大气科学2012，Vol.36Issue(6)：1112-1122,11.DOI:10.3878/j.issn.1006-9895.2011.11174
夏季黄河下游地区中尺度对流系统的气候特征分布
Analysis of Climatic Characteristics of Mesoscale Convective System Over the Lower Reaches of the Yellow River during Summer
摘要
Abstract
Mesoscale convective system (MCS), including mesoscale convective complexe (MCC), permanent elongated convective system (PECS), meso-P-scale convective complexe (MpCC), and meso-P-scale PECS (MJ3PECS), over the lower reaches of the Yellow River during summer from 1996 to 2008 were analyzed using hourly 1996—2008 satellite date, NCEP data, and a statistical method. MCC and PECS were the main MCS in this region, and the number of MCC, most of which appear in July, is greater than that of PECS. The mean mature areas (≤—52°C cold cloud shield), eccentricities (minor axis/major axis), and lifetimes of MCC and PECS that occur in this region are much larger than those of MCS that occur in the United States. However, the mean eccentricities of M(3CC and MpPECS resemble those of systems in the United States, and their lifetimes are shorter than those of systems in the United States. PECS have a mean minimum temperature of black body of —72 °C, 1°C lower than that of MCC, and a mean lifetime 0.9 h longer than that of MCC, indicating rapid maturing and slow extinction. Two peaks corresponding to the diurnal cycle are clearly seen in the formation, maturation, and extinction period of MCC, but PECS exhibit only one peak. MCC over the lower reaches of the Yellow River occur mainly in two periods. One type forms in the afternoon, matures in the late afternoon, and is extinct in the early morning; the other forms in the late evening, matures in the early morning, and is extinct in the morning, or as late as noon. MCS show obvious yearly variations. For example, in 1999, when there were fewer MCS, the West Pacific subtropical high at 500 hPa leaned southward, and the geopotential at 500 hPa in North China was higher than in normal years. In 2001, however, when there were more MCS, the subtropical high was abnormally strong, the geopotential at 500 hPa in North China was lower than usual, and a trough of low pressure appeared at 850 hPa. Consequently, the lower reaches of the Yellow River region was influenced by the southwest airflow located at the edge of the subtropical anticyclone.关键词
MCC PECS/气候特征/黄河下游Key words
MCC, PECS, Climatic characteristics, lower reaches of the Yellow River分类
天文与地球科学引用本文复制引用
卓鸿,赵平,李春虎,蒲章绪..夏季黄河下游地区中尺度对流系统的气候特征分布[J].大气科学,2012,36(6):1112-1122,11.基金项目
中国气象科学研究院灾害天气国家重点实验室项目2009LASW-B08、2008LASWZI01,山东省气象局项目2005sdqxz17 （）
