Teleconnection–extreme precipitation relationships over the Mediterranean region

• Published in: Theoretical and applied climatology Vol. 117; no. 3-4; pp. 679 - 692
• Main Authors: Krichak, Simon O., Breitgand, Joseph S., Gualdi, Silvio, Feldstein, Steven B.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.08.2014; Springer; Springer Nature B.V
• Subjects: Analysis; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric research; Atmospheric Sciences; Climate; Climatology; Earth and Environmental Science; Earth Sciences; Earth, ocean, space; El Nino; Exact sciences and technology; External geophysics; Extreme weather; Meteorology; Ocean currents; Ocean-atmosphere interaction; Original Paper; Precipitation; Precipitation (Meteorology); Southern Oscillation; Spatial distribution; Teleconnections; Tropopause; Troposphere; Waste Water Technology; Water in the atmosphere (humidity, clouds, evaporation, precipitation); Water Management; Water Pollution Control; Mediterranean Basin; Middle East; PN, Arctic; ANE, Europe, Iberian Peninsula; AE, East Atlantic; AN, North Atlantic, North Atlantic Oscillation; MED, Western Mediterranean; Europe, Mediterranean Region; Extreme Precipitation; North Atlantic Oscillation Index; North Atlantic Oscillation; Potential Vorticity; Teleconnection Pattern; Teleconnection; Spatial distribution; atmospheric precipitation; extreme value; Periodic oscillation; Mediterranean region; Interannual variation
• ISSN: 0177-798X; 1434-4483
• DOI: 10.1007/s00704-013-1036-4

The relationship between five teleconnection patterns (North Atlantic Oscillation (NAO), Arctic Oscillation (AO), East Atlantic/Western Russian (EAWR) pattern, Scandinavian (SCAND) pattern, and El Niño Southern Oscillation (ENSO)) and the frequency of occurrence of days (per month) with extreme precipitation in the Euro-Mediterranean region is investigated with National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis data. To quantify the teleconnection–precipitation relationships over the Euro-Mediterranean region, linear correlations are calculated between the monthly teleconnection indices for the five patterns and time series at each grid point of the monthly frequency of days with extreme precipitation, focusing on daily precipitation amounts that exceed a particular threshold value (a 90 % threshold is used). To evaluate dynamical processes, the teleconnection indices are also correlated with the frequencies of days with extreme values of dynamic tropopause pressure and precipitable water. The former quantity is used as a proxy for potential vorticity intrusions and the latter to identify regions of enhanced moisture. The results of this analysis indicates positive, statistically significant correlations between the NAO, AO, and SCAND indices and the frequency of extreme precipitation in the western Mediterranean; positive (negative) correlations between the EAWR index and the extreme precipitation frequency in the eastern (western) Mediterranean; and a positive correlation between the Niño3.4 index and the extreme precipitation frequency over the Iberian Peninsula and the Middle East. For all of the teleconnection patterns other than ENSO, the dynamic tropopause pressure correlation patterns resemble those for the precipitation. In contrast, similar precipitation and precipitable water correlation patterns are observed only for ENSO. These findings suggest that the teleconnections affect the interannual variation of the frequency of days with extreme precipitation over a large part of the Euro-Mediterranean region through their impact on the spatial distribution of regions with enhanced potential vorticity and air moisture.