A study of meso-alpha-scale disturbances on the Baiu Front and their environmental field

作者：Tagami Hirotaka^*; Niino Hiroshi; Kato Teruyuki

来源：Journal of the Meteorological Society of Japan, 2007, 85(6): 767-784.

DOI：10.2151/jmsj.85.767

Several meso-alpha-scale lows (MAL), which developed along the Baiu Front in the year of 2001 are studied by an observational analysis and a numerical experiment. The observational analysis utilizes the GANAL and RANAL data which have a horizontal resolution of 125 km and 20 km, respectively. The observed MALs are found to be categorized into two types: One is accompanied by an upper-level disturbance, and has a trough tilting westward with increasing height. The other is not accompanied by an upper-level disturbance, and has a trough tilting eastward with height. A MAL of the latter type that appeared on 20 June 2001 is examined in detail. This MAL had a horizontal pressure trough which runs in the southwest-northeast direction. It was associated with a cold temperature anomaly at the low-level to the east side of the low center, which is consistent with the eastward tilting trough in view of the hydrostatic balance. A numerical simulation using a 5 km-mesh Japan Meteorological Agency Non-Hydrostatic Model, without a cumulus parameterization, successfully reproduced the observed characteristics of the MAL. A budget analysis of the thermodynamic equation shows that the cold anomaly at the low-level in the east side of the MAL, is caused by an adiabatic cooling associated with the strong updraft induced by a condensational heating in the mid- and upper-levels.

• 出版日期2007-12
• 单位中国气象科学研究院