Numerical simulations of an isolated microburst. I - Dynamics and structure

Abstract Isolated and stationary microbursts are simulated using a time-dependent, high-resolution, axisymmetric numerical model. A microburst downdraft is initiated by specifying a distribution of precipitation at the top boundary of the model and allowing it to fall into the domain. Part I of this two-part series focuses on two case studies of a hazardous wet (high reflectivity) microburst. The first case assumes the environmental conditions that were observed on 30 June 1982 during the JAWS field experiment. The simulated microburst produced mean horizontal wind shears in excess of 10−2 s−1 for several minutes and was of an intensity similar to the observed microbursts on that date. The second case attempts to simulate the isolated microburst which occurred near the Dallas–Fort Worth airport on 2 August 1985. A comparison of the results to actual flight recorder data showed good agreement. Based on these case studies, the evolution and structure of the microbursts are discussed. The simulated microburs...