Total energy equation method for calculating hurricane intensity

Summary Surface pressure reduction in hurricanes is calculated by applying the total energy equation (TEE) to ideal isentropic upflow in a vertical tube. The pressure reduction at the base of the tube, called the intensity, is calculated for three upflow processes: reversible upflow of air approaching equilibrium with the sea at the sea level pressure outside the tube; irreversible upflow of air approaching equilibrium with the sea at the sea-level pressure outside the tube; and upflow of air approaching equilibrium with the sea at the reduced surface pressure inside the tube. The sensitivity of intensity to the type of upflow process and to the sea surface temperature is investigated. Intensities calculated with the TEE are shown to be consistent with observations and to be close to intensities calculated with more complex methods. The TEE method is simple and can help understand the basic mechanism responsible for surface pressure reduction and for energy production. The method is used to show that approximately 20% of the heat taken from the sea during a hurricane is converted to mechanical energy. Received December 4, 2000/Revised March 29, 2001