Observations of the climate in the southern part of the north basin of Lake Biwa, Japan by a meteorological station mounted on a buoy
Okumura, Y.; Endoh, S.
Japanese Journal of Limnology 64(2): 103-112
2003
ISSN/ISBN: 0021-5104 Accession: 011079881
A meteorological station mounted on a buoy (the buoy station) was moored in the southern part of the north basin of Lake Biwa, Japan from August 1998 to December 2001. The buoy station was able to measure the direction and velocity of wind, the temperature of air and water, or the temperature of air and the relative humidity. These data were transferred to the base station by an MCA (Multi-Channel Access) radio system. The data were occasionally interrupted, e.g., when the buoy was struck by a boat and damaged, the radio receiver of the base station was struck by lightning and the power from its solar cell proved insufficient in winter. The average wind velocity observed by the buoy station was 3.0 m s-1 over the whole period, and the data of that same period in Hikone observed by AMeDAS was 2.7 m s-1. The minimum monthly average wind velocity occurred in July, while the maximum occurred from January to March. Wind roses for the buoy station, Hikone and Minamikomatsu were drawn monthly throughout 2001. The most frequent wind directions observed by the buoy station were northwesterly and southeasterly, with less frequent southerly and south-southeasterly winds. An annual peak-to-peak air temperature difference at the buoy station was 33.3degreeC from August 1998 to August 1999, and the corresponding value in Hikone was 41.3degreeC for the same period. The annual average of the daily peak-to-peak air temperature difference was 4.5degreeC, which is considerably lower than the value away from the lake. The annual average relative humidity at the buoy station in 2001 was 75%, and in Hikone it was 71%.