40 Projects, page 1 of 8
This proposal will develop new methodology for summarising the spatial information obtained from analysing multiple time series of spatial trajectories. The project will involve adapting recent methodology by the applicants for the analysis of single time series trajectories, to develop the coherent analysis of multiple trajectories observed in a given spatial region. From these advances, summaries of regional spatial structure will be proposed, as well as methods for assessing the uncertainty inherent to such summaries. In particular, as a testbed, such will be implemented for regional sets of oceanographic observations from the Global Drifter Program, which contributes to providing deeper understanding of ocean circulation and its impact on climate change. The main scope of this proposal is therefore to test the feasibility of aggregate statistical analysis of the spatial information contained in multiple sets of trajectory observations. It is an ambitious research project which, if successful, would open the door to a wide set of applications such as ecology, oceanography and traffic management.
Recent advances in global lightning detection have revealed that volcanic plumes rising to 10 km altitude and higher tend to generate lightning. Volcanic lightning is so common that volcano observatories and weather advisory centres around the globe have begun using it to detect eruptions in near-real-time. Only a few months ago, the eruption of a submarine volcano in Tonga produced more lightning than any single event yet documented, including the most severe storms on Earth. It is clear that volcanic plumes can sustain the conditions for extreme lightning production, yet much remains unknown about the relative roles of turbulent updrafts, particle collisions, and the freezing of water to ice. Data from lightning networks also hold important clues about how electrical charging in plumes makes the tiny rock particles (volcanic ash) stick together and form larger clusters. This aggregation process has profound effects on how long the ash remains aloft-where it threatens aircraft safety-and represents a major source of uncertainty in models of both ash hazard forecasts, and interpretations of eruption deposits in the geological record. Despite active and growing research interest in this field, the volcanic electrification process has never been modelled in a way that could be validated with the high-fidelity observations now available. The objective of this project is to develop the first field-tested numerical model of volcanic plume electrification. We propose to integrate two well-established codes from different scientific applications-the volcanic plume model known as ATHAM, and the electrification scheme from NOAA's National Severe Storms Laboratory storm module. Complementary work is being conducted as part of our ongoing NERC project on Radar-supported Next-Generation Forecasting of Volcanic Ash Hazard. Our overall aims are to create a robust numerical model of volcanic lightning and electrostatic ash aggregation that can be fine-tuned using observations from recent volcanic eruptions. These efforts will shed light on long-standing scientific challenges in the study of explosive eruption plumes and, more broadly, will expand our understanding of atmospheric electrification processes leading to the most powerful lightning storms on Earth.
We are all aware of how carbon emissions are leading to concern about a warming of the planet. In our view, the climate response to carbon emissions can be divided into the following stages: 1. Past and on going increases in atmospheric CO2 are leading to a global warming of up to 0.6C over the last 50 years. The regional variability is though much larger than this global signal. 2. Continuing emissions are increasing atmospheric CO2 and driving a heat flux into the ocean, leading to ocean warming. The amount of warming is sensitive to the carbon emission scenario, as well as the rate of carbon uptake by the ocean and terrestrial system. 3. The regional distribution of warming and carbon drawdown is sensitive to how the ocean interior takes up heat and carbon, involving the transfer of surface properties into the thermocline and deep ocean. 4. In the future, after emissions cease may be after many hundreds of years, the atmosphere and ocean will approach an equilibrium with each other. At this point, the final atmospheric CO2 and the amount of climate warming is simply related to cumulative sum of all the previously carbon emitted. One of the key findings of the latest IPCC report is how climate model projections suggest that global warming varies nearly linearly with cumulative carbon emissions. This response is not fully explained or understood, in terms of the essential underlying mechanisms or why different climate models reveal a different amount of warming to each other. We have established a new theory to explain how surface warming varies in time with carbon emissions. The aim of the proposal is to investigate the climate warming in the following manner: (i) apply our new theory of how surface warming compares to cumulative carbon emissions, modified from an equilibrium response by the transient uptake of heat and carbon by the ocean and terrestrial systems; (ii) conduct diagnostics of how the ocean is taking up heat, examining how the ocean is ventilated in terms of volumetric changes in ocean density classes; (iii) develop ocean ventilation experiments with a range of ocean and climate models on timescales of decades to a thousand years, designed to explore the extent that the ocean uptake of heat and carbon are similar to each other, and assess their partly compensating effects on how surface warming links to carbon emissions; (iv) compare with and analyse diagnostics of state of the art climate models, integrated for a century, including climate models driven by emissions, terrestrial uptake of heat and carbon, and radiative forcing from non-CO2 greenhouse gases and aerosols. Our new theoretical framework has the potential to provide (i) improved understanding of the mechanisms controlling the relationship between surface warming and carbon emissions, particularly focusing on the role of the ocean; (ii) traceability between different ocean and climate models, identifying clearly which factors are leading to different climate responses; (iii) reconcile Earth System model investigations over a wider parameter regime with IPCC class climate models. This study is relevant for policy makers interested in different energy policies, and a link to end users is provided via the collaboration with the Hadley Centre and NOAA GFDL. The study emphases the importance of engaging with the wider public by developing 4 targeted short and accessible videos on the climate problem, emphasising our new viewpoint.
RAPID-WATCH is providing a unique continuous observational time series of the Atlantic meridional overturning circulation (MOC) at 26 N for the first time. The crucial question in this proposal is the link between the MOC and meridional heat transport (MHT) from the RAPID-WATCH observing system and the variability of oceanic heat content in the whole of the North Atlantic inferred from Argo floats. We have strong evidence that the ocean heat content variability from seasonal to interannual time scales (months-10 years) is mainly in the upper 2000 m of the ocean, and therefore can be sampled using the Argo floats. Argo is an international experiment to measure the temperature and salinity of the upper 2000 m of the global ocean using over 3000 profiling floats. Understanding the links between the full depth monitoring of the MOC at 26 N and the heat content of the upper 2000m of the North Atlantic is important. For example, a decrease in heat transport at 26 N and a normal heat transport at the latitude of UK, would lead to cooling of the ocean between these two latitudes, which could influence the strength of westerly winds and alter the temperature and rainfall patterns over the UK and Northern Europe.
This project seeks to bring together UK, US and Australian scientists to establish a set of proto-operational tools for predicting and projecting stress on global coral reefs, and deliver a long-term partnership to provide coral reef managers with a step-change in decision-making support. Warm water corals are large colonies of individual organisms, coral polyps, which act as hosts to photosynthesising unicellular organisms known as zooxanthellae. The zooxanthellae and polyp symbiosis are mutually beneficial, with the zooxanthellae providing the polyp with oxygen and nutrients, and the polyps providing physical protection and supplying carbon dioxide from respiration. When stressed, zooxanthellae die or leave the polyp, in turn stressing the polyp, potentially leading to the coral's mortality (Baird and Marshall, 2002). Zooxanthellae are very sensitive to high temperatures, and while different zooxanthellae have different temperature thresholds (Hume et al., 2015), a simple metric known as Degree Heating Weeks has proved to be a very effective way of identifying when corals are likely to bleach (Skirving et al., 2019). For more than 20 years, Coral Reef Watch has utilized remote sensing, modelling and in-situ data to observe, predict and alert its users to coral reef threats worldwide. ~1,000 resource managers, scientists, elected officials, educators, and the public subscribe to Coral Reef Watch's automated satellite coral bleaching alert system. Coral Reef Watch's DHW based alerts allow reef managers to mitigate some of the worse effects of temperature extremes by guiding when they should be making in situ temperature measurements to identify if their reefs are under imminent threat, checking for initial evidence of bleaching, then protecting herbivore populations, protecting water quality and restricting development and recreational use of at-risk areas (https://www.coris.noaa.gov/activities/reef_managers_guide/welcome.html). Coral Reef Watch is made up of a world leading team of remote sensing scientists, biologists and ecologists. Their state-of-the-art tools have been built to take advantage of these expertise. As user requirements become increasingly sophisticated, and baselines shift in response to climate change, there is a need to move beyond what can be directly observed. This project builds a new partnership to bring climate and coastal modelling expertise and approaches into the Coral Reef Watch toolkit. This partnership will collaboratively generate and verify a large set of reduced-complexity coastal model simulations spanning the entirety of the global tropical oceans. These model simulations will provide not only semi-dynamical downscaling or future projections, but also, using state-of-the art atmospheric reanalyses, push back in time and supplement satellite observations with subsurface information. Working together this partnership will develop coral reef stress products based on this data, but will do so by building on the more than 20 years of experience NOAA Coral Reef Watch have in developing and distributing the results from such tools. Finally, this project will identify the optimal pathway for transition these new tools into operationally produced outputs delivered directly into the hands of managers and decision makers.