Boundary Layer Structural Analysis of Large Scale Precipitation at Weather Front
Abstract
Atmospheric precipitation forecasting has long been a difficult problem. One of the main reasons is possibly that the median scale triggering regime of precipitation has not been sufficiently explained. This paper uses observation data at the 325-m meteorological tower at the Inst. of Atmospheric Physics of the Chinese Academy of Sciences, sounding data of acoustic radar, and conventional data to analyze the triggering regime of two heavy rainfalls in the Beijing area from 0230 to 0430 hours, 27 Aug. 1980. By analyzing the continuous observation data through sounding of the boundary layer, it was discovered that the heavy precipitation process of the large scale front precipitation is triggered by a medium scale system. In this process, the medium scale system with period about 8 to 9 minutes was the one. This wavy motion occurred at night, caused by shallow density flow at low layers; this is a gravity internal wave. In the Beijing area when a front passes at night, consideration should be given to the superposition of mountain wind and slightly deviated northerly air flow; this superposition intensifies the density flow at low layers following the front and will cause the establishment of the 2nd temperature inversion layer and stimulate the inversion layer to produce gravity waves. Thus, for night passage of a weather front, consideration should be given to this amplitude increase function. Chinese translations.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 09, 1983
- Accession Number
- ADA210867
Entities
People
- T. Shiyan
- Y. Zhoujia
- Z. Cuiquan
Organizations
- National Air and Space Intelligence Center