Comment on “Importance of pre‐existing oceanic conditions to upper ocean response induced by Super Typhoon Hai‐Tang” by Z.‐W. Zheng, C.‐R. Ho, and N.‐J. Kuo

Abstract

[1] Understanding the impact of pre-existing oceanic conditions on the upper ocean response to tropical cyclones (TCs) is one of the important issues for understanding the short-term occurrence of TC-ocean interaction and its impact on TC intensity. Zheng et al. [2008] showed that preexisting cyclonic flow represented by negative sea-surface height anomalies (SSHA) played a crucial role in enhancing sea-surface cooling (SSC) caused by Typhoon Hai-Tang in 2005. On the other hand, the impact of initial oceanic mixedlayer depth and the vertical sea-temperature gradient in the thermocline on the amplitude of SSC has been considered to be small compared with that of the Ekman pumping and entrainment/vertical turbulent mixing [e.g., Wada, 2002]. Therefore, we hardly accept the discussion of Zheng et al. [2008] that the impact of Ekman pumping on SSC is less significant for local SSC occurred in certain areas than that of pre-existing oceanic condition. [2] Zheng et al. [2008] provide no quantitative evidence that SSC caused by the passage of Hai-Tang is irrelevant to the Ekman pumping or that the amplitude of SSC caused by the Ekman pumping is negligibly smaller than that due to relatively low sea surface height (SSH). In this paper, we revisit the relationship between SSC and SSH using a daily oceanic reanalysis dataset [Wada and Usui, 2007] produced by the North Pacific version of the Japan Meteorological Agency/Meteorological Research Institute Multivariate Ocean Variational Estimation system (MOVE) [Usui et al., 2006] in section 2. In section 3, we revisit the impact of the pre-existing oceanic condition on the ocean response to HaiTang using the Argo profiling float data. Section 4 presents our concluding remarks.