Coastal and orographic effects on extreme precipitation revealed by weather radar observations
<p>The yearly exceedance probability of extreme precipitation of multiple durations is crucial for infrastructure design, risk management, and policymaking. Local extremes emerge from the interaction of weather systems with local terrain features such as coastlines and orography; however, mult...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-03-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://hess.copernicus.org/articles/26/1439/2022/hess-26-1439-2022.pdf |
| _version_ | 1819153243029110784 |
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| author | F. Marra M. Armon M. Armon E. Morin |
| author_facet | F. Marra M. Armon M. Armon E. Morin |
| author_sort | F. Marra |
| collection | DOAJ |
| description | <p>The yearly exceedance probability of extreme precipitation of multiple durations is crucial for infrastructure design, risk management, and policymaking. Local extremes emerge from the interaction of weather systems with local terrain features such as coastlines and orography; however, multi-duration extremes do not follow exactly the patterns of cumulative precipitation and are still not well understood. High-resolution information from weather radars could help us quantify their patterns better, but traditional extreme value analyses based on radar records were found to be too inaccurate for quantifying the extreme intensities required for impact studies. Here, we propose a novel methodology for extreme precipitation frequency analysis based on relatively short weather radar records, and we use it to investigate the coastal and orographic effects on extreme precipitation of durations between 10 min and 24 h. Combining 11 years of radar data with 10 min rain gauge data in the southeastern Mediterranean, we obtain estimates of the once in 100 years precipitation intensities with <span class="inline-formula">∼26</span> % standard error, which is lower than those obtained using traditional approaches on rain gauge data. We identify the following three distinct regimes which respond differently to coastal and orographic forcing: short durations (<span class="inline-formula">∼10</span> min), related to peak convective rain rates, hourly durations (<span class="inline-formula">∼1</span> h), related to the yield of individual convective cells, and long durations (<span class="inline-formula">∼6</span>–24 h), related to the accumulation of multiple convective cells and to stratiform processes. At short and hourly durations, extreme return levels peak at the coastline, while at longer durations they peak corresponding to the orographic barriers. The distributions tail heaviness is rather uniform above the sea and rapidly changes in presence of orography, with opposing directions at short (decreasing tail heaviness, with a peak at hourly durations) and long (increasing) durations. These distinct effects suggest that short-scale hazards, such as urban pluvial floods, could be more of concern for the coastal regions, while longer-scale hazards, such as flash floods, could be more relevant in mountainous areas.</p> |
| first_indexed | 2024-12-22T15:02:05Z |
| format | Article |
| id | doaj.art-c8ce3340456c47bf8adbbbcf4cd5e310 |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-12-22T15:02:05Z |
| publishDate | 2022-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-c8ce3340456c47bf8adbbbcf4cd5e3102022-12-21T18:22:06ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382022-03-01261439145810.5194/hess-26-1439-2022Coastal and orographic effects on extreme precipitation revealed by weather radar observationsF. Marra0M. Armon1M. Armon2E. Morin3Institute of Atmospheric Sciences and Climate (CNR-ISAC), National Research Council of Italy, Bologna 40129, ItalyThe Fredy and Nadine Herrmann Institute of Earth Sciences, the Hebrew University of Jerusalem, Jerusalem, IsraelInstitute for Atmospheric and Climate Science, ETH Zurich, Zurich, SwitzerlandThe Fredy and Nadine Herrmann Institute of Earth Sciences, the Hebrew University of Jerusalem, Jerusalem, Israel<p>The yearly exceedance probability of extreme precipitation of multiple durations is crucial for infrastructure design, risk management, and policymaking. Local extremes emerge from the interaction of weather systems with local terrain features such as coastlines and orography; however, multi-duration extremes do not follow exactly the patterns of cumulative precipitation and are still not well understood. High-resolution information from weather radars could help us quantify their patterns better, but traditional extreme value analyses based on radar records were found to be too inaccurate for quantifying the extreme intensities required for impact studies. Here, we propose a novel methodology for extreme precipitation frequency analysis based on relatively short weather radar records, and we use it to investigate the coastal and orographic effects on extreme precipitation of durations between 10 min and 24 h. Combining 11 years of radar data with 10 min rain gauge data in the southeastern Mediterranean, we obtain estimates of the once in 100 years precipitation intensities with <span class="inline-formula">∼26</span> % standard error, which is lower than those obtained using traditional approaches on rain gauge data. We identify the following three distinct regimes which respond differently to coastal and orographic forcing: short durations (<span class="inline-formula">∼10</span> min), related to peak convective rain rates, hourly durations (<span class="inline-formula">∼1</span> h), related to the yield of individual convective cells, and long durations (<span class="inline-formula">∼6</span>–24 h), related to the accumulation of multiple convective cells and to stratiform processes. At short and hourly durations, extreme return levels peak at the coastline, while at longer durations they peak corresponding to the orographic barriers. The distributions tail heaviness is rather uniform above the sea and rapidly changes in presence of orography, with opposing directions at short (decreasing tail heaviness, with a peak at hourly durations) and long (increasing) durations. These distinct effects suggest that short-scale hazards, such as urban pluvial floods, could be more of concern for the coastal regions, while longer-scale hazards, such as flash floods, could be more relevant in mountainous areas.</p>https://hess.copernicus.org/articles/26/1439/2022/hess-26-1439-2022.pdf |
| spellingShingle | F. Marra M. Armon M. Armon E. Morin Coastal and orographic effects on extreme precipitation revealed by weather radar observations Hydrology and Earth System Sciences |
| title | Coastal and orographic effects on extreme precipitation revealed by weather radar observations |
| title_full | Coastal and orographic effects on extreme precipitation revealed by weather radar observations |
| title_fullStr | Coastal and orographic effects on extreme precipitation revealed by weather radar observations |
| title_full_unstemmed | Coastal and orographic effects on extreme precipitation revealed by weather radar observations |
| title_short | Coastal and orographic effects on extreme precipitation revealed by weather radar observations |
| title_sort | coastal and orographic effects on extreme precipitation revealed by weather radar observations |
| url | https://hess.copernicus.org/articles/26/1439/2022/hess-26-1439-2022.pdf |
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