Y. Castro Díez, D. Pozo-Vázquez, M.J. Esteban-Parra and S.R. Gámiz-Fortis Grupo de Física de la Atmósfera. Dpto. Física Aplicada. Facultad de Ciencias, Universidad de Granada, 18071 Granada. Spain. E-mail: ycastro@ugr.es RESULT 2nd REOF DATA: Gridded winter air-temperature (Jones et al., 1994) METHOD: PCA OBJECTIVE: to obtain the general spatio-temporal characteristics of the temperature variability PERIOD: 1852-1997 AREA: 10ºW-20ºE •Explains 20% of the total variance •Representative mainly of the variability over southwestern Europe, specially over the Iberian Peninsula 35ºN-60ºN Loading factors (by ten) for the 2nd REOF 2nd PC series Temperaturas PC 2 invierno 3 Correlation Coef. = 0.06 Temperaturas (ºC)(ºC) Temperature 2 between 2nd PC series and NAO index 1 Fig b) pág 167 0 non-stat. significant -1 -2 2000 1990 1980 1970 1960 1950 1940 1930 1920 1910 1900 1890 1880 1870 1860 1850 -3 Tiempo (años) Year NCEP/NCAR reanalysis data 1959-1997 SLP and Wind Surface Anomalies Indice NAO y anomalías temperatura (º C) NAO Index & Temperature anomaly (ºC) Continuous Line: 2nd PC series Dashed Line: 1826-1997 winter index representative of the NAO (Jones et al., 1997) 4 3 2 1 0 -1 -2 -3 1950 1960 1970 1980 1990 Tiempo (años) Year Years corresponding to extreme negative NAO phase Winter 1963 NAO Index = -2.3 Temperature anomaly = -1.0ºC positive precipitation anomaly Years corresponding to extreme positive NAO phase Winter 1981 NAO Index = +1.3 Temperature anomaly = -0.8ºC Negative precipitation anomaly Positive and negative temperature anomalies can be found The same NAO extreme phase Winter 1965 NAO Index = -1.5 Temperature anomaly = -1.3ºC negative precipitation anomaly different locations of the south dipole centre Winter 1990 NAO Index = +2.3 Temperature anomaly = +2.2ºC positive precipitation anomaly different temperature anomalies patterns The location of the south dipole centre (not the positive or negative character of the NAO phase) determines the circulation type over the Iberian Peninsula and, thus, the thermal behaviour Winter 1979 NAO Index = -1.8 Temperature anomaly = +1.8ºC positive precipitation anomaly Winter 1995 NAO Index = +3.0 Temperature anomaly = +2.0ºC negative precipitation anomaly