| 摘要: |
| 对渤、黄海14个主要海湾的原始验潮记录进行了分析,从中筛选出水位变化幅度大于或等于50cm的54个假潮个例,着重分析了伴随假潮过程的天气形势,把可能引发假潮的天气形势归纳为4种基本类型。分析结果显示:绝大多数(92%)引发假潮的天气个例都与锋面活动有关;所有个例中低层大气基本上都是弱静力稳定的,且都具有较强的垂直风速切变。根据观测事实和稳定度理论分析认为,低层大气的弱静力稳定层结以及由垂直风速切变引起的剪切不稳定性,是假潮气象学成因的一种必要条件和物理机制。 |
| 关键词: 假潮 天气型 大气重力波 |
| DOI： |
| 分类号: |
| 基金项目:国家自然科学基金项目4967628号;山东省科技计划专项合同96第40号 |
|
| THE METEOROLOGICAL ORIGIN OF SEICHE IN BOHAI SEA AND YELLOW SEA |
|
LONG Bao-Sen, CHEN Ze-Shi
|
|
First Institute of Oceanography, State Oceanic Administration, 266061
|
| Abstract: |
| The original tide records of 14 bays in Bohai Sea and Yellow Sea have been analyzed. 54 seiche cases in which the variations in sea level height ≥50cm are chosen among all the seiche processes. The corresponding weather conditions are also analyzed and induced to 4 basic weather types that can result in seiches: (1) Type A—the observational station is located west of a cyclonic cold front; (2) Type B—the station is located east of a cyclonic cold front and at the west edge of a high pressure; (3) Type C—the station is located north of a cyclonic warm front; (4) Type D—the station is located at the west edge of a high pressure and the east of a low pressure. Analytical results show that the most weather cases (92%) resulting in seiches are accompanied by cyclonic fronts; in fifty percent of these cases the station is located west of the cyclonic cold front and a jet stream exists above the station or upstream. The stratifications of mid-low level atmosphere are basically weak static stability in all the cases, with strong vertical wind shears. Based on the study of weather conditions and the stability theoretical analyses, the mid-low level atmosphere with the weak static stability stratification is a necessary background condition for the occurrence of atmospheric gravity wave and the combination of the weak static stability with the shearing instability caused by the vertical wind shear is one of physical mechanisms of meteorological causes for seiche occurrence. And cyclonic front activities are the most favourable weather background for this mechanism. |
| Key words: Seiche, Weather types, Atmospheric gravity wave |
