“…Other climate signals, such as the North Atlantic Oscillation (NAO, e.g. Lamb and Peppler, 1987;Hurrell et al, 2003), the Pacific-North American (PNA) pattern (Frankignoul and Sennechael, 2007), the Indian Ocean Dipole (IOD, Luo et al, 2008) also provide regional predictive potential on the seasonal time scale. For instance, the NAO, a seesaw in pressure between the Icelandic Low and Azores High first introduced by Walker (1924), is now the focal point for much research on climate at mid-high Northern Hemisphere latitudes, especially in western Europe variations from seasonal to decadal time scales (Hurrell, 1995;Katz, 2002).…”