Article
A downscaling technique to simulate changes in western North Pacific tropical cyclone activity between two types of El Nio events
Theoretical and Applied Climatology
Haikun Zhao
Abstract
Changes in tropical cyclone (TC) activity over the western North Pacific (WNP) basin between the Modoki and canonical El Niño years have been simulated and examined in this study based on a downscaling technique. The downscaling technique is used for generating synthetic TCs based on TC formation, TC track, and TC intensity models. Results suggest that the downscaling technique can well simulate the spatial distribution of TC activity during the two types of El Niño years and their differences. It is found that the observed changes in TC tracks during the two types of El Niño years are mainly due to the combined effects of changes in TC formation locations and large-scale steering flows. Further examinations have shown that changes in large-scale steering flows play a more important role than changes in TC formation locations. These results are in accordance with the cyclonic circulation anomaly found during the Modoki El Niño years compared to that during the canonical El Niño years. Numerical simulations further suggest that changes in TC tracks between the two types of El Niño years appear to be the most important factor affecting the TC intensity change. Compared to that during the Modoki El Niño years, TC formation is enhanced in the south quadrant of the WNP basin and more TCs take a northwestward track during the canonical El Niño years, leading to a longer TC lifespan and greater TC intensity.
http://link.springer.com/article/10.1007%2Fs00704-015-1374-5
