Observation and modeling of the Kampachi Cloud (the cloud street over Tokyo in summer)

最近，夏天在东京的大都会环线8号路上，经常可以看到一条街道的积云（所谓的“坎帕奇云”）。1995年至1997年在三个激光雷达站进行了激光雷达网和空中观测，以研究坎帕奇云的形成机制。主要研究结果总结如下：(1)对东京地区地面风温分布的分析表明，云街的地理位置是由热岛环流与东京地区陆海风环流的相互作用决定的。(2)在东京地区对坎帕奇云进行了激光雷达网和探空观测，研究了坎帕奇云的结构。1994年8月8日下午，当来自东京湾和相模湾的海风吹入东京热岛时，激光雷达在混合层上方1200米处观测到典型的云街。(3) 1996年的大气观测表明，东京上空存在人为源造成的气溶胶层。在白天，气溶胶层与混合层重合。结果表明，坎帕奇云街的凝结核和水汽可能来自混合层。提出了东京上空大气环境和坎帕奇云的观测模式。从东京湾和相模湾吹来的海风、沿着环路8号的热岛、气溶胶层和坎帕奇云是夏季东京上空大气环境的特征。

Recently, a street of cumulus clouds (the so-called "Kampachi Cloud") was frequently observed over the Metropolitan Loop Road No.8 in Tokyo in summer. The lidar network and airborne observations were carried out at three lidar stations from 1995 to 1997 in order to investigate the mechanism of the Kampachi cloud. The main results are summarized as follows.(1) The analysis of surface wind and temperature distributions in Tokyo revealed that the geographical location of the cloud street was determined by the interaction between the heat island circulation and the land and sea breeze circulation in Tokyo.(2) The lidar network and radiosonde observations of the cloud were carried out in Tokyo in order to investigate the structure of the Kampachi Cloud. A typical cloud street was observed by lidar at 1200m just above the mixed layr in the afternoon on 8 August 1994, when the sea breezes from the Tokyo and Sagami Bays were blowing into the heat island of Tokyo.(3) The airborne observations in 1996 demonstrated that there was the aerosol layr over Tokyo due to the anthropogenic sources. In the daytime, the aerosol layr coincides the mixed layr. The results suggested that the condensation nuclei and water vapor for the Kampachi Cloud street may be supplied from the mixed layr.We proposed an observational model of the atmospheric environment and the Kampachi Cloud over Tokyo. Sea breezes from the Tokyo and Sagami Bays, the heat island along the Loop 8, the aerosol layr and the Kampachi Cloud characterize the atmospheric environment over Tokyo in summer.