Budget Studies of a Prefrontal Convective Rainband in Northern Taiwan Determined from TAMEX Data
Abstract
The budgets of total kinetic energy, horizontal momentum flux and three-dimensional vorticity for a subtropical prefrontal convective rainband associated with the Mei-Yu front on 25 June 1987 over northern Taiwan are investigated. This slow-moving system lasted for more than 10 hours and produced heavy precipitation over northern and central Taiwan. Doppler radar data from the TOGA and CP-4 radars captured this event during the morning hours. Dual- Doppler derived three-dimensional winds and retrieved thermodynamic parameters were processed from the 0653 and 0700 LST 25 June volume scans. A 25 x 40 kM2 rotated horizontal domain encompassing the investigated rainband with a 1 km three-dimensional grid spacing was used for the budget calculations. The total kinetic energy budget revealed that there was an upward transport of mean kinetic energy throughout the rainband with the strongest transport within the middle levels. The main sources of kinetic energy generation were due to the horizontal generation and the total buoyancy production terms. The two main processes that reduced the kinetic energy of the system were horizontal flux divergence and dissipation due to frictional forces. The momentum-flux budget showed that the shear production, the total buoyancy production and the velocity-pressure interaction terms were the strongest contributors to the local time-change of eddy horizontal momentum flux. The three-dimensional vorticity budget analyses implied that the tilting/tipping of vorticity into the horizontal and the vertical very likely increased circulation thus prolonging the lifetime of the rainband.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1993
- Accession Number
- ADA268358
Entities
People
- Martin R. Martino
Organizations
- Air Force Institute of Technology