Structural and Intensity Changes of Concentric Eyewall Typhoons in the Western North Pacific Basin

摘要

An objective method is developed to identify concentric eyewalls (CEs) for typhoons using passive microwave satellite imagery from 1997 to 2011 in the western North Pacific basin.Three CE types are identified:CE with an eyewall replacement cycle (ERC; 37 cases),CE with no replacement cycle (NRC; 17 cases),and CE is maintained for an extended period (CEM; 16 eases).The inner eyewall (outer eyewall) of the ERC (NRC) type dissipates within 20 h after CE formation.The CEM type has its CE structure maintained for more than 20 h (mean duration time is 31 h).