A Comparison of Different Definitions of the North Atlantic Oscillation Index based on their correlations with Surface Climate Elements in the Czech Republic

• Main Authors: Pokorná, L. (Lucie), Huth, R. (Radan)
• Format: Other/Unknown Material
• Language: English
• Published: 2012
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: http://hdl.handle.net/11104/0246387

The different influence of 7 NAO indexes on eleven climate elements in the CR is demonstrated for winter and summer seasons. The period used for the comparison is 1961-98, the Pearson correlation coefficient is employed to quantify the relationships. The correlations of different NAO indexes for each climate element were compared at all stations and statistically significant differences were identified for some pairs of NAO indices. The seven monthly NAO indices are compared: two are station-based, two are based on the position and intensity of the action centres, and three are outcomes of principal component analysis applied to 500 hPa heights or sea level pressure (here indicated as score). Correlations among the indices range from 0.64 to 0.86 in winter, while from 0.50 to 0.87 in summer; correlations of all pairs of indices are statistically significant. Mean monthly values of surface climatic elements at 21 stations in the Czech Republic are calculated for daily maximum, minimum, and mean surface temperature, cloudiness, sunshine duration, relative humidity, and wind components. Additional two precipitation characteristics calculated at 71 stations are the relative number of precipitation days and monthly precipitation amount.