Problems in Risk Management of Regional, Local and Micro-scale Winds in Relation to Global Change

摘要

This article first describes winds at regional, local and micro-scales, with special reference to methods of observation and analysis according to the order of the scales. It shows that in studies at the regional scale, data derived from detailed observations under the network of second-order observation stations and AMeDAS arranged by the Japan Meteorological Agency are utilized, with the main study method being synoptic climatology. These were established in Japan in 1960s and 1970s. Mesh data were used mainly in the 1980s and 1990s, presenting air flow in accordance with directions of prevailing upper winds, geostro-phic winds, etc.rnRegarding local-scale winds, the main topic of concern has been winds occurring under certain topographical conditions such as in V-shaped or U-shaped valleys, on mountain ridges and along valley side slopes. Observations are carried out by temporally organized groups using instruments and indicators such as wind-shaped trees. These studies started in Europe in the early 20th century, but have been undertaken intensively since the 1950s. For agricultural land use, wind power stations, air pollution, city planning and construction of structures such as bridges, tall buildings, highways, etc., knowledge of local wind conditions has been an essential requirement in recent years. It has been pointed out that these conditions should be elucidated not only by model simulation or wind tunnel experiments, but also by field observations. This article also considers changes in winds on the local scale under the influence of global warming, taking an example of Santa Ana in the U.S.A. It discusses risk problems based on recent studies. The last part deals with risk management and insurance, based on statistics available.