... ENSO 45± 2. 1MEI ENSO 30± 2. 1 45 ± 2. 1NAO (CPC) 34± 2. 1NAO (CRU) 34± 2. 1NOI 32 ± 2. 3NP 43± 2. 4PDO 26 ± 2. 4 40 ± 2. 3PNA 45± 2. 4SOI 30± 2. 2SOI* 30± 2. 5 44 ± 2. 6Table 2. Cycles ... Letters, 26 6: 22 1 23 2. Hughes, M.K. and Diaz, H.F., 1994: Was there a ‘medieval warm period’, and if so, where and when?. Climatic Change, 26 , 109–1 42. IPCC, 20 07: Climate Change 20 07: The ... Letters, 26 6: 22 1 23 2. Hughes, M.K. and Diaz, H.F., 1994: Was there a ‘medieval warm period’, and if so, where and when?. Climatic Change, 26 , 109–1 42. IPCC, 20 07: Climate Change 20 07: The...