Structure and Behavior of Mesoscale Cloud Clusters Traveling over the Baiu-Frontal Zone

Abstract

A case study was made of long-lasting mesoscale cloud clusters observed by the Geostationary Meteorological Satellite (GMS) from 13 to 15 July 1986, which formed on the continent and traveled over the Baiu-frontal zone. The cloud clusters separated into southern-and northern-cloud groups around 130E. The southern-cloud group decreased its traveling speed. New cumulonimbus-cloud groups formed 40 to 80km to the west of the pre-existing group in the southern-cloud group. Further, new cumulonimbus clouds appeared about 15km to the west of the pre-existing one in each group. Simultaneous formation of two scales of convective clouds occurred in the slow-moving cloud group.The area of traveling clouds, which originated from deep convective clouds in the northern cloud group, lasted for more than 10 hours after the deep convection decayed. Bright bands and streaks were recognized in their radar echo around 135E. They were located in the layer of convective instability at middle to upper levels, with a large gradient of temperature at 850mb and a synoptic-scale updraft at the middle level around 140E. It is suggested that the cloud area originating from "convective clouds" was changed to "stratiform clouds."

Nocturnal Evolution of Cloud Clusters over Eastern China during the Intensive Observation Periods of GAME/HUBEX in 1998 and 1999

“…Regions with T BB colder than À70 C relate directly to heavy rainfall Mapes and Houze 1993). Iwasaki and Takeda (1993) referred to such cold T BB areas as ''cold regions''. The regions correspond to meso-b-scale convective systems within the meso-a-scale cloud cluster (Ninomiya et al 1988a).…”

Convective Cloud Systems over the Tibetan Plateau and Their Impact on Meso-Scale Disturbances in the Meiyu/Baiu Frontal Zone

“…(4) the BMF embeds many medium to mesoscale disturbances, which move eastward along the front as developing and cause heavy rains. The disturbances tend to develop near Japan, where the temperature gradient is large (e.g., Iwasaki and Takeda 1993;Ninomiya 2000;Shibagaki et al 2000).…”

A Diagnostic Study of Formation and Structures of the Meiyu Front System over East Asia

“…Previous research shows that the Meiyu is caused mainly by the Meiyu front (or ''Baiu front'' in Japan)-a quasi-stationary front oriented in the northeast-southwest direction at the lower troposphere. Chinese and Japanese meteorologists have studied various aspects of the Meiyu front (Akiyama 1973(Akiyama , 1984(Akiyama , 1987(Akiyama , 1989(Akiyama , 1990Gao et al 1990;Hu 1997;Matsumoto et al 1970Matsumoto et al , 1971Iwasaki and Takeda 1993;Ninomiya 1984Ninomiya , 1999Ninomiya and Kurihara 1987;Ninomiya and Akiyama 1992;Ninomiya et al 1988), and concluded that (i) the Meiyu front is a belt with a large humidity gradient stretching along the MRYR from China to Japan; (ii) the Meiyu front should be expressed by a very dense gradient zone of equivalent potential temperature ðy e Þ isolines rather than by a dense gradient zone of temperature (T) isolines; (iii) the Meiyu front should be classified as a subtropical front with a multi-scale (large, synoptic and mesoscale) structure; (iv) convective activities often occur along the Meiyu front; and (v) the Meiyu front is related to the subtropical anticyclone, the South Asia anticyclone, the blocking anticyclone at mid-high latitudes, the southwest monsoon flow, the low-level jet (LLJ), the upper-level jet, and other large-scale atmospheric phenomena. Matsumoto et al (1971) pointed out that the Meiyu front is a warmmoist band lying at the mid-troposphere, accompanied by a strong cyclonic shear and neutral thermodynamic stratification.…”