ORCID Profile
0000-0002-1051-8749
Current Organisation
University of Southampton
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Publisher: American Meteorological Society
Date: 07-2015
DOI: 10.1175/BAMS-D-13-00212.1
Abstract: Understanding observed changes to the global water cycle is key to predicting future climate changes and their impacts. While many datasets document crucial variables such as precipitation, ocean salinity, runoff, and humidity, most are uncertain for determining long-term changes. In situ networks provide long time series over land, but are sparse in many regions, particularly the tropics. Satellite and reanalysis datasets provide global coverage, but their long-term stability is lacking. However, comparisons of changes among related variables can give insights into the robustness of observed changes. For ex le, ocean salinity, interpreted with an understanding of ocean processes, can help cross-validate precipitation. Observational evidence for human influences on the water cycle is emerging, but uncertainties resulting from internal variability and observational errors are too large to determine whether the observed and simulated changes are consistent. Improvements to the in situ and satellite observing networks that monitor the changing water cycle are required, yet continued data coverage is threatened by funding reductions. Uncertainty both in the role of anthropogenic aerosols and because of the large climate variability presently limits confidence in attribution of observed changes.
Publisher: Wiley
Date: 12-10-2011
Publisher: IOP Publishing
Date: 06-2023
Abstract: Climatic and anthropogenic changes appear to be driving the emergence of new ecosystem and human health risks. As new risks emerge, and the severity or frequency of known risks change, we ask: what evidence is there of past adaptations to emergent risks? What scientific and policy processes lead to adaptive solutions that minimise the impacts of these events, and draw out opportunities? We identify science and policy lessons learned from coping with, and responding to, the sudden arrival of brown macroalgae (pelagic sargassum) that has proliferated across the tropical Atlantic since 2011. Drawing on an evidence base developed from a systematic search of literature relating to sargassum seaweed, and using event timelines and word clouds, we provide an analysis of lessons learned from a case study of adaptive responses across three continents to an emergent risk over the course of a decade. We reflect on successes and failures as well as opportunities taken in building adaptive capacity to address the risk in four key domains: policy, knowledge and evidence, monitoring and early warning, and technology and valorisation. Failures include: lack of environmental risk registries missed opportunities to share monitoring data and lack of a shared approach to manage the risk. Successes include: development of national management strategies open-access knowledge hubs, networks and webinars sharing information and best practice semi-operational early advisory systems using open access remote sensing data numerous innovations customising clean-up and harvesting equipment, and research and development of new uses and value-added products.
Publisher: Springer Science and Business Media LLC
Date: 22-04-2014
DOI: 10.1038/NCOMMS4660
Abstract: Pumice rafts are floating mobile accumulations of low-density pumice clasts generated by silicic volcanic eruptions. Pumice in rafts can drift for years, become waterlogged and sink, or become stranded on shorelines. Here we show that the pumice raft formed by the impressive, deep submarine eruption of the Havre caldera volcano (Southwest Pacific) in July 2012 can be mapped by satellite imagery augmented by sailing crew observations. Far from coastal interference, the eruption produced a single km 2 raft in 1 day, thus initiating a gigantic, high-precision, natural experiment relevant to both modern and prehistoric oceanic surface dispersal dynamics. Observed raft dispersal can be accurately reproduced by simulating drift and dispersal patterns using currents from an eddy-resolving ocean model hindcast. For future eruptions that produce potentially hazardous pumice rafts, our technique allows real-time forecasts of dispersal routes, in addition to inference of ash umice deposit distribution in the deep ocean.
Publisher: Springer Science and Business Media LLC
Date: 09-12-2016
DOI: 10.1038/SREP38752
Abstract: A change in the cycle of water from dry to wet regions of the globe would have far reaching impact on humanity. As air warms, its capacity to hold water increases at the Clausius-Clapeyron rate (CC, approximately 7% °C −1 ). Surface ocean salinity observations have suggested the water cycle has lified at close to CC following recent global warming, a result that was found to be at odds with state-of the art climate models. Here we employ a method based on water mass transformation theory for inferring changes in the water cycle from changes in three-dimensional salinity. Using full depth salinity observations we infer a water cycle lification of 3.0 ± 1.6% °C −1 over 1950–2010. Climate models agree with observations in terms of a water cycle lification (4.3 ± 2.0% °C −1 ) substantially less than CC adding confidence to projections of total water cycle change under greenhouse gas emission scenarios.
Publisher: The Royal Society
Date: 08-02-2012
Abstract: For many species, there is broad-scale dispersal of juvenile stages and/or long-distance migration of in iduals and hence the processes that drive these various wide-ranging movements have important life-history consequences. Sea turtles are one of these paradigmatic long-distance travellers, with hatchlings thought to be dispersed by ocean currents and adults often shuttling between distant breeding and foraging grounds. Here, we use multi-disciplinary oceanographic, atmospheric and genetic mixed stock analyses to show that juvenile turtles are encountered ‘downstream’ at sites predicted by currents. However, in some cases, unusual occurrences of juveniles are more readily explained by storm events and we show that juvenile turtles may be displaced thousands of kilometres from their expected dispersal based on prevailing ocean currents. As such, storms may be a route by which unexpected areas are encountered by juveniles which may in turn shape adult migrations. Increased stormy weather predicted under climate change scenarios suggests an increasing role of storms in dispersal of sea turtles and other marine groups with life-stages near the ocean surface.
Publisher: Inter-Research Science Center
Date: 21-06-2012
DOI: 10.3354/MEPS09581
Publisher: American Meteorological Society
Date: 15-12-2015
Abstract: The global water cycle leaves an imprint on ocean salinity through evaporation and precipitation. It has been proposed that observed changes in salinity can be used to infer changes in the water cycle. Here salinity is characterized by the distribution of water masses in salinity coordinates. Only mixing and sources and sinks of freshwater and salt can modify this distribution. Mixing acts to collapse the distribution, making saline waters fresher and fresh waters more saline. Hence, in steady state, there must be net precipitation over fresh waters and net evaporation over saline waters. A simple model is developed to describe the relationship between the breadth of the distribution, the water cycle, and mixing—the latter being characterized by an e-folding time scale. In both observations and a state-of-the-art ocean model, the water cycle maintains a salinity distribution in steady state with a mixing time scale of the order of 50 yr. The same simple model predicts the response of the salinity distribution to a change in the water cycle. This study suggests that observations of changes in ocean salinity could be used to infer changes in the hydrological cycle.
Publisher: Springer Science and Business Media LLC
Date: 03-11-2011
Publisher: Springer Science and Business Media LLC
Date: 05-09-2015
Publisher: American Geophysical Union (AGU)
Date: 02-03-2020
DOI: 10.1029/2019GL086768
Publisher: Springer Science and Business Media LLC
Date: 19-07-2012
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2014
End Date: 2017
Funder: Natural Environment Research Council
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