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The paper examines the relationships between ENSO events and tropical cyclones (TCs) in the western North Pacific (WNP) during the ENSO decaying phase of March to July [MAMJJ(1)]. It is shown that WNP TC response is asymmetric to ENSO warm and cold events during MAMJJ(1), associated with the asymmetric patterns of oceanic and atmospheric environmental variables. Eastern Pacific warm events correspond to a westward shift in TC genesis location and a significant decrease of the TC number in the southwest subregion of the WNP, which is consistent with unfavorable atmospheric and oceanic conditions for TC activity during MAMJJ(1). Correspondingly, there is a much less WNP TC number, a shorter TC duration, and a decreased tendency in all three primary TC tracks. During MAMJJ(1) of eastern Pacific cold events, an increased TC activity in the northeast subregion results in an enhanced TC genesis number in the WNP. Central Pacific ENSO events have little effect on WNP TC activity during MAMJJ(1), except that central Pacific warm events are unfavorable for TCs to form in the northwest subregion associated with atmospheric and oceanic conditions. The paper also compares and discusses the TC response to ENSO events during the ENSO developing year of March-July. [ABSTRACT FROM AUTHOR]

The statistical method, Average Predictability Time (APT) decomposition, is used in the present paper to estimate the decadal predictability of upper ocean heat content over the global ocean, North Pacific and North Atlantic, respectively. The twentieth century simulations from CMIP5 outputs are the main data sources in this study. On global scale, the leading predictable component is characterized by a warming trend over the majority of oceans, which is related to the anthropogenic forced response. The second predictable component has significant loadings in the North Atlantic, especially in the subtropical region, which originates from the Atlantic Multidecadal Oscillation (AMO) predictability. To separate interactions among different ocean basins, we further maximize APT in individual North Pacific and North Atlantic oceans. It is found that the second and the third predictable component in North Pacific are significantly correlated with the well-known North Pacific Gyre Oscillation mode and the Pacific Decadal Oscillation respectively. Upper limit prediction skill of these two components are on the order of 6 years. In contrast, the most predictable component derived from the North Atlantic features an AMO-like spatial structure with its prediction skill up to 18 years, while the basin mode due to global warming only exists as the third component. This indicates the interdecadal variability in the North Atlantic is strong enough to mask the anthropogenic climate signals. Furthermore, predictability in the real world is also investigated and compared with model results by using observation-based data. [ABSTRACT FROM AUTHOR]