Modelling the spring ozone maximum and the interhemispheric asymmetry in the remote marine boundary layer 1. Comparison with surface and ozonesonde measurements

Here we report a modelling study of the spring ozone maximum and its interhemispheric asymmetry in the remote marine boundary layer (MBL). The modelled results are examined at the surface and on a series of time-height cross sections at several locations spread over the Atlantic, the Indian, and the Pacific Oceans. Comparison of model with surface measurements at remote MBL stations indicate a close agreement. The most striking feature of the hemispheric spring ozone maximum in the MBL can be most easily identified at the NH sites of Westman Island, Bermuda, and Mauna Loa, and at the SH site of Samoa. Modelled ozone vertical distributions in the troposphere are compared with ozone profiles. For the Atlantic and the Indian sites, the model generally produces a hemispheric spring ozone maximum close to those of the measurements. The model also produces a spring ozone maximum in the northeastern and tropical north Pacific close to those measurements, and at sites in the NH high latitudes. The good agreement between model and measurements indicate that the model can reproduce the proposed mechanisms responsible for producing the spring ozone maximum in these regions of the MBL, lending confidence in the use of the model to investigate MBL ozone chemistry (see part 2 and part 3). The spring ozone maximum in the tropical central south Pacific and eastern equatorial Pacific are less well reproduced by the model, indicating that both the transport of $O_3$ precursors from biomass burning emissions taking place in southeastern Asia, Australia, Oceania, southern Africa, and South America are not well represented in the model in these regions. Overall, the model produces a better simulation at sites where the stratosphere and biomass burning emissions are the major contributors.Comment: 24 pages, 8 figure

What’s in a grade? The real meaning of mathematics grades at GCSE and A-Level

The scheme of work in mathematics and science subjects at GCSE and A-Level has been constantly changing over the last fifteen years. Under the auspices of a pilot scheme funded by Chemistry for our Future (CFOF) we review the current scheme of work in mathematics at both GCSE and A-Level from the three main examining boards and provide insight into what mathematical skills one might expect from a student entering a Physical Science degree programme, in particular in Chemistry

Towards sustainable public engagement (outreach)

There are myriad benefits to science departments that have a public engagement in science portfolio in addition to any recruitment of new undergraduates. These benefits are discussed in this paper and include: improving congruence between A level and first year undergraduate courses, training in science communication and the breaking down of barriers between the public and universities. All activity requires investment of personnel and incurs a financial cost. Small scale activities may be able to absorb this cost, but ultimately as the portfolio grows this will become an increasing drain on resources. Bristol ChemLabS Outreach has, from the very start, set out to be fully sustainable financially and in terms of personnel. A very important component is the full support of the senior management team. In this paper we discuss how we have achieved this

A Two-Decade Anthropogenic and Biogenic Isoprene Emissions Study in a London Urban Background and a London Urban Traffic Site

A relationship between isoprene and 1,3-butadiene mixing ratios was established to separate the anthropogenic and biogenic fractions of the measured isoprene in London air in both urban background (Eltham) and urban traffic (Marylebone Road) areas over two decades (1997–2017). The average daytime biogenic isoprene mixing ratios over this period reached 0.09 ± 0.04 ppb (Marylebone Road) and 0.11 ± 0.06 ppb (Eltham) between the period of 6:00 to 20:00 local standard time, contributing 40 and 75% of the total daytime isoprene mixing ratios. The average summertime biogenic isoprene mixing ratios for 1997–2017 are found to be 0.13 ± 0.02 and 0.15 ± 0.04 ppb which contribute 50 and 90% of the total summertime isoprene mixing ratios for Marylebone Road and Eltham, respectively. Significant anthropogenic isoprene mixing ratios are found during night-time (0.11 ± 0.04 ppb) and winter months (0.14 ± 0.01 ppb) at Marylebone Road. During high-temperature and high-pollution events (high ozone) there is a suggestion that ozone itself may be directly responsible for some of the isoprene emission. By observing the positive correlation between biogenic isoprene levels with temperature, photosynthetically active radiation and ozone mixing ratios during heatwave periods, the Cobb-Douglas production function was used to obtain a better understanding of the abiotic factors that stimulate isoprene emission from plants. Other reasons for a correlation between ozone and isoprene are discussed. The long-term effects of urban stressors on vegetation were also observed, with biogenic isoprene mixing ratios on Marylebone Road dropping over a 20-year period regardless of the sustained biomass levels.NERC (grant code-NE/K004905/1) and Bristol ChemLabS under whose auspices various aspects of this work was funded. Department for Environment, Food and Rural Affairs (Defra) and London Air Quality Network-King’s College London for supporting UK monitoring network and dat

Modelling atmospheric chemistry and long-range transport of emerging Asian pollutants

Modeling is a very important tool for scientific processes, requiring long-term dedication, desire, and continuous reflection. In this work, we discuss several aspects of modeling, and the reasons for doing it. We discuss two major modeling systems that have been built by us over the last 10 years. It is a long and arduous process but the reward of understanding can be enormous, as demonstrated in the examples shown in this work. We found that long-range transport of emerging Asian pollutants can be interpreted using a Lagrangian framework for wind analysis. More detailed processes still need to be modeled but an accurate representation of the wind structure is the most important thing above all others. Our long-term chemistry integrations reveal the capability of the IMS model in simulating tropospheric chemistry on a climate scale. These long-term integrations also show ways for further model development. Modeling is a quantitative process, and the understanding can be sustained only when theories are vigorously tested in the models and compared with high quality measurements. We should also not over look the importance of data visualization techniques. Humans feel more confident when they see things. Hence, modeling is an incredible journey, combining data collection, theoretical formulation, detailed computer coding and harnessing computer power. The best is yet to come.Comment: 30 pages, 18 figure

The myriad positive impacts of the Virtual Learning Environment, from LabSims to Smart Worksheets (a 17 year journey)

PROBLEM Introducing a virtual learning environment (VLE) in support of practical teaching in Chemistry is not trivial. In this study we identify keys areas which are essential for successful implementation based on 17 years of experience. PLAN We have analysed a range of metrics from first initiating a VLE in the Centre for Excellence in Teaching and Learning (CETL) called Bristol CemLabS in 2006 and compare and contrast a similar implementation in the Faculty of Natural Sciences at The University of the Western Cape in South Africa in 2020. ACTION There are strong similarities in both environments following implementation of a VLE. Raising of confidence of students in using instruments and carrying out techniques found in an undergraduate chemistry laboratory is clear, increasing students understanding of the theory behind techniques and their real appreciation of health and safety. For demonstrators, their role changes from one where they are giving instruction to one where they are discussing the development of the practical investigation with the students. For academics, the transformation in ability of students, and long-term impacts on practical ability and final year projects that can be undertaken are noted. REFLECTION The transformation in both case studies was pretty much instant and irreversible for the students. Key elements required are strong IT support, strong collaboration between staff, demonstrators and technical staff. The main question to ask is why did we take so long to do this