53 research outputs found

    Very Shallow Water Bathymetry Retrieval from Hyperspectral Imagery at the Virginia Coast Reserve (VCR\u2707) Multi-Sensor Campaign

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    A number of institutions, including the Naval Research Laboratory (NRL), have developed look up tables for remote retrieval of bathymetry and in-water optical properties from hyperspectral imagery (HSI) [6]. For bathymetry retrieval, the lower limit is the very shallow water case (here defined as \u3c 2m), a depth zone which is not well resolved by many existing bathymetric LIDAR sensors, such as SHOALS [4]. The ability to rapidly model these shallow water depths from HSI directly has potential benefits for combined HSI/LIDAR systems such as the Compact Hydrographic Airborne Rapid Total Survey (CHARTS) [10]. In this study, we focused on the validation of a near infra-red feature, corresponding to a local minimum in absorption (and therefore a local peak in reflectance), which can be correlated directly to bathymetry with a high degree of confidence. Compared to other VNIR wavelengths, this particular near-IR feature corresponds to a peak in the correlation with depth in this very shallow water regime, and this is a spectral range where reflectance depends primarily on water depth (water absorption) and bottom type, with suspended constituents playing a secondary role

    Dedicated JPSS VIIRS Ocean Color Calibration/Validation Cruise

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    The NOAA/STAR ocean color team is focused on “end-to-end” production of high quality satellite ocean color products. In situ validation of satellite data is essential to produce the high quality, “fit for purpose” remotely sensed ocean color products that are required and expected by all NOAA line offices, as well as by external (both applied and research) users. In addition to serving the needs of its diverse users within the U.S., NOAA has an ever increasing role in supporting the international ocean color community and is actively engaged in the International Ocean-Colour Coordinating Group (IOCCG). The IOCCG, along with the Committee on Earth Observation Satellites (CEOS) Ocean Colour Radiometry Virtual Constellation (OCR-VC), is developing the International Network for Sensor Inter-comparison and Uncertainty assessment for Ocean Color Radiometry (INSITU-OCR). The INSITU-OCR has identified, amongst other issues, the crucial need for sustained in situ observations for product validation, with longterm measurement programs established and maintained beyond any individual mission. Recently, the NOAA/STAR Ocean Color Team has been making in situ validation measurements continually since the launch in fall 2011 of the Visible Infrared Imaging Radiometer Suite (VIIRS) aboard the Suomi National Polar-orbiting Partnership (SNPP) platform, part of the U.S. Joint Polar Satellite System (JPSS) program. NOAA ship time for the purpose of ocean color validation, however, had never been allocated until the cruise described herein. As the institutional lead for this cruise, NOAA/STAR invited external collaborators based on scientific objectives and existing institutional collaborations. The invited collaborators are all acknowledged professionals in the ocean color remote sensing community. Most of the cruise principal investigators (PIs) are also PIs of the VIIRS Ocean Color Calibration and Validation (Cal/Val) team, including groups from Stennis Space Center/Naval Research Laboratory (SSC/NRL) and the University of Southern Mississippi (USM); City College of New York (CCNY); University of Massachusetts Boston (UMB); University of South Florida (USF); University of Miami (U. Miami); and, the National Institute of Standards and Technology (NIST). These Cal/Val PIs participated directly, sent qualified researchers from their labs/groups, or else contributed specific instruments or equipment. Some of the cruise PIs are not part of the NOAA VIIRS Ocean Color Cal/Val team but were chosen to complement and augment the strengths of the Cal/Val team participants. Outside investigator groups included NASA Goddard Space Flight Center (NASA/GSFC), Lamont-Doherty Earth Observatory at Columbia University (LDEO), and the Joint Research Centre of the European Commission (JRC). This report documents the November 2014 cruise off the U.S. East Coast aboard the NOAA Ship Nancy Foster. This cruise was the first dedicated ocean color validation cruise to be supported by the NOAA Office of Marine and Air Operations (OMAO). A second OMAO-supported cruise aboard the Nancy Foster is being planned for late 2015. We at NOAA/STAR are looking forward to continuing dedicated ocean color validation cruises, supported by OMAO on NOAA vessels, on an annual basis in support of JPSS VIIRS on SNPP, J-1, J-2 and other forthcoming satellite ocean color missions from the U.S as well as other countries. We also look forward to working with the U.S. and the international ocean community for improving our understanding of global ocean optical, biological, and biogeochemical properties.JRC.H.1-Water Resource

    A vein bypass first versus a best endovascular treatment first revascularization strategy for patients with chronic limb-threatening ischaemia who require an infra-popliteal, with or without an additional more proximal infra-inguinal, revascularization procedure to restore limb perfusion:the BASIL-2 within-trial health economic analysis

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    BackgroundChronic limb-threatening ischaemia (CLTI) places a considerable socioeconomic burden health and social care systems worldwide. The objective of this health economic analysis was to investigate the cost-effectiveness (CEA) and cost-utility (CUA) of a vein bypass (VB) first versus a best endovascular treatment (BET) first revascularization strategy in patients with CLTI who require an infra-popliteal revascularization procedure to restore limb perfusion. Methods CEA and CUA analyses were conducted from the perspective of the UK National Health Service. Patient-level resource use and health outcomes data collected from the BASIL-2 trial over 2-7 years of follow-up were utilized to estimate incremental cost-effectiveness ratios expressed as cost per amputation-free life year (AFLY) and cost per quality-adjusted life year (QALY). EQ-5D-5L was used to generate participant QALYs at 2 and 3 years. Results At two years, the mean(s.d.) discounted hospital cost was £15 742.59(16 182.60) and £13 273.66(15 446.92) in the VB-first and BET-first revascularization strategy groups respectively. The lower costs (-£2524.23, 95% c.i., -£5844.93 to £1131.52) in the BET-first group were mainly due to the reduced number of days in hospital and lower procedural costs. BET-first was also more effective leading to additional AFLYs (0.429, 95% c.i., 0.03 to 0.88) at 7 years and discounted QALYs (0.016, 95% c.i., -0.08 to 0.12) at 2 years. Conclusion A best endovascular first revascularization strategy dominated a vein bypass first strategy in the cost-effectiveness and cost-utility analyses. The findings were robust across different scenarios and prespecified subgroups.<p/
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