Study of the spatial structure of urban heat island in regional central cities by laser radar

最近，东京看八街上空经常出现一串积云（称为看八积云）。通过对1989年日本岛链的个例分析，得出如下结论：1）日本岛链出现在太平洋高压覆盖下; 2）相模湾西南偏南海风和东京湾东南偏南海风在白天沿看八街形成沿着的局地辐合区。因此，在看八街附近出现了上升气流。3）白天，在看八街附近形成了明显的热岛。1992年夏季，我们利用低空无线电音响、气球等观测了冠八街上空的云链。主要结果如下：4）云顶高度约为15000 m，比以往研究的云顶高约500 m; 5）白天，从东京湾和相模湾吹来的海风在看八街上空存在辐合区; 6）下午，沿看八街沿着出现高温带。我们成功地获得了气溶胶的垂直分布，以显示城市热岛的结构。

Recently, a chain of cumulus (called Kanpachi Gumo) frequently appears over the Kanpachi Street in Tokyo. From the case studies of the temperature and wind distributions in relation to the cloud chain in 1989, it is concluded as follows:1) The cloud chain appeared, when Japan Islands were covered with the Pacific high.2) The south-southewest sea breeze from Sagami Bay and the south-southeast sea breeze from Tokyo Bay formed a local convergence area along the Kanpachi Street during the daytime. Consequently, an ascending air current occurred around Kanpachi Street.3) A remarkable heat island was formed around Kanpachi Street during the day time. As a result, the convection was reinforced by the heat island circulation.The observation of the cloud chain over the Kanpachi Street was carried out by using low-level radio sound, pilot balloon, etc. during the summer in 1992. The main results are summarized as follows:4) The height of the cloud top was about 15000 m, and was about 500 m higher than that of the previous study.5) In the daytime, the convergence are of sea breezes from the Tokyo Bay and from the Sagami Bay existed over the Kanpachi Street.6) In the afternoon, high temperature zone was observed along the Kanpachi Street.In the present study, a portable laser radar for meteorological measurements in atmospheric boundary layer and troposphere has been developed. We succeeded to obrained vertical distribution of aerosols to show the structure of the urban heat island.