2,929 research outputs found

    Biooptical variability in the Greenland Sea observed with the Multispectral Airborne Radiometer System (MARS)

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    A site-specific ocean color remote sensing algorithm was developed and used to convert Multispectral Airborne Radiometer System (MARS) spectral radiance measurements to chlorophyll-a concentration profiles along aircraft tracklines in the Greenland Sea. The analysis is described and the results given in graphical or tabular form. Section 2 describes the salient characteristics and history of development of the MARS instrument. Section 3 describes the analyses of MARS flight segments over consolidated sea ice, resulting in a set of altitude dependent ratios used (over water) to estimate radiance reflected by the surface and atmosphere from total radiance measured. Section 4 presents optically weighted pigment concentrations calculated from profile data, and spectral reflectances measured in situ from the top meter of the water column; this data was analyzed to develop an algorithm relating chlorophyll-a concentrations to the ratio of radiance reflectances at 441 and 550 nm (with a selection of coefficients dependent upon whether significant gelvin presence is implied by a low ratio of reflectances at 410 and 550 nm). Section 5 describes the scaling adjustments which were derived to reconcile the MARS upwelled radiance ratios at 410:550 nm and 441:550 nm to in situ reflectance ratios measured simultaneously on the surface. Section 6 graphically presents the locations of MARS data tracklines and positions of the surface monitoring R/V. Section 7 presents stick-plots of MARS tracklines selected to illustrate two-dimensional spatial variability within the box covered by each day's flight. Section 8 presents curves of chlorophyll-a concentration profiles derived from MARS data along survey tracklines. Significant results are summarized in Section 1

    Economia, entropia e sustentabilidade: abordagem e visões de futuro da Economia da sobrevivência

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    The paper evaluates theeconomics of survival - o school of thought that emphasizes thepreservation of the opportunities of future generations on an extended time horizon. Itexamines the school's approach on the interactions between the economic system andthe environment, and its main analytical concepts, particularly that of entropy. It showsthat the concern of the school's founders was mainly with the consequences of a seriousdepletion of natural resources - particularly those of the earth's energy capital. Recently,however, emphasis was placed on problems stemming from the fragility of the globalsystem in face of growing disturbances imposed by mankind's entropic acceleration.There are vital environmental functions, especially the preservation of ecosystem resiliency,and it is argued that a continued expansion of the scale of the economy may bring aboutirreversible damages to these fundamental functions.O artigo avalia corrente de pensamento - a da economia da sobrevivência -, que se caracteriza por forte compromisso com a preservação das oportunidades das gerações futuras, numa perspectiva temporal muito extensa

    Sustainable development: conceptualizations and measurement

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    The paper builds up from a review of some expected, but other quite surprising results regarding country estimates for the year 2000 of genuine saving, a sustainability indicator developed by a World Bank research team. We examine this indicator, founded on neoclassical welfare theory, and discuss one of its major problems. Theoretical developments from ecological economics are then considered, together with insights from Georgescu-Roegen's approach to the production process, in search for an alternative approach. A model with potentially fruitful contributions in this direction is reviewed; it points the course efforts could take enable sustainability evaluations based on a more realistic set of interrelated monetary and biophysical indicators

    Hospital Community Benefits After the ACA: The Emerging Federal Framework

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    Outlines the federal framework on requirements for hospitals to provide community benefit activities in exchange for tax-exempt status under the 2010 healthcare reform, including community health needs assessments; state policy options; and challenges

    Alternativen der parlamentarischen Demokratie

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    Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.It is often said that the parliament should represent the opinions found in the population and that the government should be held accountable for its political program. It is shown in the paper that these two functions rely on two different basic models of democracy which are not fully compatible with each other: the model of a pure representative democracy and the model of a pure two party competition. Unaccountable governments, voter alienation, strategic voting, and governmental instability are shown to be consequences of this institutional mix. These problems may be avoided with reforms towards one or the other basic model.Peer Reviewe

    Fronteira agrícola, tecnologia e margem intensiva: algumas reflexôes sobre o papel desses fatores para o crescimento agrícola brasileiro

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    O presente trabalho visa provocar discussSes sobre aspectos pouco estudados da maneira pela qual vem sendo promovido o crescimento do setor agrícola no Brasil

    SeaWiFS Technical Report Series

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    This document provides brief reports, or case studies, on a number of investigations sponsored by the Calibration and Validation Team (CVT) within the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project. Chapter I describes the calibration and characterization of the GSFC sphere, which was used in the recent recalibration of the SeaWiFS instrument. Chapter 2 presents a revision of the diffuse attenuation coefficient, K(490), algorithm based on the SeaWiFS wavelengths. Chapter 3 provides an implementation scheme for an algorithm to remove out-of-band radiance when using a sensor calibration based on a finite width (truncated) spectral response function, e.g., between the 1% transmission points. Chapter 4 describes the implementation schemes for the stray light quality flag (local area coverage [LAC] and global area coverage [GAC]) and the LAC stray light correction

    Sunda-Banda arc transition: incipient continent-island arc collision (Northwest Australia)

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    The eastern Sunda arc represents one of the few regions globally where the early stages of continent-arc collision can be studied. We studied along the western limit of the collision zone at the Sunda-Banda arc transition, where the Australian margin collides with the Banda island arc, causing widespread back arc thrusting. We present integrated results of a refraction/wide-angle reflection tomography, gravity modeling, and multichannel reflection seismic imaging using data acquired in 2006 southeast of Sumba Island. The composite structural model reveals the previously unresolved deep geometry of the collision zone. Changes in crustal structure encompass the 10 - 12 km thick Australian basement in the south and the 22 - 24 kmthick Sumba ridge in the north, where backthrusting of the 130 km wide accretionary prism is documented. The structural diversity along this transect could be characteristic of young collisional systems at the transition from oceanic subduction to continent-arc collision. Citation: Shulgin, A., H. Kopp, C. Mueller, E. Lueschen, L. Planert, M. Engels, E. R. Flueh, A. Krabbenhoeft, and Y. Djajadihardja (2009), Sunda-Banda arc transition: Incipient continent-island arc collision (northwest Australia), Geophys. Res. Lett., 36, L10304, doi: 10.1029/2009GL037533

    Changing impacts of Alaska-Aleutian subduction zone tsunamis in California under future sea-level rise

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    The amplification of coastal hazards such as distant-source tsunamis under future relative sea-level rise (RSLR) is poorly constrained. In southern California, the Alaska-Aleutian subduction zone has been identified as an earthquake source region of particular concern for a worst-case scenario distant-source tsunami. Here, we explore how RSLR over the next century will influence future maximum nearshore tsunami heights (MNTH) at the Ports of Los Angeles and Long Beach. Earthquake and tsunami modeling combined with local probabilistic RSLR projections show the increased potential for more frequent, relatively low magnitude earthquakes to produce distant-source tsunamis that exceed historically observed MNTH. By 2100, under RSLR projections for a high-emissions representative concentration pathway (RCP8.5), the earthquake magnitude required to produce \u3e1 m MNTH falls from ~Mw9.1 (required today) to Mw8.0, a magnitude that is ~6.7 times more frequent along the Alaska-Aleutian subduction zone
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