Abstract
In Japan, forested area is generally distributed at higher elevation than other land-use such as agricultural area and urban area. Several observational studies have reported that precipitation amounts increase with elevation. These two facts imply that forested area has greater precipitation amounts than other land-use. However, no studies have quantified the difference in precipitation amounts between forest and other land-use such as agricultural area and urban area. The purpose of this study is to quantify the difference by using GIS datasets.
Annual precipitation for forested area, agricultural area, and urban area was 1900.7 mm, 1565.7 mm, and 1575.3 mm, respectively. The average of annual precipitation amounts for forested area was greater than those for agricultural area and urban area by ca. 330mmy-1. This difference was caused by following two facts, as expected before. First, forested area is generally distributed at higher elevation than other land- use. Second, precipitation amounts increase with elevation. Therefore, we should consider this difference, when comparing runoff and/or evapotranspiration between forested area and other land-use.
