Statistical Analysis of Tropical Disturbances over the South China Sea During 1997-2006

Tropical disturbances over the South China Sea (SCS) during the period of 1997-2006 are analyzed using the Tropical Storm and Hurricane WX products. A total of 158 tropical disturbances were formed over the SCS from 1997 to 2006, with 54 de-veloping tropical disturbances which developed into tropical depressions and 104 non-developing tropical disturbances which never developed into tropical depressions. The development rate of tropical disturbances into tropical depressions was 34.18% in these ten years. During the period of this study, total annual numbers of tropical disturbances and developing tropical disturbances over the SCS had significant decreasing trends; however, the development rate of tropical disturbances had an insignificant increasing trend.

Synergistic effects of tropical cyclones on forest ecosystems:a global synthesis

Tropical cyclones are large-scale strong wind disturbance events that occur frequently in tropical and subtropical coastal regions and often bring catastrophic physical destruction to ecosystems and economic disruption to societies along their paths. Major tropical cyclones can infrequently move into the midaltitudes and inland areas. Ecologically, tropical cyclones have profound impacts on diversity, structure, succession and function of forest ecosystems. The ecological effects are both dramatic and subtle. The dramatic effects can be visible, noticeable and to some extent predictable over the short-term and relatively well documented in the literature. However, the subtle effects are often invisible, complex and at smaller scale relatively unpredictable in the long-term. Many factors, meteorologic, topographic and biologic, simultaneously interact to influence the complexity of patterns of damage and dynamics of recovery. I present a global synthesis on the effects of tropical cyclones on forest ecosystems and the complexity of forest responses, with particular attention on the response to large hurricanes in the neotropics and the temperate North America, and strong typhoons on the subtropical and temperate forests in the East and Southeast Asia. Four major aspects provide on organizational framework for this synthesis：（1） consistent damage patterns,（2） factors that influence response patterns and predict damage risks,（3） complexity of forest responses and recovery, and（4） the long-term effects. This review reveals highly variable and complex effects of tropical cyclones on forest ecosystems. A deep understanding of the synergistic effects of tropical cyclones is essential for effective forest management and biodiversity conservation.

Recent advances in research on tropical cyclogenesis

This review article summarizes recent(2014-2019)advances in our understanding of tropical cyclogenesis,stemming from activities at the ninth International Workshop on Tropical Cyclones.Tropical cyclogenesis involves the interaction of dynamic and thermodynamic processes at multiple spatio-temporal scales.Studies have furthered our understanding of how tropical cyclogenesis may be affected by external processes,such as intraseasonal oscillations,monsoon circulations,the intertropical convergence zone,and midlatitude troughs and cutoff lows.Additionally,studies have furthered our understanding of how tropical cyclogenesis may be affected by internal processes,such as the organization of deep convection;the evolution of the"pouch"structure;the role of friction;the development of the moist,warm core;the importance of surface fluxes;and the role of the mid-level vortex.A relatively recent class of idealized,numerical simulations of tropical cyclogenesis in radiativeconvective equilibrium have highlighted the potential importance of radiative feedbacks on tropical cyclogenesis.We also offer some recommendations to the community on future directions for tropical cyclogenesis research.