417 research outputs found

    TAPEWORMS OF ELASMOBRANCHS (Part III) A Monograph on the Phyllobothriidae (Platyhelminthes, Cestoda)

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    This monograph aims to provide information on the taxonomic status of all genera associated with the tetraphyllidean family Phyllobothriidae. Full treatments of the three valid species of the type genus, Phyllobothrium, in addition to the 47 valid species of Clistobothrium, Crossobothrium, Marsupiobothrium, Monorygma, Nandocestus, Orectolobicestus, Orygmatobothrium, Paraorygmatobothrium, Ruhnkecestus, and Scyphophyllidium are provided, as is a taxonomic history of the family. Of the valid genera historically associated with the family, only Phyllobothrium is considered to be an unambiguous member of the family. The genera Bibursibothrium, Calyptrobothrium, Cardiobothrium, Clistobothrium, Crossobothrium, Doliobothrium, Flexibothrium, Marsupiobothrium, Monorygma, Nandocestus, Orectolobicestus, Orygmatobothrium, Paraorygmatobothrium, Ruhnkecestus, Scyphophyllidium, and Thysanocephalum are valid, but are considered provisional members of the family. The taxonomic status of the remaining genera was also addressed. Aocobothrium, Dittocephalus, Hoaleshwaria, Phanobothrium, and Shindeobothrium are considered nomina dubia. Phyllobothrideum has been determined to be a nomen ad interim. Bilocularia, Biporophyllaeus, Cyatocotyle, Kowsalyabothrium, Maccallumiella, Mastacembellophyllaeus, Pillersium, Pithophorus, and Polipobothrium are considered genera inquirendae. Anindobothrium, Anthobothrium, Carpobothrium, Caulobothrium, Caulopatera, Ceratobothrium, Dinobothrium, Gastrolecithus, Guidus, Mixophyllobothrium, Myzocephalus, Myzophyllobothrium, Pelichnibothrium, Rhoptrobothrium, Trilocularia, and Zyxibothrium are considered valid, but incertae sedis with respect to their familial placements. Anthocephalum, Echeneibothrium, Rhabdotobothrium, Rhinebothrium, Rhinebothroides, Rhodobothrium, Scalithrium, and Spongiobothrium are valid members of the Rhinebothriidea

    Reaching the lower stratosphere: Validating an extended vertical grid for COSMO

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    This study presents an extended vertical grid for the regional atmospheric model COSMO (COnsortium for Small-scale MOdeling) reaching up to 33 km. The extended setup has been used to stably simulate 11 months in a domain covering central and northern Europe. Temperature and relative humidity have been validated using radiosonde data in polar and temperate latitudes, focussing on the polar and mid-latitude stratosphere over Europe. Temperature values are reproduced very well by the model. Relative humidity could only be met in the mean over the whole time period after excluding data from Russian stations, which showed significantly higher values. A sensitivity study shows the stability of the model against different forcing intervals and damping layer heights. © Author(s) 2015

    A model study of the January 2006 low total ozone episode over Western Europe and comparison with ozone sonde data

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    Total column and stratospheric ozone levels at mid-latitudes often reveal strong fluctuations on time scales of days caused by dynamic processes. In some cases the total ozone column is distinctly reduced below climatological values. Here, a very low total ozone episode around 19 January 2006 over Western Europe is investigated when the observed total ozone column over Uccle (BE), measured by a Brewer spectrophotometer, reached a daily minimum of 200 DU, the lowest recorded value at this station. In order to investigate the mechanisms leading to the ozone minimum, the present study used data from (i) six ozone sounding stations in Western and Middle Europe, (ii) ECMWF meteorological fields, (iii) a simulation of the CLaMS model for January 2006, (iv) a multi-year run of the chemistry transport model KASIMA, and (v) a six-year run of the climate chemistry model ECHAM5/MESSy1. The ozone decrease at different heights was quantified and it was determined to what extent different transport mechanisms, and instantaneous, in-situ chemical ozone depletion contributed to the event. All three models reproduced the evolution and formation of the event. The ozone column decrease between Theta=300 and 750K was strongest at Uccle (BE) and De Bilt (NL) with 108 and 103 DU, respectively, and somewhat lower at Hohenpeissenberg (DE), Payerne (CH), Prague (CZ) and Lerwick (UK) with 85, 84, 83 and 74 DU, respectively. This analysis demonstrated that mainly the displacement of the ozone depleted polar vortex contributed to the ozone column decrease. Advection of ozone-poor low-latitude air masses was important in the UTLS region. The vertical displacement of isentropes connected with divergence of air out of the column was found to be of minor importance compared to the horizontal transport processes. Severe low total ozone episodes seem to occur when the mentioned mechanisms are superimposed. Instantaneous, in-situ chemical ozone depletion accounted for only 2+/-1% of the overall total ozone decrease at the sounding stations

    Trends of HCl, ClONOâ‚‚, and HF column abundances from ground-based FTIR measurements in Kiruna (Sweden) in comparison with KASIMA model calculations

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    Trends of hydrogen chloride (HCl), chlorine nitrate (ClONO2), and hydrogen fluoride (HF) total column abundances above Kiruna (Northern Sweden, 67.84∘N^\circ\text{N}, 20.41∘E^\circ\text{E}) derived from nearly 14 years (1996–2009) of measurement and model data are presented. The measurements have been performed with a Bruker 120HR (later Bruker 125 HR) Fourier transform infrared (FTIR) spectrometer and the chemistry-transport model (CTM) used was KASIMA (KArlsruhe SImulation model of the Middle Atmosphere). The total column abundances of ClONO2 and HF calculated by KASIMA agree quite well with the FTIR measurements while KASIMA tends to underestimate the HCl columns. To calculate the long-term trends, a linear function combined with an annual cycle was fitted to the data using a least squares method. The precision of the resulting trends was estimated with the bootstrap resampling method. For HF, both model and measurements show a positive trend that seems to decrease in the last few years. This suggests a stabilisation of the HF total column abundance. Between 1996 and 2009, KASIMA simulates an increase of (+1.51±0.07) %/yr which exceeds the FTIR result of (+0.65±0.25) %/yr. The trends determined for HCl and ClONO2 are significantly negative over the time period considered here. This is expected because the emission of their precursors (chlorofluorocarbons and hydrochlorofluorocarbons) has been restricted in the Montreal Protocol in 1987 and its amendments and adjustments. The trend for ClONO2 from the FTIR measurements amounts to (−3.28±0.56)%/yr and the one for HCl to (−0.81±0.23)%/yr. KASIMA simulates a weaker decrease: For ClONO2, the result is (−0.90±0.10) %/yr and for HCl (−0.17±0.06) %/yr. Part of the difference between measurement and model data can be explained by sampling and the stronger annual cycle indicated by the measurements. There is a factor of about four between the trends of HCl and ClONO2 above Kiruna for both measurement and model data

    Simulation of polar stratospheric clouds in the chemistry-climate-model EMAC via the submodel PSC

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    The submodel PSC of the ECHAM5/MESSy Atmospheric Chemistry model (EMAC) has been developed to simulate the main types of polar stratospheric clouds (PSC). The parameterisation of the supercooled ternary solutions (STS, type 1b PSC) in the submodel is based on Carslaw et al. (1995b), the thermodynamic approach to simulate ice particles (type 2 PSC) on Marti and Mauersberger (1993). For the formation of nitric acid trihydrate (NAT) particles (type 1a PSC) two different parameterisations exist. The first is based on an instantaneous thermodynamic approach from Hanson and Mauersberger (1988), the second is new implemented and considers the growth of the NAT particles with the aid of a surface growth factor based on Carslaw et al. (2002). It is possible to choose one of this NAT parameterisation in the submodel. This publication explains the background of the submodel PSC and the use of the submodel with the goal of simulating realistic PSC in EMAC
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