Machine summary:
Part of the studies in the literature include the investigation of climate change in the behaviors of climatic indices, the positive trend of North Atlantic Oscillation since 1979-1989 and northern hemisphere activity centers (Mote, 1998; Ostermeier &Wallace, 2003; Rauthe, Hense, & Paeth, 2004), the positive trend of the Mediterranean Oscillation Index, the negative trend of meridional circulation of Mediterranean and non-trend of the Eastern Atlantic Jet in the late 1980s (Dunkeloh, 2003), the shift of the East/West Center of Asian Summer index to the northwest and southeast and the reduction of their power after 1970 (Wu, 2002), the positive trend of East Atlantic Western Russia index, a reduction of pressure in high-pressure center of Siberia after 1970 (Panagiotopoulos, Shahgedanova, Hannachi, & Stephenson, 2005), the negative trends of North Atlantic Oscillation in winter, an increase in anticyclone and a decrease in cyclone in Europe since 1960 to the early 1990s related to the severity of zonal flow (positive index) from 1960s to early 1990s, and an increase in the maintenance of pressure patterns and the stronger blockings in the 1990s with the rising trend of Summer anti-cyclones (Kysely & Huth, 2006), the positive trend of North Atlantic Oscillation and the Azores center for the 500 Hp Europe is over the past 40 years in winter and spring (Casty, Raible, Stocker,Wanner, & Luterbacher, Corresponding Author: Email :doostan@um.