Wind Fields over Lake Biwa and Their Effect on Water Circulation

Abstract

Horizontal distributions of wind over Lake Biwa have been measured almost simultaneously using three boats. Time changes in wind were also measured at several coastal points. These data, including AMeDAS and continuous records in Shiga Prefecture, were analyzed to find the characteristics of wind fields over and around Lake Biwa. Results show that the wind is not spatially uniform, and that the dominant strong northerly wind has a positive curl in the northern area of the lake and a negative curl in the south. This wind distribution is considered to be one of the most important maintenance mechanisms of the horizontal water circulation (gyres) often observed in Lake Biwa. This possibility is confirmed in part by numerical calculations with a simple two-layer circulation model. © 1995, The Japanese Society of Limnology. All rights reserved.