Cluster analysis of typhoon tracks. Part II: Large-scale circulation and ENSO

Publication Type  Journal Article
Year of Publication  2007
Authors  Camargo, S. J.; Robertson, A. W.; Gaffney, S. J.; Smyth, P.; Ghil, M.
Journal Title  Journal of Climate
Volume  20
Issue  14
Pages  3654-3676
Journal Date  Jul 15
ISBN Number  0894-8755
Accession Number  ISI:000248484700019
Key Words  western north pacific; tropical cyclone activity; nino-southern-oscillation; intraseasonal convection anomalies; surrounding flow relationships; rossby-gravity-waves; el-nino; interannual variation; hurricane intensity; equatorial waves
Abstract  

A new probabilistic clustering method, based on a regression mixture model, is used to describe tropical cyclone (TC) propagation in the western North Pacific (WNP). Seven clusters were obtained and described in Part I of this two-part study. In Part II, the present paper, the large-scale patterns of atmospheric circulation and sea surface temperature associated with each of the clusters are investigated, as well as associations with the phase of the El Nino-Southern Oscillation (ENSO). Composite wind field maps over the WNP provide a physically consistent picture of each TC type, and of its seasonality. Anomalous vorticity and outgoing longwave radiation indicate changes in the monsoon trough associated with different types of TC genesis and trajectory. The steering winds at 500 hPa are more zonal in the straight-moving clusters, with larger meridional components in the recurving ones. Higher values of vertical wind shear in the midlatitudes also accompany the straight-moving tracks, compared to the recurving ones.The influence of ENSO on TC activity over the WNP is clearly discerned in specific clusters. Two of the seven clusters are typical of El Nino events; their genesis locations are shifted southeastward and they are more intense. The largest cluster is recurving, located northwestward, and occurs more often during La Nina events. Two types of recurving and one of straight-moving tracks occur preferentially when the Madden-Julian oscillation is active over the WNP region.

Notes  

196LZTimes Cited:5Cited References Count:93

URL  <Go to ISI>://000248484700019
DOI  Doi 10.1175/Jcli4203.1