Tropical Cyclone Activity in the Northwest Pacific in Relation to the El Niño/Southern Oscillation Phenomenon
Chan, Johnny C.L.
MetadataShow full item record
The interannual variations in tropical cyclone activity in the northwest Pacific (NWPAC) and their relationships with the EI Nino/Southern Oscillation (ENSO) phenomenon were studied using the method of spectral analyses. Time series of a Southern Oscillation Index (SOl, defined as the sea-level pressure difference between Easter Island and Darwin) and tropical cyclone activity in the entire (NWPAC) ocean basin as well as in different regions of the NWPAC were analyzed. Two spectral peaks are apparent in all these time series. One corresponds to the generally accepted Southern Oscillation with a period of - 3 to 3.5 years and another at the quasi-biennial oscillation (QBO) frequency. Cross-spectral analyses between the SOl and tropical cyclone activity show significant coherence in these two spectral peaks. The dominant peak is at the Southern Oscillation frequency with the SOl leading typhoon activity by almost a year. At the QBO frequency, the two series are almost in phase. Cyclone activity in the eastern part of NWPAC, however, is -180' out of phase with the SOl series at the Southern Oscillation frequency. It appears that fluctuations of cyclone activity at the dominant Southern Oscillation frequency may be explained in terms of the change in the horizontal and vertical circulations in the atmosphere during periods of low SOl. The establishment of an anomalous Walker Circulation shifts areas of enhanced or suppressed convection, leading to the observed variations in cyclone activity.
RightsThis publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
Showing items related by title, author, creator and subject.
Observations of the temporal variability in aerosol properties and their relationships to meteorology in the summer monsoonal South China Sea/East Sea: the scale-dependent role of monsoonal flows, the Madden-Julian Oscillation, tropical cyclones, squall lines and cold pools Reid, J.S.; Lagrosas, N.D.; Jonsson, H.H.; Reid, E.A.; Sessions, W.R.; Simpas, J.B.; Uy, S.N.; Boyd, T.J.; Atwood, S.A.; Blake, D.R.; Campbell, J.R.; Cliff, S.S.; Holben, B.N.; Holz, R.E.; Hyer, E.J.; Lynch, P.; Meinardi, S.; Posselt, D.J.; Richardson, K.A.; Salinas, S.V.; Smirnov, A.; Wang, Q.; Yu, L.; Zhang, J. (2015);In a joint NRL/Manila Observatory mission, as part of the Seven SouthEast Asian Studies program (7- SEAS), a 2-week, late September 2011 research cruise in the northern Palawan archipelago was undertaken to observe the ...
Large-Scale Circulation Variability and Impacts on North Indian Ocean Tropical Cyclones Christensen, Adrian S. (Monterey, California. Naval Postgraduate School, 2012-03);Analysis of the relationships between different phases of El Nio-Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Madden-Julian Oscillation (MJO) with tropical cyclone (TC) activity in the North Indian Ocean ...
Intraseasonal, large-scale circulations and tropical cyclcone activity over the Western North Pacific during Boreal summer Delk, Tracey Lee (Monterey, California. Naval Postgraduate School, 2004-06);Large-scale circulations in the 15-25 day period over the western North Pacific during northern summer were determined using the leading modes of a Singular Value Decomposition of 850 hPa winds and outgoing longwave ...