The Slow Coastal-Trapped Waves off Subei Bank in the Yellow Sea and Their Climatic Change in the Past Decades

Coastal-trapped waves (CTWs) are a class of subinertial signals in the weather frequency band that play a pivotal role in coastal air-sea interaction. However, this important topic seems to be missing in the heated debate in recent years on coastal environmental change and protection. In this chapter, a brief but self-contained introduction of the CTW theory is presented, in the hope of providing a reference for investigators in the relevant fields. Also presented is a numerical scheme for computing the wave properties. As a demonstration, we have conducted a preliminary study of the CTWs for a section across the Subei Bank in the Yellow Sea. By the results, all the computed slow modes, including a bottom-intensified one, seem to be slowing down since two decades ago. They have particularly slowed down in the event when a strong El Niño is followed by a strong La Niña, such as in the 97–98 and 09–10 El Niño events

The Cyclogenesis and Decay of Typhoon Damrey

The cyclogenesis of typhoons has been a continuing challenge in dynamic meteorology. In this study, we use a recently developed methodology, namely, multiscale window transform (MWT), together with the MWT-based localized multiscale energy and vorticity analysis and the theory of canonical transfer, to investigate the formation, maintenance, and decay of the typhoon Damrey, a rarely seen tropical storm of higher-latitude origin. The atmospheric fields are first reconstructed onto three scale subspaces or scale windows: large-scale window, tropical cyclone-scale window, and cumulus convection-scale window. On the cyclone-scale window, Damrey is found right along the edge of the subtropical high. It is generated due to a strong barotropic instability in the lower troposphere, but its subsequent rapid amplification is, however, related to a baroclinic instability in the upper troposphere. Damrey begins to decay before landfall, right over East China Sea at the mouth of Yangtze River, where a strong inverse cascade center resides and transfers the cyclone-scale energy backward to the large-scale window