Abstract
This study investigates the potential influence of the East Asian trough (EAT) on the eastern Mediterranean temperature variability in early spring. In connection with this, it also examines the extreme case of the year 2004 when anomalous warming of the eastern Anatolia resulted in unprecedented snowmelt runoff amounts in the Euphrates and Tigris basins in early March. In the analyses, we used reanalysis data, gridded products of surface temperature and snow cover, river discharge data and satellite imagery. We employed an intensity index for the EAT and a trough displacement index for the Mediterranean trough (MedT) to explore the relationship between the strength of the EAT and the displacement of the MedT at pentad resolution. Our analysis shows that there are statistically significant correlations (at 99% confidence level) between the strength of the EAT and the zonal shift of the MedT on some pentads (e.g., 3rd, 13th, 37th and 59th), but that the highest correlation occurs on the 13th pentad of the year corresponding to the early days of March. It seems that, on this pentad, when the EAT is strong, the MedT tends to be located in the west of its climatological position (about 30 - 35 ∘E) which causes warmer conditions over the eastern Mediterranean. In 2004, which appears to be an extreme year for this phenomenon, the MedT is positioned and deepened in the central Mediterranean (about 10 - 15 ∘E), and extended towards central Africa during the early days of March. This synoptic pattern provided favorable conditions for the development of a tropical plume/atmospheric river with a southwest-northeast orientation, carrying warm tropical African air towards the eastern Mediterranean and Anatolian highlands resulting in rapid melting of the snowpack as well as severe precipitation, and thus flooding events, in the eastern Anatolia. A key finding in our analysis is that the strengthening of the EAT was instrumental to the increased amplitude of the ridge-trough system over the Euro-Mediterranean region in the early days of 2004 spring. We highlight that the response of surface and upper level meteorological conditions to the amplitude of the ridge-trough system enhanced by the strength of the EAT might be crucial in the understanding of some of the extreme hydrometeorological events in the eastern Mediterranean region.
Original language | English |
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Pages (from-to) | 2309-2326 |
Number of pages | 18 |
Journal | Climate Dynamics |
Volume | 53 |
Issue number | 3-4 |
DOIs | |
Publication status | Published - 15 Aug 2019 |
Bibliographical note
Publisher Copyright:© 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Funding
This study was partially supported by FONDAP-CONICYT 15110009. The authors acknowledge two anonymous reviewers for their constructive comments that helped to improve the manuscript. We acknowledge the E-OBS dataset from the EU-FP6 project UERRA ( http://www.uerra.eu ) and the Copernicus Climate Change Service, and the data providers in the ECA&D project ( https://www.ecad.eu ). The authors are grateful to Rutgers University that provides the NOAA weekly snow cover dataset available at http://climate.rutgers.edu/snowcover/ . The authors also are grateful to the EUMETSAT for providing the METEOSAT infrared imagery data (0 DEGREE IR 03.9) available at https://www.eumetsat.int/website/home/Data/index.html . ERA-Interim Reanalysis data provided by ECMWF from their web site at http://apps.ecmwf.int/datasets/data . This study was partially supported by FONDAP-CONICYT 15110009. The authors acknowledge two anonymous reviewers for their constructive comments that helped to improve the manuscript. We acknowledge the E-OBS dataset from the EU-FP6 project UERRA (http://www.uerra.eu) and the Copernicus Climate Change Service, and the data providers in the ECA&D project (https://www.ecad.eu). The authors are grateful to Rutgers University that provides the NOAA weekly snow cover dataset available at http://climate.rutgers.edu/snowcover/. The authors also are grateful to the EUMETSAT for providing the METEOSAT infrared imagery data (0 DEGREE IR 03.9) available at https://www.eumetsat.int/website/home/Data/index.html. ERA-Interim Reanalysis data provided by ECMWF from their web site at http://apps.ecmwf.int/datasets/data.
Funders | Funder number |
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Copernicus Climate Change Service | |
ECA&D | |
FONDAP-CONICYT | 15110009 |
National Oceanic and Atmospheric Administration | |
Rutgers, The State University of New Jersey |
Keywords
- Atmospheric river
- Atmospheric teleconnections
- Euphrates-Tigris Rivers
- Euro-Mediterranean
- Hydrometeorological extreme events
- Rossby wave