ENSO EPISODES AND LOW-FREQUENCY OSCILLATION IN THE EXTRA-TROPICAL LATITUDE OF THE NORTHERN HEMISPHERE
Qiu Ming-yu · Journal of Tropical Meteorology · 2006
A diagnostic analysis is carried out to investigate the relationship of ENSO episodes and the atmospheric low-frequency oscillation (LFO) in the mid-high latitudes of the Northern Hemisphere.The power spectral analysis is performed for the daily 500 hPa height field data in the mid-high latitudes of the Northern Hemisphere from 1950 to 2003.The results show that:(1) ENSO episodes have the frequency modulation effect on low-frequency oscillation (LFO) in the extra-tropical latitudes of the Northern Hemisphere,i.e.Intensity of low-frequency oscillation in winter is stronger than that in summer.(2) The main period of low-frequency oscillation show the shortened (lengthened) tendency during E1 Ni(?)o (La Ni(?)a) episodes.(3) The frequency modulation effect of ENSO episodes on atmospheric low-frequency oscillation (LFO) in the mid-high latitudes is clearer than that in the mid-low latitudes.