THE SPATIAL DEVIATION OF CONCENTRATED HEAVY RAIN IN TOKYO - USING DETAILED URBAN GEOMETRIC DATA -

Abstract

Unusual weather, such as urban localized heavy rain, has become a serious problem lately due to the disasters caused by it. In this work, the latest data of Tokyo, Japan is used with past ones to see the dramatic change in urban geometry and to understand the spatial anomaly of concentrated heavy rain in summer time. As a result, the urban geometry in Tokyo has indeed grown. Adding the displacement height to actual elevation gives the "affective" elevation, which is very low along the bay and abruptly increases as it approaches the western areas. This sudden increase in elevation seems to correspond with where the anomaly of rainfall for concentrated heavy rain becomes positive. In addition, the 9-year data from the River Bureau shows the shift of positive anomaly into the urban area. Finally, the spatial deviation, driven by the Amesh data, indicates the strong relationship between urbanization and precipitation in Tokyo.