SPARC Data Initiative: climatology uncertainty assessment

The SPARC Data Initiative aims to produce trace gas climatologies for a number of species from a number of instruments. In order to properly compare these climatologies, and interpret differences between them, it is necessary to know the uncertainty in each calculated climatological mean field. The inhomogeneous and finite temporal-spatial sampling pattern of each instrument can lead to biases and uncertainties in the mean climatologies. Sampling which is unevenly weighted in time and space leads to biases between a data set's climatology and the truth. Furthermore, the systematic sampling patterns of some instruments may mean that uncertainties in mean fields calculated through traditional methods that assume random sampling may be inappropriate. We aim to address these issues through an exercise wherein high resolution chemical fields from a coupled Chemistry Climate Model are sub-sampled based on the sampling pattern of each instrument. Climatologies based on the sub-sampled data can be compared to those calculated with the full data set, in order to assess sampling biases. Furthermore, investigating the ensemble variability of climatologies based on subsampled fields will allow us to assess the proper methodology for estimating the uncertainty in climatological mean fields

Stratosphere troposphere coupling: the influence of volcanic eruptions

Stratospheric sulfate aerosols produced by major volcanic eruptions modify the radiative and dynamical properties of the troposphere and stratosphere through their reflection of solar radiation and absorption of infrared radiation. At the Earth's surface, the primary consequence of a large eruption is cooling, however, it has long been known that major tropical eruptions tend to be followed by warmer than usual winters over the Northern Hemisphere (NH) continents. This volcanic "winter-warming" effect in the NH is understood to be the result of changes in atmospheric circulation patterns resulting from heating in the stratosphere, and is often described as positive anomalies of the Northern Annular Mode (NAM) that propagate downward from the stratosphere to the troposphere. In the southern hemisphere, climate models tend to also predict a positive Southern Annular Mode (SAM) response to volcanic eruptions, but this is generally inconsistent with post-eruption observations during the 20th century. We review present understanding of the influence of volcanic eruptions on the large scale modes of atmospheric variability in both the Northern and Southern Hemispheres. Using models of varying complexity, including an aerosol-climate model, an Earth system model, and CMIP5 simulations, we assess the ability of climate models to reproduce the observed post-eruption climatic and dynamical anomalies. We will also address the parametrization of volcanic eruptions in simulations of the past climate, and identify possibilities for improvemen

The impact of volcanic aerosol on the Northern Hemisphere stratospheric polar vortex: mechanisms and sensitivity to forcing structure

Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosol–climate model simulations. For all forcings, we find that simulated temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high-latitude effects result from enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High-latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. Both observation-based forcing sets result in insignificant changes in vortex strength. For the model-based forcing sets, the vortex response is found to be sensitive to the structure of the forcing, with one forcing set leading to significant strengthening of the polar vortex in rough agreement with observation-based expectations. Differences in the dynamical response to the forcing sets imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the space–time structure of the volcanic aerosol forcing

The Research Unit VolImpact: Revisiting the volcanic impact on atmosphere and climate – preparations for the next big volcanic eruption

This paper provides an overview of the scientific background and the research objectives of the Research Unit “VolImpact” (Revisiting the volcanic impact on atmosphere and climate – preparations for the next big volcanic eruption, FOR 2820). VolImpact was recently funded by the Deutsche Forschungsgemeinschaft (DFG) and started in spring 2019. The main goal of the research unit is to improve our understanding of how the climate system responds to volcanic eruptions. Such an ambitious program is well beyond the capabilities of a single research group, as it requires expertise from complementary disciplines including aerosol microphysical modelling, cloud physics, climate modelling, global observations of trace gas species, clouds and stratospheric aerosols. The research goals will be achieved by building on important recent advances in modelling and measurement capabilities. Examples of the advances in the observations include the now daily near-global observations of multi-spectral aerosol extinction from the limb-scatter instruments OSIRIS, SCIAMACHY and OMPS-LP. In addition, the recently launched SAGE III/ISS and upcoming satellite missions EarthCARE and ALTIUS will provide high resolution observations of aerosols and clouds. Recent improvements in modeling capabilities within the framework of the ICON model family now enable simulations at spatial resolutions fine enough to investigate details of the evolution and dynamics of the volcanic eruptive plume using the large-eddy resolving version, up to volcanic impacts on larger-scale circulation systems in the general circulation model version. When combined with state-of-the-art aerosol and cloud microphysical models, these approaches offer the opportunity to link eruptions directly to their climate forcing. These advances will be exploited in VolImpact to study the effects of volcanic eruptions consistently over the full range of spatial and temporal scales involved, addressing the initial development of explosive eruption plumes (project VolPlume), the variation of stratospheric aerosol particle size and radiative forcing caused by volcanic eruptions (VolARC), the response of clouds (VolCloud), the effects of volcanic eruptions on atmospheric dynamics (VolDyn), as well as their climate impact (VolClim)

Building motivation to participate in a quality improvement collaborative in NHS hospital trusts in Southeast England: a qualitative participatory evaluation.

OBJECTIVES: This study explores the barriers and facilitators that impact on the motivation of practitioners to participate in a quality improvement collaborative. DESIGN: A qualitative and formative evaluation using a participatory approach, the researcher-in-residence model which embraces the concept of 'coproducing' knowledge between researchers and practitioners using a range of research methods such as participant observation, interviews and documentary analysis. The design, creation and application of newly generated evidence are facilitated by the researcher through negotiation and compromise with team members. PARTICIPANTS: Senior and middle managers, doctors and nurses. SETTING: Two hospitals in Southeast England participating in a Patient Safety Improvement Collaborative and the facilitator (host) of the collaborative, based in Central London. RESULTS: The evaluation has revealed facilitators and barriers to motivation categorised under two main themes: (1) inherent motivation and (2) factors that influence motivation, interorganisational and intraorganisational features as well as external factors. Facilitators included collaborative 'champions,' individuals who drove the quality improvement agenda at a local level, raising awareness and inspiring colleagues. The collaborative itself acted as a facilitator, promoting shared learning as well as building motivation for participation. A key barrier was the lack of board engagement in the participating National Health Service organisations which may have affected motivation among front-line staff. CONCLUSIONS: Collaboratives maybe an important way of engaging practitioners in quality improvement initiatives. This study highlights that despite a challenging healthcare environment in the UK, there remains motivation among individuals to participate in quality improvement programmes as they recognise that improvement approaches may facilitate positive change in local clinical processes and systems. Collaboratives can harness this individual motivation to facilitate spread and adoption of improvement methodology and build engagement across their membership

Introducing the concept of Potential Aerosol Mass (PAM)

International audiencePotential Aerosol Mass (PAM) can be defined as the maximum aerosol mass that the oxidation of precursor gases produces. In the measurement, all precursor gases are rapidly oxidized with extreme amounts of oxidants to low volatility compounds, resulting in the aerosol formation. Oxidation occurs in a small, simple, flow-through chamber that has a short residence time and is irradiated with ultraviolet light. The amount of the oxidants ozone (O3), hydroxyl (OH), and hydroperoxyl (HO2) were measured directly and can be controlled by varying the UV light and the relative humidity. Maximum values were 40 ppmv for O3 500 pptv for OH, and 4 ppbv for HO2. The oxidant amounts are 100 to 1000 times troposphere values, but the ratios OH/O3 and HO2/OH are similar to troposphere values. The aerosol production mechanism and the aerosol mass yield were studied for several controlling variables, such as temperature, relative humidity, oxidant concentration, presence of nitrogen oxides (NOx), precursor gas composition and amount, and the presence of acidic seed aerosol. The measured secondary organic aerosol (SOA) yield of several natural and anthropogenic volatile organic compounds and a mixture of hydrocarbons in the PAM chamber were similar to those obtained in large, batch-style environmental chambers. This PAM method is being developed for measuring potential aerosol mass in the atmosphere, but is also useful for examining SOA processes in the laboratory and in environmental chambers

Ozone loss derived from balloon-borne tracer measurements in the 1999/2000 Arctic winter

Balloon-borne measurements of CFC11 (from the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 Arctic winter as part of the SOLVE-THESEO 2000 campaign, based in Kiruna (Sweden). Here we present the CFC11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC11 and O3 measured on the flights. The peak ozone loss (~1200ppbv) occurs in the 440-470K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days

'Here be dragons, here be savages, here be bad plumbing: Australian media representations of sport and terrorism

As 'Propaganda Theorists argue, an examination of key discourses can enhance our understanding of how economic, political and social debate is shaped by mainstream media reporting. In this essay we present content and discourse analysis of Australian media reporting on the nexus of sport and terrorism. Examining newspaper reports over a five-year period, from 1996-2001, which included the 11 September 2001 terrorist tragedy in the United States (9/11), provides useful insights into how public discourse might be influenced with regard to sport and terrorism interrelationships. The results of the media analysis suggest that hegemonic tropes are created around sport and terrorism. The distilled message is one of good and evil, with homilies of sport employed in metaphors for western society and its values. The reactions and responses of sport administrators and athletes to terrorist acts and the threat of terrorism to sport are used to exemplify these ideals, providing newspaper readers a context within which to localize meaning and relevance

Building motivation to participate in a quality improvement collaborative in NHS hospital trusts in Southeast England: a qualitative participatory evaluation.

OBJECTIVES: This study explores the barriers and facilitators that impact on the motivation of practitioners to participate in a quality improvement collaborative. DESIGN: A qualitative and formative evaluation using a participatory approach, the researcher-in-residence model which embraces the concept of 'coproducing' knowledge between researchers and practitioners using a range of research methods such as participant observation, interviews and documentary analysis. The design, creation and application of newly generated evidence are facilitated by the researcher through negotiation and compromise with team members. PARTICIPANTS: Senior and middle managers, doctors and nurses. SETTING: Two hospitals in Southeast England participating in a Patient Safety Improvement Collaborative and the facilitator (host) of the collaborative, based in Central London. RESULTS: The evaluation has revealed facilitators and barriers to motivation categorised under two main themes: (1) inherent motivation and (2) factors that influence motivation, interorganisational and intraorganisational features as well as external factors. Facilitators included collaborative 'champions,' individuals who drove the quality improvement agenda at a local level, raising awareness and inspiring colleagues. The collaborative itself acted as a facilitator, promoting shared learning as well as building motivation for participation. A key barrier was the lack of board engagement in the participating National Health Service organisations which may have affected motivation among front-line staff. CONCLUSIONS: Collaboratives maybe an important way of engaging practitioners in quality improvement initiatives. This study highlights that despite a challenging healthcare environment in the UK, there remains motivation among individuals to participate in quality improvement programmes as they recognise that improvement approaches may facilitate positive change in local clinical processes and systems. Collaboratives can harness this individual motivation to facilitate spread and adoption of improvement methodology and build engagement across their membership