Objective Measures of Tropical Cyclone Structure and Intensity Change From Remotely Sensed Infrared Image Data

An objective technique for obtaining features associated with the shape and dynamics of cloud structures embedded in tropical cyclones from satellite infrared images is described. As the tropical cyclone develops from an unstructured cloud cluster and intensifies, the cloud structures become more axisymmetric about an identified reference point. Using variables derived from remotely sensed data, the technique calculates the gradient of the brightness temperatures to measure the level of symmetry of each structure, which characterizes the degree of cloud organization of the tropical cyclone. The results presented show that the technique provides an objective measure of both the structure and the intensity of the tropical cyclone from early stages, through intensification, maturity, and dissipation.