Objective Comparison of Vertical Motions from the Kinematic Method and Three Forms of the Omega Equation

摘要

Subjective and objective comparisons were performed on large scale vertical motions from the kinematic method, the traditional omega equation, Trenberth's form of the omega equation, and the Q vector approach. Vertical motions from these routines were qualitatively compared to flow patterns and cloud/precipitation regions associated with a developing midlatitude springtime cyclone during the period 17-19 March 1986. Objective comparisons were also accomplished using a scoring scheme which rated each method. Results showed that kinematic motions were far superior to those from any of the three omega equation techniques. However, when the various omega equation output was compared with each other, they were found to be very similar. The Q vector method yielded slightly better scores for the entire 48 h period, but none of the three methods was clearly superior at the individual times. Because of the closeness of results, the omega equation routines were judged according to their ease of use and computation. From this analysis, the Q vector algorithm was chosen as the best of the three methods. Keywords: Atmospheric motion models. Theses. (edc)