particularly colorful (i.e., saturated), they would "jump out to the eye." This would explain why even fundamentally different languages have distinct color terms for these focal colors, and why unique hues play a prominent role in subjective color appearance. In this study, the subjective saturation of 10 colors around each of these focal colors was measured through a pairwise matching task. Results show that subjective saturation changes systematically across hues in a way that is strongly correlated to the visual gamut, and exponentially related to sensitivity but not to focal colors.

Using color management in color document processing

Science.gov (United States)

Nehab, Smadar

1995-04-01

Color Management Systems have been used for several years in Desktop Publishing (DTP) environments. While this development hasn't matured yet, we are already experiencing the next generation of the color imaging revolution-Device Independent Color for the small office/home office (SOHO) environment. Though there are still open technical issues with device independent color matching, they are not the focal point of this paper. This paper discusses two new and crucial aspects in using color management in color document processing: the management of color objects and their associated color rendering methods; a proposal for a precedence order and handshaking protocol among the various software components involved in color document processing. As color peripherals become affordable to the SOHO market, color management also becomes a prerequisite for common document authoring applications such as word processors. The first color management solutions were oriented towards DTP environments whose requirements were largely different. For example, DTP documents are image-centric, as opposed to SOHO documents that are text and charts centric. To achieve optimal reproduction on low-cost SOHO peripherals, it is critical that different color rendering methods are used for the different document object types. The first challenge in using color management of color document processing is the association of rendering methods with object types. As a result of an evolutionary process, color matching solutions are now available as application software, as driver embedded software and as operating system extensions. Consequently, document processing faces a new challenge, the correct selection of the color matching solution while avoiding duplicate color corrections.

Automatic color preference correction for color reproduction

Science.gov (United States)

Tsukada, Masato; Funayama, Chisato; Tajima, Johji

2000-12-01

The reproduction of natural objects in color images has attracted a great deal of attention. Reproduction more pleasing colors of natural objects is one of the methods available to improve image quality. We developed an automatic color correction method to maintain preferred color reproduction for three significant categories: facial skin color, green grass and blue sky. In this method, a representative color in an object area to be corrected is automatically extracted from an input image, and a set of color correction parameters is selected depending on the representative color. The improvement in image quality for reproductions of natural image was more than 93 percent in subjective experiments. These results show the usefulness of our automatic color correction method for the reproduction of preferred colors.

2015 NOAA Ortho-rectified Color Mosaic of San Diego, California: Integrated Ocean and Coastal Mapping Product

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

NOAA Integrated Ocean and Coastal Mapping (IOCM) orthorectified mosaic image tiles, Merrimack River and Plum Island Sound, Massachusetts, June 2011 (NODC Accession 0103944)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains both true color (RGB) and infrared (IR) ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping...

A Study on Fuel Estimation Algorithms for a Geostationary Communication & Broadcasting Satellite

Directory of Open Access Journals (Sweden)

Jong Won Eun

2000-12-01

Full Text Available It has been developed to calculate fuel budget for a geostationary communication and broadcasting satellite. It is quite essential that the pre-launch fuel budget estimation must account for the deterministic transfer and drift orbit maneuver requirements. After on-station, the calculation of satellite lifetime should be based on the estimation of remaining fuel and assessment of actual performance. These estimations step from the proper algorithms to produce the prediction of satellite lifetime. This paper concentrates on the fuel estimation method that was studied for calculation of the propellant budget by using the given algorithms. Applications of this method are discussed for a communication and broadcasting satellite.

Development of Mission and Spacecraft Dynamics Analysis System for Geostationary Communication Satellite

Directory of Open Access Journals (Sweden)

Hyeon Cheol Gong

1998-06-01

Full Text Available We consider the motion of the subsystems as separate bodies as well as the entire satellite for the attitude and orbit control of a communication satellite by multi-body modeling technique. Thus, the system can be applied to a general communication satellite as well as a specific communication satellite, i.e. Koreasat I, II. The simulation results can be viewed by two-dimensional graphics and three-dimensional animation. The graphical user interface (GUI makes its usage much simpler. We have simulated a couple of scenarios for Koreasat I, II which are being operated as geostationary communication satellites to verify the system performance.

Embedding Color Watermarks in Color Images

Directory of Open Access Journals (Sweden)

Wu Tung-Lin

2003-01-01

Full Text Available Robust watermarking with oblivious detection is essential to practical copyright protection of digital images. Effective exploitation of the characteristics of human visual perception to color stimuli helps to develop the watermarking scheme that fills the requirement. In this paper, an oblivious watermarking scheme that embeds color watermarks in color images is proposed. Through color gamut analysis and quantizer design, color watermarks are embedded by modifying quantization indices of color pixels without resulting in perceivable distortion. Only a small amount of information including the specification of color gamut, quantizer stepsize, and color tables is required to extract the watermark. Experimental results show that the proposed watermarking scheme is computationally simple and quite robust in face of various attacks such as cropping, low-pass filtering, white-noise addition, scaling, and JPEG compression with high compression ratios.

A synthesis of light absorption properties of the Pan-Arctic Ocean: application to semi-analytical estimates of dissolved organic carbon concentrations from space

Science.gov (United States)

Matsuoka, A.; Babin, M.; Doxaran, D.; Hooker, S. B.; Mitchell, B. G.; Bélanger, S.; Bricaud, A.

2013-11-01

The light absorption coefficients of particulate and dissolved materials are the main factors determining the light propagation of the visible part of the spectrum and are, thus, important for developing ocean color algorithms. While these absorption properties have recently been documented by a few studies for the Arctic Ocean (e.g., Matsuoka et al., 2007, 2011; Ben Mustapha et al., 2012), the datasets used in the literature were sparse and individually insufficient to draw a general view of the basin-wide spatial and temporal variations in absorption. To achieve such a task, we built a large absorption database at the pan-Arctic scale by pooling the majority of published datasets and merging new datasets. Our results showed that the total non-water absorption coefficients measured in the Eastern Arctic Ocean (EAO; Siberian side) are significantly higher than in the Western Arctic Ocean (WAO; North American side). This higher absorption is explained by higher concentration of colored dissolved organic matter (CDOM) in watersheds on the Siberian side, which contains a large amount of dissolved organic carbon (DOC) compared to waters off North America. In contrast, the relationship between the phytoplankton absorption (aφ(λ)) and chlorophyll a (chl a) concentration in the EAO was not significantly different from that in the WAO. Because our semi-analytical CDOM absorption algorithm is based on chl a-specific aφ(λ) values (Matsuoka et al., 2013), this result indirectly suggests that CDOM absorption can be appropriately derived not only for the WAO but also for the EAO using ocean color data. Derived CDOM absorption values were reasonable compared to in situ measurements. By combining this algorithm with empirical DOC vs. CDOM relationships, a semi-analytical algorithm for estimating DOC concentrations for coastal waters at the Pan-Arctic scale is presented and applied to satellite ocean color data.

Color evaluation of computer-generated color rainbow holography

International Nuclear Information System (INIS)

Shi, Yile; Wang, Hui; Wu, Qiong

2013-01-01

A color evaluation approach for computer-generated color rainbow holography (CGCRH) is presented. Firstly, the relationship between color quantities of a computer display and a color computer-generated holography (CCGH) colorimetric system is discussed based on color matching theory. An isochromatic transfer relationship of color quantity and amplitude of object light field is proposed. Secondly, the color reproduction mechanism and factors leading to the color difference between the color object and the holographic image that is reconstructed by CGCRH are analyzed in detail. A quantitative color calculation method for the holographic image reconstructed by CGCRH is given. Finally, general color samples are selected as numerical calculation test targets and the color differences between holographic images and test targets are calculated based on our proposed method. (paper)

Sensory Drive, Color, and Color Vision.

Science.gov (United States)

Price, Trevor D

2017-08-01

Colors often appear to differ in arbitrary ways among related species. However, a fraction of color diversity may be explained because some signals are more easily perceived in one environment rather than another. Models show that not only signals but also the perception of signals should regularly evolve in response to different environments, whether these primarily involve detection of conspecifics or detection of predators and prey. Thus, a deeper understanding of how perception of color correlates with environmental attributes should help generate more predictive models of color divergence. Here, I briefly review our understanding of color vision in vertebrates. Then I focus on opsin spectral tuning and opsin expression, two traits involved in color perception that have become amenable to study. I ask how opsin tuning is correlated with ecological differences, notably the light environment, and how this potentially affects perception of conspecific colors. Although opsin tuning appears to evolve slowly, opsin expression levels are more evolutionarily labile but have been difficult to connect to color perception. The challenge going forward will be to identify how physiological differences involved in color vision, such as opsin expression levels, translate into perceptual differences, the selection pressures that have driven those differences, and ultimately how this may drive evolution of conspecific colors.

Color planner for designers based on color emotions

Science.gov (United States)

Cheng, Ka-Man; Xin, John H.; Taylor, Gail

2002-06-01

During the color perception process, an associated feeling or emotion is induced in our brains, and this kind of emotion is termed as 'color emotion.' The researchers in the field of color emotions have put many efforts in quantifying color emotions with the standard color specifications and evaluating the influence of hue, lightness and chroma to the color emotions of human beings. In this study, a color planner was derived according to these findings so that the correlation of color emotions and standard color specifications was clearly indicated. Since people of different nationalities usually have different color emotions as different cultural and traditional backgrounds, the subjects in this study were all native Hong Kong Chinese and the color emotion words were all written in Chinese language in the visual assessments. Through the color planner, the designers from different areas, no matter fashion, graphic, interior or web site etc., can select suitable colors for inducing target color emotions to the customers or product-users since different colors convey different meanings to them. In addition, the designers can enhance the functionality and increase the attractiveness of their designed products by selecting suitable colors.

A Novel Location-Awareness Method Using CubeSats for Locating the Spot Beam Emitters of Geostationary Communications Satellites

Directory of Open Access Journals (Sweden)

Weicai Yang

2018-01-01

Full Text Available As more spacecraft are launched into the Geostationary Earth Orbit (GEO belt, the possibility of fatal collisions or unnecessary interference between spacecraft increases. In this paper, a new location-awareness method that uses CubeSats is proposed to assist with radiofrequency (RF domain verification by means of awareness and identification of the positions of the spot beam emitters of communications satellites in geostationary orbit. By flying a CubeSat (or a constellation of CubeSats through the coverage area of a spot beam, the spot beam emitter’s position is identified and the spot beam’s pattern knowledge is characterized. The geometry, the equations of motion of the spacecraft, the measurement process, and the filtering equations in a location system are addressed with respect to the location methods investigated in this study. A realistic scenario in which a CubeSat receives signals from GEO communications satellites is simulated using the Systems Tool Kit (STK. The results of the simulation and the analysis presented in this study provide a thorough verification of the performance of the location-awareness method.

The Copernicus Sentinel 4 mission: a geostationary imaging UVN spectrometer for air quality monitoring

Science.gov (United States)

Bazalgette Courrèges-Lacoste, G.; Sallusti, M.; Bulsa, G.; Bagnasco, G.; Veihelmann, Ben; Riedl, S.; Smith, D. J.; Maurer, R.

2017-09-01

Sentinel-4 is an imaging UVN (UV-VIS-NIR) spectrometer, developed by Airbus Defence and Space under ESA contract in the frame of the joint EU/ESA COPERNICUS program. The mission objective is the operational monitoring of trace gas concentrations for atmospheric chemistry and climate applications - hence the motto of Sentinel-4 "Knowing what we breathe". Sentinel-4 will provide accurate measurements of key atmospheric constituents such as ozone, nitrogen dioxide, sulfur dioxide, methane, and aerosol properties over Europe and adjacent regions from a geostationary orbit (see Fig. 1). In the family of already flown UVN spectrometers (SCIAMACHY, OMI, GOME and GOME 2) and of those spectrometers currently under development (Sentinel-5p and Sentinel-5), Sentinel-4 is unique in being the first geostationary UVN mission. Furthermore, thanks to its 60-minutes repeat cycle measurements and high spatial resolution (8x8 km2), Sentinel-4 will increase the frequency of cloud-free observations, which is necessary to assess troposphere variability. Two identical Sentinel-4 instruments (PFM and FM-2) will be embarked, as Customer Furnished Item (CFI), fully verified, qualified and calibrated respectively onto two EUMETSAT satellites: Meteosat Third Generation-Sounder 1 and 2 (MTG-S1 and MTG-S2), whose Flight Acceptance Reviews are presently planned respectively in Q4 2021 and Q1 2030. This paper gives an overview of the Sentinel-4 system1 architecture, its design and development status, current performances and the key technological challenges.

DeepSAT's CloudCNN: A Deep Neural Network for Rapid Cloud Detection from Geostationary Satellites

Science.gov (United States)

Kalia, S.; Li, S.; Ganguly, S.; Nemani, R. R.

2017-12-01

Cloud and cloud shadow detection has important applications in weather and climate studies. It is even more crucial when we introduce geostationary satellites into the field of terrestrial remotesensing. With the challenges associated with data acquired in very high frequency (10-15 mins per scan), the ability to derive an accurate cloud/shadow mask from geostationary satellite data iscritical. The key to the success for most of the existing algorithms depends on spatially and temporally varying thresholds, which better capture local atmospheric and surface effects.However, the selection of proper threshold is difficult and may lead to erroneous results. In this work, we propose a deep neural network based approach called CloudCNN to classifycloud/shadow from Himawari-8 AHI and GOES-16 ABI multispectral data. DeepSAT's CloudCNN consists of an encoder-decoder based architecture for binary-class pixel wise segmentation. We train CloudCNN on multi-GPU Nvidia Devbox cluster, and deploy the prediction pipeline on NASA Earth Exchange (NEX) Pleiades supercomputer. We achieved an overall accuracy of 93.29% on test samples. Since, the predictions take only a few seconds to segment a full multi-spectral GOES-16 or Himawari-8 Full Disk image, the developed framework can be used for real-time cloud detection, cyclone detection, or extreme weather event predictions.

A TEMPORAL MAP IN GEOSTATIONARY ORBIT: THE COVER ETCHING ON THE EchoStar XVI ARTIFACT

Energy Technology Data Exchange (ETDEWEB)

Weisberg, Joel M., E-mail: jweisber@carleton.edu [Department of Physics and Astronomy, Carleton College, Northfield, MN 55057 (United States); Paglen, Trevor, E-mail: trevor@paglen.com

2012-10-01

Geostationary satellites are unique among orbital spacecraft in that they experience no appreciable atmospheric drag. After concluding their respective missions, geostationary spacecraft remain in orbit virtually in perpetuity. As such, they represent some of human civilization's longest lasting artifacts. With this in mind, the EchoStar XVI satellite, to be launched in fall 2012, will play host to a time capsule intended as a message for the deep future. Inspired in part by the Pioneer Plaque and Voyager Golden Records, the EchoStar XVI Artifact is a pair of gold-plated aluminum jackets housing a small silicon disk containing 100 photographs. The Cover Etching, the subject of this paper, is etched onto one of the two jackets. It is a temporal map consisting of a star chart, pulsar timings, and other information describing the epoch from which EchoStar XVI came. The pulsar sample consists of 13 rapidly rotating objects, 5 of which are especially stable, having spin periods <10 ms and extremely small spin-down rates. In this paper, we discuss our approach to the time map etched onto the cover and the scientific data shown on it, and we speculate on the uses that future scientists may have for its data. The other portions of the EchoStar XVI Artifact will be discussed elsewhere.

A TEMPORAL MAP IN GEOSTATIONARY ORBIT: THE COVER ETCHING ON THE EchoStar XVI ARTIFACT

International Nuclear Information System (INIS)

Weisberg, Joel M.; Paglen, Trevor

2012-01-01

Geostationary satellites are unique among orbital spacecraft in that they experience no appreciable atmospheric drag. After concluding their respective missions, geostationary spacecraft remain in orbit virtually in perpetuity. As such, they represent some of human civilization's longest lasting artifacts. With this in mind, the EchoStar XVI satellite, to be launched in fall 2012, will play host to a time capsule intended as a message for the deep future. Inspired in part by the Pioneer Plaque and Voyager Golden Records, the EchoStar XVI Artifact is a pair of gold-plated aluminum jackets housing a small silicon disk containing 100 photographs. The Cover Etching, the subject of this paper, is etched onto one of the two jackets. It is a temporal map consisting of a star chart, pulsar timings, and other information describing the epoch from which EchoStar XVI came. The pulsar sample consists of 13 rapidly rotating objects, 5 of which are especially stable, having spin periods <10 ms and extremely small spin-down rates. In this paper, we discuss our approach to the time map etched onto the cover and the scientific data shown on it, and we speculate on the uses that future scientists may have for its data. The other portions of the EchoStar XVI Artifact will be discussed elsewhere.

Analysis of Specular Reflections Off Geostationary Satellites

Science.gov (United States)

Jolley, A.

2016-09-01

Many photometric studies of artificial satellites have attempted to define procedures that minimise the size of datasets required to infer information about satellites. However, it is unclear whether deliberately limiting the size of datasets significantly reduces the potential for information to be derived from them. In 2013 an experiment was conducted using a 14 inch Celestron CG-14 telescope to gain multiple night-long, high temporal resolution datasets of six geostationary satellites [1]. This experiment produced evidence of complex variations in the spectral energy distribution (SED) of reflections off satellite surface materials, particularly during specular reflections. Importantly, specific features relating to the SED variations could only be detected with high temporal resolution data. An update is provided regarding the nature of SED and colour variations during specular reflections, including how some of the variables involved contribute to these variations. Results show that care must be taken when comparing observed spectra to a spectral library for the purpose of material identification; a spectral library that uses wavelength as the only variable will be unable to capture changes that occur to a material's reflected spectra with changing illumination and observation geometry. Conversely, colour variations with changing illumination and observation geometry might provide an alternative means of determining material types.

Tracing the transport of colored dissolved organic matter in water masses of the Southern Beaufort Sea: relationship with hydrographic characteristics

Science.gov (United States)

Matsuoka, A.; Bricaud, A.; Benner, R.; Para, J.; Sempéré, R.; Prieur, L.; Bélanger, S.; Babin, M.

2012-03-01

Light absorption by colored dissolved organic matter (CDOM) [aCDOM(λ)] plays an important role in the heat budget of the Arctic Ocean, contributing to the recent decline in sea ice, as well as in biogeochemical processes. We investigated aCDOM(λ) in the Southern Beaufort Sea where a significant amount of CDOM is delivered by the Mackenzie River. In the surface layer, aCDOM(440) showed a strong and negative correlation with salinity, indicating strong river influence and conservative transport in the river plume. Below the mixed layer, a weak but positive correlation between aCDOM(440) and salinity was observed above the upper halocline, resulting from the effect of removal of CDOM due to brine rejection and lateral intrusion of Pacific summer waters into these layers. In contrast, the relationship was negative in the upper and the lower haloclines, suggesting these waters originated from Arctic coastal waters. DOC concentrations in the surface layer were strongly correlated with aCDOM(440) (r2 = 0.97), suggesting that this value can be estimated in this area, using aCDOM(440) that is retrieved using satellite ocean color data. Implications for estimation of DOC concentrations in surface waters using ocean color remote sensing are discussed.

A geostationary satellite system for mobile multimedia applications using portable, aeronautical and mobile terminals

Science.gov (United States)

Losquadro, G.; Luglio, M.; Vatalaro, F.

1997-01-01

A geostationary satellite system for mobile multimedia services via portable, aeronautical and mobile terminals was developed within the framework of the Advanced Communications Technology Service (ACTS) programs. The architecture of the system developed under the 'satellite extremely high frequency communications for multimedia mobile services (SECOMS)/ACTS broadband aeronautical terminal experiment' (ABATE) project is presented. The system will be composed of a Ka band system component, and an extremely high frequency band component. The major characteristics of the space segment, the ground control station and the portable, aeronautical and mobile user terminals are outlined.

Derivation and evaluation of land surface temperature from the geostationary operational environmental satellite series

Science.gov (United States)

Fang, Li

The Geostationary Operational Environmental Satellites (GOES) have been continuously monitoring the earth surface since 1970, providing valuable and intensive data from a very broad range of wavelengths, day and night. The National Oceanic and Atmospheric Administration's (NOAA's) National Environmental Satellite, Data, and Information Service (NESDIS) is currently operating GOES-15 and GOES-13. The design of the GOES series is now heading to the 4 th generation. GOES-R, as a representative of the new generation of the GOES series, is scheduled to be launched in 2015 with higher spatial and temporal resolution images and full-time soundings. These frequent observations provided by GOES Image make them attractive for deriving information on the diurnal land surface temperature (LST) cycle and diurnal temperature range (DTR). These parameters are of great value for research on the Earth's diurnal variability and climate change. Accurate derivation of satellite-based LSTs from thermal infrared data has long been an interesting and challenging research area. To better support the research on climate change, the generation of consistent GOES LST products for both GOES-East and GOES-West from operational dataset as well as historical archive is in great demand. The derivation of GOES LST products and the evaluation of proposed retrieval methods are two major objectives of this study. Literature relevant to satellite-based LST retrieval techniques was reviewed. Specifically, the evolution of two LST algorithm families and LST retrieval methods for geostationary satellites were summarized in this dissertation. Literature relevant to the evaluation of satellite-based LSTs was also reviewed. All the existing methods are a valuable reference to develop the GOES LST product. The primary objective of this dissertation is the development of models for deriving consistent GOES LSTs with high spatial and high temporal coverage. Proper LST retrieval algorithms were studied

High Temporal and Spatial Resolution Coverage of Earth from Commercial AVSTAR Systems in Geostationary Orbit

Science.gov (United States)

Lecompte, M. A.; Heaps, J. F.; Williams, F. H.

Imaging the earth from Geostationary Earth Orbit (GEO) allows frequent updates of environmental conditions within an observable hemisphere at time and spatial scales appropriate to the most transient observable terrestrial phenomena. Coverage provided by current GEO Meteorological Satellites (METSATS) fails to fully exploit this advantage due primarily to obsolescent technology and also institutional inertia. With the full benefit of GEO based imaging unrealized, rapidly evolving phenomena, occurring at the smallest spatial and temporal scales that frequently have significant environmental impact remain unobserved. These phenomena may be precursors for the most destructive natural processes that adversely effect society. Timely distribution of information derived from "real-time" observations thus may provide opportunities to mitigate much of the damage to life and property that would otherwise occur. AstroVision International's AVStar Earth monitoring system is designed to overcome the current limitations if GEO Earth coverage and to provide real time monitoring of changes to the Earth's complete atmospheric, land and marine surface environments including fires, volcanic events, lightning and meteoritic events on a "live," true color, and multispectral basis. The understanding of severe storm dynamics and its coupling to the earth's electro-sphere will be greatly enhanced by observations at unprecedented sampling frequencies and spatial resolution. Better understanding of these natural phenomena and AVStar operational real-time coverage may also benefit society through improvements in severe weather prediction and warning. AstroVision's AVStar system, designed to provide this capability with the first of a constellation of GEO- based commercial environmental monitoring satellites to be launched in late 2003 will be discussed, including spatial and temporal resolution, spectral coverage with applications and an inventory of the potential benefits to society

Estimating absorption coefficients of colored dissolved organic matter (CDOM) using a semi-analytical algorithm for Southern Beaufort Sea (Canadian Arctic) waters: application to deriving concentrations of dissolved organic carbon from space

Science.gov (United States)

Matsuoka, A.; Hooker, S. B.; Bricaud, A.; Gentili, B.; Babin, M.

2012-10-01

A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM), has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM) was developed for Southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows to separate colored detrital matter (CDM) into CDOM and non-algal particles (NAP) by determining NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, that were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and turbid waters, respectively. In situ measurements showed that dissolved organic carbon (DOC) concentrations were tightly correlated with CDOM absorption (r2 = 0.97). By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the Southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

Colorization-Based RGB-White Color Interpolation using Color Filter Array with Randomly Sampled Pattern.

Science.gov (United States)

Oh, Paul; Lee, Sukho; Kang, Moon Gi

2017-06-28

Recently, several RGB-White (RGBW) color filter arrays (CFAs) have been proposed, which have extra white (W) pixels in the filter array that are highly sensitive. Due to the high sensitivity, the W pixels have better SNR (Signal to Noise Ratio) characteristics than other color pixels in the filter array, especially, in low light conditions. However, most of the RGBW CFAs are designed so that the acquired RGBW pattern image can be converted into the conventional Bayer pattern image, which is then again converted into the final color image by using conventional demosaicing methods, i.e., color interpolation techniques. In this paper, we propose a new RGBW color filter array based on a totally different color interpolation technique, the colorization algorithm. The colorization algorithm was initially proposed for colorizing a gray image into a color image using a small number of color seeds. Here, we adopt this algorithm as a color interpolation technique, so that the RGBW color filter array can be designed with a very large number of W pixels to make the most of the highly sensitive characteristics of the W channel. The resulting RGBW color filter array has a pattern with a large proportion of W pixels, while the small-numbered RGB pixels are randomly distributed over the array. The colorization algorithm makes it possible to reconstruct the colors from such a small number of RGB values. Due to the large proportion of W pixels, the reconstructed color image has a high SNR value, especially higher than those of conventional CFAs in low light condition. Experimental results show that many important information which are not perceived in color images reconstructed with conventional CFAs are perceived in the images reconstructed with the proposed method.

Of colored numbers and numbered colors: interactive processes in grapheme-color synesthesia.

Science.gov (United States)

Gebuis, Titia; Nijboer, Tanja C W; van der Smagt, Maarten J

2009-01-01

Grapheme-color synesthetes experience a specific color when they see a grapheme but they do not report to perceive a grapheme when a color is presented. In this study, we investigate whether color can still evoke number-processes even when a vivid number experience is absent. We used color-number and number-color priming, both revealing faster responses in congruent compared to incongruent conditions. Interestingly, the congruency effect was of similar magnitude for both conditions, and a numerical distance effect was present only in the color-number priming task. In addition, a priming task in which synesthetes had to judge the parity of a colored number revealed faster responses in parity congruent than in parity incongruent trials. These combined results demonstrate that synesthesia is indeed bi-directional and of similar strength in both directions. Furthermore, they illustrate the precise nature of these interactions and show that the direction of these interactions is determined by task demands, not by the more vividly experienced aspect of the stimulus.

Estimating absorption coefficients of colored dissolved organic matter (CDOM) using a semi-analytical algorithm for southern Beaufort Sea waters: application to deriving concentrations of dissolved organic carbon from space

Science.gov (United States)

Matsuoka, A.; Hooker, S. B.; Bricaud, A.; Gentili, B.; Babin, M.

2013-02-01

A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM), has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM) was developed for southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows the separation of colored detrital matter (CDM) into CDOM and non-algal particles (NAP) through the determination of NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, which were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and coastal waters, respectively. A previous paper (Matsuoka et al., 2012) showed that dissolved organic carbon (DOC) concentrations were tightly correlated with CDOM absorption in our study area (r2 = 0.97). By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

Verification of mid-ocean ballast water exchange using naturally occurring coastal tracers

Energy Technology Data Exchange (ETDEWEB)

Murphy, Kathleen; Boehme, Jennifer; Coble, Paula; Cullen, Jay; Field, Paul; Moore, Willard; Perry, Elgin; Sherrell, Robert; Ruiz, Gregory

2004-04-01

We examined methods for verifying whether or not ships have performed mid-ocean ballast water exchange (BWE) on four commercial vessels operating in the Pacific and Atlantic Oceans. During BWE, a ship replaces the coastal water in its ballast tanks with water drawn from the open ocean, which is considered to harbor fewer organisms capable of establishing in coastal environments. We measured concentrations of several naturally occurring chemical tracers (salinity, six trace elements, colored dissolved organic matter fluorescence and radium isotopes) along ocean transects and in ballast tanks subjected to varying degrees of BWE (0-99%). Many coastal tracers showed significant concentration changes due to BWE, and our ability to detect differences between exchanged and unexchanged ballast tanks was greatest under multivariate analysis. An expanded dataset, which includes additional geographic regions, is now needed to test the generality of our results.

Verification of mid-ocean ballast water exchange using naturally occurring coastal tracers

International Nuclear Information System (INIS)

Murphy, Kathleen; Boehme, Jennifer; Coble, Paula; Cullen, Jay; Field, Paul; Moore, Willard; Perry, Elgin; Sherrell, Robert; Ruiz, Gregory

2004-01-01

We examined methods for verifying whether or not ships have performed mid-ocean ballast water exchange (BWE) on four commercial vessels operating in the Pacific and Atlantic Oceans. During BWE, a ship replaces the coastal water in its ballast tanks with water drawn from the open ocean, which is considered to harbor fewer organisms capable of establishing in coastal environments. We measured concentrations of several naturally occurring chemical tracers (salinity, six trace elements, colored dissolved organic matter fluorescence and radium isotopes) along ocean transects and in ballast tanks subjected to varying degrees of BWE (0-99%). Many coastal tracers showed significant concentration changes due to BWE, and our ability to detect differences between exchanged and unexchanged ballast tanks was greatest under multivariate analysis. An expanded dataset, which includes additional geographic regions, is now needed to test the generality of our results

Precision of synesthetic color matching resembles that for recollected colors rather than physical colors.

Science.gov (United States)

Arnold, Derek H; Wegener, Signy V; Brown, Francesca; Mattingley, Jason B

2012-10-01

Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but hearing the name of a grapheme does not. This dissociation allowed us to compare the precision with which synesthetes are able to match their color experiences triggered by visible graphemes, with the precision of their matches for recalled colors based on the same graphemes spoken aloud. In six synesthetes, color matching for printed graphemes was equally variable relative to recalled experiences. In a control experiment, synesthetes and age-matched controls either matched the color of a circular patch while it was visible on a screen, or they judged its color from memory after it had disappeared. Both synesthetes and controls were more variable when matching from memory, and the variance of synesthetes' recalled color judgments matched that associated with their synesthetic judgments for visible graphemes in the first experiment. Results suggest that synesthetic experiences of color triggered by achromatic graphemes are analogous to recollections of color.

Color Terms and Color Concepts

Science.gov (United States)

Davidoff, Jules

2006-01-01

In their lead articles, both Kowalski and Zimiles (2006) and O'Hanlon and Roberson (2006) declare a general relation between color term knowledge and the ability to conceptually represent color. Kowalski and Zimiles, in particular, argue for a priority for the conceptual representation in color term acquisition. The complexities of the interaction…

Color Categories and Color Appearance

Science.gov (United States)

Webster, Michael A.; Kay, Paul

2012-01-01

We examined categorical effects in color appearance in two tasks, which in part differed in the extent to which color naming was explicitly required for the response. In one, we measured the effects of color differences on perceptual grouping for hues that spanned the blue-green boundary, to test whether chromatic differences across the boundary…

Temperature, salinity, and optical characteristics data from NOAA Office of Ocean Exploration Operation Deep Scope cruise in the Gulf of Mexico, August 7-17, 2004 (NODC Accession 0001965)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This accession includes physical, chemical, optical and ocean color measurements, video and still photography data collected during the Operation Deep Scope cruise,...

Color Memory of University Students: Influence of Color Experience and Color Characteristic

Science.gov (United States)

Bynum, Carlisle; Epps, Helen H.; Kaya, Naz

2006-01-01

The ability to select a previously viewed color specimen from an array of specimens that differ in hue, value, or chroma varies among individuals, and may be related to one's basic color discrimination ability or to prior experience with color. This study investigated short-term color memory of 40 college students, 20 of whom were interior design…

Memory for color reactivates color processing region.

Science.gov (United States)

Slotnick, Scott D

2009-11-25

Memory is thought to be constructive in nature, where features processed in different cortical regions are synthesized during retrieval. In an effort to support this constructive memory framework, the present functional magnetic resonance imaging study assessed whether memory for color reactivated color processing regions. During encoding, participants were presented with colored and gray abstract shapes. During retrieval, old and new shapes were presented in gray and participants responded 'old-colored', 'old-gray', or 'new'. Within color perception regions, color memory related activity was observed in the left fusiform gyrus, adjacent to the collateral sulcus. A retinotopic mapping analysis indicated this activity occurred within color processing region V8. The present feature specific evidence provides compelling support for a constructive view of memory.

The Potential of Autonomous Ship-Borne Hyperspectral Radiometers for the Validation of Ocean Color Radiometry Data

Directory of Open Access Journals (Sweden)

Vittorio E. Brando

2016-02-01

Full Text Available Calibration and validation of satellite observations are essential and on-going tasks to ensure compliance with mission accuracy requirements. An automated above water hyperspectral radiometer significantly augmented Australia’s ability to contribute to global and regional ocean color validation and algorithm design activities. The hyperspectral data can be re-sampled for comparison with current and future sensor wavebands. The continuous spectral acquisition along the ship track enables spatial resampling to match satellite footprint. This study reports spectral comparisons of the radiometer data with Visible Infrared Imaging Radiometer Suite (VIIRS and Moderate Resolution Imaging Spectroradiometer (MODIS-Aqua for contrasting water types in tropical waters off northern Australia based on the standard NIR atmospheric correction implemented in SeaDAS. Consistent match-ups are shown for transects of up to 50 km over a range of reflectance values. The MODIS and VIIRS satellite reflectance data consistently underestimated the in situ spectra in the blue with a bias relative to the “dynamic above water radiance and irradiance collector” (DALEC at 443 nm ranging from 9.8 × 10−4 to 3.1 × 10−3 sr−1. Automated acquisition has produced good quality data under standard operating and maintenance procedures. A sensitivity analysis explored the effects of some assumptions in the data reduction methods, indicating the need for a comprehensive investigation and quantification of each source of uncertainty in the estimate of the DALEC reflectances. Deployment on a Research Vessel provides the potential for the radiometric data to be combined with other sampling and observational activities to contribute to algorithm development in the wider bio-optical research community.

Advancing Ocean Monitoring Near Coral Reefs

Science.gov (United States)

Heron, Scott F.; Steinberg, Craig R.; Heron, Mal L.; Mantovanelli, Alessandra; Jaffrés, Jasmine B. D.; Skirving, William J.; McAllister, Felicity; Rigby, Paul; Wisdom, Daniel; Bainbridge, Scott

2010-10-01

Corals, the foundation of tropical marine ecosystems, exist in a symbiotic relationship with zooxanthellae (algae). The corals obtain much of their energy by consuming compounds derived from photosynthesis by these microorganisms; the microorganisms, which reside in the coral tissue, in turn use waste products from the corals to sustain photosynthesis. This symbiosis is very sensitive to subtle changes in environment, such as increased ocean acidity, temperature, and light. When unduly stressed, the colorful algae are expelled from the corals, causing the corals to “bleach” and potentially die [e.g., van Oppen and Lough, 2009].

Using long-term ground-based HSRL and geostationary observations in combination with model re-analysis to help disentangle local and long-range transported aerosols in Seoul, South Korea

Science.gov (United States)

Phillips, C.; Holz, R.; Eloranta, E. W.; Reid, J. S.; Kim, S. W.; Kuehn, R.; Marais, W.

2017-12-01

The University of Wisconsin High Spectral Resolution Lidar (HSRL) has been continuously operating at Seoul National University as part of the Korea-United States Air Quality Study (KORUS-AQ). The instrument was installed in March of 2016 and continues to operate as of August 2017, providing a truly unique data set to monitor aerosol and cloud properties. With its capability to separate the molecular and particulate scattering, the HSRL is able to detect extremely thin aerosol layers with sub-molecular scattering sensitivity. The system deployed in Seoul has depolarization measurements at 532 nm as well as a near IR channel at 1064 nm providing discrimination between dust, smoke, pollution, water clouds, and ice clouds. As will be presented, these capabilities can be used to produce three channel combined RGB images that provide visualization of small changes in the aerosol properties. A primary motivation of KORUS-AQ was to determine the relative effects of transported pollution and local pollution on air quality in Seoul. We hypothesize that HSRL-based image analysis algorithms combined with satellite and model re-analysis has the potential to identify cases when remote sources of aerosols and pollution are advected into the boundary layer with impacts to the surface air quality. To facilitate this research we have developed the capability to combine ten-minute geostationary imagery from Himawari-8, nearby radiosondes, model output, surface PM measurements, and AERONET data over the HSRL site. On a case-by-case basis, it is possible to separate layers of aerosols with different scattering properties using these tools. Additionally, a preliminary year-long aerosol climatology with integrated geo-stationary retrievals and modeling data will be presented. The focus is on investigating correlations between the HSRL aerosol measurements (depolarization, color ratio, extinction, and lidar ratio) with the model output and aerosol sources. This analysis will use recently

Preliminary Results of BTDF Calibration of Transmissive Solar Diffusers for Remote Sensing

Science.gov (United States)

Georgiev, Georgi T.; Butler, James J.; Thome, Kurt; Cooksey, Catherine; Ding, Leibo

2016-01-01

Satellite instruments operating in the reflected solar wavelength region require accurate and precise determination of the optical properties of their diffusers used in pre-flight and post-flight calibrations. The majority of recent and current space instruments use reflective diffusers. As a result, numerous Bidirectional Reflectance Distribution Function (BRDF) calibration comparisons have been conducted between the National Institute of Standards and Technology (NIST) and other industry and university-based metrology laboratories. However, based on literature searches and communications with NIST and other laboratories, no Bidirectional Transmittance Distribution Function (BTDF) measurement comparisons have been conducted between National Measurement Laboratories (NMLs) and other metrology laboratories. On the other hand, there is a growing interest in the use of transmissive diffusers in the calibration of satellite, air-borne, and ground-based remote sensing instruments. Current remote sensing instruments employing transmissive diffusers include the Ozone Mapping and Profiler Suite instrument (OMPS) Limb instrument on the Suomi-National Polar-orbiting Partnership (S-NPP) platform,, the Geostationary Ocean Color Imager (GOCI) on the Korea Aerospace Research Institute's (KARI) Communication, Ocean, and Meteorological Satellite (COMS), the Ozone Monitoring Instrument (OMI) on NASA's Earth Observing System (EOS) Aura platform, the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument and the Geostationary Environmental Monitoring Spectrometer (GEMS).. This ensemble of instruments requires validated BTDF measurements of their on-board transmissive diffusers from the ultraviolet through the near infrared. This paper presents the preliminary results of a BTDF comparison between the NASA Diffuser Calibration Laboratory (DCL) and NIST on quartz and thin Spectralon samples.

Preliminary results of BTDF calibration of transmissive solar diffusers for remote sensing

Science.gov (United States)

Georgiev, Georgi T.; Butler, James J.; Thome, Kurt; Cooksey, Catherine; Ding, Leibo

2016-09-01

Satellite instruments operating in the reflected solar wavelength region require accurate and precise determination of the optical properties of their diffusers used in pre-flight and post-flight calibrations. The majority of recent and current space instruments use reflective diffusers. As a result, numerous Bidirectional Reflectance Distribution Function (BRDF) calibration comparisons have been conducted between the National Institute of Standards and Technology (NIST) and other industry and university-based metrology laboratories. However, based on literature searches and communications with NIST and other laboratories, no Bidirectional Transmittance Distribution Function (BTDF) measurement comparisons have been conducted between National Measurement Laboratories (NMLs) and other metrology laboratories. On the other hand, there is a growing interest in the use of transmissive diffusers in the calibration of satellite, air-borne, and ground-based remote sensing instruments. Current remote sensing instruments employing transmissive diffusers include the Ozone Mapping and Profiler Suite instrument (OMPS) Limb instrument on the Suomi-National Polar-orbiting Partnership (S-NPP) platform,, the Geostationary Ocean Color Imager (GOCI) on the Korea Aerospace Research Institute's (KARI) Communication, Ocean, and Meteorological Satellite (COMS), the Ozone Monitoring Instrument (OMI) on NASA's Earth Observing System (EOS) Aura platform, the Tropospheric Emissions: Monitoring of Pollution (TEMPO) instrument and the Geostationary Environmental Monitoring Spectrometer (GEMS).. This ensemble of instruments requires validated BTDF measurements of their onboard transmissive diffusers from the ultraviolet through the near infrared. This paper presents the preliminary results of a BTDF comparison between the NASA Diffuser Calibration Laboratory (DCL) and NIST on quartz and thin Spectralon samples.

Using Single Colors and Color Pairs to Communicate Basic Tastes II: Foreground-Background Color Combinations.

Science.gov (United States)

Woods, Andy T; Marmolejo-Ramos, Fernando; Velasco, Carlos; Spence, Charles

2016-01-01

People associate basic tastes (e.g., sweet, sour, bitter, and salty) with specific colors (e.g., pink or red, green or yellow, black or purple, and white or blue). In the present study, we investigated whether a color bordered by another color (either the same or different) would give rise to stronger taste associations relative to a single patch of color. We replicate previous findings, highlighting the existence of a robust crossmodal correspondence between individual colors and basic tastes. On occasion, color pairs were found to communicate taste expectations more consistently than were single color patches. Furthermore, and in contrast to a recent study in which the color pairs were shown side-by-side, participants took no longer to match the color pairs with tastes than the single colors (they had taken twice as long to respond to the color pairs in the previous study). Possible reasons for these results are discussed, and potential applications for the results, and for the testing methodology developed, are outlined.

Colorism/Neo-Colorism

Science.gov (United States)

Snell, Joel

2017-01-01

There are numerous aspects to being non-Caucasian that may not be known by Whites. Persons of color suggest folks who are African, South Americans, Native Americans, Biracial, Asians and others. The question is what do these individuals feel relative to their color and facial characteristics. Eugene Robinson suggest that the future favorable color…

Luminance contours can gate afterimage colors and "real" colors.

Science.gov (United States)

Anstis, Stuart; Vergeer, Mark; Van Lier, Rob

2012-09-06

It has long been known that colored images may elicit afterimages in complementary colors. We have already shown (Van Lier, Vergeer, & Anstis, 2009) that one and the same adapting image may result in different afterimage colors, depending on the test contours presented after the colored image. The color of the afterimage depends on two adapting colors, those both inside and outside the test. Here, we further explore this phenomenon and show that the color-contour interactions shown for afterimage colors also occur for "real" colors. We argue that similar mechanisms apply for both types of stimulation.

Estimating absorption coefficients of colored dissolved organic matter (CDOM using a semi-analytical algorithm for southern Beaufort Sea waters: application to deriving concentrations of dissolved organic carbon from space

Directory of Open Access Journals (Sweden)

A. Matsuoka

2013-02-01

Full Text Available A series of papers have suggested that freshwater discharge, including a large amount of dissolved organic matter (DOM, has increased since the middle of the 20th century. In this study, a semi-analytical algorithm for estimating light absorption coefficients of the colored fraction of DOM (CDOM was developed for southern Beaufort Sea waters using remote sensing reflectance at six wavelengths in the visible spectral domain corresponding to MODIS ocean color sensor. This algorithm allows the separation of colored detrital matter (CDM into CDOM and non-algal particles (NAP through the determination of NAP absorption using an empirical relationship between NAP absorption and particle backscattering coefficients. Evaluation using independent datasets, which were not used for developing the algorithm, showed that CDOM absorption can be estimated accurately to within an uncertainty of 35% and 50% for oceanic and coastal waters, respectively. A previous paper (Matsuoka et al., 2012 showed that dissolved organic carbon (DOC concentrations were tightly correlated with CDOM absorption in our study area (r² = 0.97. By combining the CDOM absorption algorithm together with the DOC versus CDOM relationship, it is now possible to estimate DOC concentrations in the near-surface layer of the southern Beaufort Sea using satellite ocean color data. DOC concentrations in the surface waters were estimated using MODIS ocean color data, and the estimates showed reasonable values compared to in situ measurements. We propose a routine and near real-time method for deriving DOC concentrations from space, which may open the way to an estimate of DOC budgets for Arctic coastal waters.

Ocean outfall plume characterization using an Autonomous Underwater Vehicle.

Science.gov (United States)

Rogowski, Peter; Terrill, Eric; Otero, Mark; Hazard, Lisa; Middleton, William

2013-01-01

A monitoring mission to map and characterize the Point Loma Ocean Outfall (PLOO) wastewater plume using an Autonomous Underwater Vehicle (AUV) was performed on 3 March 2011. The mobility of an AUV provides a significant advantage in surveying discharge plumes over traditional cast-based methods, and when combined with optical and oceanographic sensors, provides a capability for both detecting plumes and assessing their mixing in the near and far-fields. Unique to this study is the measurement of Colored Dissolved Organic Matter (CDOM) in the discharge plume and its application for quantitative estimates of the plume's dilution. AUV mission planning methodologies for discharge plume sampling, plume characterization using onboard optical sensors, and comparison of observational data to model results are presented. The results suggest that even under variable oceanic conditions, properly planned missions for AUVs equipped with an optical CDOM sensor in addition to traditional oceanographic sensors, can accurately characterize and track ocean outfall plumes at higher resolutions than cast-based techniques.

Comparative analysis of long-time variations of multicomponent ion ring current according to data of geostationary Gorizont satellite

International Nuclear Information System (INIS)

Kovtyukh, A.S.; Panasyuk, M.I.; Vlasova, N.A.; Sosnovets, Eh.N.

1990-01-01

Long-time variations of the fluxes of the H + , [N,O] 2+ and [C,N,O] 6 6 + ions with energy E/Q∼60-120 keV/e measured by the GORIZONT (1985-07A) satellite in the geostationary orbit at noon time are analyzed. The results are dsicussed and are compared with current models of the formation of the Earth's ion ring current

Tracing the transport of colored dissolved organic matter in water masses of the Southern Beaufort Sea: relationship with hydrographic characteristics

Directory of Open Access Journals (Sweden)

A. Matsuoka

2012-03-01

Full Text Available Light absorption by colored dissolved organic matter (CDOM [a_CDOM(λ] plays an important role in the heat budget of the Arctic Ocean, contributing to the recent decline in sea ice, as well as in biogeochemical processes. We investigated a_CDOM(λ in the Southern Beaufort Sea where a significant amount of CDOM is delivered by the Mackenzie River. In the surface layer, a_CDOM(440 showed a strong and negative correlation with salinity, indicating strong river influence and conservative transport in the river plume. Below the mixed layer, a weak but positive correlation between a_CDOM(440 and salinity was observed above the upper halocline, resulting from the effect of removal of CDOM due to brine rejection and lateral intrusion of Pacific summer waters into these layers. In contrast, the relationship was negative in the upper and the lower haloclines, suggesting these waters originated from Arctic coastal waters. DOC concentrations in the surface layer were strongly correlated with a_CDOM(440 (r² = 0.97, suggesting that this value can be estimated in this area, using a_CDOM(440 that is retrieved using satellite ocean color data. Implications for estimation of DOC concentrations in surface waters using ocean color remote sensing are discussed.

Using Single Colors and Color Pairs to Communicate Basic Tastes II: Foreground–Background Color Combinations

Science.gov (United States)

Marmolejo-Ramos, Fernando; Velasco, Carlos; Spence, Charles

2016-01-01

People associate basic tastes (e.g., sweet, sour, bitter, and salty) with specific colors (e.g., pink or red, green or yellow, black or purple, and white or blue). In the present study, we investigated whether a color bordered by another color (either the same or different) would give rise to stronger taste associations relative to a single patch of color. We replicate previous findings, highlighting the existence of a robust crossmodal correspondence between individual colors and basic tastes. On occasion, color pairs were found to communicate taste expectations more consistently than were single color patches. Furthermore, and in contrast to a recent study in which the color pairs were shown side-by-side, participants took no longer to match the color pairs with tastes than the single colors (they had taken twice as long to respond to the color pairs in the previous study). Possible reasons for these results are discussed, and potential applications for the results, and for the testing methodology developed, are outlined. PMID:27708752

Color adaptation induced from linguistic description of color.

Directory of Open Access Journals (Sweden)

Liling Zheng

Full Text Available Recent theories propose that language comprehension can influence perception at the low level of perceptual system. Here, we used an adaptation paradigm to test whether processing language caused color adaptation in the visual system. After prolonged exposure to a color linguistic context, which depicted red, green, or non-specific color scenes, participants immediately performed a color detection task, indicating whether they saw a green color square in the middle of a white screen or not. We found that participants were more likely to perceive the green color square after listening to discourses denoting red compared to discourses denoting green or conveying non-specific color information, revealing that language comprehension caused an adaptation aftereffect at the perceptual level. Therefore, semantic representation of color may have a common neural substrate with color perception. These results are in line with the simulation view of embodied language comprehension theory, which predicts that processing language reactivates the sensorimotor systems that are engaged during real experience.

Shift Colors

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Publications & News Shift Colors Pages default Sign In NPC Logo Banner : Shift Colors Search Navy Personnel Command > Reference Library > Publications & News > Shift Colors Top Link Bar Navy Personnel Library Expand Reference Library Quick Launch Shift Colors Shift Colors Archives Mailing Address How to

Natural Colorants: Food Colorants from Natural Sources.

Science.gov (United States)

Sigurdson, Gregory T; Tang, Peipei; Giusti, M Mónica

2017-02-28

The color of food is often associated with the flavor, safety, and nutritional value of the product. Synthetic food colorants have been used because of their high stability and low cost. However, consumer perception and demand have driven the replacement of synthetic colorants with naturally derived alternatives. Natural pigment applications can be limited by lower stability, weaker tinctorial strength, interactions with food ingredients, and inability to match desired hues. Therefore, no single naturally derived colorant can serve as a universal alternative for a specified synthetic colorant in all applications. This review summarizes major environmental and biological sources for natural colorants as well as nature-identical counterparts. Chemical characteristics of prevalent pigments, including anthocyanins, carotenoids, betalains, and chlorophylls, are described. The possible applications and hues (warm, cool, and achromatic) of currently used natural pigments, such as anthocyanins as red and blue colorants, and possible future alternatives, such as purple violacein and red pyranoanthocyanins, are also discussed.

Analysing the advantages of high temporal resolution geostationary MSG SEVIRI data compared to Polar operational environmental satellite data for land surface monitoring in Africa

DEFF Research Database (Denmark)

Fensholt, Rasmus; Anyamba, Assaf; Huber Gharib, Silvia

2011-01-01

Since 1972, satellite remote sensing of the environment has been dominated by polar-orbiting sensors providing useful data for monitoring the earth’s natural resources. However their observation and monitoring capacity are inhibited by daily to monthly looks for any given ground surface which often...... is obscured by frequent and persistent cloud cover creating large gaps in time series measurements. The launch of the Meteosat Second Generation (MSG) satellite into geostationary orbit has opened new opportunities for land surface monitoring. The Spinning Enhanced Visible and Infrared Imager (SEVIRI...... affected by droughts and floods in 2008 caused by periods of abnormally low and high rainfall, respectively. Based on the effectiveness of monitoring these events from Earth Observation (EO) data the current analyses show that the new generation of geostationary remote sensing data can provide higher...

Colors, colored overlays, and reading skills

Directory of Open Access Journals (Sweden)

Arcangelo eUccula

2014-07-01

Full Text Available In this article, we are concerned with the role of colors in reading written texts. It has been argued that colored overlays applied above written texts positively influence both reading fluency and reading speed. These effects would be particularly evident for those individuals affected by the so called Meares-Irlen syndrome, i.e. who experience eyestrain and/or visual distortions – e.g. color, shape or movement illusions – while reading. This condition would interest the 12-14% of the general population and up to the 46% of the dyslexic population. Thus, colored overlays have been largely employed as a remedy for some aspects of the difficulties in reading experienced by dyslexic individuals, as fluency and speed. Despite the wide use of colored overlays, how they exert their effects has not been made clear yet. Also, according to some researchers, the results supporting the efficacy of colored overlays as a tool for helping readers are at least controversial. Furthermore, the very nature of the Meares-Irlen syndrome has been questioned. Here we provide a concise, critical review of the literature.

Application of in situ observations, high frequency radars, and ocean color, to study suspended matter, particulate carbon, and dissolved organic carbon fluxes in coastal waters of the Barents Sea - the NORDFLUX project

Science.gov (United States)

Stramska, Malgorzata; Yngve Børsheim, Knut; Białogrodzka, Jagoda; Cieszyńska, Agata; Ficek, Dariusz; Wereszka, Marzena

2016-04-01

There is still a limited knowledge about suspended and dissolved matter fluxes transported from coastal regions into the open sea regions in the Arctic. The land/sea interface is environmentally important and sensitive to climate change. Important biogeochemical material entering the oceans (including carbon) passes through this interface, but too little is known about the efficiency of this transport. Our goal in the NORDFLUX program is to improve quantitative understanding of the environmental feedbacks involved in these processes through an interdisciplinary study with innovative in situ observations. Completed work includes two in situ experiments in the Norwegian fiord (Porsangerfjorden) in the summers of 2014 and 2015. Experiments used research boat for collection of water samples and in situ bio-optical data, an autonomous glider, mooring with T S sensors, and a high frequency radar system. We have used these data to derive spatial maps of water temperature, salinity, surface currents, chlorophyll fluorescence, dissolved organic matter (DOM) fluorescence, and inherent optical properties (IOPs) of the water. The interpretation of these data in terms of suspended matter concentration and composition is possible by in situ 'calibrations' using water samples from discrete hydrographic stations. Total suspended matter (TSM), particulate carbon (POC and PIC), and dissolved organic carbon (DOC) concentrations together with measured water currents will allow us to estimate reservoirs and fluxes. Concentrations and fluxes will be related to physical conditions and meteorological data. An important aspect of this project is the work on regional ocean color algorithms. Global ocean color (OC) algorithms currently used by NASA do not perform sufficiently well in coastal Case 2 waters. Our data sets will allow us to derive such local algorithms. We will then use these algorithms for interpretation of OC data in terms of TSM concentrations and composition and DOC. After

Precision of Synesthetic Color Matching Resembles That for Recollected Colors Rather than Physical Colors

Science.gov (United States)

Arnold, Derek H.; Wegener, Signy V.; Brown, Francesca; Mattingley, Jason B.

2012-01-01

Grapheme-color synesthesia is an atypical condition in which individuals experience sensations of color when reading printed graphemes such as letters and digits. For some grapheme-color synesthetes, seeing a printed grapheme triggers a sensation of color, but "hearing" the name of a grapheme does not. This dissociation allowed us to…

Pre-Launch GOES-R Risk Reduction Activities for the Geostationary Lightning Mapper

Science.gov (United States)

Goodman, S. J.; Blakeslee, R. J.; Boccippio, D. J.; Christian, H. J.; Koshak, W. J.; Petersen, W. A.

2005-01-01

The GOES-R Geostationary Lightning Mapper (GLM) is a new instrument planned for GOES-R that will greatly improve storm hazard nowcasting and increase warning lead time day and night. Daytime detection of lightning is a particularly significant technological advance given the fact that the solar illuminated cloud-top signal can exceed the intensity of the lightning signal by a factor of one hundred. Our approach is detailed across three broad themes which include: Data Processing Algorithm Readiness, Forecast Applications, and Radiance Data Mining. These themes address how the data will be processed and distributed, and the algorithms and models for developing, producing, and using the data products. These pre-launch risk reduction activities will accelerate the operational and research use of the GLM data once GOES-R begins on-orbit operations. The GLM will provide unprecedented capabilities for tracking thunderstorms and earlier warning of impending severe and hazardous weather threats. By providing direct information on lightning initiation, propagation, extent, and rate, the GLM will also capture the updraft dynamics and life cycle of convective storms, as well as internal ice precipitation processes. The GLM provides information directly from the heart of the thunderstorm as opposed to cloud-top only. Nowcasting applications enabled by the GLM data will expedite the warning and response time of emergency management systems, improve the dispatch of electric power utility repair crews, and improve airline routing around thunderstorms thereby improving safety and efficiency, saving fuel and reducing delays. The use of GLM data will assist the Bureau of Land Management (BLM) and the Forest Service in quickly detecting lightning ground strikes that have a high probability of causing fires. Finally, GLM data will help assess the role of thunderstorms and deep convection in global climate, and will improve regional air quality and global chemistry/climate modeling

Variability in global ocean phytoplankton distribution over 1979-2007

Science.gov (United States)

Masotti, I.; Alvain, S.; Moulin, C.; Antoine, D.

2009-04-01

Recently, reanalysis of long-term ocean color data (CZCS and SeaWiFS; Antoine et al., 2005) has shown that world ocean average phytoplankton chlorophyll levels show an increase of 20% over the last two decades. It is however unknown whether this increase is associated with a change in the distribution of phytoplankton groups or if it simply corresponds to an increase of the productivity. Within the framework of the GLOBPHY project, the distribution of the phytoplankton groups was monitored by applying the PHYSAT method (Alvain et al., 2005) to the historical ocean color data series from CZCS, OCTS and SeaWiFS sensors. The PHYSAT algorithm allows identification of several phytoplankton, like nanoeucaryotes, prochlorococcus, synechococcus and diatoms. Because both sensors (OCTS-SeaWiFS) are very similar, OCTS data were processed with the standard PHYSAT algorithm to cover the 1996-1997 period during which a large El Niño event occurred, just before the SeaWiFS era. Our analysis of this dataset (1996-2006) evidences a strong variability in the distribution of phytoplankton groups at both regional and global scales. In the equatorial region (0°-5°S), a three-fold increase of nanoeucaryotes frequency was detected in opposition to a two-fold decrease of synechococcus during the early stages of El Niño conditions (May-June 1997, OCTS). The impact of this El Niño is however not confined to the Equatorial Pacific and has affected the global ocean. The processing of CZCS data with PHYSAT has required several adaptations of this algorithm due to the lower performances and the reduced number of spectral bands of the sensor. Despites higher uncertainties, the phytoplankton groups distribution obtained with CZCS is globally consistent with that of SeaWiFS. A comparison of variability in global phytoplankton distribution between 1979-1982 (CZCS) and 1999-2002 (SeaWiFS) suggests an increase in nanoeucaryotes at high latitudes (>40°) and in the equatorial region (10°S-10�

Comparison Study of Lightning observations from VHF interferometer and Geostationary Lightning Mapper

Science.gov (United States)

Kudo, A.; Stock, M.; Ushio, T.

2017-12-01

We compared the optical observation from Geostationary Lightning Mapper (GLM) which is mounted on the geostationary meteorological satellite GOES-16 launched last year, and the radio observations from the ground-based VHF broad band interferometer. GLM detects 777.4 nm wavelength infrared optical signals from thunderstorm cells which are illuminated by the heated path during lightning discharge, and was developed mainly for the purpose of increasing the lead time for warning of severe weather and clarifying the discharge mechanism. Its detection has 2 ms frame rate, and 8 km square of space resolution at nadir. The VHF broad band interferometer is able to capture the electromagnetic waves from 20 MHz to 75 MHz and estimate the direction of arrival of the radiation sources using the interferometry technique. This system also has capability of observing the fast discharge process which cannot be captured by other systems, so it is expected to able to make detailed comparison. The recording duration of the system is 1 second. We installed the VHF broad band interferometer which consists of three VHF antenna and one fast antenna at Huntsville, Alabama from April 22nd to May 15th and in this total observation period, 720 triggers of data were observed by the interferometer. For comparison, we adopted the data from April 27th , April 30th. Most April 27th data has GLM "event" detection which is coincident time period. In time-elevation plot comparison, we found GLM detection timing was well coincide with interferometer during K-changes or return strokes and few detection during breakdown process. On the other hand, no GLM detection near the site for all data in April 30th and we are triyng to figure out the reason. We would like to thank University of Alabama Huntsville, New Mexico Institute of Mining and Technology, and RAIRAN Pte. Ltd for the help during the campaign.

Color Analysis

Science.gov (United States)

Wrolstad, Ronald E.; Smith, Daniel E.

Color, flavor, and texture are the three principal quality attributes that determine food acceptance, and color has a far greater influence on our judgment than most of us appreciate. We use color to determine if a banana is at our preferred ripeness level, and a discolored meat product can warn us that the product may be spoiled. The marketing departments of our food corporations know that, for their customers, the color must be "right." The University of California Davis scorecard for wine quality designates four points out of 20, or 20% of the total score, for color and appearance (1). Food scientists who establish quality control specifications for their product are very aware of the importance of color and appearance. While subjective visual assessment and use of visual color standards are still used in the food industry, instrumental color measurements are extensively employed. Objective measurement of color is desirable for both research and industrial applications, and the ruggedness, stability, and ease of use of today's color measurement instruments have resulted in their widespread adoption.

Temporal and spatial variability of phytoplankton pigment concentrations in the Indian Ocean, derived from the CZCS time series images

Directory of Open Access Journals (Sweden)

2005-01-01

Full Text Available A total of 93 monthly global composite remotely sensed ocean color images from the Coastal Zone Color Scanner (CZCS on board the Nimbus-7 satellite were extracted for the Indian Ocean region (35ºN–55ºS; 30–120ºE to examine the seasonal variations in phytoplankton pigment concentrations, resulting from large-scale changes in physical oceanographic processes. The CZCS data sets were analyzed with the PC-SEAPAK software, and revealed large phytoplankton blooms in the northwest Arabian Sea and off the Somali coast. The blooms were triggered by wind-driven upwelling during the southwest monsoonal months of August and September. In the northern Arabian Sea, phytoplankton blooms, detected from January to March, appeared to be associated with nutrient enhancement resulting from winter convective mixing. In the Bay of Bengal, higher pigment concentrations were confined to the coastal regions but varied only marginally between seasons both in the coastal and offshore regions. Phytoplankton pigment concentrations were consistently low in the open Indian Ocean. Analysis of pigment concentrations extracted from the monthly-accumulated images revealed that the Arabian Sea sustained a greater biomass of phytoplankton compared with any other region of the Indian Ocean. Overall, the coastal regions of the Indian Ocean are richer in phytoplankton pigment than the open Indian Ocean. The number of images in individual areas was highly variable throughout the region due to varying cloud cover.

InSAR atmospheric correction using Himawari-8 Geostationary Meteorological Satellite

Science.gov (United States)

Kinoshita, Y.; Nimura, T.; Furuta, R.

2017-12-01

The atmospheric delay effect is one of the limitations for the accurate surface displacement detection by Synthetic Aperture Radar Interferometry (InSAR). Many previous studies have attempted to mitigate the neutral atmospheric delay in InSAR (e.g. Jolivet et al. 2014; Foster et al. 2006; Kinoshita et al. 2013). Hanssen et al. (2001) investigated the relationship between the 27 hourly observations of GNSS precipitable water vapor (PWV) and the infrared brightness temperature derived from visible satellite imagery, and showed a good correlation. Here we showed a preliminary result of the newly developed method for the neutral atmospheric delay correction using the Himawari-8 Japanese geostationary meteorological satellite data. The Himawari-8 satellite is the Japanese state-of-the-art geostationary meteorological satellite that has 16 observation channels and has spatial resolutions of 0.5 km (visible) and 2.0 km (near-infrared and infrared) with an time interval of 2.5 minutes around Japan. To estimate the relationship between the satellite brightness temperature and the atmospheric delay amount. Since the InSAR atmospheric delay is principally the same as that in GNSS, we at first compared the Himawari-8 data with the GNSS zenith tropospheric delay data derived from the Japanese dense GNSS network. The comparison of them showed that the band with the wavelength of 6.9 μm had the highest correlation to the GNSS observation. Based on this result, we developed an InSAR atmospheric delay model that uses the Himawari-8 6.9 μm band data. For the model validation, we generated InSAR images from the ESA's C-band Sentinel-1 SLC data with the GAMMA SAR software. We selected two regions around Tokyo and Sapporo (both in Japan) as the test sites because of the less temporal decorrelation. The validation result showed that the delay model reasonably estimate large scale phase variation whose spatial scale was on the order of over 20 km. On the other hand, phase variations of

Color Memory

OpenAIRE

Pate, Monica; Raclariu, Ana-Maria; Strominger, Andrew

2017-01-01

A transient color flux across null infinity in classical Yang-Mills theory is considered. It is shown that a pair of test `quarks' initially in a color singlet generically acquire net color as a result of the flux. A nonlinear formula is derived for the relative color rotation of the quarks. For weak color flux the formula linearizes to the Fourier transform of the soft gluon theorem. This color memory effect is the Yang-Mills analog of the gravitational memory effect.

Land Surface Temperature- Comparing Data from Polar Orbiting and Geostationary Satellites

Science.gov (United States)

Comyn-Platt, E.; Remedios, J. J.; Good, E. J.; Ghent, D.; Saunders, R.

2012-04-01

Land Surface Temperature (LST) is a vital parameter in Earth climate science, driving long-wave radiation exchanges that control the surface energy budget and carbon fluxes, which are important factors in Numerical Weather Prediction (NWP) and the monitoring of climate change. Satellites offer a convenient way to observe LST consistently and regularly over large areas. A comparison between LST retrieved from a Geostationary Instrument, the Spinning Enhanced Visible and InfraRed Imager (SEVIRI), and a Polar Orbiting Instrument, the Advanced Along Track Scanning Radiometer (AATSR) is presented. Both sensors offer differing benefits. AATSR offers superior precision and spatial resolution with global coverage but given its sun-synchronous platform only observes at two local times, ~10am and ~10pm. SEVIRI provides the high-temporal resolution (every 15 minutes) required for observing diurnal variability of surface temperatures but given its geostationary platform has a poorer resolution, 3km at nadir, which declines at higher latitudes. A number of retrieval methods are applied to the raw satellite data: First order coefficient based algorithms provided on an operational basis by the LandSAF (for SEVIRI) and the University of Leicester (for AATSR); Second order coefficient based algorithms put forward by the University of Valencia; and an optimal estimation method using the 1DVar software provided by the NWP SAF. Optimal estimation is an iterative technique based upon inverse theory, thus is very useful for expanding into data assimilation systems. The retrievals are assessed and compared on both a fine scale using in-situ data from recognised validation sites and on a broad scale using two 100x100 regions such that biases can be better understood. Overall, the importance of LST lies in monitoring daily temperature extremes, e.g. for estimating permafrost thawing depth or risk of crop damage due to frost, hence the ideal dataset would use a combination of observations

Ionic ring current during magnetic disturbances according to observations at geostationary orbit

International Nuclear Information System (INIS)

Vlasova, N.A.; Kovtyukh, A.S.; Panasyuk, M.I.; Sosnovets, Eh.N.; Grafodanskij, O.S.; Islyaev, Sh.N.; Kozlov, A.G.

1988-01-01

Experimental data on variations of H + , (N,O) 2+ and (C,N,O) 4+ flows acquired at communication geostationary satellite GORIZONT (1985-07A) during and after weak magnetic disturbances (with amplitudes of D st -variations which are less than a few tens of nT) are analyzed. Dynamics of ion relative content is investigated. Change of ring current ionic composition within ∼ 50-120 keV/c energy range characterized by the increase of relative content of heavy ions of both solar and ionospheric origin was observed after two weak geomagnetic disturbances on 19-20.02 and 07.03.1985. Examples of disturbances where H + ions and (N,O) 2+ ionospheric ions are the main components of the injected ring current are presented along with the disturbances of such type

Color Algebras

Science.gov (United States)

Mulligan, Jeffrey B.

2017-01-01

A color algebra refers to a system for computing sums and products of colors, analogous to additive and subtractive color mixtures. The difficulty addressed here is the fact that, because of metamerism, we cannot know with certainty the spectrum that produced a particular color solely on the basis of sensory data. Knowledge of the spectrum is not required to compute additive mixture of colors, but is critical for subtractive (multiplicative) mixture. Therefore, we cannot predict with certainty the multiplicative interactions between colors based solely on sensory data. There are two potential applications of a color algebra: first, to aid modeling phenomena of human visual perception, such as color constancy and transparency; and, second, to provide better models of the interactions of lights and surfaces for computer graphics rendering.

NOAA Integrated Ocean and Coastal Mapping (IOCM) orthorectified mosaic image tiles for Brunswick, Kings Bay and Fernandina Beach, and Savannah and the Savannah River, Georgia, 2009-2010 (NODC Accession 0092435)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains orthorectified true color (RGB) and infrared (IR) image mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping...

Regal phylogeography: Range-wide survey of the marine angelfish Pygoplites diacanthus reveals evolutionary partitions between the Red Sea, Indian Ocean, and Pacific Ocean

KAUST Repository

Coleman, Richard R.

2016-04-08

The regal angelfish (Pygoplites diacanthus; family Pomacanthidae) occupies reefs from the Red Sea to the central Pacific, with an Indian Ocean/Rea Sea color morph distinct from a Pacific Ocean morph. To assess population differentiation and evaluate the possibility of cryptic evolutionary partitions in this monotypic genus, we surveyed mtDNA cytochrome b and two nuclear introns (S7 and RAG2) in 547 individuals from 15 locations. Phylogeographic analyses revealed four mtDNA lineages (d = 0.006 – 0.015) corresponding to the Pacific Ocean, the Red Sea, and two admixed lineages in the Indian Ocean, a pattern consistent with known biogeographical barriers. Christmas Island in the eastern Indian Ocean had both Indian and Pacific lineages. Both S7 and RAG2 showed strong population-level differentiation between the Red Sea, Indian Ocean, and Pacific Ocean (ΦST = 0.066 – 0.512). The only consistent population sub-structure within these three regions was at the Society Islands (French Polynesia), where surrounding oceanographic conditions may reinforce isolation. Coalescence analyses indicate the Pacific (1.7 Ma) as the oldest extant lineage followed by the Red Sea lineage (1.4 Ma). Results from a median-joining network suggest radiations of two lineages from the Red Sea that currently occupy the Indian Ocean (0.7 – 0.9 Ma). Persistence of a Red Sea lineage through Pleistocene glacial cycles suggests a long-term refuge in this region. The affiliation of Pacific and Red Sea populations, apparent in cytochrome b and S7 (but equivocal in RAG2) raises the hypthosis that the Indian Ocean was recolonized from the Red Sea, possibly more than once. Assessing the genetic architecture of this widespread monotypic genus reveals cryptic evolutionary diversity that merits subspecific recognition.

Regal phylogeography: Range-wide survey of the marine angelfish Pygoplites diacanthus reveals evolutionary partitions between the Red Sea, Indian Ocean, and Pacific Ocean

KAUST Repository

Coleman, Richard R.; Eble, Jeffrey A.; DiBattista, Joseph; Rocha, Luiz A.; Randall, John E.; Berumen, Michael L.; Bowen, Brian W.

2016-01-01

The regal angelfish (Pygoplites diacanthus; family Pomacanthidae) occupies reefs from the Red Sea to the central Pacific, with an Indian Ocean/Rea Sea color morph distinct from a Pacific Ocean morph. To assess population differentiation and evaluate the possibility of cryptic evolutionary partitions in this monotypic genus, we surveyed mtDNA cytochrome b and two nuclear introns (S7 and RAG2) in 547 individuals from 15 locations. Phylogeographic analyses revealed four mtDNA lineages (d = 0.006 – 0.015) corresponding to the Pacific Ocean, the Red Sea, and two admixed lineages in the Indian Ocean, a pattern consistent with known biogeographical barriers. Christmas Island in the eastern Indian Ocean had both Indian and Pacific lineages. Both S7 and RAG2 showed strong population-level differentiation between the Red Sea, Indian Ocean, and Pacific Ocean (ΦST = 0.066 – 0.512). The only consistent population sub-structure within these three regions was at the Society Islands (French Polynesia), where surrounding oceanographic conditions may reinforce isolation. Coalescence analyses indicate the Pacific (1.7 Ma) as the oldest extant lineage followed by the Red Sea lineage (1.4 Ma). Results from a median-joining network suggest radiations of two lineages from the Red Sea that currently occupy the Indian Ocean (0.7 – 0.9 Ma). Persistence of a Red Sea lineage through Pleistocene glacial cycles suggests a long-term refuge in this region. The affiliation of Pacific and Red Sea populations, apparent in cytochrome b and S7 (but equivocal in RAG2) raises the hypthosis that the Indian Ocean was recolonized from the Red Sea, possibly more than once. Assessing the genetic architecture of this widespread monotypic genus reveals cryptic evolutionary diversity that merits subspecific recognition.

Color-Blind Racism, Color-Blind Theology, and Church Practices

Science.gov (United States)

Hearn, Mark

2009-01-01

Color-blind racism develops when persons ignore color in people and see them simply as individuals. As persons of color in racialized societies such as the United States are unequally treated on account of their color, the issue becomes a matter of faith and religious experience as religious leaders and educators, who disregard color, overlook…

Combined high and low-thrust geostationary orbit insertion with radiation constraint

Science.gov (United States)

Macdonald, Malcolm; Owens, Steven Robert

2018-01-01

The sequential use of an electric propulsion system is considered in combination with a high-thrust propulsion system for application to the propellant-optimal Geostationary Orbit insertion problem, whilst considering both temporal and radiation flux constraints. Such usage is found to offer a combined propellant mass saving when compared with an equivalent high-thrust only transfer. This propellant mass saving is seen to increase as the allowable transfer duration is increased, and as the thrust from the low-thrust system is increased, assuming constant specific impulse. It was found that the required plane change maneuver is most propellant-efficiently performed by the high-thrust system. The propellant optimal trajectory incurs a significantly increased electron flux when compared to an equivalent high-thrust only transfer. However, the electron flux can be reduced to a similar order of magnitude by increasing the high-thrust propellant consumption, whilst still delivering an improved mass fraction.

Asynchronous Processing of a Constellation of Geostationary and Polar-Orbiting Satellites for Fire Detection and Smoke Estimation

Science.gov (United States)

Hyer, E. J.; Peterson, D. A.; Curtis, C. A.; Schmidt, C. C.; Hoffman, J.; Prins, E. M.

2014-12-01

The Fire Locating and Monitoring of Burning Emissions (FLAMBE) system converts satellite observations of thermally anomalous pixels into spatially and temporally continuous estimates of smoke release from open biomass burning. This system currently processes data from a constellation of 5 geostationary and 2 polar-orbiting sensors. Additional sensors, including NPP VIIRS and the imager on the Korea COMS-1 geostationary satellite, will soon be added. This constellation experiences schedule changes and outages of various durations, making the set of available scenes for fire detection highly variable on an hourly and daily basis. Adding to the complexity, the latency of the satellite data is variable between and within sensors. FLAMBE shares with many fire detection systems the goal of detecting as many fires as possible as early as possible, but the FLAMBE system must also produce a consistent estimate of smoke production with minimal artifacts from the changing constellation. To achieve this, NRL has developed a system of asynchronous processing and cross-calibration that permits satellite data to be used as it arrives, while preserving the consistency of the smoke emission estimates. This talk describes the asynchronous data ingest methodology, including latency statistics for the constellation. We also provide an overview and show results from the system we have developed to normalize multi-sensor fire detection for consistency.

Detecting Canopy Water Status Using Shortwave Infrared Reflectance Data From Polar Orbiting and Geostationary Platforms

DEFF Research Database (Denmark)

Fensholt, Rasmus; Huber Gharib, Silvia; Proud, Simon Richard

2010-01-01

-based canopy water status detection from geostationary Meteosat Second Generation (MSG) Spinning Enhanced Visible and Infrared Imager (SEVIRI) data as compared to polar orbiting environmental satellite (POES)-based moderate resolution imaging spectroradiometer (MODIS) data. The EO-based SWIR water stress index...... (SIWSI) is evaluated against in situ measured canopy water content indicators at a semi-arid grassland savanna site in Senegal 2008. Daily SIWSI from both MODIS and SEVIRI data show an overall inverse relation to Normalized Difference Vegetation Index (NDVI) throughout the growing season. SIWSI...... for SWIR-based canopy water status and stress monitoring in a semi-arid environment....

Experimental Study on Color Durability of Color Asphalt Pavement

Science.gov (United States)

Ning, Shi; Huan, Su

2017-06-01

Aiming at the poor Color durability and the lack of research on Color asphalt pavement, spraying an anti-tire trace seal resin emulsion on the surface, a Color durable asphalt pavement was proposed. After long-term rolling and long-term aging test, the Color durability was evaluated by RGB function in Photoshop and trace residue rate formula. Test results proved that the Evaluation method was simple and effective. After long-term rolling, the Color of the road surface tends to a constant value. Spraying the emulsion on the road surface can resist tire traces. After long-term aging test, the resistance to tire traces was increased by 26.6% compared with the conventional type, while the former was 44.1% higher than the latter without long-term aging. The Color durable asphalt pavement can effectively improve the ability of Color asphalt pavement to resist tire traces, and significantly improve the Color durability of Color asphalt pavement.

The use of a MODIS band-ratio algorithm versus a new hybrid approach for estimating colored dissolved organic matter (CDOM)

Science.gov (United States)

Satellite remote sensing offers synoptic and frequent monitoring of optical water quality parameters, such as chlorophyll-a, turbidity, and colored dissolved organic matter (CDOM). While traditional satellite algorithms were developed for the open ocean, these algorithms often do...

Tree Colors: Color Schemes for Tree-Structured Data.

Science.gov (United States)

Tennekes, Martijn; de Jonge, Edwin

2014-12-01

We present a method to map tree structures to colors from the Hue-Chroma-Luminance color model, which is known for its well balanced perceptual properties. The Tree Colors method can be tuned with several parameters, whose effect on the resulting color schemes is discussed in detail. We provide a free and open source implementation with sensible parameter defaults. Categorical data are very common in statistical graphics, and often these categories form a classification tree. We evaluate applying Tree Colors to tree structured data with a survey on a large group of users from a national statistical institute. Our user study suggests that Tree Colors are useful, not only for improving node-link diagrams, but also for unveiling tree structure in non-hierarchical visualizations.

Illuminant color estimation based on pigmentation separation from human skin color

Science.gov (United States)

Tanaka, Satomi; Kakinuma, Akihiro; Kamijo, Naohiro; Takahashi, Hiroshi; Tsumura, Norimichi

2015-03-01

Human has the visual system called "color constancy" that maintains the perceptive colors of same object across various light sources. The effective method of color constancy algorithm was proposed to use the human facial color in a digital color image, however, this method has wrong estimation results by the difference of individual facial colors. In this paper, we present the novel color constancy algorithm based on skin color analysis. The skin color analysis is the method to separate the skin color into the components of melanin, hemoglobin and shading. We use the stationary property of Japanese facial color, and this property is calculated from the components of melanin and hemoglobin. As a result, we achieve to propose the method to use subject's facial color in image and not depend on the individual difference among Japanese facial color.

Promoting Implementation of Multi-Disciplinary Sustained Ocean Observations

Science.gov (United States)

Pearlman, Jay; Bourassa, Mark; Hill, Katherine; Miloslavich, Patricia; Simmons, Samantha; Sloyan, Bernadette; Telszewski, Maciej

2017-04-01

Since the OceanObs'09 Conference, the ocean observing community has been improving coordination and collaboration amongst physical, biogeochemical and biology/ecosystem communities. Societal and scientific requirements for sustained observations are being captured in Essential Ocean Variables (EOVs), many of which are also Essential Climate Variables (ECVs) as defined by the Global Climate Observing System reporting to the UNFCCC. Significant progress has been made through the introduction of the Framework for Ocean Observing in 2012 and the creation and refinement of the disciplinary EOVs, based on expert evaluation of feasibility and impact. With advances in observing technology, and the definition of EOVs, clear opportunities exist to improve the coordinated planning and implementation of observing activities measuring EOVs across the three disciplines of physical, biogeochemical and biology/ecosystem oceanography. In early 2017, a workshop examined priority steps forward with the objectives: • To build on the established societal and scientific requirements expressed in EOVs, identify the key applications and phenomena that will benefit from co-located multi-disciplinary sustained observations • To identify near-term innovation priorities for observing platforms and sensors to enable multi-disciplinary observations, and • To identify programmatic and professional connections between existing and emerging observing networks that will increase multi-disciplinary observations. To support these objectives and to provide a mechanism for looking at convergence across the oceans disciplines, three preselected demonstration themes were defined and discussed: • Changes in plankton communities (including ocean color), • Oxygen minimum zones, • Open ocean/shelf interactions (including boundary currents) These themes were chosen because they represent global and challenging problems that are best addressed through collaboration of physical, biogeochemical and

Correlated observations of intensified whistler waves and electron acceleration around the geostationary orbit

International Nuclear Information System (INIS)

Xiao Fuliang; He Zhaoguo; Tang Lijun; Zong Qiugang; Wang Chengrui; Su Zhenpeng

2012-01-01

We report correlated observations of enhanced whistler waves and energetic electron acceleration collected by multiple satellites specifically near the geostationary orbit during the 7–10 November 2004 superstorms, together with multi-site observations of ULF wave power measured on the ground. Energetic (>0.6 MeV) electron fluxes are found to increase significantly during the recovery phase, reaching a peak value by ∼100 higher than the prestorm level. In particular, such high electron flux corresponds to intensified whistler wave activities but to the weak ULF wave power. This result suggests that wave–particle interaction appears to be more important than inward radial diffusion in acceleration of outer radiation belt energetic electrons in this event, assisting to better understand the acceleration mechanism. (paper)

INFRARED COLOR-COLOR DIAGRAMS FOR AGB STARS

Directory of Open Access Journals (Sweden)

Kyung-Won Suh

2007-09-01

Full Text Available We present infrared color-color diagrams of AGB stars from the observations at near and mid infrared bands. We compile the observations for hundreds of OH/IR stars and carbon stars using the data from the Midcourse Space Experiment (MSX, the two micron sky survey (2MASS, and the IRAS point source catalog (PSC. We compare the observations with the theoretical evolutionary tracks of AGB stars. From the new observational data base and the theoretical evolution tracks, we discuss the meaning of the infrared color-color diagrams at different wavelengths.

Color digital halftoning taking colorimetric color reproduction into account

Science.gov (United States)

Haneishi, Hideaki; Suzuki, Toshiaki; Shimoyama, Nobukatsu; Miyake, Yoichi

1996-01-01

Taking colorimetric color reproduction into account, the conventional error diffusion method is modified for color digital half-toning. Assuming that the input to a bilevel color printer is given in CIE-XYZ tristimulus values or CIE-LAB values instead of the more conventional RGB or YMC values, two modified versions based on vector operation in (1) the XYZ color space and (2) the LAB color space were tested. Experimental results show that the modified methods, especially the method using the LAB color space, resulted in better color reproduction performance than the conventional methods. Spatial artifacts that appear in the modified methods are presented and analyzed. It is also shown that the modified method (2) with a thresholding technique achieves a good spatial image quality.

Color preferences change after experience with liked/disliked colored objects.

Science.gov (United States)

Strauss, Eli D; Schloss, Karen B; Palmer, Stephen E

2013-10-01

How are color preferences formed, and can they be changed by affective experiences with correspondingly colored objects? We examined these questions by testing whether affectively polarized experiences with images of colored objects would cause changes in color preferences. Such changes are implied by the ecological valence theory (EVT), which posits that color preferences are determined by people's average affective responses to correspondingly colored objects (Palmer & Schloss, Proceedings of the National Academy of Sciences, 107, 8877-8882, 2010). Seeing images of strongly liked (and disliked) red and green objects, therefore, should lead to increased (and decreased) preferences for correspondingly colored red and green color patches. Experiment 1 showed that this crossover interaction did occur, but only if participants were required to evaluate their preferences for the colored objects when they saw them. Experiment 2 showed that these overall changes decreased substantially over a 24-h delay, but the degree to which the effect lasted for individuals covaried with the magnitude of the effects immediately after object exposure. Experiment 3 demonstrated a similar, but weaker, effect of affectively biased changes in color preferences when participants did not see, but only imagined, the colored objects. The overall pattern of results indicated that color preferences are not fixed, but rather are shaped by affective experiences with colored objects. Possible explanations for the observed changes in color preferences were considered in terms of associative learning through evaluative conditioning and/or priming of prior knowledge in memory.

Influence of color word availability on the Stroop color-naming effect.

Science.gov (United States)

Kim, Hyosun; Cho, Yang Seok; Yamaguchi, Motonori; Proctor, Robert W

2008-11-01

Three experiments tested whether the Stroop color-naming effect is a consequence of word recognition's being automatic or of the color word's capturing visual attention. In Experiment 1, a color bar was presented at fixation as the color carrier, with color and neutral words presented in locations above or below the color bar; Experiment 2 was similar, except that the color carrier could occur in one of the peripheral locations and the color word at fixation. The Stroop effect increased as display duration increased, and the Stroop dilution effect (a reduced Stroop effect when a neutral word is also present) was an approximately constant proportion of the Stroop effect at all display durations, regardless of whether the color bar or color word was at fixation. In Experiment 3, the interval between the onsets of the to-be-named color and the color word was manipulated. The Stroop effect decreased with increasing delay of the color word onset, but the absolute amount of Stroop dilution produced by the neutral word increased. This study's results imply that an attention shift from the color carrier to the color word is an important factor modulating the size of the Stroop effect.

Representing Color Ensembles.

Science.gov (United States)

Chetverikov, Andrey; Campana, Gianluca; Kristjánsson, Árni

2017-10-01

Colors are rarely uniform, yet little is known about how people represent color distributions. We introduce a new method for studying color ensembles based on intertrial learning in visual search. Participants looked for an oddly colored diamond among diamonds with colors taken from either uniform or Gaussian color distributions. On test trials, the targets had various distances in feature space from the mean of the preceding distractor color distribution. Targets on test trials therefore served as probes into probabilistic representations of distractor colors. Test-trial response times revealed a striking similarity between the physical distribution of colors and their internal representations. The results demonstrate that the visual system represents color ensembles in a more detailed way than previously thought, coding not only mean and variance but, most surprisingly, the actual shape (uniform or Gaussian) of the distribution of colors in the environment.

Modeling directional effects in land surface temperature derived from geostationary satellite data

DEFF Research Database (Denmark)

Rasmussen, Mads Olander

This PhD-thesis investigates the directional effects in land surface temperature (LST) estimates from the SEVIRI sensor onboard the Meteosat Second Generation (MSG) satellites. The directional effects are caused by the land surface structure (i.e. tree size and shape) interacting with the changing...... sun-target-sensor geometry. The directional effects occur because the different surface components, e.g. tree canopies and bare soil surfaces, will in many cases have significantly different temperatures. Depending on the viewing angle, different fractions of each of the components will be viewed...... by the sensor. This is further complicated by temperature differences between the sunlit and shaded parts of each of the components, controlled by the exposure of the components to direct sunlight. As the SEVIRI sensor is onboard a geostationary platform, the viewing geometry is fixed (for each pixel), while...

Luminance contours can gate afterimage colors and 'real' colors

NARCIS (Netherlands)

Anstis, S.; Vergeer, M.L.T.; Lier, R.J. van

2012-01-01

It has long been known that colored images may elicit afterimages in complementary colors. We have already shown (Van Lier, Vergeer, & Anstis, 2009) that one and the same adapting image may result in different afterimage colors, depending on the test contours presented after the colored image. The

Digital color imaging

CERN Document Server

Fernandez-Maloigne, Christine; Macaire, Ludovic

2013-01-01

This collective work identifies the latest developments in the field of the automatic processing and analysis of digital color images.For researchers and students, it represents a critical state of the art on the scientific issues raised by the various steps constituting the chain of color image processing.It covers a wide range of topics related to computational color imaging, including color filtering and segmentation, color texture characterization, color invariant for object recognition, color and motion analysis, as well as color image and video indexing and retrieval. <

Color-quality control using color-difference formulas: progress and problems

Science.gov (United States)

Melgosa, M.; Gómez-Robledo, L.; García, P. A.; Morillas, S.; Fernández-Maloigne, C.; Richard, N.; Huang, M.; Li, C.; Cui, G.

2017-08-01

We report on some recent advances in industrial color-difference evaluation focused in three main fields: Development of reliable experimental visual datasets; proposal of new color spaces and color-difference formulas; tools to evaluate the merits of color-difference formulas. The use of fuzzy techniques to assign consistency degrees to color pairs in combined visual datasets is described. The CIE/ISO joint proposal of the CIEDE2000 color-difference formula as a standard will facilitate the communication among companies and users. The CIE recommendation of the STRESS index to assess observers' variability and relative merits of different color-difference formulas is reported. Power functions are an efficient method to improve the performance of modern color-difference formulas. We need of advanced color-difference formulas accounting for new materials with different kind of textures and gonioapparent effects.

Characterization of Angle Dependent Color Travel of Printed Multi-Color Effect Pigment on Different Color Substrates

Directory of Open Access Journals (Sweden)

Mirica Karlovits

2015-03-01

Full Text Available Color-travel pigments, which exhibit much more extensive color change as well provide angle-dependent optical effect can be used in many industrial products. In present paper the multi-color effect pigment printed on three different foils with different background color (black, silver and transparent was investigated. The pigment was based on synthetically produced transparent silicon dioxide platelets coated with titanium dioxide. CIEL*a*b* values and reflection of prints were measured by multi-angle spectrophotometer at constant illumination at an angle of 45º and different viewing angles (-15º, 15°, 25º, 45º, 75º and 110º were used. The measurements of printed multi-color pigment showed that CIEL*a*b* color coordinates varied to great extents, depending on detection angles as well on color of the printing substrate. The study revealed that pigmnet printed on black background obtained significant change in color. The study has also shown that when viewing angle increases, the reflection curves decreases.

Regal phylogeography: Range-wide survey of the marine angelfish Pygoplites diacanthus reveals evolutionary partitions between the Red Sea, Indian Ocean, and Pacific Ocean.

Science.gov (United States)

Coleman, Richard R; Eble, Jeffrey A; DiBattista, Joseph D; Rocha, Luiz A; Randall, John E; Berumen, Michael L; Bowen, Brian W

2016-07-01

The regal angelfish (Pygoplites diacanthus; family Pomacanthidae) occurs on reefs from the Red Sea to the central Pacific, with an Indian Ocean/Rea Sea color morph distinct from a Pacific Ocean morph. To assess population differentiation and evaluate the possibility of cryptic evolutionary partitions in this monotypic genus, we surveyed mtDNA cytochrome b and two nuclear introns (S7 and RAG2) in 547 individuals from 15 locations. Phylogeographic analyses revealed four mtDNA lineages (d=0.006-0.015) corresponding to the Pacific Ocean, the Red Sea, and two admixed lineages in the Indian Ocean, a pattern consistent with known biogeographic barriers. Christmas Island in the eastern Indian Ocean had both Indian and Pacific lineages. Both S7 and RAG2 showed strong population-level differentiation between the Red Sea, Indian Ocean, and Pacific Ocean (ΦST=0.066-0.512). The only consistent population sub-structure within these three regions was at the Society Islands (French Polynesia), where surrounding oceanographic conditions may reinforce isolation. Coalescence analyses indicate the Pacific (1.7Ma) as the oldest extant lineage followed by the Red Sea lineage (1.4Ma). Results from a median-joining network suggest radiations of two lineages from the Red Sea that currently occupy the Indian Ocean (0.7-0.9Ma). Persistence of a Red Sea lineage through Pleistocene glacial cycles suggests a long-term refuge in this region. The affiliation of Pacific and Red Sea populations, apparent in cytochrome b and S7 (but equivocal in RAG2) raises the hypothesis that the Indian Ocean was recolonized from the Red Sea, possibly more than once. Assessing the genetic architecture of this widespread monotypic genus reveals cryptic evolutionary diversity that merits subspecific recognition. We recommend P.d. diacanthus and P.d. flavescens for the Pacific and Indian Ocean/Red Sea forms. Copyright © 2016 Elsevier Inc. All rights reserved.

Seasonality and flux estimates of dissolved organic carbon in tidal wetlands and estuaries in the U.S. Mid- Atlantic Bight and Gulf of Mexico from ocean color

Science.gov (United States)

Cao, F.; Tzortziou, M.; Hu, C.; Najjar, R.

2016-02-01

Tidal wetlands and estuaries are dynamic features of coastal ocean and play critical roles in the global carbon cycle. Exchanges of dissolved organic carbon (DOC) between tidal wetlands and adjacent estuaries have important implications for carbon sequestration in tidal wetlands as well as biogeochemical cycling of wetlands derived material in the coastal zones. Recent studies demonstrated that the absorption coefficients of chromophoric dissolved organic matter at λ= 275 and 295 nm, which can be derived from satellite ocean color observations, can be used to accurately retrieve dissolved organic carbon (DOC) in some coastal waters. Based on a synthesis of existing field observations collected covering wide spatial and temporal variability in the Mid-Atlantic Bight and the Gulf of Mexico, here we developed and validated new empirical models to estimate coastal DOC from remotely sensed bio-optical properties of the surface water. We focused on the interfaces between tidal wetland-estuary and estuary-shelf water domains. The DOC algorithms were applied to SeaWiFs and MODIS observations to generate long-term climatological DOC distributions from 1998 to 2014. Empirical orthogonal function analysis revealed strong seasonality and spatial gradients in the satellite retrieved DOC in the tidal wetlands and estuaries. Combined with field observations and biogeochemical models, satellite retrievals can be used to scale up carbon fluxes from individual marshes and sub-estuaries to the whole estuarine system, and improve understanding of biogeochemical exchanges between terrestrial and aquatic ecosystems.

COLOR IMAGES

Directory of Open Access Journals (Sweden)

Dominique Lafon

2011-05-01

Full Text Available The goal of this article is to present specific capabilities and limitations of the use of color digital images in a characterization process. The whole process is investigated, from the acquisition of digital color images to the analysis of the information relevant to various applications in the field of material characterization. A digital color image can be considered as a matrix of pixels with values expressed in a vector-space (commonly 3 dimensional space whose specificity, compared to grey-scale images, is to ensure a coding and a representation of the output image (visualisation printing that fits the human visual reality. In a characterization process, it is interesting to regard color image attnbutes as a set of visual aspect measurements on a material surface. Color measurement systems (spectrocolorimeters, colorimeters and radiometers and cameras use the same type of light detectors: most of them use Charge Coupled Devices sensors. The difference between the two types of color data acquisition systems is that color measurement systems provide a global information of the observed surface (average aspect of the surface: the color texture is not taken into account. Thus, it seems interesting to use imaging systems as measuring instruments for the quantitative characterization of the color texture.

Examination of Color-Lighting Control System Using Colored Paper User Interface

Directory of Open Access Journals (Sweden)

Aida Hiroto

2016-01-01

Full Text Available In recent year, Full-Color LED Lighting that can be changed to various color such as red, green, blue has been appeared with development of LED Lighting. By Color-Lighting control, users affected such as concentrating and relaxing. Therefore, Color-lighting control will spread to various place such as home, offices, stations. However color-lighting control affected some disturbance such as daylight, display when Full-Color LED controlled indoors. Also, information devices control get difficult with information technology develop. I propose Color-Lighting Control System using Colored Paper User Interface(CLC/CPUI. The purpose of CLC/CPUI is that anyone can intuitively control Full-Color LED Lighting. CLC/CPUI uses colored paper as user interface by sensing the paper. CLC/CPUI realizes lighting color that user demanded to do feedback control. I conduct accuracy verification experiment of CLC/CPUI.

Colored Chaos

Science.gov (United States)

2004-01-01

[figure removed for brevity, see original site] Released 7 May 2004 This daytime visible color image was collected on May 30, 2002 during the Southern Fall season in Atlantis Chaos. The THEMIS VIS camera is capable of capturing color images of the martian surface using its five different color filters. In this mode of operation, the spatial resolution and coverage of the image must be reduced to accommodate the additional data volume produced from the use of multiple filters. To make a color image, three of the five filter images (each in grayscale) are selected. Each is contrast enhanced and then converted to a red, green, or blue intensity image. These three images are then combined to produce a full color, single image. Because the THEMIS color filters don't span the full range of colors seen by the human eye, a color THEMIS image does not represent true color. Also, because each single-filter image is contrast enhanced before inclusion in the three-color image, the apparent color variation of the scene is exaggerated. Nevertheless, the color variation that does appear is representative of some change in color, however subtle, in the actual scene. Note that the long edges of THEMIS color images typically contain color artifacts that do not represent surface variation. Image information: VIS instrument. Latitude -34.5, Longitude 183.6 East (176.4 West). 38 meter/pixel resolution. Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time. NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D

Analysing the Advantages of High Temporal Resolution Geostationary MSG SEVIRI Data Compared to Polar Operational Environmental Satellite Data for Land Surface Monitoring in Africa

Science.gov (United States)

Fensholt, R.; Anyamba, A.; Huber, S.; Proud, S. R.; Tucker, C. J.; Small, J.; Pak, E.; Rasmussen, M. O.; Sandholt, I.; Shisanya, C.

2011-01-01

Since 1972, satellite remote sensing of the environment has been dominated by polar-orbiting sensors providing useful data for monitoring the earth s natural resources. However their observation and monitoring capacity are inhibited by daily to monthly looks for any given ground surface which often is obscured by frequent and persistent cloud cover creating large gaps in time series measurements. The launch of the Meteosat Second Generation (MSG) satellite into geostationary orbit has opened new opportunities for land surface monitoring. The Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument on-board MSG with an imaging capability every 15 minutes which is substantially greater than any temporal resolution that can be obtained from existing polar operational environmental satellites (POES) systems currently in use for environmental monitoring. Different areas of the African continent were affected by droughts and floods in 2008 caused by periods of abnormally low and high rainfall, respectively. Based on the effectiveness of monitoring these events from Earth Observation (EO) data the current analyses show that the new generation of geostationary remote sensing data can provide higher temporal resolution cloud-free (less than 5 days) measurements of the environment as compared to existing POES systems. SEVIRI MSG 5-day continental scale composites will enable rapid assessment of environmental conditions and improved early warning of disasters for the African continent such as flooding or droughts. The high temporal resolution geostationary data will complement existing higher spatial resolution polar-orbiting satellite data for various dynamic environmental and natural resource applications of terrestrial ecosystems.

Color vision test

Science.gov (United States)

... present from birth) color vision problems: Achromatopsia -- complete color blindness , seeing only shades of gray Deuteranopia -- difficulty telling ... Vision test - color; Ishihara color vision test Images Color blindness tests References Bowling B. Hereditary fundus dystrophies. In: ...

Colors, colored overlays, and reading skills

OpenAIRE

Uccula, Arcangelo; Enna, Mauro; Mulatti, Claudio

2014-01-01

In this article, we are concerned with the role of colors in reading written texts. It has been argued that colored overlays applied above written texts positively influence both reading fluency and reading speed. These effects would be particularly evident for those individuals affected by the so called Meares-Irlen syndrome, i.e., who experience eyestrain and/or visual distortions – e.g., color, shape, or movement illusions – while reading. This condition would interest the 12–14% of the ge...

Global-scale Observations of the Limb and Disk (GOLD) Mission -Ultraviolet Remote Sensing of Earth's Space Environment from Geostationary Orbit

Science.gov (United States)

Burns, A. G.; Eastes, R.

2017-12-01

The GOLD mission of opportunity will fly a far ultraviolet imaging spectrograph in geostationary (GEO) orbit as a hosted payload. The mission is scheduled for launch in late January 2018 on SES-14, a commercial communications satellite that will be stationed over eastern South America at 47.5 degrees west longitude. GOLD is on schedule to be the first NASA science mission to fly as a hosted payload on a commercial communications satellite. The GOLD imager has two identical channels. Each channel can scan the full disk at a 30 minute cadence, making spectral images of Earth's UV emission from 132 to 162 nm, as well as make a measurement on the Earth's limb. Remote sensing techniques that have been proven on previous Low Earth Orbit (LEO) missions will be used to derive fundamental parameters for the neutral and ionized space environment. Parameters that will be derived include composition (O/N2 ratio) and temperature of the neutral atmosphere on the dayside disk. On the nightside, peak electron densities will be obtained in the low latitude ionosphere. Many of the algorithms developed for the mission are extensions of ones used on previous earth and planetary missions, with modifications for observations from geostationary orbit. All the algorithms have been tested using simulated observations based on the actual instrument performance. From geostationary orbit, GOLD can repeatedly image the same geographic locations over most of the hemisphere at a cadence comparable to that of the T-I system (order of an hour). Such time resolution and spatial coverage will allow the mission to track the changes due to geomagnetic storms, variations in solar extreme ultraviolet radiation, and forcing from the lower atmosphere. In addition to providing a new perspective by being able to repeatedly remotely sense the same hemisphere at a high cadence, GOLD's simultaneous measurements of not only composition but also temperatures across the disk will provide a valuable, new parameter

Decadal Changes in Global Ocean Annual Primary Production

Science.gov (United States)

Gregg, Watson; Conkright, Margarita E.; Behrenfeld, Michael J.; Ginoux, Paul; Casey, Nancy W.; Koblinsky, Chester J. (Technical Monitor)

2002-01-01

The Sea-viewing Wide Field-of-View Sensor (SeaWiFS) has produced the first multi-year time series of global ocean chlorophyll observations since the demise of the Coastal Zone Color Scanner (CZCS) in 1986. Global observations from 1997-present from SeaWiFS combined with observations from 1979-1986 from the CZCS should in principle provide an opportunity to observe decadal changes in global ocean annual primary production, since chlorophyll is the primary driver for estimates of primary production. However, incompatibilities between algorithms have so far precluded quantitative analysis. We have developed and applied compatible processing methods for the CZCS, using modern advances in atmospheric correction and consistent bio-optical algorithms to advance the CZCS archive to comparable quality with SeaWiFS. We applied blending methodologies, where in situ data observations are incorporated into the CZCS and SeaWiFS data records, to provide improvement of the residuals. These re-analyzed, blended data records provide maximum compatibility and permit, for the first time, a quantitative analysis of the changes in global ocean primary production in the early-to-mid 1980's and the present, using synoptic satellite observations. An intercomparison of the global and regional primary production from these blended satellite observations is important to understand global climate change and the effects on ocean biota. Photosynthesis by chlorophyll-containing phytoplankton is responsible for biotic uptake of carbon in the oceans and potentially ultimately from the atmosphere. Global ocean annual primary decreased from the CZCS record to SeaWiFS, by nearly 6% from the early 1980s to the present. Annual primary production in the high latitudes was responsible for most of the decadal change. Conversely, primary production in the low latitudes generally increased, with the exception of the tropical Pacific. The differences and similarities of the two data records provide evidence

Color Appearance of the Neon Color Spreading Effect

Directory of Open Access Journals (Sweden)

Damir Vusić

2017-04-01

Full Text Available As a part of this paper, the influence of various parameters within the target process of graphic reproduction on the color appearance of the neon color spreading effect was investigated. The shift in a color appearance qualitatively is determined through the calculation of changes in perceptual attributes of color, i.e. differences in lightness, chroma and hue. The influence of different media (printed images, and LCD display in the “cross-media” system was examined, as well as the role of the inserted segment color choice and background of the primary stimulus as an element of design solutions. These parameters were evaluated in a variety of ambient conditions and under the observation of three CIE standard light sources and illuminants. It was found that it was mostly the changes of the chroma and lightness. The change in the color hue is the lowest.

Using Single Colors and Color Pairs to Communicate Basic Tastes

Directory of Open Access Journals (Sweden)

Andy T. Woods

2016-07-01

Full Text Available Recently, it has been demonstrated that people associate each of the basic tastes (e.g., sweet, sour, bitter, and salty with specific colors (e.g., red, green, black, and white. In the present study, we investigated whether pairs of colors (both associated with a particular taste or taste word would give rise to stronger associations relative to pairs of colors that were associated with different tastes. We replicate the findings of previous studies highlighting the existence of a robust crossmodal correspondence between individual colors and basic tastes. However, while there was evidence that pairs of colors could indeed communicate taste information more consistently than single colors, our participants took more than twice as long to match the color pairs with tastes than the single colors. Possible reasons for these results are discussed.

Using Single Colors and Color Pairs to Communicate Basic Tastes.

Science.gov (United States)

Woods, Andy T; Spence, Charles

2016-01-01

Recently, it has been demonstrated that people associate each of the basic tastes (e.g., sweet, sour, bitter, and salty) with specific colors (e.g., red, green, black, and white). In the present study, we investigated whether pairs of colors (both associated with a particular taste or taste word) would give rise to stronger associations relative to pairs of colors that were associated with different tastes. We replicate the findings of previous studies highlighting the existence of a robust crossmodal correspondence between individual colors and basic tastes. However, while there was evidence that pairs of colors could indeed communicate taste information more consistently than single colors, our participants took more than twice as long to match the color pairs with tastes than the single colors. Possible reasons for these results are discussed.

The interaction between surface color and color knowledge: behavioral and electrophysiological evidence.

Science.gov (United States)

Bramão, Inês; Faísca, Luís; Forkstam, Christian; Inácio, Filomena; Araújo, Susana; Petersson, Karl Magnus; Reis, Alexandra

2012-02-01

In this study, we used event-related potentials (ERPs) to evaluate the contribution of surface color and color knowledge information in object identification. We constructed two color-object verification tasks - a surface and a knowledge verification task - using high color diagnostic objects; both typical and atypical color versions of the same object were presented. Continuous electroencephalogram was recorded from 26 subjects. A cluster randomization procedure was used to explore the differences between typical and atypical color objects in each task. In the color knowledge task, we found two significant clusters that were consistent with the N350 and late positive complex (LPC) effects. Atypical color objects elicited more negative ERPs compared to typical color objects. The color effect found in the N350 time window suggests that surface color is an important cue that facilitates the selection of a stored object representation from long-term memory. Moreover, the observed LPC effect suggests that surface color activates associated semantic knowledge about the object, including color knowledge representations. We did not find any significant differences between typical and atypical color objects in the surface color verification task, which indicates that there is little contribution of color knowledge to resolve the surface color verification. Our main results suggest that surface color is an important visual cue that triggers color knowledge, thereby facilitating object identification. Copyright © 2011 Elsevier Inc. All rights reserved.

2015 NOAA Ortho-rectified Color Mosaic of Los Angeles and Long Beach, California: Integrated Ocean and Coastal Mapping Product

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains ortho-rectified mosaic tiles, created as a product from the NOAA Integrated Ocean and Coastal Mapping (IOCM) initiative. The source imagery...

Chemical data assimilation of geostationary aerosol optical depth and PM surface observations on regional aerosol modeling over the Korean Peninsula during KORUS-AQ campaign

Science.gov (United States)

Jung, J.; Choi, Y.; Souri, A.; Jeon, W.

2017-12-01

Particle matter(PM) has played a significantly deleterious role in affecting human health and climate. Recently, continuous high concentrations of PM in Korea attracted public attention to this critical issue, and the Korea-United States Air Quality Study(KORUS-AQ) campaign in 2016 was conducted to investigate the causes. For this study, we adjusted the initial conditions in the chemical transport model(CTM) to improve its performance over Korean Peninsula during KORUS-AQ period, using the campaign data to evaluate our model performance. We used the Optimal Interpolation(OI) approach and used hourly surface air quality measurement data from the Air Quality Monitoring Station(AQMS) by NIER and the aerosol optical depth(AOD) measured by a GOCI sensor from the geostationary orbit onboard the Communication Ocean and Meteorological Satellite(COMS). The AOD at 550nm has a 6km spatial resolution and broad coverage over East Asia. After assimilating the surface air quality observation data, the model accuracy significantly improved compared to base model result (without assimilation). It reported very high correlation value (0.98) and considerably decreased mean bias. Especially, it well captured some high peaks which was underpredicted by the base model. To assimilate satellite data, we applied AOD scaling factors to quantify each specie's contribution to total PM concentration and find-mode fraction(FMF) to define vertical distribution. Finally, the improvement showed fairly good agreement.

Color-Blindness Study: Color Discrimination on the TICCIT System.

Science.gov (United States)

Asay, Calvin S.; Schneider, Edward W.

The question studied whether the specific seven TICCIT system colors used within color coding schemes can be a source of confusion, or not seen at all, by the color-blind segment of target populations. Subjects were 11 color-blind and three normally sighted students at Brigham Young University. After a preliminary training exercise to acquaint the…

Human preferences for colorful birds: Vivid colors or pattern?

Science.gov (United States)

Lišková, Silvie; Landová, Eva; Frynta, Daniel

2015-04-29

In a previous study, we found that the shape of a bird, rather than its color, plays a major role in the determination of human preferences. Thus, in the present study, we asked whether the preferences of human respondents towards uniformly shaped, colorful birds are determined by pattern rather than color. The experimental stimuli were pictures of small passerine birds of the family Pittidae possessing uniform shape but vivid coloration. We asked 200 participants to rank 43 colored and 43 identical, but grayscaled, pictures of birds. To find the traits determining human preferences, we performed GLM analysis in which we tried to explain the mean preference ranks and PC axes by the following explanatory variables: the overall lightness and saturation, edges (pattern), and the portion of each of the basic color hues. The results showed that the mean preference ranks of the grayscale set is explained mostly by the birds' pattern, whereas the colored set ranking is mostly determined by the overall lightness. The effect of colors was weaker, but still significant, and revealed that people liked blue and green birds. We found no significant role of the color red, the perception of which was acquired relatively recently in evolution.

Human Preferences for Colorful Birds: Vivid Colors or Pattern?

Directory of Open Access Journals (Sweden)

Silvie Lišková

2015-04-01

Full Text Available In a previous study, we found that the shape of a bird, rather than its color, plays a major role in the determination of human preferences. Thus, in the present study, we asked whether the preferences of human respondents towards uniformly shaped, colorful birds are determined by pattern rather than color. The experimental stimuli were pictures of small passerine birds of the family Pittidae possessing uniform shape but vivid coloration. We asked 200 participants to rank 43 colored and 43 identical, but grayscaled, pictures of birds. To find the traits determining human preferences, we performed GLM analysis in which we tried to explain the mean preference ranks and PC axes by the following explanatory variables: the overall lightness and saturation, edges (pattern, and the portion of each of the basic color hues. The results showed that the mean preference ranks of the grayscale set is explained mostly by the birds' pattern, whereas the colored set ranking is mostly determined by the overall lightness. The effect of colors was weaker, but still significant, and revealed that people liked blue and green birds. We found no significant role of the color red, the perception of which was acquired relatively recently in evolution.

Industrial Color Physics

CERN Document Server

Klein, Georg A

2010-01-01

This unique book starts with a short historical overview of the development of the theories of color vision and applications of industrial color physics. The three dominant factors producing color - light source, color sample, and observer - are described in detail. The standardized color spaces are shown and related color values are applied to characteristic color qualities of absorption as well as of effect colorants. The fundamentals of spectrometric and colorimetric measuring techniques together with specific applications are described. Theoretical models for radiative transfer in transparent, translucent, and opaque layers are detailed; the two, three, and multi-flux approximations are presented for the first time in a coherent formalism. These methods constitute the fundamentals not only for the important classical methods, but also modern methods of recipe prediction applicable to all known colorants. The text is supplied with 52 tables, more than 200 partially colored illustrations, an appendix, and a...

OW NOAA GOES-POES Sea Surface Temperature

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains blended satellite-derived sea-surface temperature measurements collected by means of the Geostationary Orbiting Environmental Satellites (GOES)...

GHRSST Level 2P Atlantic Regional Skin Sea Surface Temperature from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on the Meteosat Second Generation (MSG-2) satellite (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Meteosat Second Generation (MSG) satellites are spin stabilized geostationary satellites operated by the European Organization for the Exploitation of...

GHRSST Level 2P Atlantic Regional Skin Sea Surface Temperature from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on the Meteosat Second Generation (MSG-1) satellite (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Meteosat Second Generation (MSG) satellites are spin stabilized geostationary satellites operated by the European Organization for the Exploitation of...

Color naming

OpenAIRE

Şahin, Ebru

1998-01-01

Ankara : Bilkent University, Department of Interior Architecture and Environmental Design and Institute of Fine Arts, 1998. Thesis (Ph.D) -- Bilkent University, 1998 Includes bibliographical refences. In this study, visual aspects of color and neurophysiological processes involved in the phenomenon, language of color and color models were explained in addition to the discussion of different ideas, orientations and previous works behind the subject of matter. Available color ...

Color response and color transport in a quark-gluon plasma

International Nuclear Information System (INIS)

Heinz, U.

1986-01-01

Using color kinetic theory, we discuss color conduction and color response in a quark-gluon plasma. Collective color oscillations and their damping rates are investigated. An instability of the thermal equilibrium state in high T QCD is discovered

Cognitive aspects of color

Science.gov (United States)

Derefeldt, Gunilla A. M.; Menu, Jean-Pierre; Swartling, Tiina

1995-04-01

This report surveys cognitive aspects of color in terms of behavioral, neuropsychological, and neurophysiological data. Color is usually defined as psychophysical color or as perceived color. Behavioral data on categorical color perception, absolute judgement of colors, color coding, visual search, and visual awareness refer to the more cognitive aspects of color. These are of major importance in visual synthesis and spatial organization, as already shown by the Gestalt psychologists. Neuropsychological and neurophysiological findings provide evidence for an interrelation between cognitive color and spatial organization. Color also enhances planning strategies, as has been shown by studies on color and eye movements. Memory colors and the color- language connections in the brain also belong among the cognitive aspects of color.

Color response and color transport in a quark-gluon plasma

International Nuclear Information System (INIS)

Heinz, U.

1986-01-01

Using color kinetic theory, the authors discuss color conduction and color response in a quark-gluon plasma. Collective color oscillations and their damping rates are investigated. An instability of the thermal equilibrium state in high T QCD is discovered

A Study of Color Transformation on Website Images for the Color Blind

OpenAIRE

Siew-Li Ching; Maziani Sabudin

2010-01-01

In this paper, we study on color transformation method on website images for the color blind. The most common category of color blindness is red-green color blindness which is viewed as beige color. By transforming the colors of the images, the color blind can improve their color visibility. They can have a better view when browsing through the websites. To transform colors on the website images, we study on two algorithms which are the conversion techniques from RGB colo...

Color reproduction system based on color appearance model and gamut mapping

Science.gov (United States)

Cheng, Fang-Hsuan; Yang, Chih-Yuan

2000-06-01

By the progress of computer, computer peripherals such as color monitor and printer are often used to generate color image. However, cross media color reproduction by human perception is usually different. Basically, the influence factors are device calibration and characterization, viewing condition, device gamut and human psychology. In this thesis, a color reproduction system based on color appearance model and gamut mapping is proposed. It consists of four parts; device characterization, color management technique, color appearance model and gamut mapping.

Color inference in visual communication: the meaning of colors in recycling.

Science.gov (United States)

Schloss, Karen B; Lessard, Laurent; Walmsley, Charlotte S; Foley, Kathleen

2018-01-01

People interpret abstract meanings from colors, which makes color a useful perceptual feature for visual communication. This process is complicated, however, because there is seldom a one-to-one correspondence between colors and meanings. One color can be associated with many different concepts (one-to-many mapping) and many colors can be associated with the same concept (many-to-one mapping). We propose that to interpret color-coding systems, people perform assignment inference to determine how colors map onto concepts. We studied assignment inference in the domain of recycling. Participants saw images of colored but unlabeled bins and were asked to indicate which bins they would use to discard different kinds of recyclables and trash. In Experiment 1, we tested two hypotheses for how people perform assignment inference. The local assignment hypothesis predicts that people simply match objects with their most strongly associated color. The global assignment hypothesis predicts that people also account for the association strengths between all other objects and colors within the scope of the color-coding system. Participants discarded objects in bins that optimized the color-object associations of the entire set, which is consistent with the global assignment hypothesis. This sometimes resulted in discarding objects in bins whose colors were weakly associated with the object, even when there was a stronger associated option available. In Experiment 2, we tested different methods for encoding color-coding systems and found that people were better at assignment inference when color sets simultaneously maximized the association strength between assigned color-object parings while minimizing associations between unassigned pairings. Our study provides an approach for designing intuitive color-coding systems that facilitate communication through visual media such as graphs, maps, signs, and artifacts.

Comparison of the simultaneous measurement results of SCR fluxes received by geostationary satellites 'Electro-L' and 'GOES'

International Nuclear Information System (INIS)

Arakelov, A S; Burov, V A; Ochelkov, Y P

2013-01-01

In the present paper the comparison of the results of the simultaneous measurements of solar proton fluxes on board geostationary satellites 'GOES' and 'Electro' was made for the purpose of calibration of 'Electro-L' detectors and determination of the possibility to utilize 'Electro-L' data for space weather monitoring. It was shown that the solar proton observation data on board 'Electro-L' recalculated to energy thresholds of 'GOES' 10 and 30 MeV are in a good consistent with 'GOES' data and may be used for control of radiation conditions in near-earth space.

Demonstration of intradyne BPSK optical free-space transmission in representative atmospheric turbulence conditions for geostationary uplink channel.

Science.gov (United States)

Surof, Janis; Poliak, Juraj; Calvo, Ramon Mata

2017-06-01

Binary phase-shift keying optical transmission in the C-band with coherent intradyne reception is demonstrated over a long-range (10.45 km) link through the atmosphere. The link emulates representative channel conditions for geostationary optical feeder uplinks in satellite communications. The digital signal processing used in recovering the transmitted data and the performed measurements are described. Finally, the bit error rate results for 10 Gbit/s, 20 Gbit/s, and 30 Gbit/s of the outdoor experiments are presented and compared with back-to-back measurements and theory.

A subjective evaluation of high-chroma color with wide color-gamut display

Science.gov (United States)

Kishimoto, Junko; Yamaguchi, Masahiro; Ohyama, Nagaaki

2009-01-01

Displays tends to expand its color gamut, such as multi-primary color display, Adobe RGB and so on. Therefore displays got possible to display high chroma colors. However sometimes, we feel unnatural some for the image which only expanded chroma. Appropriate gamut mapping method to expand color gamut is not proposed very much. We are attempting preferred expanded color reproduction on wide color gamut display utilizing high chroma colors effectively. As a first step, we have conducted an experiment to investigate the psychological effect of color schemes including highly saturated colors. We used the six-primary-color projector that we have developed for the presentation of test colors. The six-primary-color projector's gamut volume in CIELAB space is about 1.8 times larger than the normal RGB projector. We conducted a subjective evaluation experiment using the SD (Semantic Differential) technique to find the quantitative psychological effect of high chroma colors.

Challenges and potential solutions for European coastal ocean modelling

Science.gov (United States)

She, Jun; Stanev, Emil

2017-04-01

and on-going altimetry missions, contributing to resolving (sub-)mesoscale eddies, more currents measurements from ADCPs and HF radars, geostationary data for suspended sediment and diurnal observations from satellite SST products. These developments will make it possible to generate new knowledge and build up new capacities for modelling and forecasting systems, e.g., improved currents forecast, improved water skin temperature and surface winds forecast, improved modelling and forecast of (sub) mesoscale activities and drift forecast, new forecast capabilities on SPM (Suspended Particle Matter) and algae bloom. There will be much more in-situ and satellite data available for assimilation. The assimilation of sea level, chl-a, ferrybox and profile observations will greatly improves the ocean-ice-ecosystem forecast quality.

Role of color memory in successive color constancy.

Science.gov (United States)

Ling, Yazhu; Hurlbert, Anya

2008-06-01

We investigate color constancy for real 2D paper samples using a successive matching paradigm in which the observer memorizes a reference surface color under neutral illumination and after a temporal interval selects a matching test surface under the same or different illumination. We find significant effects of the illumination, reference surface, and their interaction on the matching error. We characterize the matching error in the absence of illumination change as the "pure color memory shift" and introduce a new index for successive color constancy that compares this shift against the matching error under changing illumination. The index also incorporates the vector direction of the matching errors in chromaticity space, unlike the traditional constancy index. With this index, we find that color constancy is nearly perfect.

ColorPhylo: A Color Code to Accurately Display Taxonomic Classifications.

Science.gov (United States)

Lespinats, Sylvain; Fertil, Bernard

2011-01-01

Color may be very useful to visualise complex data. As far as taxonomy is concerned, color may help observing various species' characteristics in correlation with classification. However, choosing the number of subclasses to display is often a complex task: on the one hand, assigning a limited number of colors to taxa of interest hides the structure imbedded in the subtrees of the taxonomy; on the other hand, differentiating a high number of taxa by giving them specific colors, without considering the underlying taxonomy, may lead to unreadable results since relationships between displayed taxa would not be supported by the color code. In the present paper, an automatic color coding scheme is proposed to visualise the levels of taxonomic relationships displayed as overlay on any kind of data plot. To achieve this goal, a dimensionality reduction method allows displaying taxonomic "distances" onto a Euclidean two-dimensional space. The resulting map is projected onto a 2D color space (the Hue, Saturation, Brightness colorimetric space with brightness set to 1). Proximity in the taxonomic classification corresponds to proximity on the map and is therefore materialised by color proximity. As a result, each species is related to a color code showing its position in the taxonomic tree. The so called ColorPhylo displays taxonomic relationships intuitively and can be combined with any biological result. A Matlab version of ColorPhylo is available at http://sy.lespi.free.fr/ColorPhylo-homepage.html. Meanwhile, an ad-hoc distance in case of taxonomy with unknown edge lengths is proposed.

OW NOAA GOES Sea-Surface Temperature

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The dataset contains satellite-derived sea-surface temperature measurements collected by means of the Geostationary Orbiting Environmental Satellite. The data is...

GHRSST Level 2P Atlantic Regional Skin Sea Surface Temperature from the Spinning Enhanced Visible and InfraRed Imager (SEVIRI) on the Meteosat Second Generation (MSG-3) satellite (GDS version 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Meteosat Second Generation (MSG-3) satellites are spin stabilized geostationary satellites operated by the European Organization for the Exploitation of...

V color centers in electrolytically colored hydroxyl-doped sodium chloride crystals

International Nuclear Information System (INIS)

Gu Hongen; Song Cuiying; Han Li

2006-01-01

Hydroxyl-doped sodium chloride crystals were successfully colored electrolytically by using pointed anode and flat cathode at various temperatures and under various electric field strengths. V 2 and V 3 color centers were produced in the colored crystals. Current-time curves for the electrolytic colorations were given, and activation energy for the V 2 and V 3 color center migration was determined. Production of the V 2 and V 3 color centers and formation of current zones for the electrolytic colorations of the hydroxyl-doped sodium chloride crystals are explained

Evolution of pygmy angelfishes: Recent divergences, introgression, and the usefulness of color in taxonomy

KAUST Repository

Gaither, Michelle R.

2014-05-01

The pygmy angelfishes (genus Centropyge, family Pomacanthidae) are brightly colored species that occupy reef habitats in every tropical ocean. Some species are rarely observed because they occur below conventional scuba depths. Their striking coloration can command thousands of U.S. dollars in the aquarium trade, and closely related species are often distinguished only by coloration. These factors have impeded phylogenetic resolution, and every phylogeographic survey to date has reported discordance between coloration, taxonomy, and genetic partitions. Here we report a phylogenetic survey of 29 of the 34 recognized species (N= 94 plus 23 outgroups), based on two mtDNA and three nuclear loci, totaling 2272. bp. The resulting ML and Baysian trees are highly concordant and indicate that the genus Centropyge is paraphyletic, consistent with a previous analysis of the family Pomacanthidae. Two recognized genera (Apolemichthys and Genicanthus) nest within Centropyge, and two subgenera (Xiphypops and Paracentropyge) comprise monophyletic lineages that should be elevated to genus level. Based on an age estimate of 38. Ma for the family Pomacanthidae, Centropyge diverged from the closest extant genus Pygoplites about 33. Ma, three deep lineages within Centropyge diverged about 18-28. Ma, and four species complexes diverged 3-12. Ma. However, in 11 of 13 cases, putative species in these complexes are indistinguishable based on morphology and genetics, being defined solely by coloration. These cases indicate either emerging species or excessive taxonomic splitting based on brightly colored variants. © 2014 Elsevier Inc.

Ocean Acidification | Smithsonian Ocean Portal

Science.gov (United States)

Natural History Blog For Educators At The Museum Media Archive Ocean Life & Ecosystems Mammals Sharks Mangroves Poles Census of Marine Life Planet Ocean Tides & Currents Waves & Storms The Seafloor ocean is affected. Such a relatively quick change in ocean chemistry doesn't give marine life, which

Color Space and Its Divisions: Color Order from Antiquity to the Present

Science.gov (United States)

Kuehni, Rolf G.

2003-03-01

It has been postulated that humans can differentiate between millions of gradations in color. Not surprisingly, no completely adequate, detailed catalog of colors has yet been devised, however the quest to understand, record, and depict color is as old as the quest to understand the fundamentals of the physical world and the nature of human consciousness. Rolf Kuehni's Color Space and Its Divisions: Color Order from Antiquity to the Present represents an ambitious and unprecedented history of man's inquiry into color order, focusing on the practical applications of the most contemporary developments in the field. Kuehni devotes much of his study to geometric, three-dimensional arrangements of color experiences, a type of system developed only in the mid-nineteenth century. Color spaces are of particular interest for color quality-control purposes in the manufacturing and graphics industries. The author analyzes three major color order systems in detail: Munsell, OSA-UCS, and NCS. He presents historical and current information on color space developments in color vision, psychology, psychophysics, and color technology. Chapter topics include: A historical account of color order systems Fundamentals of psychophysics and the relationship between stimuli and experience Results of perceptual scaling of colors according to attributes History of the development of mathematical color space and difference formulas Analysis of the agreements and discrepancies in psychophysical data describing color differences An experimental plan for the reliable, replicated perceptual data necessary to make progress in the field Experts in academia and industry, neuroscientists, designers, art historians, and anyone interested in the nature of color will find Color Space and Its Divisions to be the authoritative reference in its field.

Data Processing and First Products from the Hyperspectral Imager for the Coastal Ocean (HICO) on the International Space Station

Science.gov (United States)

2010-04-01

NRL Stennis Space Center (NRL-SSC) for further processing using the NRL SSC Automated Processing System (APS). APS was developed for processing...have not previously developed automated processing for 73 hyperspectral ocean color data. The hyperspectral processing branch includes several

Satellite Radiation Products for Ocean Biology and Biogeochemistry: Needs, State-of-the-Art, Gaps, Development Priorities, and Opportunities

Directory of Open Access Journals (Sweden)

Robert Frouin

2018-02-01

cosine for PAR, and sub-surface spectral scalar fluxes are presented. A procedure to estimate algorithm uncertainties in the total uncertainty budget for above-surface daily PAR, based on radiative simulations for expected situations, is described. In the future, space-borne lidars with ocean profiling capability offer the best hope for improving our knowledge of sub-surface fields. To maximize temporal coverage, space agencies should consider placing ocean-color instruments in L1 orbit, where the sunlit part of the Earth can be frequently observed.

COLORS AND COLOR GRADIENTS IN BULGES OF GALAXIES

NARCIS (Netherlands)

BALCELLS, M; PELETIER, RF

We have obtained surface photometry in U, B, R, and I for a complete optically selected sample of 45 early-type spiral galaxies, to investigate the colors and color gradients of spiral bulges. Color profiles in U-R, B-R, U-B, and R-I have been determined in wedges opening on the semiminor axes.

Examination of Color-Lighting Control System Using Colored Paper User Interface

OpenAIRE

Aida Hiroto; Matsui Kento; Keisuke Soma; Murakami Hiroki; Miki Mistunori

2016-01-01

In recent year, Full-Color LED Lighting that can be changed to various color such as red, green, blue has been appeared with development of LED Lighting. By Color-Lighting control, users affected such as concentrating and relaxing. Therefore, Color-lighting control will spread to various place such as home, offices, stations. However color-lighting control affected some disturbance such as daylight, display when Full-Color LED controlled indoors. Also, information devices control get difficul...

Combining fine texture and coarse color features for color texture classification

Science.gov (United States)

Wang, Junmin; Fan, Yangyu; Li, Ning

2017-11-01

Color texture classification plays an important role in computer vision applications because texture and color are two fundamental visual features. To classify the color texture via extracting discriminative color texture features in real time, we present an approach of combining the fine texture and coarse color features for color texture classification. First, the input image is transformed from RGB to HSV color space to separate texture and color information. Second, the scale-selective completed local binary count (CLBC) algorithm is introduced to extract the fine texture feature from the V component in HSV color space. Third, both H and S components are quantized at an optimal coarse level. Furthermore, the joint histogram of H and S components is calculated, which is considered as the coarse color feature. Finally, the fine texture and coarse color features are combined as the final descriptor and the nearest subspace classifier is used for classification. Experimental results on CUReT, KTH-TIPS, and New-BarkTex databases demonstrate that the proposed method achieves state-of-the-art classification performance. Moreover, the proposed method is fast enough for real-time applications.

A relativistic colored spinning particle in an external color field

International Nuclear Information System (INIS)

Heinz, U.

1984-01-01

I derive fully covariant equations of motion for a classical colored spinning particle in an external SU(3) color field. Although the total color charge and total spin of the particle are found to be separately constants of motion (here I disagree with a recent paper by Arodz), the dynamics of the orientation of the color and spin vectors are coupled to each other through interaction with the color field, even if the latter is homogeneous. (orig.)

A Color-Opponency Based Biological Model for Color Constancy

Directory of Open Access Journals (Sweden)

Yongjie Li

2011-05-01

Full Text Available Color constancy is the ability of the human visual system to adaptively correct color-biased scenes under different illuminants. Most of the existing color constancy models are nonphysiologically plausible. Among the limited biological models, the great majority is Retinex and its variations, and only two or three models directly simulate the feature of color-opponency, but only of the very earliest stages of visual pathway, i.e., the single-opponent mechanisms involved at the levels of retinal ganglion cells and lateral geniculate nucleus (LGN neurons. Considering the extensive physiological evidences supporting that both the single-opponent cells in retina and LGN and the double-opponent neurons in primary visual cortex (V1 are the building blocks for color constancy, in this study we construct a color-opponency based color constancy model by simulating the opponent fashions of both the single-opponent and double-opponent cells in a forward manner. As for the spatial structure of the receptive fields (RF, both the classical RF (CRF center and the nonclassical RF (nCRF surround are taken into account for all the cells. The proposed model was tested on several typical image databases commonly used for performance evaluation of color constancy methods, and exciting results were achieved.

Colored operads

CERN Document Server

Yau, Donald

2016-01-01

The subject of this book is the theory of operads and colored operads, sometimes called symmetric multicategories. A (colored) operad is an abstract object which encodes operations with multiple inputs and one output and relations between such operations. The theory originated in the early 1970s in homotopy theory and quickly became very important in algebraic topology, algebra, algebraic geometry, and even theoretical physics (string theory). Topics covered include basic graph theory, basic category theory, colored operads, and algebras over colored operads. Free colored operads are discussed in complete detail and in full generality. The intended audience of this book includes students and researchers in mathematics and other sciences where operads and colored operads are used. The prerequisite for this book is minimal. Every major concept is thoroughly motivated. There are many graphical illustrations and about 150 exercises. This book can be used in a graduate course and for independent study.

Color management of porcelain veneers: influence of dentin and resin cement colors.

Science.gov (United States)

Dozic, Alma; Tsagkari, Maria; Khashayar, Ghazal; Aboushelib, Moustafa

2010-01-01

Porcelain veneers have become an interesting treatment option to correct the shape and color of anterior teeth. Because of their limited thickness and high translucency, achieving a good color match is influenced by several variables. The aim of this work was to investigate the influence of natural dentin and resin cement colors on final color match of porcelain veneers. A preselected shade tab (A1) was chosen as the target color for a maxillary central incisor, and its color parameters (L*a*b*) were measured using a digital spectrophotometer (SpectroShade, MHT). Nine natural dentin colors (Natural Die Material, Ivoclar Vivadent) representing a wide range of tooth colors were used to prepare resin replicas of the maxillary central incisor with a standard preparation for porcelain veneers. The prepared porcelain veneers (IPS Empress Esthetic, A1, 0.6 mm thick, Ivoclar Vivadent) were cemented on the resin dies (nine groups of natural dentin colors) using seven shades of resin cement (Variolink Veneers, Ivoclar Vivadent). The L*a*b* values of the cemented veneers were measured, and DE values were calculated against the preselected target color (A1). DE greater than 3.3 was considered as a significant color mismatch detectable by the human eye. The seven shades of resin cement had no significant influence on the final color of the veneers, as the measured DE values were almost identical for every test group. On the other hand, the color of natural dentin was a significant factor that influenced final color match. None of the 63 tested combinations (nine natural dentin colors and seven resin cement colors) produced an acceptable color match. Thin porcelain veneers cannot mask underlying tooth color even when different shades of resin cement are used. Incorporation of opaque porcelain (high chroma) may improve final color match.

P1-15: Categorical Color Perception of LED Illuminant Color for Deuteranomals

Directory of Open Access Journals (Sweden)

Saeko Oishi

2012-10-01

Full Text Available Color information has great value in our everyday lives, but it is not mindful of people with color vision deficiency (CVD. We can choose several color names to categorize a lot of colors around us. Eleven color names (white, black, red, green, yellow, blue, brown, orange, pink, and gray are known as basic color categories, but people with CVD cannot necessarily describe colors as people who are color vision normal (CVN do. Previous studies showed that it was hard for people with CVD to discriminate illuminant color from object color, and their color perception changed largely depending on experimental conditions. In this study we investigated categorical color perception of illuminant color for deuteranomals, using a mixture of light which consists of a red, a green, and a blue LED as a test stimulus. We tested those stimuli with three luminance levels (180 cd/m2, 18 cd/m2, 1.8 cd/m2 and two visual angles (10 deg, 0.5 deg. Subjects were three deuteranomals and three people who are CVN. Our result showed that the categorical color of mild deuteranomals was similar to that of those who were CVN, but that of severe deuteranomals was not. Severe deuteranomals judged more low chromatic colors as achromatic colors than those who were CVN. The smaller visual angle or lower luminance level the test stimulus had, the more deuteranomals confused color. The results suggest that the effect of the Bezold-Brucke phenomenon is greater to deuteranomals than to those who are CVN. Furthermore, deuteranomals use not only chromatic information but also luminance information when they describe color.

GHRSST Level 2P Western Pacific Regional Skin Sea Surface Temperature from the Multifunctional Transport Satellite 1R (MTSAT-1R) (GDS version 1)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Multi-functional Transport Satellites (MTSAT) are a series of geostationary weather satellites operated by the Japan Meteorological Agency (JMA). MTSAT carries an...

GHRSST Level 2P Western Pacific Regional Skin Sea Surface Temperature from the Multifunctional Transport Satellite 2 (MTSAT-2) (GDS versions 1 and 2)

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Multi-functional Transport Satellites (MTSAT) are a series of geostationary weather satellites operated by the Japan Meteorological Agency (JMA). MTSAT carries an...

Colored tracks of heavy ion particles recorded on photographic color film

International Nuclear Information System (INIS)

Kuge, K.; Yasuda, N.; Kumagai, H.; Aoki, N.; Hasegawa, A.

2002-01-01

A new method to obtain the three-dimensional information on nuclear tracks was developed using color photography. Commercial color films were irradiated with ion beam and color-developed. The ion tracks were represented with color images in which different depths were indicated by different colors, and the three-dimensional information was obtained from color changes. Details of this method are reported, and advantages and limitations are discussed in comparison with a conventional method using a nuclear emulsion

ColorTracker

NARCIS (Netherlands)

Holzheu, Stefanie; Lee, S.; Herneoja, Aulikki; Österlund, Toni; Markkanen, Piia

2016-01-01

With the work-in-progress research project ColorTracker we explore color as a formal design tool. This project-based paper describes a novel software application that processes color composition of a place and transcribes the data into three-dimensional geometries for architectural design. The

Colors in mind: a novel paradigm to investigate pure color imagery.

Science.gov (United States)

Wantz, Andrea L; Borst, Grégoire; Mast, Fred W; Lobmaier, Janek S

2015-07-01

Mental color imagery abilities are commonly measured using paradigms that involve naming, judging, or comparing the colors of visual mental images of well-known objects (e.g., "Is a sunflower darker yellow than a lemon"?). Although this approach is widely used in patient studies, differences in the ability to perform such color comparisons might simply reflect participants' general knowledge of object colors rather than their ability to generate accurate visual mental images of the colors of the objects. The aim of the present study was to design a new color imagery paradigm. Participants were asked to visualize a color for 3 s and then to determine a visually presented color by pressing 1 of 6 keys. We reasoned that participants would react faster when the imagined and perceived colors were congruent than when they were incongruent. In Experiment 1, participants were slower in incongruent than congruent trials but only when they were instructed to visualize the colors. The results in Experiment 2 demonstrate that the congruency effect reported in Experiment 1 cannot be attributed to verbalization of the color that had to be visualized. Finally, in Experiment 3, the congruency effect evoked by mental imagery correlated with performance in a perceptual version of the task. We discuss these findings with respect to the mechanisms that underlie mental imagery and patients suffering from color imagery deficits. (c) 2015 APA, all rights reserved.

Coloring mixed hypergraphs

CERN Document Server

Voloshin, Vitaly I

2002-01-01

The theory of graph coloring has existed for more than 150 years. Historically, graph coloring involved finding the minimum number of colors to be assigned to the vertices so that adjacent vertices would have different colors. From this modest beginning, the theory has become central in discrete mathematics with many contemporary generalizations and applications. Generalization of graph coloring-type problems to mixed hypergraphs brings many new dimensions to the theory of colorings. A main feature of this book is that in the case of hypergraphs, there exist problems on both the minimum and th

Perception of color emotions for single colors in red-green defective observers.

Science.gov (United States)

Sato, Keiko; Inoue, Takaaki

2016-01-01

It is estimated that inherited red-green color deficiency, which involves both the protan and deutan deficiency types, is common in men. For red-green defective observers, some reddish colors appear desaturated and brownish, unlike those seen by normal observers. Despite its prevalence, few studies have investigated the effects that red-green color deficiency has on the psychological properties of colors (color emotions). The current study investigated the influence of red-green color deficiency on the following six color emotions: cleanliness, freshness, hardness, preference, warmth, and weight. Specifically, this study aimed to: (1) reveal differences between normal and red-green defective observers in rating patterns of six color emotions; (2) examine differences in color emotions related to the three cardinal channels in human color vision; and (3) explore relationships between color emotions and color naming behavior. Thirteen men and 10 women with normal vision and 13 men who were red-green defective performed both a color naming task and an emotion rating task with 32 colors from the Berkeley Color Project (BCP). Results revealed noticeable differences in the cleanliness and hardness ratings between the normal vision observers, particularly in women, and red-green defective observers, which appeared mainly for colors in the orange to cyan range, and in the preference and warmth ratings for colors with cyan and purple hues. Similarly, naming errors also mainly occurred in the cyan colors. A regression analysis that included the three cone-contrasts (i.e., red-green, blue-yellow, and luminance) as predictors significantly accounted for variability in color emotion ratings for the red-green defective observers as much as the normal individuals. Expressly, for warmth ratings, the weight of the red-green opponent channel was significantly lower in color defective observers than in normal participants. In addition, the analyses for individual warmth ratings in

Perception of color emotions for single colors in red-green defective observers

Directory of Open Access Journals (Sweden)

Keiko Sato

2016-12-01

Full Text Available It is estimated that inherited red-green color deficiency, which involves both the protan and deutan deficiency types, is common in men. For red-green defective observers, some reddish colors appear desaturated and brownish, unlike those seen by normal observers. Despite its prevalence, few studies have investigated the effects that red-green color deficiency has on the psychological properties of colors (color emotions. The current study investigated the influence of red-green color deficiency on the following six color emotions: cleanliness, freshness, hardness, preference, warmth, and weight. Specifically, this study aimed to: (1 reveal differences between normal and red-green defective observers in rating patterns of six color emotions; (2 examine differences in color emotions related to the three cardinal channels in human color vision; and (3 explore relationships between color emotions and color naming behavior. Thirteen men and 10 women with normal vision and 13 men who were red-green defective performed both a color naming task and an emotion rating task with 32 colors from the Berkeley Color Project (BCP. Results revealed noticeable differences in the cleanliness and hardness ratings between the normal vision observers, particularly in women, and red-green defective observers, which appeared mainly for colors in the orange to cyan range, and in the preference and warmth ratings for colors with cyan and purple hues. Similarly, naming errors also mainly occurred in the cyan colors. A regression analysis that included the three cone-contrasts (i.e., red-green, blue-yellow, and luminance as predictors significantly accounted for variability in color emotion ratings for the red-green defective observers as much as the normal individuals. Expressly, for warmth ratings, the weight of the red-green opponent channel was significantly lower in color defective observers than in normal participants. In addition, the analyses for individual warmth

H31G-1596: DeepSAT's CloudCNN: A Deep Neural Network for Rapid Cloud Detection from Geostationary Satellites

Science.gov (United States)

Kalia, Subodh; Ganguly, Sangram; Li, Shuang; Nemani, Ramakrishna R.

2017-01-01

Cloud and cloud shadow detection has important applications in weather and climate studies. It is even more crucial when we introduce geostationary satellites into the field of terrestrial remote sensing. With the challenges associated with data acquired in very high frequency (10-15 mins per scan), the ability to derive an accurate cloud shadow mask from geostationary satellite data is critical. The key to the success for most of the existing algorithms depends on spatially and temporally varying thresholds,which better capture local atmospheric and surface effects.However, the selection of proper threshold is difficult and may lead to erroneous results. In this work, we propose a deep neural network based approach called CloudCNN to classify cloudshadow from Himawari-8 AHI and GOES-16 ABI multispectral data. DeepSAT's CloudCNN consists of an encoderdecoder based architecture for binary-class pixel wise segmentation. We train CloudCNN on multi-GPU Nvidia Devbox cluster, and deploy the prediction pipeline on NASA Earth Exchange (NEX) Pleiades supercomputer. We achieved an overall accuracy of 93.29% on test samples. Since, the predictions take only a few seconds to segment a full multispectral GOES-16 or Himawari-8 Full Disk image, the developed framework can be used for real-time cloud detection, cyclone detection, or extreme weather event predictions.

Color Degree Sum Conditions for Rainbow Triangles in Edge-Colored Graphs

NARCIS (Netherlands)

Li, Ruonan; Ning, Bo; Zhang, Shenggui

Let G be an edge-colored graph and v a vertex of G. The color degree of v is the number of colors appearing on the edges incident to v. A rainbow triangle in G is one in which all edges have distinct colors. In this paper, we first prove that an edge-colored graph on n vertices contains a rainbow

What is Color Blindness?

Science.gov (United States)

... Color Blindness? Who Is at Risk for Color Blindness? Color Blindness Causes Color Blindness Diagnosis and Treatment How Color Blindness Is Tested What Is Color Blindness? Leer en Español: ¿Qué es el daltonismo? Written ...

Color Calibration for Colorized Vision System with Digital Sensor and LED Array Illuminator

Directory of Open Access Journals (Sweden)

Zhenmin Zhu

2016-01-01

Full Text Available Color measurement by the colorized vision system is a superior method to achieve the evaluation of color objectively and continuously. However, the accuracy of color measurement is influenced by the spectral responses of digital sensor and the spectral mismatch of illumination. In this paper, two-color vision system illuminated by digital sensor and LED array, respectively, is presented. The Polynomial-Based Regression method is applied to solve the problem of color calibration in the sRGB and CIE  L⁎a⁎b⁎ color spaces. By mapping the tristimulus values from RGB to sRGB color space, color difference between the estimated values and the reference values is less than 3ΔE. Additionally, the mapping matrix ΦRGB→sRGB has proved a better performance in reducing the color difference, and it is introduced subsequently into the colorized vision system proposed for a better color measurement. Necessarily, the printed matter of clothes and the colored ceramic tile are chosen as the application experiment samples of our colorized vision system. As shown in the experimental data, the average color difference of images is less than 6ΔE. It indicates that a better performance of color measurement is obtained via the colorized vision system proposed.

NESDIS Blended Rain Rate (RR) Products

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The blended Rain Rate (RR) product is derived from multiple sensors/satellites. The blended products were merged from polar-orbiting and geostationary satellite...

Observation of The Top of The Atmosphere Outgoing Longwave Radiation Using The Geostationary Earth Radiation Budget Sensor

Science.gov (United States)

Spencer, G.; Llewellyn-Jones, D.

In the summer of 2002 the Meteosat Second Generation (MSG) satellite is due to be launched. On board the MSG satellite is the Geostationary Earth Radiation Budget (GERB) sensor. This is a new radiometer that will be able to observe and measure the outgoing longwave radiation from the top of the atmosphere for the whole ob- served Earth disc, due to its unique position in geostationary orbit. Every 15 minutes the GERB sensor will make a full Earth disc observation, centred on the Greenwich meridian. Thus, the GERB sensor will provide unprecedented coupled temporal and spatial resolution of the outgoing longwave radiation (4.0 to 30.0 microns), by first measuring the broadband radiation (0.32 to 30.0 microns) and then subtracting the measured reflected shortwave solar radiation (0.32 to 4.0 microns), from the earth- atmosphere system. The GERB sensor is able to make measurements to within an accuracy of 1 W/sq. m. A forward model is being developed at Leicester to simulate the data from the GERB sensor for representative geophysical scenes and to investigate key parameters and processes that will affect the top of the atmosphere signal. At the heart of this model is a line-by-line radiative transfer model, the Oxford Reference Forward Model (RFM) that is to be used with model atmospheres generated from ECMWF analysis data. When MSG is launched, cloud data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI), also on board, is to be used in conjunction with GERB data.

Degradation Signatures of Open Ocean Microplastic Debris

Science.gov (United States)

Lavender Law, K. L.; Donohue, J. L.; Collins, T.; Proskurowsi, G.; Andrady, A. L.

2016-02-01

Microplastics collected from the open ocean offer few clues about their origin and history. There is currently no method to determine how long ocean plastic has undergone environmental weathering, how quickly fragmentation has occurred, or how small microplastic particles will ultimately become before (or if) they are fully degraded by microbial action. In the current absence of results from laboratory and field experiments designed to address these questions, we meticulously examined physical and chemical characteristics of open ocean microplastic particles collected over a 16-year period for clues about their weathering history. More than 1000 microplastic particles collected in the western North Atlantic between 1991 and 2007 were analyzed to determine polymer type, material density, mass and particle size, and were used to create a detailed catalogue of common microscopic surface features likely related to environmental exposure and weathering. Polyethylene and polypropylene, the two buoyant resins most commonly collected at the sea surface, can typically be distinguished by visual microscopy alone, and their particular characteristics lead us to hypothesize that these two resins weaken and fragment in different ways and on different time scales. A subset of resin pellets collected at sea were also analyzed using FTIR-ATR and/or FTIR microscopy for signatures of chemical degradation (e.g., carbonyl index) that are related to physical weathering characteristics such as color, quantified by the yellowness index.

Preliminary Assessment of Detection Efficiency for the Geostationary Lightning Mapper Using Intercomparisons with Ground-Based Systems

Science.gov (United States)

Bateman, Monte; Mach, Douglas; Blakeslee, Richard J.; Koshak, William

2018-01-01

As part of the calibration/validation (cal/val) effort for the Geostationary Lightning Mapper (GLM) on GOES-16, we need to assess instrument performance (detection efficiency and accuracy). One major effort is to calculate the detection efficiency of GLM by comparing to multiple ground-based systems. These comparisons will be done pair-wise between GLM and each other source. A complication in this process is that the ground-based systems sense different properties of the lightning signal than does GLM (e.g., RF vs. optical). Also, each system has a different time and space resolution and accuracy. Preliminary results indicate that GLM is performing at or above its specification.

Impacts of pre-existing ocean cyclonic circulation on sea surface chlorophyll-a concentrations off northeastern Taiwan following episodic typhoon passages

Science.gov (United States)

Xu, Fanghua; Yao, Yuan; Oey, Leo; Lin, Yanluan

2017-08-01

Off northeastern Taiwan, enhancement of sea surface chlorophyll-a (Chl-a) concentration is frequently found after typhoon passages. From 1998 to 2013, 46 typhoon events are analyzed to examine the variations in Chl-a concentration from satellite ocean color data. On average, Chl-a concentration increased by 38% after a typhoon passage. Noticeably, four remarkable Chl-a increases after typhoons coincide with pre-existing oceanic cyclones in the study area. The Chl-a increase is significantly anticorrelated (p typhoons, we conduct a series of numerical experiments to simulate the oceanic response to Typhoon Kaemi (2006) with or without a pre-existing oceanic cyclone, and with or without strong typhoon winds. The results show that the experiment with a pre-existing oceanic cyclone produces the largest upwelling due to cyclone intensification, mainly induced by the positive wind stress curl dipole northeast of Taiwan.

Focal colors across languages are representative members of color categories.

Science.gov (United States)

Abbott, Joshua T; Griffiths, Thomas L; Regier, Terry

2016-10-04

Focal colors, or best examples of color terms, have traditionally been viewed as either the underlying source of cross-language color-naming universals or derived from category boundaries that vary widely across languages. Existing data partially support and partially challenge each of these views. Here, we advance a position that synthesizes aspects of these two traditionally opposed positions and accounts for existing data. We do so by linking this debate to more general principles. We show that best examples of named color categories across 112 languages are well-predicted from category extensions by a statistical model of how representative a sample is of a distribution, independently shown to account for patterns of human inference. This model accounts for both universal tendencies and variation in focal colors across languages. We conclude that categorization in the contested semantic domain of color may be governed by principles that apply more broadly in cognition and that these principles clarify the interplay of universal and language-specific forces in color naming.

Effect of Ionosphere on Geostationary Communication Satellite Signals