Original
Correction of Shipboard Wind Speed and Direction toward the Utilization of Big Data
2020 年 5 巻 1 号 p. 29-37
詳細
2020 年 5 巻 1 号 p. 29-37
When marine weather data measured on board are gathered by LAN and transferred from vessels automatically, the big data sets which are connected seamlessly between the sea and the land according to a combination of the shipboard data, the ocean buoy data, AMEDAS data, etc., will have more high-resolution both temporally and spatially and will be more useful for coastal and inland seas. However, the wind data measured on board includes wake of wind caused by the structure on the vessel. Therefore, it is desirable to be corrected for each vessel. The correction of wind data measured automatically every minute on board was attempted using the reference wind data at a stationary site. The shipboard wind was measured by a vane anemometer, and the reference wind was measured by an ultrasonic anemometer. Correction for the wind direction was not necessary for the experiment ship. The corrective equation for wind speed was obtained, and is available in all wind directions. The wind speed increases by 1.3 times on board. The error observed was around 2 times of the nominal accuracy of the vane anemometer for the wind direction and was 2 or 3 times for the wind speed. The error includes the characteristics of the anemometer, the influence of the structure on the vessel, the variations of the heading direction, and the altitude adjustment for the wind speed. Our understanding of these errors that each vessel has will be advanced significantly when big data sets are gathered by the automatic measurement.
