15 research outputs found

    Implications of potential future grand solar minimum for ozone layer and climate

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    Continued anthropogenic greenhouse gas (GHG) emissions are expected to cause further global warming throughout the 21st century. Understanding the role of natural forcings and their influence on global warming is thus of great interest. Here we investigate the impact of a recently proposed 21st century grand solar minimum on atmospheric chemistry and climate using the SOCOL3-MPIOM chemistry-climate model with an interactive ocean element. We examine five model simulations for the period 2000-2199, following the greenhouse gas concentration scenario RCP4.5 and a range of different solar forcings. The reference simulation is forced by perpetual repetition of solar cycle 23 until the year 2199. This reference is compared with grand solar minimum simulations, assuming a strong decline in solar activity of 3.5 and 6.5Wm−2, respectively, that last either until 2199 or recover in the 22nd century. Decreased solar activity by 6.5Wm−2 is found to yield up to a doubling of the GHG-induced stratospheric and mesospheric cooling. Under the grand solar minimum scenario, tropospheric temperatures are also projected to decrease compared to the reference. On the global scale a reduced solar forcing compensates for at most 15% of the expected greenhouse warming at the end of the 21st and around 25% at the end of the 22nd century. The regional effects are predicted to be significant, in particular in northern high-latitude winter. In the stratosphere, the reduction of around 15% of incoming ultraviolet radiation leads to a decrease in ozone production by up to 8%, which overcompensates for the anticipated ozone increase due to reduced stratospheric temperatures and an acceleration of the Brewer–Dobson circulation. This, in turn, leads to a delay in total ozone column recovery from anthropogenic halogen-induced depletion, with a global ozone recovery to the pre-ozone hole values happening only upon completion of the grand solar minimum

    Images and Spectral Performance of WFC3 Interference Filters

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    The Wide Field Camera 3 (WFC3) is a panchromatic imager that will be deployed in the Hubble Space Telescope (HST). The mission of the WFC3 is to enhance HST1s imaging capability in the ultraviolet, visible and near-infrared spectral regions. Together with a wavelength coverage spanning 2000A to 1.7 micron, the WFC3 high sensitivity, high spatial resolution, and large field-of-view provide the astronomer with an unprecedented set of tools for exploring all types of exciting astrophysical terrain and for addressing many key questions in astronomy today. The filter compliment, which includes broad, medium, and narrow band filters, naturally reflects the diversity of astronomical programs to be targeted with WFC3. The WFC3 holds 61 UVIS filters elements, 14 IR filters, and 3 dispersive elements. During ground testing, the majority of the UVIS filters were found to exhibit excellent performance consistent with or exceeding expectations; however, a subset of filters showed considerable ghost images; some with relative intensity as high as 10-15%. Replacement filters with band-defining coatings that substantially reduce these ghost images were designed and procured. A state-of-the-art characterization setup was developed to measured the intensity of ghost images, focal shift, wedge direction , transmitted uniformity and surface feature of filters that could effect uniform flat field images. We will report on this new filter characterization methods, as well as the spectral performance measurements of the in-band transmittance and blocking

    Technology Development Roadmap: A Technology Development Roadmap for a Future Gravitational Wave Mission

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    Humankind will detect the first gravitational wave (GW) signals from the Universe in the current decade using ground-based detectors. But the richest trove of astrophysical information lies at lower frequencies in the spectrum only accessible from space. Signals are expected from merging massive black holes throughout cosmic history, from compact stellar remnants orbiting central galactic engines from thousands of close contact binary systems in the Milky Way, and possibly from exotic sources, some not yet imagined. These signals carry essential information not available from electromagnetic observations, and which can be extracted with extraordinary accuracy. For 20 years, NASA, the European Space Agency (ESA), and an international research community have put considerable effort into developing concepts and technologies for a GW mission. Both the 2000 and 2010 decadal surveys endorsed the science and mission concept of the Laser Interferometer Space Antenna (LISA). A partnership of the two agencies defined and analyzed the concept for a decade. The agencies partnered on LISA Pathfinder (LPF), and ESA-led technology demonstration mission, now preparing for a 2015 launch. Extensive technology development has been carried out on the ground. Currently, the evolved Laser Interferometer Space Antenna (eLISA) concept, a LISA-like concept with only two measurement arms, is competing for ESA's L2 opportunity. NASA's Astrophysics Division seeks to be a junior partner if eLISA is selected. If eLISA is not selected, then a LISA-like mission will be a strong contender in the 2020 decadal survey. This Technology Development Roadmap (TDR) builds on the LISA concept development, the LPF technology development, and the U.S. and European ground-based technology development. The eLISA architecture and the architecture of the Mid-sized Space-based Gravitational-wave Observatory (SGO Mid)-a competitive design with three measurement arms from the recent design study for a NASA-led mission after 2020-both use the same technologies. Further, NASA participation in an ESA-led mission would likely augment the eLISA architecture with a third arm to become the SGO Mid architecture. For these reasons, this TDR for a future GW mission applies to both designs and both programmatic paths forward. It is adaptable to the different timelines and roles for an ESA-led or a NASA-led mission, and it is adaptable to available resources. Based on a mature understanding of the interaction between technology and risk, the authors of this TDR have chosen a set of objectives that are more expansive than is usual. The objectives for this roadmap are: (1) reduce technical and development risks and costs; (2) understand and, where possible, relieve system requirements and consequences; (3) increase technical insight into critical technologies; and (4) validate the design at the subsystem level. The emphasis on these objectives, particularly the latter two, is driven by outstanding programmatic decisions, namely whether a future GW mission is ESA-led or NASA-led, and availability of resources. The relative emphasis is best understood in the context of prioritization

    The response of mesospheric Hâ‚‚O and CO to solar irradiance variability in models and observations

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    Water vapor (H2O) is the source of reactive hydrogen radicals in the middle atmosphere, whereas carbon monoxide (CO), being formed by CO2 photolysis, is suitable as a dynamical tracer. In the mesosphere, both H2O and CO are sensitive to solar irradiance (SI) variability because of their destruction/production by solar radiation. This enables us to analyze the solar signal in both models and observed data. Here, we evaluate the mesospheric H2O and CO response to solar irradiance variability using the Chemistry-Climate Model Initiative (CCMI-1) simulations and satellite observations. We analyzed the results of four CCMI models (CMAM, EMAC-L90MA, SOCOLv3, and CESM1-WACCM 3.5) operated in CCMI reference simulation REF-C1SD in specified dynamics mode, covering the period from 1984–2017. Multiple linear regression analyses show a pronounced and statistically robust response of H2O and CO to solar irradiance variability and to the annual and semiannual cycles. For periods with available satellite data, we compared the simulated solar signal against satellite observations, namely the GOZCARDS composite for 1992–2017 for H2O and Aura/MLS measurements for 2005–2017 for CO. The model results generally agree with observations and reproduce an expected negative and positive correlation for H2O and CO, respectively, with solar irradiance. However, the magnitude of the response and patterns of the solar signal varies among the considered models, indicating differences in the applied chemical reaction and dynamical schemes, including the representation of photolyzes. We suggest that there is no dominating thermospheric influence of solar irradiance in CO, as reported in previous studies, because the response to solar variability is comparable with observations in both low-top and high-top models. We stress the importance of this work for improving our understanding of the current ability and limitations of state-of-the-art models to simulate a solar signal in the chemistry and dynamics of the middle atmosphere

    The Suzaku High Resolution X-ray Spectrometer

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    The high resolution X-Ray Spectrometer (XRS) has been designed to provide the Suzaku Observatory with very high spectral resolution, non-dispersive spectroscopy from 0.3 to 12 keV. This energy range encompasses the most diagnostically-rich part of the x-ray band. The sensor consists of a 32 channel array of x-ray of microcalorimeters, each with an energy resolution of about 6 eV. The very low temperature required for operation of the array (60 mK) is provided by a four-stage cooling system containing a single stage ADR, superfluid He Cryostat, solid Ne Dewar, and a single-stage Stirling-cycle cooler. The Suzaku/XRS is the first orbiting x-ray microcalorimeter spectrometer and has been designed to last more than three years in orbit. The early verification phase of the mission demonstrated that the instrument was working properly and that the cryogen consumption rate was low enough to ensure a mission lifetime exceeding 3 years. However, the liquid He cryogen was completely vaporized two weeks after opening the dewar guard vacuum vent. The problem has been traced to inadequate venting of the dewar He and Ne gases out of the spacecraft into space. In this paper we present the design of the XRS instrument and describe the in-flight performance

    Going the Extra Mile, Now or After a While : The Impact of Employee Proactivity in Retail Service Encounters on Customers’ Shopping Responses

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    Employee proactivity has been discussed as a key predictor of firm success and organi-zational performance. However, previous proactivity research has rarely focused on cus-tomers, and the few available proactivity studies from retail settings are either cross-sectional, solely based on subjective outcomes (e.g. customer satisfaction) or restricted toaggregateddata of objective outcomes (e.g. profits per store). We investigate the causaleffect of employee proactivity in retail service encounters on customers’ actual purchasebehaviour and satisfaction ratings at the fine-grained level ofindividualcustomers. Byintegrating theories on social perception with prior proactivity findings, we find that em-ployee proactivity positively predicts customers’ shopping responses. This finding extendsfrom correlational to experimental designs across sample types and paradigms, is repli-cated in actual retail settings, and is mediated by customers’ perceptions of employeewarmth and competence. Furthermore, the effect generalizes across several focal out-comes, including behavioural variables (spending and purchase likelihood), and is moder-ated by the time to employee-initiated contact in a way that goes against customers’ ownbeliefs. In sum, the present research quantifies the financial consequences of employeeproactivity and indicates that in ordinary retail service encounters, high proactivity cancompensate for delays, thus counteracting the aversive aspects of waiting.This paper was included as a manuscript entitled "Going the Extra Mile, Now or After a While: The Impact of Employee Proactivity on Customers’ Responses and the Moderating Role of Time to Contact" in the doctoral thesis "Proactivity in Service Failure and Service Recovery" KUS 2021:25.</p

    Implications of potential future grand solar minimum for ozone layer and climate

    No full text
    Continued anthropogenic greenhouse gas (GHG) emissions are expected to cause further global warming throughout the 21st century. Understanding the role of natural forcings and their influence on global warming is thus of great interest. Here we investigate the impact of a recently proposed 21st century grand solar minimum on atmospheric chemistry and climate using the SOCOL3-MPIOM chemistry–climate model with an interactive ocean element. We examine five model simulations for the period 2000–2199, following the greenhouse gas concentration scenario RCP4.5 and a range of different solar forcings. The reference simulation is forced by perpetual repetition of solar cycle 23 until the year 2199. This reference is compared with grand solar minimum simulations, assuming a strong decline in solar activity of 3.5 and 6.5 W m−2, respectively, that last either until 2199 or recover in the 22nd century. Decreased solar activity by 6.5 W m−2 is found to yield up to a doubling of the GHG-induced stratospheric and mesospheric cooling. Under the grand solar minimum scenario, tropospheric temperatures are also projected to decrease compared to the reference. On the global scale a reduced solar forcing compensates for at most 15 % of the expected greenhouse warming at the end of the 21st and around 25 % at the end of the 22nd century. The regional effects are predicted to be significant, in particular in northern high-latitude winter. In the stratosphere, the reduction of around 15 % of incoming ultraviolet radiation leads to a decrease in ozone production by up to 8 %, which overcompensates for the anticipated ozone increase due to reduced stratospheric temperatures and an acceleration of the Brewer–Dobson circulation. This, in turn, leads to a delay in total ozone column recovery from anthropogenic halogen-induced depletion, with a global ozone recovery to the pre-ozone hole values happening only upon completion of the grand solar minimum.ISSN:1680-7375ISSN:1680-736

    Reactive nitrogen (NOy) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

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    Energetic particle precipitation (EPP) affects the chemistry of the polar middle atmosphere by producing reactive nitrogen (NOy) and hydrogen (HOx) species, which then catalytically destroy ozone. Recently, there have been major advances in constraining these particle impacts through a parametrization of NOy based on high-quality observations. Here we investigate the effects of low (auroral) and middle (radiation belt) energy range electrons, separately and in combination, on reactive nitrogen and hydrogen species as well as on ozone during Southern Hemisphere winters from 2002 to 2010 using the SOCOL3-MPIOM chemistry-climate model. Our results show that, in the absence of solar proton events, low-energy electrons produce the majority of NOy in the polar mesosphere and stratosphere. In the polar vortex, NOy subsides and affects ozone at lower altitudes, down to 10 hPa. Comparing a year with high electron precipitation with a quiescent period, we found large ozone depletion in the mesosphere; as the anomaly propagates downward, 15 % less ozone is found in the stratosphere during winter, which is confirmed by satellite observations. Only with both lowand middle-energy electrons does our model reproduce the observed stratospheric ozone anomaly. © 2019 Author(s).This research has been supported by the Swiss National Science Foundation (grant no. CRSII2-147659), the FONDECYT (grant no. 1171690), the MCINN (grant no. ESP2014-54362-P), the JST/CREST/EMS/TEEDDA (grant JPMJCR15K4), the EC FEDER, and the Russian Science Foundation (grant no. 17-17-01060).Peer reviewe

    Kattifiering : Anpassa ditt hem för katten

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    Katten är bland de vanligaste husdjuren i Sverige och att ha innekatt blir alltmer vanligt. Katten har många behov som exempelvis att få röra på sig och vässa klorna, vilket är stora aspekter i deras natur. Att aktivera katten är en viktig del i deras vardag för att undvika att de utvecklar oönskade beteenden som exempelvis att riva sin ägare. Bor man på en mindre yta kan det dock vara mer utmanande samt problematiskt att tillfredsställa detta behov tillräckligt. Mitt fokus har därmed varit att ta fram ett alternativt koncept på klösmöbel som även passar kattägare som bor mindre. På dagens marknad kräver de stora varianterna på klösmöbler ofta mycket golvyta, vilket kan bli ett problem om man bor mindre. Idag är det vanligt att kattägare bygger egna klösmöbler, men det är tidskrävande och därmed inte alltid önskvärt. Under projektets gång har jag intervjuat er kattägare och funnit ett behov av en större klösmöbel som passar in i det vardagliga hemmet och som lämpar sig om man bor mindre. En enkät skickades ut i olika kattforum där det tydligt syntes att kattägare ser ett värde om de själva kunde utnyttja klösmöbeln. Därmed designade jag en klösmöbel i kombination med en möbel som ofta nns i det vardagliga hemmet för både katten och kattägaren.The cat is among the most popular pets in Sweden and having an indoor cat has become more common. A cat has many needs. For example, they need to be activated through play and allowed to sharpen their claws by scratching since these are major aspects in their nature. Activating your cat is an important part of their everyday life and to prevent them from obtaining unwanted behaviours, such as scratching their owner. However, satisfying the needs of a cat can become a di cult task and problematic for cat owners living more cramped home accommodations. Therefore, my focus has been to develop an alternate concept of a scratching post that also suits cat owners living in smaller homes. Larger scratching posts on today’s market often require considerable space on the oor, which can be a problem if you have a small home. It has become common for cat owners to construct their own scratching posts today, but that can be rather time consuming and thus often not desirable. During the course of my project, I have interviewed multiple cat owners and found a need for a larger scratching post that blends into the ordinary household. A survey was submitted onto various cat forums where the response clearly showed that cat owners found value in the concepts where they themselves could utilise the scratching post. Thus, I combined a scratching post with a typical type of furniture you often see in the ordinary household, one that can be used by both cat and cat owner

    Reactive nitrogen (NOy) and ozone responses to energetic electron precipitation during Southern Hemisphere winter

    No full text
    Energetic particle precipitation (EPP) affects the chemistry of the polar middle atmosphere by producing reactive nitrogen (NOy) and hydrogen (HOx) species, which then catalytically destroy ozone. Recently, there have been major advances in constraining these particle impacts through a parametrization of NOy based on high-quality observations. Here we investigate the effects of low (auroral) and middle (radiation belt) energy range electrons, separately and in combination, on reactive nitrogen and hydrogen species as well as on ozone during Southern Hemisphere winters from 2002 to 2010 using the SOCOL3-MPIOM chemistry-climate model. Our results show that, in the absence of solar proton events, low-energy electrons produce the majority of NOy in the polar mesosphere and stratosphere. In the polar vortex, NOy subsides and affects ozone at lower altitudes, down to 10 hPa. Comparing a year with high electron precipitation with a quiescent period, we found large ozone depletion in the mesosphere; as the anomaly propagates downward, 15 % less ozone is found in the stratosphere during winter, which is confirmed by satellite observations. Only with both low- and middle-energy electrons does our model reproduce the observed stratospheric ozone anomaly.ISSN:1680-7375ISSN:1680-736
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