Assess the effect of heavy rainfall through the integration of remote sensing and in situ measurements

Abstract

In the context of climate change, extreme weather events are becoming increasingly frequent, and coastal regions are particularly vulnerable due to rising sea levels and the torrential rainfall characteristic of the Mediterranean climate, which has also made them vulnerable to flooding. The great flood produced by DANA1 (a “cold drop” that has commonly come to refer to any high impact rainfall event occurring in the autumn along the Mediterranean coast) on 10/29/2024 in the province of Valencia (Spain) highlights the need to improve knowledge of the factors that lead to torrential rainfall. The catastrophic events caused by the DANA (cold drop) on October 29, 2024, in Valencia (Spain) lead us to reflect on whether we are facing a trend toward extreme rainfall events never before seen. The mega-rainfalls of 10/29/24, as well as the resulting flooding, caused 228 deaths, as well as extraordinary economic damage. How could such a catastrophic outcome have occurred in a country like Spain with a long tradition of weather forecasting? Are we facing a mega-event, never seen before? The research has two main objectives. First, to model the extent of the rainfall that occurred on October 29, 2024, as well as the resulting floods (which caused 228 deaths), using information provided by Copernicus, as well as data provided by AVAMET (Valencian Meteorological Association) and AEMET (State Meteorological Agency of the Government of Spain). The integration of information provided by satellite sensors with that provided by on-site meteorological stations provides a detailed understanding of the extent and effects of the torrential rainfall that occurred in October 2024. Secondly, the research seeks to update the procedure for establishing return periods for extreme torrential rainfall in the study area. Climate change is accelerating extreme rainfall on the Spanish east coast (along with an increase in extreme drought periods). In theory, the rainfall of 11/29/2024 exceeded the estimated return period of more than 2,000 years. However, the calculation of return periods must be revised, taking into account the global warming process.

The authors would like to thank AEMET and AVAMET for providing the data that allowed this research to be carried out. They also thank Rafael Armengot (AVAMET), José Ángel Nuñez (AEMET Valencia), and Jorge Olcina (University of Alicante) for their comments.

Peer Reviewed

11 - Ciutats i Comunitats Sostenibles

13 - Acció per al Clima

3 - Salut i Benestar

Postprint (author's final draft)