Wave analysis for different time scales contributing to the anomalous long-lasting blocking high over Eastern Europe during summer 2010
Abstract
Many studies show that the anomalous long-lasting Russian heat wave in summer 2010, linked to a long-persistent blocking high, appears mainly as a result of natural atmospheric variability. This investigation analyzes the large scale flow structure based on ERA-Interim data. The anomalous long-lasting blocking over Western Russia including the heat wave occurs as an overlay of a set of anticyclonic contributions on different time scales: (i) A regime change in ENSO towards La Nina modulates the quasi-stationary wave structure in the boreal summer hemisphere supporting the eastern European blocking. The polar Arctic dipole mode is enhanced and shows a projection on the mean blocking high. (ii) Together with the quasi-stationary wave anomaly the transient eddies maintain the long-lasting blocking. (iii) Three different pathways of wave action are identified on the intermediate time scale (~10-60 days). One pathway commences over the eastern North Pacific and includes the polar Arctic region; another one runs more southward and crossing the North Atlantic, continues to eastern Europe; a third pathway southeast of the blocking high describes the downstream development over South Asia.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2012
- Bibcode:
- 2012EGUGA..14.4759P