Cirrus parameterisation and the role of ice nuclei.

A parametrization of cirrus clouds formed by homogeneous nucleation is improved so that it can be used more easily in general-circulation models (GCMs) and climate models. The improved parametrization is completely analytical and requires no fitting of parameters to models or measurements; it compares well with full microphysical model results even when monodisperse aerosol particles are used in the parametrization to determine cirrus ice-crystal number densities. However, the presence of ice nuclei in the atmosphere can modify the formation of cirrus clouds. If sufficient ice particles have been generated by heterogeneous nucleation, the saturation ratio of the air parcel will never reach that required for homogeneous nucleation. We calculate the critical number density of ice nuclei, above which homogeneous nucleation will be suppressed. The critical number density depends on the temperature, the updraught velocity, and the supersaturation at which ice nuclei activate. The theory points to key uncertainties in our observations of ice nuclei in the upper troposphere; for ice nuclei that activate at relatively low supersaturations, number density is more important than a precise knowledge of the activation supersaturation. Overall, the theory provides a general framework within which to interpret observations and the results of full microphysical cloud models. The theory can provide analytical test cases as benchmarks for the testing of models in development, and can be implemented itself into larger-scale atmospheric models, such as GCMs. Copyright © 2005 Royal Meteorological Societ

Health human resources planning and the production of health: Development of an extended analytical framework for needs-based health human resources planning.

Traditional approaches to health human resources planning emphasize the role of demographic change on the needs for health human resources. Conceptual frameworks have been presented that recognize the limited role of demographic change and the broader determinants of health human resource requirements. Nevertheless, practical applications of health human resources planning continue to base plans on the size and demographic mix of the population applied to simple population-provider or population-utilization ratios. In this paper an analytical framework is developed based on the production of health care services and the multiple determinants of health human resource requirements. In this framework attention is focused on estimating the ‘flow’ of services required to meet the needs of the population that is then translated into the required ‘stock’ of providers to deliver this ‘flow’ of services. The requirements for human resources in the future is shown to depend on four elements: the size and demographic mix of the population (demography), the levels of risks to health and morbidity in the population (epidemiology), the services deemed appropriate to address the levels of risks to health and morbidity (standards of care), and the rate of service delivery by providers (productivity). Application of the framework is illustrated using hypothetical scenarios.health human resources planning, demography, epidemiology, standards of care, productivity

Volatile organic compound fluxes and concentrations in London (ClearfLo)

Volatile organic compounds (VOCs) from anthropogenic sources such as fuel combustion or evaporative emissions can directly and indirectly affect human health. Some VOCs, such as benzene and 1,3- butadiene are carcinogens. These and other VOCs contribute to the formation of ozone (O3) and aerosol particles, which have effects on human health and the radiative balance of the atmosphere. Although in the UK VOC emissions are subject to control under European Commission Directive 2008/50/EC and emission reducing echnologies have been implemented, urban air pollution remains a concern. Urban air quality is likely to remain a priority since currently >50% of the global population live in urban areas with trends in urbanization and population migration predicted to increase. The ClearfLo project is a large multi-institutional consortium funded by the UK Natural Environment Research Council (NERC) and provides integrated measurements of meteorology, gas phase and particulate composition of the atmosphere over London. Both long term and IOP measurements were made at street and elevated locations at a range of sites across London and its surroundings during 2011 and 2012. Mixing ratios of a selection of nine VOCs were measured using a high sensitivity proton transfer reaction-mass spectrometer (PTR-MS) at a ground level urban background (North Kensington) and kerbside (Marylebone Road) site during the winter IOP. VOC fluxes were measured by virtually disjunct eddy covariance (vDEC) at an elevated urban site (King’s College Strand) in Aug-Dec 2012. Our results for the first IOP showed that most of the selected compound concentrations depended on traffic emissions, although there was a marked difference between the urban ackground and kerbside sites. We identified some temperature effects on VOC concentrations. We also present the first analyses of VOC flux measurements over London. Preliminary analyses indicate most compounds associated with vehicle emissions closely followed diurnal traffic counts. Fluxes of isoprene and methanol appear to be controlled by light intensity and temperature, consistent with a redominantly biogenic source of these compounds

Human monocyte heat shock protein 72 responses to acute hypoxic exercise after 3 days of exercise heat acclimation

The aim of this study was to determine whether short-term heat acclimation (STHA) could confer increased cellular tolerance to acute hypoxic exercise in humans as determined via monocyte HSP72 (mHSP72) expression. Sixteen males were separated into two matched groups. The STHA group completed 3 days of exercise heat acclimation; 60 minutes cycling at 50% V˙O2peak in 40°C 20% relative humidity (RH). The control group (CON) completed 3 days of exercise training in 20°C, 40% RH. Each group completed a hypoxic stress test (HST) one week before and 48 hours following the final day of CON or STHA. Percentage changes in HSP72 concentrations were similar between STHA and CON following HST1 (P=0.97). STHA induced an increase in basal HSP72 (P=0.03) with no change observed in CON (P=0.218). Basal mHSP72 remained elevated before HST2 for the STHA group (P0.05). Percent change in mHSP72 was lower after HST2 in STHA compared to CON (P=0.02). The mHSP72 response to hypoxic exercise was attenuated following 3 days of heat acclimation. This is indicative of improved tolerance and ability to cope with the hypoxic insult, potentially mediated in part by increased basal reserves of HSP72

Seasonal trends in concentrations and fluxes of volatile organic compounds above central London

Concentrations and fluxes of seven volatile organic compounds (VOCs) were measured between August and December 2012 at a roof-top site in central London as part of the ClearfLo project (Clean Air for London). VOC concentrations were quantified using a proton transfer reaction-mass spectrometer and fluxes were calculated using a virtual disjunct eddy covariance technique. The median VOC fluxes, including aromatics, oxygenated compounds and isoprene, ranged from 0.07 to 0.33 mg m−2 h−1 and mixing ratios were 7.27 ppb for methanol (m / z 33) and <1 ppb for the remaining compounds. Strong relationships were observed between most VOC fluxes and concentrations with traffic density, but also with photosynthetically active radiation (PAR) and temperature for the oxygenated compounds and isoprene. An estimated 50–90 % of aromatic fluxes were attributable to traffic activity, which showed little seasonal variation, suggesting boundary layer effects or possibly advected pollution may be the primary causes of increased concentrations of aromatics in winter. PAR and temperature-dependent processes accounted for the majority of isoprene, methanol and acetaldehyde fluxes and concentrations in August and September, when fluxes and concentrations were largest. Modelled biogenic isoprene fluxes using the G95 algorithm agreed well with measured fluxes in August and September, due to urban vegetation. Comparisons of estimated annual benzene emissions from the London and National Atmospheric Emissions Inventory agreed well with measured benzene fluxes. Flux footprint analysis indicated emission sources were localized and that boundary layer dynamics and source strengths were responsible for temporal and spatial VOC flux and concentration variability during the measurement period

Forest innovation to tackle the climate and biodiversity emergencies

Overview • Planting mixed woodland enhances tree growth and productivity. Mixed woodland plantations should, therefore, play a key role enabling the UK to meet its 2050 net zero greenhouse gas emissions targets. • Elevated atmospheric CO2 concentrations (eCO2) increase photosynthesis, which is necessary (but not in itself sufficient) for increased carbon storage in forests. Remote sensing data have revealed an increased greening of the earth over the last 20 years that is largely due to greater leaf area in forests. Such findings demonstrate that UK forests are effective in carbon uptake in the future, as well as improving soil health. • Undisturbed forests eventually reach carbon balance. They may continue to provide long-term carbon draw-down and storage by building ‘recalcitrant’ soil carbon. To secure and enhance long-term draw-down and storage in the forest canopy above ground, wood products must be taken from the forest and stored long term. Hence, woodland planning must incorporate harvesting for timber and other wood products in order to contribute to long-term carbon budgeting, biodiversity enhancement, and the delivery of societal benefits. • Current afforestation and forest management regulations and guidelines are innovation-averse and highly vulnerable to globalised disease and climate risks. Neither the Nature for Climate Fund1, nor the ongoing series of UK Carbon Budgets2, provide the space for innovation to manage these risks. • Private actors are pathfinding recolonisation and silvicultural portfolio approaches to increase resilience and manage social risks such as ‘carbon colonialism’. • Choosing forest-facing post-16, apprenticeship, and degree training is a direct route to climate action for UK school leavers but this case is not being made to them. • Forest-facing education is tarnished by outmoded and educationally indefensible caricatures of practice-based learning (cf. medicine or veterinary science), severely hindering One Health responses to the climate and nature emergencies and the pandemic. • The benefits of woodland creation are inherently context-dependent, and sensitive to what tree species are used. For example, as sources of nitrogen pollution come under control in the UK, adding nitrogen fixing tree species will enhance woodland carbon sequestration rates under most circumstances