Suchergebnisse

Abstract. In coastal regions, floods can arise through a combination of multiple
drivers, including direct surface run-off, river discharge, storm surge, and
waves. In this study, we analyse compound flood potential in Europe and
environs caused by these four main flooding sources using state-of-the-art
databases with coherent forcing (i.e. ERA5). First, we analyse the
sensitivity of the compound flooding potential to several factors: (1)
sampling method, (2) time window to select the concurrent event of the
conditioned driver, (3) dependence metrics, and (4) wave-driven sea level
definition. We observe higher correlation coefficients using annual maxima
than peaks over threshold. Regarding the other factors, our results show
similar spatial distributions of the compound flooding potential. Second, the
dependence between the pairs of drivers using the Kendall rank correlation
coefficient and the joint occurrence are synthesized for coherent patterns of
compound flooding potential using a clustering technique. This quantitative
multi-driver assessment not only distinguishes where overall compound flooding
potential is the highest, but also discriminates which driver combinations are
more likely to contribute to compound flooding. We identify that hotspots of
compound flooding potential are located along the southern coast of the North
Atlantic Ocean and the northern coast of the Mediterranean Sea.

Abstract. Coastal floods, driven by extreme sea levels, are one of the most dangerous
natural hazards. The people at highest risk are those living in low-lying
coastal areas exposed to tropical-cyclone-forced storm surges. Here we
apply a novel modelling framework to estimate past and/or present and future storm-surge-level and extreme-sea-level probabilities along the coastlines of southern
China, Vietnam, Cambodia, Thailand, and Malaysia. A regional hydrodynamic
model is configured to simulate 10 000 years of synthetic tropical cyclone
activity, representative of a past/present (1980–2017) and high-emission-scenario future (2015–2050) period. Results show that extreme storm surges, and therefore total water levels, will increase substantially in the coming decades, driven by an increase in the frequency of intense tropical
cyclones. Storm surges along the southern Chinese and northern and southern Vietnamese
coastlines increase by up to 1 m, significantly larger than expected changes in mean sea-level rise over the same period. The length of coastline that is presently exposed to storm surge levels of 2.5 m or greater will more than double by 2050. Sections of Cambodian, Thai, and Malaysian coastlines are projected to experience storm surges (at higher return periods) in the
future, not previously seen, due to a southward shift in tropical cyclone
tracks. Given these findings, coastal flood management and adaptation in
these areas should be reviewed for their resilience against future extreme
sea levels.

Autonomous Underwater Vehicles (AUVs) have a wide range of applications in marine geoscience, and are increasingly being used in the scientific, military, commercial, and policy sectors. Their ability to operate autonomously of a host vessel makes them well suited to exploration of extreme environments, from the world's deepest hydrothermal vents to beneath polar ice sheets. They have revolutionised our ability to image the seafloor, providing higher resolution seafloor mapping data than can be achieved from surface vessels, particularly in deep water. This contribution focuses on the major advances in marine geoscience that have resulted from AUV data. The primary applications are i) submarine volcanism and hydrothermal vent studies, ii) mapping and monitoring of low-temperature fluid escape features and chemosynthetic ecosystems, iii) benthic habitat mapping in shallow- and deep-water environments, and iv) mapping of seafloor morphological features (e.g. bedforms generated beneath ice or sediment-gravity flows). A series of new datasets is presented that highlight the growing versatility of AUVs for marine geoscience studies, including i) multi-frequency acoustic imaging of trawling impacts on deep-water coral mounds, iii) collection of high-resolution seafloor photomosaics at abyssal depths, and iii) velocity measurements of active submarine density flows. Future developments in AUV technology of potential relevance to marine geoscience include new vehicles with enhanced hovering, long endurance, extreme depth, or rapid response capabilities, while development of new sensors will further expand the range of geochemical parameters that can be measured.

Autonomous Underwater Vehicles (AUVs) have a wide range of applications in marine geoscience, and are increasingly being used in the scientific, military, commercial, and policy sectors. Their ability to operate autonomously of a host vessel makes them well suited to exploration of extreme environments, from the World's deepest hydrothermal vents to beneath polar ice sheets. They have revolutionized our ability to image the seafloor, providing higher resolution seafloor mapping data than can be achieved from surface vessels, particularly in deep water. This contribution focuses on the major advances in marine geoscience that have resulted from AUV data. The primary applications are i) submarine volcanism and hydrothermal vent studies, ii) mapping and monitoring of low-temperature fluid escape features and chemosynthetic ecosystems, iii) benthic habitat mapping in shallow- and deep-water environments, and iv) mapping of seafloor morphological features (e.g. bedforms generated beneath ice or sediment-gravity flows). A series of new datasets are presented that highlight the growing versatility of AUVs for marine geoscience studies, including i) multi-frequency acoustic imaging of trawling impacts on deep-water coral mounds, iii) collection of high-resolution seafloor photomosaics at abyssal depths, and iii) velocity measurements of active submarine density flows. Future developments in AUV technology of potential relevance to marine geoscience include new vehicles with enhanced hovering, long endurance, extreme depth, or rapid response capabilities, while development of new sensors will further expand the range of geochemical parameters that can be measured.