| ABSTRACT | Thanks to satellite observation and daily monitoring of meteorological conditions for more than ten years, we have observed that the positive balance has shifted more towards the poles, mainly in the northern hemisphere. Subtropical anticyclones are strengthened and have extended to high latitudes, especially over the Atlantic and Pacific oceans. This situation creates global peaks strengthened in winter periods, and imposes on cosmic cold the deep advection toward the south under the form of planetary valleys "Polar Vortex".This situation imposes on the jet stream a pronounced ripple and installs a Meridian Atmospheric Circulation (MAC) in winter, which brings the warm tropical air masses to reach the Arctic Circle, and cold polar air masses to reach Western Mediterranean and Florida.This situation creates unusual atmospheric events, characterized by hydrothermal "extreme" conditions: excessive heat at high latitudes, accompanied by heavy rains and floods, as well as cold at low latitudes and the appearance of snow in the Sahara!The populations are profoundly influenced by the new phenomena. The socioeconomic infrastructures can no longer assume their basic functions and man when unprotected is weak and hence the advanced vulnerability of all the regions especially those belonging to poor and developing countries.The recent example of autumn 2014 and autumn-winter 2015-2016 reveals these conditions which left a deep psychological, economic and social impact on Moroccans in particular, and the Western Mediterranean in general.In autumn 2014, atmospheric conditions were marked by a stronger meridian atmospheric circulation, characterized by the persistence of high temperatures during this autumn period in Morocco, mainly south of the Atlas, combined with the intrusion of a drop cold at the beginning of the event on 17/11/2014, and the frank installation of a very deep planetary valley off the Moroccan coasts on 24/11/2014, which evolved in storm (Xandra) where the depression reached the surprising value of 975 hPa on 28/11/2014.These events, and other similar in Western Mediterranean area: floods of El Attaf, Ain Defla and M'sila in October 2007, Ghardaïa in October 2008, Algiers in October 2015 (Algeria), Tunis in October 2007, Sfax 2009 (Tunisia), Andaloucia (Spain) in December 2010, the Var (France) in June 2010, Genoa (Italy) in November 2011, ... etc., as well as many cases of floods, should be considered as reference laboratory case for the simulation of future situations, and integration into development plans in the future. |