Modeling Hydrometeorological Extremes of Japan Tropical Cyclone Rainfall

Tropical cyclone frequency across Japan leads to many of the hydrometeorological extremes experienced across the country. Here, a framework is developed to employ a numerical weather prediction model, WRF, to simulate the structure of past historical tropical cyclones making landfall or bypassing the country.  The rainfall structure from all these events is then used to inform a stochastic model that examines the EOF patterns of rainfall to produce a catalog of 10,000 years of stochastically generated rainfall.  Due to the stationary assumption of the stochastic model, it is necessary to develop an algorithm which determines the stages of a tropical cyclone within the WRF simulation, where spatial patterns are consistent.  Therefore, several stochastic models are built based on developing, mature, dissipation and dissipation via extra-tropical transitioning.  The latter is determined by using the phase-space work of Hart, 2003.  Results from this work include the numerical simulation of approximately 800 tropical cyclone across Japan over the last 35 years and the delineation of each event into proper stages of the cyclone’s lifecycle.  The results are successfully used as a library for the stochastic model, and a catalog-worth of 10,000 stochastic years of tropical cyclone rainfall is produced.