To search, Click below search items.


All Published Papers Search Service


Subtropical anticyclone tracking using Principal Component Analysis


Saqib Ur Rehman, Bilal Ahmed Usmani, Kamran Khan, Abdul Jamil Khan, Mustafain Ali, Absar Ahmed and Sara Ali


Vol. 19  No. 4  pp. 284-288


Using the National Centers for Environmental Prediction (NCEP) reanalysis daily mean sea level pressure data, the climatology of the subtropical Indian Ocean anticyclone was described for the 58-year period of 1951?2008. Principal components analysis was used to identify the attributes and variability of this quasi-permanent feature. We consider the first two principal components which describe 60% of the total variance. The spatial variance structure of the first principal component (PC1) describes that PC1 is related to winter mode in which anticyclones are present over the maximum region of the subtropical Indian Ocean, Western Australia and South-eastern Africa. Time series of the mean annual principal component scores of PC1 indicate that anticyclones system density has been increasing over the Indian Ocean and adjacent land areas. Principal component two (PC2) is related to the late winter and predominant summer pattern, in which anticyclones are present over the central part of the Indian Ocean. The frequency count analysis, tracking and strength of these systems were accomplished using a numerical algorithm technique. The semi-monthly frequency count of anticyclones, dynamics of the anticyclone system and intensity/strength are presented.


Anticyclones High Pressure System Indian Ocean Principal Component Analysis