Mechanisms for Atmospheric chemistry: GeneratioN, Interpretation and FidelitY - MAGNIFY

The chemistry of the troposphere underlies a range of environmental issues, which have substantial societal and economic impacts. Whether it is a changing climate, a reduction in air quality affecting human health or the degradation of ecosystems due to air pollution the details of the chemistry determines the severity of the impact. Numerical models of atmospheric chemistry are essential to our ability to understand, predict and hence mitigate these problems. The description of the chemistry occurring within these models is known as the 'mechanism'. Different models use different levels of chemical complexity in deriving these mechanisms, depending on their individual foci. However, there is an overarching need for a 'gold standard' or benchmark mechanism, which contains as full a representation of our fundamental 'state of science' understanding of atmospheric chemistry as is possible. For the last decade this benchmark mechanism, both in the UK and internationally, has been the Master Chemical Mechanism (MCM).

The MCM provides a highly comprehensive representation of atmospheric volatile organic compound (VOC) degradation chemistry, which is extensively used by the atmospheric science community in a wide variety of science and policy applications where chemical detail is required. The MCM is an internationally recognised resource, with registered users worldwide, and thus represents a highly regarded flagship facility for atmospheric science in the UK. Much of its success stems from the availability of the MCM database on the web, along with the provision of a range of tools to facilitate its use.

However, both the MCM itself and its supporting infrastructure are now becoming dated. It is clear that the enormous task of bringing the entire mechanism fully up to date, and maintaining it in that condition, is becoming increasingly difficult within the resources and methods that are currently available. It is recognised, therefore, that sustainable development of the MCM as a whole requires a fundamental revision in the methods applied to its maintenance to ensure that updates/changes can be carried out thoroughly and efficiently, and which can be more readily sustained through changes of personnel in the future. Without such changes, it is probable that the MCM will stagnate, gradually fall from use and eventually become obsolete, and hence no longer a highly regarded flagship facility for atmospheric science in the UK.

The MAGNIFY project puts in place a comprehensive strategic work plan (including a number of important scientific deliverables) in order to make the MCM more sustainable, updating its construction rules and opening it up more to community, building upon its success and maintaining it as the "gold standard" benchmark mechanism for atmospheric chemistry.

This proposal will:
1) build a fully updated and revised mechanism development protocol, for the generation of a new version of the MCM (v4.0)
2) put in place a range of quality assurance methods to ensure high quality updates and changes into the future
3) develop an international community tasked with supporting the continual development of the MCM mechanism and framework.
4) investigate automated methods for mechanism generation that will reduce workload and error, ensuring responsive, efficient generation of mechanisms into the future
5) further develop and enhance the successful open access web platform used by the MCM for access, archiving and interrogation not only of the MCM and its successors, but also a range of mechanisms used by a range of NERC / MO / DEFRA supported activities and for a range of models world wide
6) provide a comprehensive evaluation methodology of all mechanisms stored in the system against the updated benchmark MCM and its successors with an emphasis on assessing those models currently being used for policy (air quality and climate) related work within the UK.

MAGNIFY has impacts on 5 key groups and activities; air quality and climate policy; operational weather and climate groups running forecast models; scientists running research models of atmospheric composition; laboratory atmospheric chemical kinetics and field groups; education.

i) Impacts on policy
Chemical mechanisms provide the route by which emissions of pollutants lead to impacts on socially important processes such as climate, air quality, food security etc. Our ability to accurately predict and understand these phenomena depends on the quality and fidelity of these simulations. A more accurate simulation will lead to better policy making. This proposal will provide a benchmark mechanism to compare simpler mechanism against, put in place the computational infrastructure to host a range of mechanisms and to automate the comparison of these mechanisms under a range of conditions. Ultimately this will lead to better mechanisms being implemented into policy models.

ii) Operational weather and climate groups
These are the organisations that run air quality and climate models as a core part of their remit. This proposal will improve the quality of the chemical mechanisms they use by providing them with a readily accessible way to assess the fidelity of their mechanism against a benchmark mechanism and other mechanisms being used by science and operational agencies.

iii) Scientists running research models of atmospheric composition
By providing a readily accessible mechanism with which to test, assess and update chemical mechanisms MAGNIFY will allow research science to progress more rapidly and to adopt updates to process understanding in an enhanced way.

iv) Laboratory and field groups
These groups have typically found it difficult to impact policy directly as numerical models are needed to fully interpret both field and laboratory measurements. Often to interpret these new results fully, new or updated mechanisms need to be generated and then comparisons made with previous mechanisms. MAGNIFY will significant decrease the time it takes to compose new mechanisms and to evaluate the impact of new results from kinetics and field studies.

v) Education
MAGNIFY will continue the open access model used for the MCM. This has proven useful for atmospheric chemistry education where students are able to explore the mechanism using the tools on the website, and can generate models for exploring the mechanisms themselves. MAGNIFY will enhance this capability by allowing students to explore a range of mechanisms and to appreciate the uncertainty associated with science.

New educational tools and resources for teachers and students will be developed and assessed in conjunction with our project partner the Royal Society of Chemistry in order to enhance the teaching and learning of the impacts of atmospheric chemistry on air quality and climate change to high school age students.