Recent Environmental Changes in the Arctic: A Review

Numerous recent observations indicate that the Arctic is undergoing a significant change. In the last decade, the hydrography of the Arctic Ocean has shifted, and the atmospheric circulation has undergone a change from the lower stratosphere to the surface. Typically the eastern Arctic Ocean, on the European side of the Lomonosov Ridge, is dominated by water of Atlantic origin. A cold halocline of varying thickness overlies the warmer Atlantic water and isolates it from the sea ice and surface mixed layer. The western Arctic Ocean, on the North American side of the Lomonosov Ridge, is characterized by an added layer of water from the Pacific immediately below the surface mixed layer. Data collected during several cruises from 1991 to 1995 indicate that in the 1990s the boundary between these eastern and western halocline types shifted from a position roughly parallel to the Lomonosov Ridge to near alignment with the Alpha and Mendeleyev Ridges. The Atlantic Water temperature has also increased, and the cold halocline has become thinner. The change has resulted in increased surface salinity in the Makarov Basin. Recent results suggest that the change also includes decreased surface salinity and greater summer ice melt in the Beaufort Sea. Atmospheric pressure fields and ice drift data show that the whole patterns of atmospheric pressure and ice drift for the early 1990s were shifted counterclockwise 40°-60° from earlier patterns. The shift in atmospheric circulation seems related to the Arctic Oscillation in the Northern Hemisphere atmospheric pressure pattern. The changes in the ocean circulation, ice drift, air temperatures, and permafrost can be explained as responses to the Arctic Oscillation, as can changes in air temperatures over the Russian Arctic. De nombreuses observations effectuées récemment indiquent qu'un changement majeur est en train de se produire dans l'Arctique. Au cours des dix dernières années, l'hydrographie de l'océan Arctique s'est déplacée et la circulation atmosphérique a subi un changement, de la basse stratosphère à la surface. En général, l'océan Arctique oriental, du côté européen de la dorsale Lomonosov, est dominé par l'eau d'origine atlantique. Une halocline froide d'épaisseur variable est sus-jacente à l'eau atlantique plus chaude et l'isole de la glace marine et de la couche mixte de surface. L'océan Arctique occidental, du côté nord-américain de la dorsale Lomonosov, se caractérise par une couche supplémentaire d'eau du Pacifique située juste au-dessous de la couche mixte de surface. Les données recueillies au cours de plusieurs croisières de 1991 à 1995 indiquent que, dans les années 1990 la limite entre ces types d'haloclines de l'est et de l'ouest est passée d'une position plus ou moins parallèle à la dorsale Lomonosov, à un alignement presque parfait avec les dorsales Alpha et Mendeleyev. La température des eaux de l'Atlantique a également augmenté, et l'halocline froide s'est amincie. Ce changement a amené une augmentation de la salinité de surface dans le bassin de Makarov. De récents résultats suggèrent que le changement s'accompagne d'une diminution de la salinité de surface et d'une augmentation de la fonte estivale de la glace dans la mer de Beaufort. Les données barométriques et celles de la dérive des glaces montrent que tous les schémas de pression atmosphérique et de dérive des glaces pour les premières années de 1990 se sont déplacés de 40 à 60° par rapport aux précédents. Le déplacement dans la circulation atmosphérique semble lié à l'oscillation arctique dans le schéma de pression atmosphérique de l'hémisphère Nord. Les changements dans la circulation océanique, la dérive des glaces, la température de l'air et le pergélisol peuvent s'expliquer comme une réponse à l'oscillation arctique, tout comme les changements dans la température de l'air au-dessus de l'Arctique russe.

Are Sand or Composted Bedding Cubicles Suitable Alternatives to Rubber Matting for Housing Dairy Cows?

PICO questionIn [Dairy Cow Management] do [Sand OR composted bedding] compared with [rubber matting] result in [fewer disease incidence] consequences?Clinical bottom lineClean, deep-bedded sand appears to be associated with the best outcomes in clinical mastitis, cow cleanliness, subclinical mastitis, cow lying times, hock lesions and cow preference. Recycled sand, composted manure and other deep-bedded systems also appear to have increased cow comfort and hygiene indices versus mattress systems. Deep-bedded, composted manure systems can also have better outcomes concerning Gram positive and negative bacterial growth versus straw and mattress systems as long as they are kept clean and renewed frequently.  <img src="https://www.veterinaryevidence.org/rcvskmod/icons/pr-icon.jpg" alt="Peer Reviewed" /

Identifying significant contributors to milk production in the absence of the Herd Size Effect

Prior to the commencement of deregulation from 1 July 2000, the Australian Dairy Research and Development Corporation conducted a large-scale telephone survey of 1826 Australian dairy farms to examine the current on-farm management practices in relation to milk production and farm and farmer demographics. The questionnaire results from the 214 dairy farms in the sub-tropical region of South East Queensland and Northern New South Wales were analysed (Zamykal et al. 2007) to uncover those significant inputs that affect milk production

Project overview and update on WEAVE: the next generation wide-field spectroscopy facility for the William Herschel Telescope

We present an overview of and status report on the WEAVE next-generation spectroscopy facility for the William Herschel Telescope (WHT). WEAVE principally targets optical ground-based follow up of upcoming ground-based (LOFAR) and space-based (Gaia) surveys. WEAVE is a multi-object and multi-IFU facility utilizing a new 2-degree prime focus field of view at the WHT, with a buffered pick-and-place positioner system hosting 1000 multi-object (MOS) fibres, 20 integral field units, or a single large IFU for each observation. The fibres are fed to a single spectrograph, with a pair of 8k(spectral) x 6k (spatial) pixel cameras, located within the WHT GHRIL enclosure on the telescope Nasmyth platform, supporting observations at R~5000 over the full 370-1000nm wavelength range in a single exposure, or a high resolution mode with limited coverage in each arm at R~20000. The project is now in the final design and early procurement phase, with commissioning at the telescope expected in 2017.Comment: 11 pages, 11 Figures, Summary of a presentation to Astronomical Telescopes and Instrumentation 201

The Baryon Oscillation Spectroscopic Survey of SDSS-III

The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7. Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000 quasar spectra (g<22) will constrain BAO over the redshift range 2.15<z<3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Lyman alpha forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance D_A to an accuracy of 1.0% at redshifts z=0.3 and z=0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Lyman alpha forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D_A(z) and H^{-1}(z) parameters to an accuracy of 1.9% at z~2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.Comment: 49 pages, 16 figures, accepted by A

An ocean-colour time series for use in climate studies: the experience of the ocean-colour climate change initiate (OC-CCI)

Ocean colour is recognised as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS); and spectrally-resolved water-leaving radiances (or remote-sensing reflectances) in the visible domain, and chlorophyll-a concentration are identified as required ECV products. Time series of the products at the global scale and at high spatial resolution, derived from ocean-colour data, are key to studying the dynamics of phytoplankton at seasonal and inter-annual scales; their role in marine biogeochemistry; the global carbon cycle; the modulation of how phytoplankton distribute solar-induced heat in the upper layers of the ocean; and the response of the marine ecosystem to climate variability and change. However, generating a long time series of these products from ocean colour data is not a trivial task: algorithms that are best suited for climate studies have to be selected from a number that are available for atmospheric correction of the satellite signal and for retrieval of chlorophyll-a concentration; since satellites have a finite life span, data from multiple sensors have to be merged to create a single time series, and any uncorrected inter-sensor biases could introduce artefacts in the series, e.g., different sensors monitor radiances at different wavebands such that producing a consistent time series of reflectances is not straightforward. Another requirement is that the products have to be validated against in situ observations. Furthermore, the uncertainties in the products have to be quantified, ideally on a pixel-by-pixel basis, to facilitate applications and interpretations that are consistent with the quality of the data. This paper outlines an approach that was adopted for generating an ocean-colour time series for climate studies, using data from the MERIS (MEdium spectral Resolution Imaging Spectrometer) sensor of the European Space Agency; the SeaWiFS (Sea viewingWide-Field-of-view Sensor) and MODIS-Aqua (Moderate-resolution Imaging Spectroradiometer-Aqua) sensors from the National Aeronautics and Space Administration (USA); and VIIRS (Visible and Infrared Imaging Radiometer Suite) from the National Oceanic and Atmospheric Administration (USA). The time series now covers the period from late 1997 to end of 2018. To ensure that the products meet, as well as possible, the requirements of the user community, marine-ecosystem modellers, and remote-sensing scientists were consulted at the outset on their immediate and longer-term requirements as well as on their expectations of ocean-colour data for use in climate research. Taking the user requirements into account, a series of objective criteria were established, against which available algorithms for processing ocean-colour data were evaluated and ranked. The algorithms that performed best with respect to the climate user requirements were selected to process data from the satellite sensors. Remote-sensing reflectance data from MODIS-Aqua, MERIS, and VIIRS were band-shifted to match the wavebands of SeaWiFS. Overlapping data were used to correct for mean biases between sensors at every pixel. The remote-sensing reflectance data derived from the sensors were merged, and the selected in-water algorithm was applied to the merged data to generate maps of chlorophyll concentration, inherent optical properties at SeaWiFS wavelengths, and the diffuse attenuation coefficient at 490 nm. The merged products were validated against in situ observations. The uncertainties established on the basis of comparisons with in situ data were combined with an optical classification of the remote-sensing reflectance data using a fuzzy-logic approach, and were used to generate uncertainties (root mean square difference and bias) for each product at each pixel