Coupling of the Intraseasonal Oscillation with the Tropical Cyclone in the Western North Pacific during the 2004 Typhoon Season

Influence of climate regime shift on the interdecadal change in tropical cyclone activity over the Pacific Basin during the middle to late 1990s

“…This observation suggests that the largescale environmental change associated with SVD1 in 1976-1977 was partially offset by the effect of SVD2. In addition to the large-scale factors, the interdecadal variation in TC activity in the WNP was also affected by other processes, such as intraseasonal oscillations (Hsu et al 2008;Kim et al 2008;Ha et al 2014), which cannot be measured using the interdecadal time scale. The interdecadal change in TC activity in other periods, such as the increase in TC activity in the ENP during 1976-1977 and the increase in TC activity in the WNP during the late 1980s, might be attributable to other processes not currently under investigation.…”

A tropical cyclone removal technique based on potential vorticity inversion to better quantify tropical cyclone contribution to the background circulation

“…As compared with Fig. 8 by Hsu et al (2008a), the variance associated with the East Asian monsoon trough in the South China Sea is much larger than the variance associated with the (Fig. 14a).…”

“…This result clearly demonstrates the mutual dependence of TCs and background mean circulations through active interaction. Hsu et al (2008a) revealed that the 32-76-day ISO was the dominant subseasonal fluctuation in JJASO 2004, and its amplitude reached the 50-year record high value. The contributions of TCs to the 32-76-day ISV at the lower layer were estimated for both TC-removed fields, as shown in Fig.…”

“…The contributions of TCs to the 32-76-day ISV at the lower layer were estimated for both TC-removed fields, as shown in Fig. 8 by Hsu et al (2008a), and the difference between these contributions were also investigated. The contributions of 32-76-day variance of the low-level vorticity indicate two major ISV regions along the TC tracks: one is located to the east of Taiwan and the northern Philippines, and the other to the south of Japan (Fig.…”

“…The derived fields are dynamically balanced in the PVI framework. We compare the TC-removed fields derived using the traditional and the proposed TC removal techniques, and reexamine the TC contribution to intraseasonal variance and seasonal-mean circulation in the tropical WNP discussed in Hsu et al (2008a) with dynamically well-balanced TCremoved data. This paper is organized as follows: Sect.…”