834 research outputs found

    Stratospheric Dynamics

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    New WHO Violence Prevention Information System, an interactive knowledge platform of scientific findings on violence.

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    Scientific information on violence can be difficult to compile and understand. It is scattered across websites, databases, technical reports and academic journals, and rarely addresses all types of violence. In response, in October 2017 WHO released the Violence Prevention Information System or Violence Info, an online interactive collection of scientific information about the prevalence, consequences, risk factors and preventability of all forms of interpersonal violence. It covers homicide, child maltreatment, youth violence, intimate partner violence, elder abuse and sexual violence

    Employment mobility in high-technology agglomerations: the cases of Oxfordshire and Cambridgeshire

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    This paper examines labour market behaviour of the highly skilled in high-tech local economies, taking the UK examples of Oxfordshire and Cambridgeshire as case studies. It reports on data from a survey of members of three scientific institutes to compare rates of employee mobility in the two locations and considers the likely explanations and implications of those patterns

    Hot and Diffuse Clouds near the Galactic Center Probed by Metastable H3+

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    Using an absorption line from the metastable (J, K) = (3, 3) level of H3+ together with other lines of H3+ and CO observed along several sightlines, we have discovered a vast amount of high temperature (T ~ 250 K) and low density (n ~ 100 cm-3) gas with a large velocity dispersion in the Central Molecular Zone (CMZ) of the Galaxy, i.e., within 200 pc of the center. Approximately three fourths of the H3+ along the line of sight to the brightest source we observed, the Quintuplet object GCS 3-2, is inferred to be in the CMZ, with the remaining H3+ located in intervening spiral arms. About half of H3+ in the CMZ has velocities near ~ - 100 km s-1 indicating that it is associated with the 180 pc radius Expanding Molecular Ring which approximately forms outer boundary of the CMZ. The other half, with velocities of ~ - 50 km s-1 and ~ 0 km s-1, is probably closer to the center. CO is not very abundant in those clouds. Hot and diffuse gas in which the (3, 3) level is populated was not detected toward several dense clouds and diffuse clouds in the Galactic disk where large column densities of colder H3+ have been reported previously. Thus the newly discovered environment appears to be unique to the CMZ. The large observed H3+ column densities in the CMZ suggests an ionization rate much higher than in the diffuse interstellar medium in the Galactic disk. Our finding that the H3+ in the CMZ is almost entirely in diffuse clouds indicates that the reported volume filling factor (f ≥ 0.1) for n ≥ 104 cm-3 clouds in the CMZ is an overestimate by at least an order of magnitude.Comment: 33 pages, 5 figures, 3 table

    A chemistry-transport model simulation of middle atmospheric ozone from 1980 to 2019 using coupled chemistry GCM winds and temperatures

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    International audienceA Global 40-year simulation from 1980 to 2019 was performed with the FinROSE chemistry-transport model based on the use of coupled chemistry GCM-data. The main focus of our analysis is on climatological-scale processes in high latitudes. The resulting trend estimates for the past period (1980?1999) agree well with observation-based trend estimates. The results for the future period (2000?2019) suggest that the extent of seasonal ozone depletion over both northern and southern high-latitudes has likely reached its maximum. Furthermore, while climate change is expected to cool the stratosphere, this cooling is unlikely to accelerate significantly high latitude ozone depletion. However, the recovery of seasonal high latitude ozone losses will not take place during the next 15 years

    Processes Controlling Tropical Tropopause Temperature and Stratospheric Water Vapor in Climate Models

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    A warm bias in tropical tropopause temperature is found in the Met Office Unified Model (MetUM), in common with most models from phase 5 of CMIP (CMIP5). Key dynamical, microphysical, and radiative processes influencing the tropical tropopause temperature and lower-stratospheric water vapor concentrations in climate models are investigated using the MetUM. A series of sensitivity experiments are run to separate the effects of vertical advection, ice optical and microphysical properties, convection, cirrus clouds, and atmospheric composition on simulated tropopause temperature and lower-stratospheric water vapor concentrations in the tropics. The numerical accuracy of the vertical advection, determined in the MetUM by the choice of interpolation and conservation schemes used, is found to be particularly important. Microphysical and radiative processes are found to influence stratospheric water vapor both through modifying the tropical tropopause temperature and through modifying upper-tropospheric water vapor concentrations, allowing more water vapor to be advected into the stratosphere. The representation of any of the processes discussed can act to significantly reduce biases in tropical tropopause temperature and stratospheric water vapor in a physical way, thereby improving climate simulations
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