Flooding caused by heavy convective rain is a serious problem in the UK. Flash floods in hilly terrain can be particularly damaging. The Convective Orographically-induced Precipitation Study (COPS) is an international project designed to address this problem and to improve predictions of heavy convective precipitation. This proposal is the UK component of COPS which adds specific objectives complementary to those of other COPS partners. It will produce an understanding of the processes that control the formation and development of convective precipitation over hilly terrain which will be used by scientists within the Mesoscale Modelling group of the Met Office in reducing uncertainty in predictability of convection over complex terrain with the Unified Model (UM). This will be achieved by synthesising COPS data alongside modelling activities focussed on interpreting the data. The problem involves five integrated parts that need to be tackled together. (1) The thermally driven flows in complex terrain depends critically on the surface exchanges of heat and water. (2) The composition and size distribution of the aerosol particles have a crucial influence on the microphysics and dynamics of the convective clouds and particularly the amount of precipitation. (3) The thermals and other features in the boundary layer that transport heat, moisture and aerosols to the convective clouds. (4) The development of precipitation depends critically on the detailed microphysics and dynamics of the convective clouds. (5) Finally, reducing uncertainty in predictability of the location and timing of convective storms in hilly terrain with the UM, depends on the knowledge gained from these four parts. In particular the relative contributions of different sources of uncertainty in predictability of convective storms in hilly terrain will be quantified, thus providing the basis for an ensemble forecast system.

In the lower atmosphere ozone (O3) is an important anthropogenic greenhouse gas and is an air pollutant responsible for several billion euros in lost plant productivity each year. Surface O3 has doubled since 1850 due to chemical emissions from vehicles, industrial processes, and the burning of forests. While land ecosystems (primarily forests) are currently slowing down global warming by storing about a quarter of human-released carbon dioxide (CO2) emissions, this could be undermined by rising O3 concentrations impacting forest growth. This in turn would result in more CO2 left in the atmosphere adding to global climate change. Tropical rainforests are responsible for nearly half of global plant productivity and it is in these tropical regions that we are likely to see the greatest expansion of human populations this century. For example, Manaus, in the centre of the Amazon rainforest has seen a population boom in the last 25 years, with the number of residents doubling to just over 2 million people. Alongside this growing population, we see the expansion of O3 precursor emissions from urbanization and high-intensity agricultural areas. The global impacts of changing air pollution on tropical forests are potentially profound. In his seminal work in 2007, PI Sitch and colleagues at the Met Office and Centre for Ecology and Hydrology, were the first to identify the large potential risk to tropical forests from O3 pollution, and how that could in turn accelerate global warming. However, their study presented two major challenges for the research community: 1) the scale of this effect is highly uncertain; as their global modelling study was based on extrapolating plant O3 sensitivity data from temperate and boreal species. This project will address this by providing the first comprehensive set of measurements of O3 effects on plant functioning and growth in tropical trees. Also, as both O3, CO2 and H2O are exchanged between the atmosphere and leaves through a plants stoma, higher levels of CO2 provide plants the opportunity to reduce their stomatal opening, which in turn leads to reduced O3 uptake and damage. This project will for the first time investigate the potential synergistic or antagonistic impacts of climate change (CO2 and Temperature) on O3 responses in tropical forest species. 2) a fundamental challenge in all global vegetation modelling is to accurately represent the structure and function of highly biodiverse ecosystems; global models are generally only able to represent a limited set of generalized plant functional types (e.g. evergreen trees, C4-grasses etc). However, recent collection and synthesis of plant functional trait data (e.g. leaf nutrient concentrations, leaf size and shape) have enabled improved representation of ecology and plant function in global models. A group of scientists, including project partner Johan Uddling, have very recently proposed a unifying theory for O3 sensitivity in temperate and boreal tree species based upon leaf-functional traits. We are in a unique position to take this work forward to test the theory in tropical forest species, and to test the implications of this at the regional and global scale. The inclusion of the relationship between O3 sensitivity and basic plant functional traits in our global vegetation model, JULES (Joint UK Land Environmental Simulator), will lead to a step-change in our ability to assess the impact of air quality on tropical forest productivity and consequences for carbon sequestration. The model will be applied at O3 hotspot locations in tropical forests and together with observed plant trait information and O3 concentrations we will be able to extrapolate beyond the single plant functional type (PFT) paradigm. Global runs of JULES will also enable us to investigate the implications of future O3 concentrations, changes in land-use, and climate change scenarios on the tropical forest productivity and the global carbon sink.

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Submarine landslides can be far larger than terrestrial landslides, and many generate destructive tsunamis. The Storegga Slide offshore Norway covers an area larger than Scotland and contains enough sediment to cover all of Scotland to a depth of 80 m. This huge slide occurred 8,200 years ago and extends for 800 km down slope. It produced a tsunami with a run up >20 m around the Norwegian Sea and 3-8 m on the Scottish mainland. The UK faces few other natural hazards that could cause damage on the scale of a repeat of the Storegga Slide tsunami. The Storegga Slide is not the only huge submarine slide in the Norwegian Sea. Published data suggest that there have been at least six such slides in the last 20,000 years. For instance, the Traenadjupet Slide occurred 4,000 years ago and involved ~900 km3 of sediment. Based on a recurrence interval of 4,000 years (2 events in the last 8,000 years, or 6 events in 20,000 years), there is a 5% probability of a major submarine slide, and possible tsunami, occurring in the next 200 years. Sedimentary deposits in Shetland dated at 1500 and 5500 years, in addition to the 8200 year Storegga deposit, are thought to indicate tsunami impacts and provide evidence that the Arctic tsunami hazard is still poorly understood. Given the potential impact of tsunamis generated by Arctic landslides, we need a rigorous assessment of the hazard they pose to the UK over the next 100-200 years, their potential cost to society, degree to which existing sea defences protect the UK, and how tsunami hazards could be incorporated into multi-hazard flood risk management. This project is timely because rapid climatic change in the Arctic could increase the risk posed by landslide-tsunamis. Crustal rebound associated with future ice melting may produce larger and more frequent earthquakes, such as probably triggered the Storegga Slide 8200 years ago. The Arctic is also predicted to undergo particularly rapid warming in the next few decades that could lead to dissociation of gas hydrates (ice-like compounds of methane and water) in marine sediments, weakening the sediment and potentially increasing the landsliding risk. Our objectives will be achieved through an integrated series of work blocks that examine the frequency of landslides in the Norwegian Sea preserved in the recent geological record, associated tsunami deposits in Shetland, future trends in frequency and size of earthquakes due to ice melting, slope stability and tsunami generation by landslides, tsunami inundation of the UK and potential societal costs. This forms a work flow that starts with observations of past landslides and evolves through modelling of their consequences to predicting and costing the consequences of potential future landslides and associated tsunamis. Particular attention will be paid to societal impacts and mitigation strategies, including examination of the effectiveness of current sea defences. This will be achieved through engagement of stakeholders from the start of the project, including government agencies that manage UK flood risk, international bodies responsible for tsunami warning systems, and the re-insurance sector. The main deliverables will be: (i) better understanding of frequency of past Arctic landslides and resulting tsunami impact on the UK (ii) improved models for submarine landslides and associated tsunamis that help to understand why certain landslides cause tsunamis, and others don't. (iii) a single modelling strategy that starts with a coupled landslide-tsunami source, tracks propagation of the tsunami across the Norwegian Sea, and ends with inundation of the UK coast. Tsunami sources of various sizes and origins will be tested (iv) a detailed evaluation of the consequences and societal cost to the UK of tsunami flooding , including the effectiveness of existing flood defences (v) an assessment of how climate change may alter landslide frequency and thus tsunami risk to the UK.

Understanding environmental systems increasingly requires measurements that simultaneously characterise multiple chemical and dynamical processes on a range of spatial and temporal scales. Satellite remote sensing provides global atmospheric observations but has limited spatial and temporal coverage, in particular for the lower atmosphere and polar regions. An instrument on the ground or deployed on an aerial/sub-orbital platform provides the higher spatial (horizontal/vertical) and temporal resolution that is essential for characterising processes on local and regional scales and with diurnal variability. Many atmospheric trace gases, aerosols, and clouds of relevance to climate change, ozone layer recovery, urban pollution, and Earth sciences/volcanology can be measured using their unique infrared spectral signatures in particular in the atmospheric 'window' region, 8-12 microns. While Fourier transform spectrometers (FTS's) provide infrared observations with sufficiently broadband, multiplex frequency coverage to further our understanding of key atmospheric parameters and processes the complexity, size/mass, limited robustness, reliability issues, and cost of high-resolution systems limit their wider deployment. Laser heterodyne radiometers (LHRs) are passive remote sensing instruments which combine high spectral resolution, high spatial resolution, high sensitivity, and compact size. An ultra-wideband laser heterodyne radiometer (UB-LHR) covering the atmospheric 'window' spectral region, 8-12 microns, now promises to offer the measurement performance of high-resolution FTS but in a smaller, more robust, and lower cost instrument. This proposal aims to characterise in the laboratory the performance of an ultra-wideband LHR (UB-LHR) incorporating for the first time a widely-tunable external-cavity quantum cascade laser obtained through collaboration with Princeton University. Although the LHR measurement principle is established, changing to a substantially-different laser source is a radical departure that requires proof-of-concept work. UB-LHR capabilities will be demonstrated through measurements from the ground of both passive atmospheric emission and infrared solar radiation transmitted through the atmosphere, directly from the sun or reflected from the moon (lunar occultation) for night-time/polar winter observations. The instrument performance will be pitched against the World's highest resolution, commercially-available FTS. From these measurements information about the vertical distribution of a range of trace gas species may be retrieved from inverting the pressure- and temperature- dependent absorption line shapes . It is anticipated that the measurement time required for all the target species will be ten minutes or less, allowing observation of highly dynamic phenomena involving O3 and H2O, e.g. in the upper troposphere-lower stratosphere (UTLS) region.