Convective activity in Catalonia (northeastern Spain) mainly occurs during summer and autumn, with severe weather occurring 33 days per year on average. In some cases, the storms have unexpected propagation characteristics, likely due to a combination of the complex topography and the thunderstorms’ propagation mechanisms. Partly due to the local nature of the events, numerical weather prediction models are not able to accurately nowcast the complex mesoscale mechanisms (i.e., local influence of topography). This directly impacts the retrieved position and motion of the storms, and consequently, the likely associated storm severity. Although a successful warning system based on lightning and radar observations has been developed, there remains a lack of knowledge of storm dynamics that could lead to forecast improvements. The present study explores the capabilities of the radar network at the Meteorological Service of Catalonia to retrieve dual-Doppler wind fields to study the dynamics of Catalan thunderstorms. A severe thunderstorm that splits and a tornado-producing supercell that is channeled through a valley are used to demonstrate the capabilities of an advanced open source technique that retrieves dynamical variables from C-band operational radars in complex terrain. For the first time in the Iberian Peninsula, complete 3D storm-relative winds are obtained, providing information about the internal dynamics of the storms. This aids in the analyses of the interaction between different storm cells within a system and/or the interaction of the cells with the local topography.
<p>The Mediterranean region is a hot spot for climate and environmental changes (Cramer et al., 2018). Climate change rates currently observed and expected in future scenarios in this region, exceed the global trends for most variables. Particularly, the average annual mean temperature has risen by 1.4&#176;C since the pre-industrial times and it is expected that it could increase more than 1&#176;C before the end of the century. The Mediterranean coastal zone comprises 75 coastal watersheds and 224 coastal administrative regions, with a total of 46,000 km of coastline. &#160;This coastal zone concentrates about the 50 % of the population of the Mediterranean region while also attracts millions of tourists, supports a large network of infrastructures and, also, supports a large set of coastal and marine ecosystems delivering valuable services.</p><p>Regional climatic and geographical characteristics determine the area to be frequently affected by multiple hydrometeorological hazards such as thunderstorms, floods, windstorms and marine storms. These hazards together with the existence of high values at exposure determine the Mediterranean coastal fringe to be highly vulnerable and subjected to a high risk to the impact of extreme events, which will likely be worsened due to climate change (IPCC, 2018). Due to this, long-term planning of these coastal areas requires a proper assessment of their vulnerability and risk. Usually, this has been done by considering these hazards in an independent manner, although it is clear that a more holistic and integrated approach considering their&#160; interdependencies and feedbacks is needed.</p><p>Within this context, this work &#160;proposes an integrated risk index to classify the Mediterranean coastal municipalities in terms of their susceptibility to be affected by multiple hydrometeorological hazards, which will be later integrated with a similar index for marine &#160;hazards. The index will be tested for a representative Mediterranean coastal area highly affected by hydrometeorological and marine hazards, the Catalonia and Valencia coastal zone (NE Spanish Mediterranean). The indicators represent different system characteristics determining the expected risk: a) climatic, b) geomorphological and &#160;c) impact and perception components. The selected climatic indicators used have been: return period of precipitation, number of lightning strikes and maximum wind speed. Geomorphological indicators include average slope of the catchment area and surface within the municipality. Socioeconomic indicators have been estimated from the economical compensations paid by the Consorcio de Compensaci&#243;n de Seguros (the National insurance company), number of flood events that have affected each municipality estimated from their impact, and population awareness and social impact measured through analysing response in social media (tweets) to the impact of these hazards. Finally, as a matter of validation, the impact of the last flood events affecting this region is compared with the spatial distribution of the developed index.</p><p>This work has been developed in the framework of the M-CostAdapt project (FEDER/MCIU-AEI/CTM2017-83655-C2-2-R) where &#160;the adaptability to Climate Change and natural risks of the Mediterranean coast is analysed by jointly considering natural maritime and terrestrial (hydrometeorological) hazards.</p>
<p>Lake Victoria is the largest freshwater lake in Africa, supporting the livelihood of more than 5 million people subsisting on its prosperous fishing industry and agriculture.&#160;However, the lake&#8217;s surrounding complex topography and geographic location makes this one of the deadliest regions of the world when it comes to weather-related accidents. It is estimated that more than 1,000 fishermen die yearly due to high waves produced by severe convective wind phenomena. Furthermore, severe hailstorms and flood-producing heavy rain events have increased in recent years in the extended East Africa (EA) regions, unfortunately also reporting several fatalities.&#160;</p> <p>In 2017, the World Meteorological Organization (WMO) launched the 3-year &#8220;High impact weather lake System&#8221; (HIGHWAY) project, with the main objective to reduce the loss of lives and goods in the lake basin and to improve resilience for the local communities. The project included a field campaign in 2019 to provide forecasters with high-resolution observations and to study the storm life cycle on the lake basin, with the utilization of S- and C-band dual-polarization radars in the surrounding countries.&#160;In this study, we use the high spatiotemporal resolution radar data from the field campaign in 2019 to investigate severe convection over the lake. We analyze two severe storms affecting the south and north shores of the lake (Tanzania and Uganda, respectively), identifying polarimetric signatures indicating severe weather, and testing the current capabilities of the radars&#8217; scanning strategies. The results presented here are part of the ongoing high impact weather forecasting trainings and advancement efforts for East African countries towards the WMO Early Warning and Early Action 2025 goal, with a joint effort between WMO-led international projects, the National Center for Atmospheric Research, international non-profit organizations, and the National Meteorological and Hydrological Services in EA countries.</p>
Hydrometeorological risks are the most important natural hazard in the world. Among them, flood risk is the one that affects more population and causes the greatest damages. Their mitigation and adaptation to the impact that climate change has on them is a priority in most government agendas. However, recent reports and papers still show significant uncertainty associated with their future development. Uncertainty is still higher when we consider the interaction with society and the changes in vulnerability. Therefore, they need to be treated from a holistic perspective that integrates bottom-up (from impact and vulnerability) and top-down (from hazard) approaches in the same methodology. Besides this, the Hyogo and Sendai protocols developed by UNISDR insist in the development of adaptation measures through the improvement in risk awareness and resilience. This communication shows a holistic approach to cope with flood risk in adaptation planning, the different tools and procedures for a better empowerment of the population, and the limits of the different adaptation measures when the impact of climate change is considered. The study is focused in Catalonia located in the east of the Iberian Peninsula.
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