Blar i forfatter "Mckee, David"

Viser treff 1-12 av 12

    • All-sky camera system providing high temporal resolution annual time series of irradiance in the arctic 

      Johnsen, Geir; Zolich, Artur; Grant, Stephen; Bjorgum, Rune; Cohen, Jonathan H.; Mckee, David; Kopec, Tomasz Piotr; Vogedes, Daniel Ludwig; Berge, Jorgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-23)
      The ArcLight observatory provides hourly continuous time series of light regime data (intensity, spectral composition, and photoperiod) from the Arctic, Svalbard at 79° N. Until now, no complete annual time series of biologically relevant light has been provided from the high Arctic due to insufficient sensitivity of commercial light sensors during the Polar Night. We describe a camera system providing ...

    • An Artificial Neural Network Algorithm to Retrieve Chlorophyll a for Northwest European Shelf Seas from Top of Atmosphere Ocean Colour Reflectance 

      Hadjal, Madjid; Medina-Lopez, Encarni; Ren, Jinchang; Gallego, Alejandro; Mckee, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-12)
      Chlorophyll-a (Chl) retrieval from ocean colour remote sensing is problematic for relatively turbid coastal waters due to the impact of non-algal materials on atmospheric correction and standard Chl algorithm performance. Artificial neural networks (NNs) provide an alternative approach for retrieval of Chl from space and results for northwest European shelf seas over the 2002–2020 period are ...

    • Development and calibration of a high dynamic range and autonomous ocean-light instrument to measure sub-surface profiles in ice-covered waters 

      Schartmuller, Bernhard; Anderson, Philip; Mckee, David; Connan-McGinty, Stacey; Kopec, Tomasz Piotr; Daase, Malin Hildegard Elisabeth; Johnsen, Geir; Berge, Jørgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-10-23)
      The optical chain and logger (OptiCAL) is an autonomous ice-tethered observatory equipped with multiple light sensors for mapping the variation of light with depth. We describe the instrument and present an ensemble calibration for downwelling irradiance E<sub>PAR</sub> in [µmolm<sup>−2</sup>s<sup>−1</sup>]. Results from a long-term deployment in the Arctic Ocean demonstrate that the OptiCAL can ...

    • Development of a bio-optical model for the Barents Sea to quantitatively link glider and satellite observations 

      Kostakis, I.; Röttgers, R.; Orkney, A.; Bouman, H.A.; Porter, M.; Cottier, Finlo Robert; Berge, Jørgen; Mckee, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-08-31)
      A bio-optical model for the Barents Sea is determined from a set of in situ observations of inherent optical properties (IOPs) and associated biogeochemical analyses. The bio-optical model provides a pathway to convert commonly measured parameters from glider-borne sensors (CTD, optical triplet sensor— chlorophyll and CDOM fluorescence, backscattering coefficients) to bulk spectral IOPs ...

    • Disruption of marine habitats by artificial light at night from global coastal megacities 

      Smyth, T.J.; Wright, A.E.; Edwards-Jones, A.; Mckee, David; Queirós, A.; Rendon, O.; Tidau, S.; Davies, T.W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-12-01)
      Half of globally significant megacities are situated near the coast, exposing urban marine ecosystems to multiple stressors such as waste-water discharge containing a host of organic and inorganic pollutants, air and noise pollution. In addition to these well recognized sources, artificial light at night (ALAN) pollution is inseparable from cities but poorly quantified in marine ecosystems to date. ...

    • A global atlas of artificial light at night under the sea 

      Smyth, T.J.; Wright, A.E.; Mckee, David; Tidau, S.; Tamir, R.; Dubinsky, Z.; Iluz, D.; Davies, T.W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-12-13)
      The impacts of artificial light at night (ALAN) on marine ecosystems have emerged as a focus for ecological light pollution research in recent years, yet the global prevalence of ALAN in underwater marine ecosystems is unknown. We have derived a global atlas of ALAN throughout the marine water column that will accelerate our understanding of its sources and environmental impacts. At a depth of 1 m, ...

    • Marine artificial light at night: An empirical and technical guide 

      Tidau, Svenja; Smyth, Tim; Mckee, David; Wiedenmann, Jörg; D’Angelo, Cecilia; Wilcockson, David; Ellison, Amy; Grimmer, Andrew J.; Jenkins, Stuart R.; Widdicombe, Stephen; Queirós, Ana M.; Talbot, Elizabeth; Wright, Adam; Davies, Thomas W. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-06-04)
      1. The increasing illumination of our world by artificial light at night (ALAN) has created a new field of global change research with impacts now being demonstrated across taxa, biological ranks and spatial scales. Following advances in terrestrial ecology, marine ALAN has become a rapidly growing research area attracting scientists from across all biomes. Technological limitations, complexities ...

    • Midnight Sun to Polar Night: A Model of Seasonal Light in the Barents Sea 

      Connan-McGinty, Stacey; Banas, Neil S.; Berge, Jørgen; Cottier, Finlo Robert; Grant, Stephen; Johnsen, Geir; Kopec, Tomasz Piotr; Porter, Marie; Mckee, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-20)
      Arctic marine ecosystems are strongly influenced by the extreme seasonality of light in the region. Accurate determination of light is essential for building a comprehensive understanding of the dynamics of animal and aquatic algae populations. Current approaches to underwater light field parameterisations rely upon shortwave radiation (300–3000 nm) estimates from satellites or surface radiometry ...

    • Optical Constituent Concentrations and Uncertainties Obtained for Case 1 and 2 Waters From a Spectral Deconvolution Model Applied to In Situ IOPs and Radiometry 

      Lo Prejato, M; Mckee, David (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-12-01)
      A spectral deconvolution model (SDM) for inversion of light absorption, a(λ) and backscattering, bb(λ), to estimate concentrations of chlorophyll (CHL), colored dissolved organic material (CDOM) and non-biogenic mineral suspended solids (MSS) in offshore and shelf waters is presented. This approach exploits the spectral information embedded in the ratio bb(λ)/a(λ), without the need to know each ...

    • Pelagic organisms avoid white, blue, and red artificial light from scientific instruments 

      Geoffroy, Maxime; Langbehn, Tom; Priou, Pierre; Varpe, Øystein; Johnsen, Geir; Le Bris, Arnault; Fisher, Jonathan A. D.; Daase, Malin; Mckee, David; Cohen, Jonathan H.; Berge, Jørgen (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-07-22)
      In situ observations of pelagic fish and zooplankton with optical instruments usually rely on external light sources. However, artificial light may attract or repulse marine organisms, which results in biased measurements. It is often assumed that most pelagic organisms do not perceive the red part of the visible spectrum and that red light can be used for underwater optical measurements of biological ...

    • Transmission across the water-air interface: resolving the impact of multiple interactions at the sea surface 

      Mckee, David; Piskozub, Jacek (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-01-07)
      A series of Monte Carlo and HydroLight radiative transfer simulations are used to demonstrate that the traditional form of the Fresnel transmission across the water-air interface is accurate. This contradicts assertions to the contrary in a recent paper [Opt. Express 25, 27086 (2017) [CrossRef] ] that suggested that the impact of multiple surface interactions had previously been ignored and that ...

    • Uptake of sympagic organic carbon by the Barents Sea benthos linked to sea ice seasonality 

      Cautain, Ivan J.; Last, Kim S.; Mckee, David; Bluhm, Bodil; Renaud, Paul Eric; Ziegler, Amanda; Narayanaswamy, Bhavani E. (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-11-11)
      On Arctic shelves, where primary production occurs in both the pelagic and sympagic (ice-associated) habitats, sympagic organic material (OM) can constitute a disproportionate fraction of benthic diets due to higher sinking rates and lower grazing pressure than pelagic OM. Less documented is how sympagic OM assimilation across feeding guilds varies seasonally and in relation to sea ice duation. We ...