Characteristics of insolation in places with toponym originated from the sun in formerly Munehi-village of Nara prefecture, Japan

Abstract

There are a lot of land names in Japan which literally mean sunshine and sunshade and they are called “HINATA” and “HIKAGE” toponyms, respectively. This study collected them from all names of “KOAZA” (a small sub-district) in the old cadastral registers of formerly Munehi Village, Nara Prefecture, Japan, and investigated the sunshine duration and the solar radiation rate in these areas by using GIS. The “HIKAGE” (sunshade) areas have lower elevation, lower sky factor, and shorter insolation time than “HINATA” (sunshine) areas. The aspects of the “HIKAGE” areas range from northeast to northwest, while most of the “HINATA” areas are located on the southwest or south facing slopes. The diffuse and direct solar irradiation of the “HIKAGE” areas at winter solstice are 81 and 21 percent of those of the “HINATA”. However, the houses and arable fields are distributed on both areas, and the recent residents rarely use these “KOAZA” names and do not remember much about the characteristics of the areas.