What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean
The Mediterranean region is particularly exposed to heavy precipitation and flash flooding. Every autumn the region is affected by these weather-related hazards, frequently with immense costly and deadly consequences. What makes an already potentially damaging period in terms of heavy precipitation,...
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| Format: | Article |
| Language: | English |
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Elsevier
2022-12-01
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| Series: | Weather and Climate Extremes |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S221209472200072X |
| _version_ | 1818065821301211136 |
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| author | Samira Khodayar Francisco Pastor Jose Antonio Valiente Pau Benetó Florian Ehmele |
| author_facet | Samira Khodayar Francisco Pastor Jose Antonio Valiente Pau Benetó Florian Ehmele |
| author_sort | Samira Khodayar |
| collection | DOAJ |
| description | The Mediterranean region is particularly exposed to heavy precipitation and flash flooding. Every autumn the region is affected by these weather-related hazards, frequently with immense costly and deadly consequences. What makes an already potentially damaging period in terms of heavy precipitation, even more intense? This is the underlying question in this study, in which the atmosphere and the ocean conditions in October 2018 are examined to identify anomalies favoring this intensification. Furthermore, the model representativity of the over-averaged precipitation period and underlying anomalies is analyzed across scales using climatological, seasonal, and event-based COSMO high-resolution model simulations.Our investigation shows that October-2018, in the context of the climatological series from 1982 to 2018, could be marked as an unprecedented period because of the presence of intense and numerous low-pressure systems. Additionally, atmospheric moisture values placed this time above the climatological average, mainly for the high percentiles of the TCWV hourly anomalies. Specific humidity showed similar behaviour as TCWV except for pressure levels lower than 700 hPa, probably in relation to the evolution of the former Hurricane Leslie. The atmosphere-ocean interaction presented combined strong sea surface temperature (SST) and evaporation anomalies. April to October SST clearly exceeds climatological values while October-2018 presents both strong monthly anomaly and intense evaporation peaks preceding the most intense precipitation events. These large-scale features’ anomalies were in general well captured by the high-resolution regional climate model simulations at climatic and seasonal scales leading to an accurate representation of accumulated precipitation for the October period. However, the numerical weather prediction simulations on an event scale revealed low predictability, in agreement with former investigations, due to differences at the location and intensity of the cut-off lows and particularly at the atmospheric moisture field.The conclusions of this study show that it is not the most extreme period in terms of single anomalies which lead to extreme wet seasons, but the synergy of atmospheric and oceanic anomaly conditions with a constant interplay which made Autumn/October 2018 an extreme season/month. |
| first_indexed | 2024-12-10T14:57:59Z |
| format | Article |
| id | doaj.art-28fa28fea19d4a2186d5535e6a2b2017 |
| institution | Directory Open Access Journal |
| issn | 2212-0947 |
| language | English |
| last_indexed | 2024-12-10T14:57:59Z |
| publishDate | 2022-12-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Weather and Climate Extremes |
| spelling | doaj.art-28fa28fea19d4a2186d5535e6a2b20172022-12-22T01:44:15ZengElsevierWeather and Climate Extremes2212-09472022-12-0138100493What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western MediterraneanSamira Khodayar0Francisco Pastor1Jose Antonio Valiente2Pau Benetó3Florian Ehmele4Mediterranean Centre for Environmental Studies (CEAM), Valencia, Spain; Corresponding author. Mediterranean Centre for Environmental Studies (CEAM), Parque Tecnológico, Charles R. Darwin Street, 14 46980, Paterna, Valencia, Spain.Mediterranean Centre for Environmental Studies (CEAM), Valencia, SpainMediterranean Centre for Environmental Studies (CEAM), Valencia, SpainMediterranean Centre for Environmental Studies (CEAM), Valencia, SpainInstitute of Meteorology and Climate Research (IMK-TRO), Karlsruhe Institute of Technology (KIT), Karlsruhe, GermanyThe Mediterranean region is particularly exposed to heavy precipitation and flash flooding. Every autumn the region is affected by these weather-related hazards, frequently with immense costly and deadly consequences. What makes an already potentially damaging period in terms of heavy precipitation, even more intense? This is the underlying question in this study, in which the atmosphere and the ocean conditions in October 2018 are examined to identify anomalies favoring this intensification. Furthermore, the model representativity of the over-averaged precipitation period and underlying anomalies is analyzed across scales using climatological, seasonal, and event-based COSMO high-resolution model simulations.Our investigation shows that October-2018, in the context of the climatological series from 1982 to 2018, could be marked as an unprecedented period because of the presence of intense and numerous low-pressure systems. Additionally, atmospheric moisture values placed this time above the climatological average, mainly for the high percentiles of the TCWV hourly anomalies. Specific humidity showed similar behaviour as TCWV except for pressure levels lower than 700 hPa, probably in relation to the evolution of the former Hurricane Leslie. The atmosphere-ocean interaction presented combined strong sea surface temperature (SST) and evaporation anomalies. April to October SST clearly exceeds climatological values while October-2018 presents both strong monthly anomaly and intense evaporation peaks preceding the most intense precipitation events. These large-scale features’ anomalies were in general well captured by the high-resolution regional climate model simulations at climatic and seasonal scales leading to an accurate representation of accumulated precipitation for the October period. However, the numerical weather prediction simulations on an event scale revealed low predictability, in agreement with former investigations, due to differences at the location and intensity of the cut-off lows and particularly at the atmospheric moisture field.The conclusions of this study show that it is not the most extreme period in terms of single anomalies which lead to extreme wet seasons, but the synergy of atmospheric and oceanic anomaly conditions with a constant interplay which made Autumn/October 2018 an extreme season/month.http://www.sciencedirect.com/science/article/pii/S221209472200072XExtreme weatherHeavy precipitationMediterraneanLarge-scale conditionsSSTHigh-resolution modelling |
| spellingShingle | Samira Khodayar Francisco Pastor Jose Antonio Valiente Pau Benetó Florian Ehmele What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean Weather and Climate Extremes Extreme weather Heavy precipitation Mediterranean Large-scale conditions SST High-resolution modelling |
| title | What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean |
| title_full | What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean |
| title_fullStr | What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean |
| title_full_unstemmed | What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean |
| title_short | What causes a heavy precipitation period to become extreme? The exceptional October of 2018 in the Western Mediterranean |
| title_sort | what causes a heavy precipitation period to become extreme the exceptional october of 2018 in the western mediterranean |
| topic | Extreme weather Heavy precipitation Mediterranean Large-scale conditions SST High-resolution modelling |
| url | http://www.sciencedirect.com/science/article/pii/S221209472200072X |
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