Developing a large-scale dataset of flood fatalities for territories in the Euro-Mediterranean region, FFEM-DB

A synergistic approach towards understanding flood risks over coastal multi-hazard environments: Appraisal of bivariate flood risk mapping through flood hazard, and socio-economic-cum-physical vulnerability dimensions

The dynamics of flood risk over Coastal Multi-hazard Catchments (CMC) exhibit bizarre characteristics. In these regions, flood hazards are governed by a complex interaction of multiple flood-inducing sources; varying in magnitudes, origin, and direction of propagation. Our conventional understanding of vulnerability may be obscure within these catchments. This can be attributable to the heterogeneous nature of various physical and socio-economic entities. The study proposes a comprehensive framework to quantify bivariate flood risks over a severely flood-prone region in India. The study considers flood hazards, along with vulnerabilities transpiring from (a) physical, (b) socio-economic, and (c) composite (combination of both) groups of indicators. To overcome data scarcity prevalent in CMCs, CHIRPS v2.0, a high-resolution Satellite Precipitation Product, along with other ancillary datasets, are forced to 1D2D coupled MIKE+ hydrodynamic model to simulate flood hazards. A set of 24 indicators are considered within the Shannon Entropy-cum-TOPSIS framework to derive three types of vulnerability. The marginal and compound contributions of hazard and each vulnerability type are represented through a novel concept of bivariate flood risk classifier at the village scale. We notice high and very-high flood hazards over the coastline and floodplains. An equitable influence of socio-economic vulnerability and hazards is reflected, as they cover 41 % of villages together under varied degrees of flood risks. The impacts of hazards are underscored in the presence of physical vulnerability, as the latter contributes to risks in about 72 % of villages. Composite vulnerability prevails its impact over 53 % of villages, dominating its influence on flood risks over hazards. The study delivers vital information to the global flood management community on the prudent selection of indicators, as their influence is markedly noticed on the overall flood risks. The diversified characteristics of flood risk inspire a rationalized implementation of structural and non-structural options in resource-constrained conditions.

Marine heat waves: Characterizing a major climate impact in the Mediterranean

Marine heat waves (MHW), considered as persistent and spatially extensive sea surface temperature (SST) anomalies, have emerged as one of the global change-induced high impact events on the oceans. The study of MHWs received significant progress in recent years, although many unknowns remain. One of the most notable weaknesses is related to the absence of a universally established definition that would allow better intercomparison of results. It is our aim to contribute to this debate by considering the spatial extent to define a MHW. By applying this hypothesis to a relatively small, but complex, basin such as the Mediterranean, MHWs have been characterized and long-term trends assessed from SST satellite data analysis. Our results show that the inclusion of a minimum area threshold, 5 % of the area basin, greatly reduces the population of MHW events by not considering local SST anomalies that do not constitute a MHW event. A trend to more frequent, intense, and longer MHWs is found in the 1982-2021 period in the Mediterranean. In the spatial characterization and long-term trend analysis, regional differences were apparent. Results evidenced variations in MHWs characteristics and trends across the different sub-basins evidencing the fact that, even in a relatively small basin such as the Mediterranean, significant regional differences make it necessary to include a spatial perspective in the studies, beyond purely local analysis at each observation point in a large basin or even in the global ocean. Regarding the characterization of MHWs and trend analysis in the Mediterranean basin, a growing trend has been found in terms of frequency, duration, and intensity that accelerated since 2000 and especially in the last decade, pointing not just to a steady intensification and higher frequency of MHWs but to the emergence of a new set of more intense, long-lasting and spatially extensive MHWs in the recent years.