Almost all active caldera volcanoes host hydrothermal systems that circulate a mixture of seawater, meteoric water and magmatic fluids through the subsurface geology to seeps or vents on the seafloor. These fluids can explosively interact with magma in volcanic eruptions and can change the physical properties of their host rocks, influencing both the likelihood of eruptions occurring and their explosivity. The nature of these interactions is poorly understood, including how fluid flow changes during periods of magmatic intrusion, how the hydrothermal system connects magmatic fluids to the surface and the spatial distribution and extent of alteration/mineralisation. While we know hydrothermal fluid flow plays an important role in modulating eruption dynamics, as long as these fundamental knowledge gaps exist it is impossible to forecast, with any degree of accuracy, what this effect will be which makes understanding hazards and impacts in eruption scenarios difficult. In this proposal we will combine novel controlled source electromagnetic mapping of porosity and permeability, with passive seismic mapping of hydrothermal fluid flow in the shallow subsurface, constrained by heat flow measurements and surface and subsurface sampling to characterise the porosity and permeability of the Santorini hydrothermal system. Santorini has been selected as the ideal natural laboratory to test these relationships because it is exceptionally well characterised geophysically and geologically, has a diversity of hydrothermal vents and has experienced recent activity which can be used to test modelling. We will quantify how magmatic fluids are partitioned between vents to identify the primary pathways for magmatic volatile escape, and quantify the impact hydrothermal mineralisation has had on the physical strength of the seafloor. Once we have a full picture of the system in its current state we will use mapping, fluid inclusions, mineralogy and the sedimentary record to establish how vent locations, subsurface fluid pathways, and fluid fluxes, temperatures and chemistries responded to the 2011/12 period of unrest. These data will be used to constrain the boundary conditions for a hydrothermal system model, which can be used to predict how the system will respond to future periods of intrusion both at Santorini and at other caldera systems around the world. This project will provide a step change in our understanding of hydrothermal interactions with volcanoes and our ability to predict their response to changes in the magmatic system. This has implications not just for understanding volcanic eruptions, but also for understanding metal and volatile fluxes from the mantle to the ocean and atmosphere, the development of economic metal deposits in these systems, the impact on ecological communities of intrusive and extrusive volcanic events, geothermal energy production, and for hazard forecasting and mitigation. The project will push the frontiers of knowledge by combining cutting edge geophysical and geochemical techniques to produce a model of a caldera hydrothermal system at a resolution previously not possible, and by developing modelling tools that would allow the application of these findings to other systems. The project is ambitious but achievable and benefits from a large team of international expert proponents, partnerships with other large international projects and high-quality pre-existing data upon which to build.

The atmosphere changes on time scales from seconds (or less) through to years. An example of the former are leaves swirling about the ground within a dust-devil, while an example of the latter is the quasibiennial oscillation (QBO) which occurs over the equator high up in the stratosphere. The QBO is seen as a slow meander of winds: from easterly to westerly to easterly over a time scale of about 2.5 years. This 'oscillation' is quite regular and so therefore is predictable out from months through to years. These winds have also been linked with weather events in the high latitude stratosphere during winter, and also with weather regimes in the North Atlantic and Europe. It is this combination of potential predictability and the association with weather which can affect people, businesses and ultimately economies which makes knowing more about these stratospheric winds desirable. However, it has been difficult to get this phenomenon reproduced in global climate models. We know that to get these winds in models one needs a good deal of (vertical) resolution. Perhaps better than 600-800m vertical resolution is needed. In most GCMs with a QBO this is the case, but why? We also know that there needs to be waves sloshing about, either ones that can be 'seen' in the models, or wave effects which are inferred by parameterisations. Get the right mix of waves and you can get a QBO. Get the wrong mix and you don't. Again we do not know entirely why. Furthermore, we also know convection bubbling up over the tropics and the slow migration of air upwards and out to the poles also has a big impact of resolving the QBO. All of these factors need to be constrained in some way to get a QBO. The trouble is that these factors are invariably different in different climate models. It is for this reason that getting a regular QBO in a climate model is so hard. This project is interested in exploring the sensitivity of the QBO to changes in resolution, diffusion and physics processes in lots of climate models and in reanalyses (models used with observations). To achieve this, we are seeking to bring together all the main modelling centres around the world and all the main researchers interested in the QBO to explore more robust ways of modelling this phenomena and looking for commonalities and differences in reanalyses. We hope that by doing this, we may get more modelling centres interested and thereby improve the number of models which can reproduce the QBO. We also hope that we can get a better understanding of those impacts seen in the North-Atlantic and around Europe and these may affect our seasonal predictions. The primary objective of QBOnet is to facilitate major advances in our understanding and modelling of the QBO by galvanizing international collaboration amongst researchers that are actively working on the QBO. Secondary objectives include: (1) Establish the methods and experiments required to most efficiently compare dominant processes involved in maintaining the QBO in different models and how they are modified by resolution, numerical representation and physics parameterisation. (2) Facilitate (1) by way of targeted visits by the PI and researchers with project partners and through a 3-4 day Workshop (3) Setup and promote a shared computing resource for both the QBOi and S-RIP QBO projects on the JASMIN facility

Plate tectonics is a fundamental theory for explaining earthquakes, volcanoes, crustal deformation and therefore the motion at the Earth's surface. However very little is known about how destructive plate boundaries initiate, evolve and end. This is central to plate tectonics, as it is thought that the dominant driving force of plate motions is the gravitational pull of subducting plates. In the Solomon Islands and Papua New Guinea, the Pacific and Australian plates are converging. In the north one subduction zone is nearing the end of its life cycle as anomalously buoyant oceanic plate is stalling subduction. To the south in the San Cristobal Trench, a new subduction zone has initiated in response to continued convergence of the Pacific and Australian plates, making this the perfect place to understand subduction initiation and cessation. In this urgency proposal we will deploy seismometers for 1 year to record aftershocks from sequence of 4 major earthquakes with magnitudes between 7.1-7.6. These recordings and other recordings of earthquakes from around the globe will allow us to delineate with high accuracy the plate interfaces of the new and old subducting slabs and image the slab structures at depth. The structure of the old and new subduction zones will illuminate the processes occurring at depth which are shifting the force balance in the region to reverse the sense of subduction. The proposed experiment will be enhanced by concurrent studies scheduled to be deployed in Fall of 2014, which includes a multimillion pound ocean bottom seismic deployment by colleagues in Japan. The combined array will allow us to image the Pacific plate which is stalling the subduction, allowing us to investigate what conditions are necessary for a plate to halt the descent of the slab into the mantle. Thus we will be able to understand how subduction stops and starts.

The West Antarctic Ice Sheet contains enough ice to cause 3.3 meters of sea level rise. The ice streams of its Amundsen Sea sector, which alone could contribute up to 1.2 meters of sea level rise, are thinning faster than in any other region on earth, and have the potential for rapid collapse due to inland-deepening bedrock. Using a combination of novel inverse modelling, a comprehensive ice-sheet model, and remote sensing we will: 1) Estimate the present state of the critical Amundsen sector 2) Predict its future behaviour 3) Quantify the uncertainty of these estimates and predictions The physics of ice-sheet retreat is qualitatively understood, but the detailed behaviour is dependent upon a very large number of parameters that cannot be measured directly (e.g, spatially-varying basal traction and ice stiffness). However, numerical ice sheet models have now evolved to the point where a number of relevant physical processes, such as grounding line movement and ice-sheet response to ocean forcing, can be represented accurately. Moreover, the satellite-observational record continues to grow, creating opportunities for assimilation of this new data into models. Such a model-data synthesis can allow key underlying and hidden physical parameters to be determined, facilitating data-driven prediction of future ice-sheet contribution to sea levels. However, techniques for the assimilation of data using ice sheet models remain at an early stage. A considerable amount of data remains unused and fundamental questions, such as the specific information required for reliable predictions, remain unanswered. Moreover, model simulations of future behaviour of ice sheets generally do not account for the uncertainty inherent in estimates of hidden parameters, which can potentially grow with forecast horizons. Accounting for these uncertainties is vital so that informed risk and cost-benefit analyses of sea-level rise protection and adaptation can be carried out. In the proposed project we will develop a model-based framework which will efficiently assimilate the data record for the Amundsen sector (Fig. 1), providing estimates of key physical quantities, and predictions of future behaviour. Crucially, measures of uncertainty will be provided for the estimate and predictions. We will further study the impact that different observations have on our model predictions and uncertainty therein, providing information that will be of value to future observational campaigns. While the Amundsen region is chosen as a focus in the interest of critical relevance and timeliness, the methodology can be applied more generally in other regions of Antarctica, or Greenland.

Antarctica is changing. In February 2022, sea ice around Antarctica reached the lowest area that has been observed since satellite records began in 1979. This marks the first time that the area of sea ice ice has been observed to shrink below 2 million square kilometres. Compared to the average minimum, the 2022 February minimum is missing an area of sea ice that is about three and a half times the size of the UK. Directly following on from the sea ice minimum, in March 2022 record air temperatures were recorded across much of East Antarctica, with some meteorological stations observing temperatures 40C warmer than normal. These unprecedented conditions were associated with a very intense 'atmospheric river', a narrow corridor of warm water vapour, bringing warm air and moisture to the high Antarctic Plateau. We do not know whether these extreme regional climatic events are just 'one offs', and highly unlikely to occur again, or whether they are an indication of how Antarctic climate will develop in the future. These recent extreme weather events and conditions in Antarctica have prompted fresh concern about how climate change in this remote region will impact Earth. The protection of coastlines around the world from the future rise in sea level from Antarctica requires a better understanding of how the weather of Antarctica will evolve over the coming century. Any loss of Antarctic ice mass as a result of weather changes may raise the sea level around the globe. SURFEIT will thus investigate how changing snow and radiation, or surface fluxes, over the coming century will affect Antarctic snow and ice. The international SURFEIT team will: (i) improve how polar clouds are represented in our climate models; (ii) use pre-existing, and new, observations alongside climate model output to help improve our understanding of changes in snowfall over Antarctica; (iii) ensure we can accurately predict small-scale and extreme-event weather changes; and (iv) improve how we link our earth and ice system model components together, so that we can make better predictions of when Antarctic ice may fracture, and so raise global sea level. Our work on improving snowfall and ice predictions will help us answer our overarching question 'How will changes in Antarctic surface fluxes impact global sea-level to 2100 and beyond?'