Abstract
GEOPHYSICAL RESEARCH LETTERS,
VOL. 38,
L09705,
5 PP., 2011
doi:10.1029/2011GL047150
West African Monsoon influence on the summer Euro-Atlantic circulation
- The role of the WAM in driving the Euro-Atlantic circulation is highlighted
- Strong WAM is related to high-pressure anomalies over Azores and positive NAO
- The nudging replaces the NAO centers of action close to their observed locations
CETEMPS, Università dell'Aquila, L'Aquila, Italy
IBIMET, CNR, Rome, Italy
CRC, CNRS, Université de Bourgogne, Dijon, France
CNRM-GAME, Météo-France, CNRS, Toulouse, France
CRC, CNRS, Université de Bourgogne, Dijon, France
The West African Monsoon (WAM) influence on the interannual variability of the summer atmospheric circulation over North Atlantic and Europe is investigated over the period 1971–2000. A set of sensitivity experiments performed through the Arpege-Climat Atmospheric General Circulation Model is analyzed, using the so-called “grid-point nudging” technique, where the simulated atmospheric fields in the WAM region are relaxed towards the ERA40 reanalysis. Observations confirm that a sizable part of the Euro-Atlantic circulation variability is related to the WAM, with anomalies of reinforced convection in the Sudan-Sahel region associated with positive North Atlantic Oscillation (NAO) phases and subsidence over eastern Mediterranean. The nudged simulations highlights the role of the WAM in driving the mid-latitude circulation. A strong monsoon is related to high-pressure anomalies over the Azores and positive NAO phases.
Received 16 February 2011; accepted 1 April 2011; published 13 May 2011.
Citation: (2011), West African Monsoon influence on the summer Euro-Atlantic circulation, Geophys. Res. Lett., 38, L09705, doi:10.1029/2011GL047150.
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