The contrasting climate response to tropical and extratropical energy perturbations

This is the final version of the article. Available from Springer Verlag via the DOI in this record.The link between cross-equatorial energy transport, the double-intertropical convergence zone (DI) problem and biases in tropical and extratropical albedo and energy budgets in climate models have been investigated in multiple studies, though DI biases persist in many models. Here, a coupled climate model, HadGEM2-ES, is used to investigate the response to idealised energy perturbations in the tropics and extratropics, in both the northern and southern hemispheres, through the imposition of stratospheric aerosols that reflect incoming radiation. The impact on the tropical climate of high and low latitude forcing strongly contrasts, with large changes in tropical precipitation and modulation of the DI bias when the tropics are cooled as precipitation moves away from the cooled hemisphere. These responses are muted when the extratropics are cooled, as the meridional energy transport anomalies that are excited by these energy budget anomalies are partitioned between the atmosphere and ocean. The results here highlight the persistence of the DI bias in HadGEM2-ES, indicating why little progress has been made in rectifying these problems through many generations of climate models. A highly linear relationship between cross-equatorial atmospheric energy transport, tropical precipitation asymmetry and tropical sea surface temperature biases is also demonstrated, giving some suggestion as to where improvements in these large scale, persistent biases may be achieved.MKH, MC and JMH were supported by the Natural Environment Research Council/Department for International Development via the Future Climates for Africa (FCFA) funded project ’Improving Model Processes for African Climate’ (IMPALA, NE/M017265/1). JMH and AJ were supported by the Joint UK BEIS/Defra Met Office Hadley Centre Climate Programme (GA01101)

How much Northern Hemisphere precipitation is associated with extratropical cyclones?

This is the final version of the article. Available from the publisher via the DOI in this record.Extratropical cyclones are often associated with heavy precipitation events and can have major socio-economic impacts. This study investigates how much of the total precipitation in the Northern Hemisphere is associated with extratropical cyclones. An objective feature tracking algorithm is used to locate cyclones and the precipitation associated with these cyclones is quantified to establish their contribution to total precipitation. Climatologies are produced from the Global Precipitation Climatology Project (GPCP) daily dataset and the ERA-Interim reanalysis. The magnitude and spatial distribution of cyclone associated precipitation and their percentage contribution to total precipitation is closely comparable in both datasets. In some regions, the contribution of extratropical cyclones exceeds 90/85% of the total DJF/JJA precipitation climatology. The relative contribution of the most intensely precipitating storms to total precipitation is greater in DJF than JJA. The most intensely precipitating 10% of storms contribute over 20% of total storm associated precipitation in DJF, whereas they provide less than 15% of this total in JJA. © 2012. American Geophysical Union. All Rights Reserved.MKH is supported by the Natural Environment Research Council’s project ‘Testing and Evaluating Model Predictions of European Storms’ (TEMPEST). The precipitation composites included in the auxiliary material were produced using scripts based on the work of Jennifer L. Catto and we thank her for their use. The authors would like to thank the reviewers for their helpful comments

In Victory, Defeat: Olivia Manning’s Balkan and Levant Trilogies and Evelyn Waugh’s Sword of Honour

Olivia Manning's Balkan and Levant trilogies (1960-65, 1977-80) and Evelyn Waugh’s Sword of Honour trilogy (1952-61) are sequences of historical novels set during the Second World War. This thesis compares and contrasts these sequences as conservative fictional voices from a period of social and literary transition. My first chapter discusses how ideas of heroism and sacrifice prove outmoded and unsupported by institutions during the war. Particularly in Waugh's trilogy, but to a lesser extent also in Manning's sequence, models of heroism taken from past texts—such as colonial adventure stories—are shown to be inadequate. Heroism is only possible on a small scale and involves moral compromises. The second chapter considers the treatment of being English outside England. Depictions of foreign countries are considered in the context of the fading of the British Empire and British global power. Colonial life is attractive in a nostalgic sense but is problematic in the present. Episodes about Jewish refugees in both sequences are discussed as symbolising defiance of the entropy of imperial decay as well as attempts to find post-imperial models for intervention. The third and final chapter examines the uses of literature and culture in the novels and how they hint at ways out of the historical binds discussed in the first two chapters. Literature and the teaching of literature have a propagandistic function but also subvert this function by offering escape from the realities of wartime. I also touch on the connection between literary creativity and the subversion of gender roles. I argue that while these sequences construct a generally negative perspective on social changes during the war, this is not unchallenged by subversive undercurrents such as these. The conservative Catholic morality of Waugh's trilogy contrasts with Manning's willingness to raise questions about gender, class and colonialism, but in both authors' works the war is presented as a time in which initially optimistic ideals and hopes are disappointed, while the validity of these ideals in the first place is also questioned

Faecal carriage of antibiotic resistant Escherichia coli in asymptomatic children and associations with primary care antibiotic prescribing:a systematic review and meta-analysis

Chloramphenicol resistance in faecal E. coli isolates from asymptomatic children, by OECD status. (DOCX 152 kb

Significantly increased extreme precipitation expected in Europe and North America from extratropical cyclones

For the Northern Hemisphere extratropics, changes in the mid-latitude storm tracks are key to understanding the impacts of climate warming, but projections of their future location in current climate models are affected by large uncertainty. Here, we show that in spite of this uncertainty in the atmospheric circulation response to warming, by analysing the behaviour of the storms (or extratropical cyclones) themselves, projections of change in the number of the most intensely precipitating extratropical cyclones are substantial and consistent across models. In particular, we show large increases in the frequency of extreme extratropical cyclones (those above the present day 99th percentile of precipitation intensity) by the end of the century. In both Europe and North America, these intensely precipitating extratropical cyclones are projected to more than triple in number by the end of the century unless greenhouse gas emissions are mitigated. Such changes in extratropical cyclone behaviour may have major impacts on society given intensely precipitating extratropical cyclones are responsible for many large-scale flooding events, and associated severe economic losses, in these regions

Residential development and environmental weeds in indigenous forest patches, Otatara, Southland

Residential development is widely perceived as a threat to indigenous vegetation and habitat. New Zealand lowland forests, which have been extensively fragmented and modified since colonisation, may be particularly vulnerable. Increased exotic plant invasion of forest remnants is a potential result of nearby residential development. Environmental weeds cause loss of biodiversity at genetic to ecosystem levels of organisation. The impact of residential development was examined in podocarp forest remnants in a matrix of rural and residential land at Otatara, Southland. Correlation between abundance of exotic plants and population density or degree of development has been observed at coarse scales in many areas but few studies have examined mechanisms underlying this pattern. Residential development is thought to exacerbate weed invasion by increasing the likelihood of exotic plant propagules entering forest remnants and by changing conditions within the forest to aid exotic plant establishment and growth. Field data was collected along transects from the forest edge into the interior for 13 study sites at Otatara. The abundance of environmental weeds was quantified at intervals along each transect. Indicators of the spatial context: distance of each quadrat from the forest edge; age of residential development and number of known weed species growing on the adjoining property, and edge structure and three environmental characteristics of the forest: light availability, soil fertility and degree of anthropogenic disturbance, were also assessed. The field data was examined using bivariate correlation analysis and multivariate regression. Weed abundance within forest was significantly correlated to light availability, degree of anthropogenic disturbance, and to distance in from the forest edge and edge structure. Even though a significant correlation was not found between weed abundance and age of residential development (perhaps because of the small scale at which this research was conducted), the factors that are correlated to weed abundance are altered by residential development in ways expected to facilitate weed invasion. Thus, it seems likely that nearby residential development exacerbates weed invasion. Maintaining a relatively closed edge structure and minimising disturbance within forest may lessen this effect

Faecal carriage of antibiotic resistant Escherichia coli in asymptomatic children and associations with primary care antibiotic prescribing: a systematic review and meta-analysis

Background The faecal reservoir provides optimal conditions for the transmission of resistance genes within and between bacterial species. As key transmitters of infection within communities, children are likely important contributors to endemic community resistance. We sought to determine the prevalence of antibiotic-resistant faecal Escherichia coli from asymptomatic children aged between 0 and 17 years worldwide, and investigate the impact of routinely prescribed primary care antibiotics to that resistance. Methods A systematic search of Medline, Embase, Cochrane and Web of Knowledge databases from 1940 to 2015. Pooled resistance prevalence for common primary care antibiotics, stratified by study country OECD status. Random-effects meta-analysis to explore the association between antibiotic exposure and resistance. Results Thirty-four studies were included. In OECD countries, the pooled resistance prevalence to tetracycline was 37.7 % (95 % CI: 25.9–49.7 %); ampicillin 37.6 % (24.9–54.3 %); and trimethoprim 28.6 % (2.2–71.0 %). Resistance in non-OECD countries was uniformly higher: tetracycline 80.0 % (59.7–95.3 %); ampicillin 67.2 % (45.8–84.9 %); and trimethoprim 81.3 % (40.4–100 %). We found evidence of an association between primary care prescribed antibiotics and resistance lasting for up to 3 months post-prescribing (pooled OR: 1.65, 1.36–2.0). Conclusions Resistance to many primary care prescribed antibiotics is common among faecal E. coli carried by asymptomatic children, with higher resistance rates in non-OECD countries. Despite tetracycline being contra-indicated in children, tetracycline resistance rates were high suggesting children could be important recipients and transmitters of resistant bacteria, or that use of other antibiotics is leading to tetracycline resistance via inter-bacteria resistance transmission

Using satellite and reanalysis data to evaluate the representation of latent heating in extratropical cyclones in a climate model

Extratropical cyclones are a key feature of the weather in the extratropics, which climate models need to represent in order to provide reliable projections of future climate. Extratropical cyclones produce significant precipitation and the associated latent heat release can play a major role in their development. This study evaluates the ability of a climate model, HiGEM, to represent latent heating in extratropical cyclones. Remote sensing data is used to investigate the ability of both the climate model and ERA-Interim (ERAI) reanalysis to represent extratropical cyclone cloud features before latent heating itself is assessed. An offline radiance simulator, COSP, and the ISCCP and CloudSat datasets are used to evaluate comparable fields from HiGEM and ERAI. HiGEM is found to exhibit biases in the cloud structure of extratropical cyclones, with too much high cloud produced in the warm conveyor belt region compared to ISCCP. Significant latent heating occurs in this region, derived primarily from HiGEM’s convection scheme. ERAI is also found to exhibit biases in cloud structure, with more clouds at lower altitudes than those observed in ISCCP in the warm conveyor belt region. As a result, latent heat release in ERAI is concentrated at lower altitudes. CloudSat indicates that much precipitation may be produced at too low an altitude in both HiGEM and ERAI, particularly ERAI, and neither capture observed variability in precipitation intensity. The potential vorticity structure in composite extratropical cyclones in HiGEM and ERAI is also compared. A more pronounced tropopause ridge evolves in HiGEM on the leading edge of the composite as compared to ERAI. One future area of research to be addressed is what impact these biases in the representation of latent heating have on climate projections produced by HiGEM. The biases found in ERAI indicate caution is required when using reanalyses to study cloud features and precipitation processes in extratropical cyclones or using reanalysis to evaluate climate models’ ability to represent their structure

Climate change in CCAFS regions: Recent trends, current projections, crop-climate suitability, and prospects for improved climate model information

Good climate projections for agriculture can help guide investments in risk management and adaptation. New reports offer insights into the reliability of future climate projections for agriculture, and show how to make the most of current data

Southern Ocean albedo, inter-hemispheric energy transports and the double ITCZ: global impacts of biases in a coupled model

A causal link has been invoked between inter-hemispheric albedo, cross-equatorial energy transport and the double-IntertropicalConvergence Zone (ITCZ) bias in climate models. Southern Ocean cloud biases are a major determinant of inter-hemispheric albedo biases in many models, including HadGEM2-ES, a fully coupled model with a dynamical ocean. In this study, targeted albedo corrections are applied to explore the dynamical response to artificially reducing these biases. The Southern Hemisphere jet increases in strength in response to the increased tropical-extratropical temperature gradient, with increased energy transport into the mid-latitudes in the atmosphere, but no improvement is observed in the double-ITCZ bias or atmospheric cross-equatorial energy transport. The majority of the adjustment in energy transport in the tropics is achieved in the ocean, with the response further limited to the Pacific Ocean. As a result, the frequently argued teleconnection between the Southern Ocean and tropical precipitation biases is muted. Further experiments in which tropical longwave biases are also reduced do not yield improvement in the representation of the tropical atmosphere. These results suggest that the dramatic improvements in tropical precipitation that have been shown in previous studies may be a function of the lack of dynamical ocean and/or the simplified hemispheric albedo bias corrections applied in that work. It further suggests that efforts to correct the double ITCZ problem in coupled models that focus on large-scale energetic controls will prove fruitless without improvements in the representation of atmospheric processes.MKH, MC and JMH were supported by the Natural Environment Research Council/Department for International Development via the Future Climates for Africa (FCFA) funded project ’Improving Model Processes for African Climate’ (IMPALA, NE/M017265/1). JMH and AJ were supported by the Joint UK DECC/Defra Met Office Hadley Centre Climate Programme (GA01101)