Impact of soil moisture on extreme maximum temperatures in Europe
Land-atmosphere interactions play an important role for hot temperature extremes in Europe. Dry soils may amplify such extremes through feedbacks with evapotranspiration. While previous observational studies generally focused on the relationship between precipitation deficits and the number of hot d...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Elsevier
2015-09-01
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| Series: | Weather and Climate Extremes |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2212094715000201 |
| _version_ | 1819163541267021824 |
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| author | Kirien Whan Jakob Zscheischler Rene Orth Mxolisi Shongwe Mohammad Rahimi Ernest O. Asare Sonia I. Seneviratne |
| author_facet | Kirien Whan Jakob Zscheischler Rene Orth Mxolisi Shongwe Mohammad Rahimi Ernest O. Asare Sonia I. Seneviratne |
| author_sort | Kirien Whan |
| collection | DOAJ |
| description | Land-atmosphere interactions play an important role for hot temperature extremes in Europe. Dry soils may amplify such extremes through feedbacks with evapotranspiration. While previous observational studies generally focused on the relationship between precipitation deficits and the number of hot days, we investigate here the influence of soil moisture (SM) on summer monthly maximum temperatures (TXx) using water balance model-based SM estimates (driven with observations) and temperature observations. Generalized extreme value distributions are fitted to TXx using SM as a covariate. We identify a negative relationship between SM and TXx, whereby a 100 mm decrease in model-based SM is associated with a 1.6 °C increase in TXx in Southern-Central and Southeastern Europe. Dry SM conditions result in a 2–4 °C increase in the 20-year return value of TXx compared to wet conditions in these two regions. In contrast with SM impacts on the number of hot days (NHD), where low and high surface-moisture conditions lead to different variability, we find a mostly linear dependency of the 20-year return value on surface-moisture conditions. We attribute this difference to the non-linear relationship between TXx and NHD that stems from the threshold-based calculation of NHD. Furthermore the employed SM data and the Standardized Precipitation Index (SPI) are only weakly correlated in the investigated regions, highlighting the importance of evapotranspiration and runoff for resulting SM. Finally, in a case study for the hot 2003 summer we illustrate that if 2003 spring conditions in Southern-Central Europe had been as dry as in the more recent 2011 event, temperature extremes in summer would have been higher by about 1 °C, further enhancing the already extreme conditions which prevailed in that year. |
| first_indexed | 2024-12-22T17:45:46Z |
| format | Article |
| id | doaj.art-714005263aad499f93eee77aec989c8c |
| institution | Directory Open Access Journal |
| issn | 2212-0947 |
| language | English |
| last_indexed | 2024-12-22T17:45:46Z |
| publishDate | 2015-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Weather and Climate Extremes |
| spelling | doaj.art-714005263aad499f93eee77aec989c8c2022-12-21T18:18:18ZengElsevierWeather and Climate Extremes2212-09472015-09-019C576710.1016/j.wace.2015.05.001Impact of soil moisture on extreme maximum temperatures in EuropeKirien Whan0Jakob Zscheischler1Rene Orth2Mxolisi Shongwe3Mohammad Rahimi4Ernest O. Asare5Sonia I. Seneviratne6The Pacific Climate Impacts Consortium, The University of Victoria, Victoria, British Columbia, CanadaMax Planck Institute for Biogeochemistry, Department for Biogeochemical Integration, Jena, GermanyInstitute for Atmospheric and Climate Science, ETH Zurich, Zurich, SwitzerlandSouth African Weather Service, Climate and Environment Research and Monitoring, Pretoria, South AfricaFaculty of Desert Studies, Semnan University, Semnan, IranDepartment of Physics, Kwame Nkrumah University of Science and Technology (KNUST), GhanaInstitute for Atmospheric and Climate Science, ETH Zurich, Zurich, SwitzerlandLand-atmosphere interactions play an important role for hot temperature extremes in Europe. Dry soils may amplify such extremes through feedbacks with evapotranspiration. While previous observational studies generally focused on the relationship between precipitation deficits and the number of hot days, we investigate here the influence of soil moisture (SM) on summer monthly maximum temperatures (TXx) using water balance model-based SM estimates (driven with observations) and temperature observations. Generalized extreme value distributions are fitted to TXx using SM as a covariate. We identify a negative relationship between SM and TXx, whereby a 100 mm decrease in model-based SM is associated with a 1.6 °C increase in TXx in Southern-Central and Southeastern Europe. Dry SM conditions result in a 2–4 °C increase in the 20-year return value of TXx compared to wet conditions in these two regions. In contrast with SM impacts on the number of hot days (NHD), where low and high surface-moisture conditions lead to different variability, we find a mostly linear dependency of the 20-year return value on surface-moisture conditions. We attribute this difference to the non-linear relationship between TXx and NHD that stems from the threshold-based calculation of NHD. Furthermore the employed SM data and the Standardized Precipitation Index (SPI) are only weakly correlated in the investigated regions, highlighting the importance of evapotranspiration and runoff for resulting SM. Finally, in a case study for the hot 2003 summer we illustrate that if 2003 spring conditions in Southern-Central Europe had been as dry as in the more recent 2011 event, temperature extremes in summer would have been higher by about 1 °C, further enhancing the already extreme conditions which prevailed in that year.http://www.sciencedirect.com/science/article/pii/S2212094715000201Soil moistureExtreme temperaturesGeneralized extreme valueExtreme value theoryQuantile regressionLand-atmosphere interactions |
| spellingShingle | Kirien Whan Jakob Zscheischler Rene Orth Mxolisi Shongwe Mohammad Rahimi Ernest O. Asare Sonia I. Seneviratne Impact of soil moisture on extreme maximum temperatures in Europe Weather and Climate Extremes Soil moisture Extreme temperatures Generalized extreme value Extreme value theory Quantile regression Land-atmosphere interactions |
| title | Impact of soil moisture on extreme maximum temperatures in Europe |
| title_full | Impact of soil moisture on extreme maximum temperatures in Europe |
| title_fullStr | Impact of soil moisture on extreme maximum temperatures in Europe |
| title_full_unstemmed | Impact of soil moisture on extreme maximum temperatures in Europe |
| title_short | Impact of soil moisture on extreme maximum temperatures in Europe |
| title_sort | impact of soil moisture on extreme maximum temperatures in europe |
| topic | Soil moisture Extreme temperatures Generalized extreme value Extreme value theory Quantile regression Land-atmosphere interactions |
| url | http://www.sciencedirect.com/science/article/pii/S2212094715000201 |
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