Instrumentation for high-frequency meteorological observations from research vessel

Abstract

Ship provides an attractive platform from which high-frequency meteorological observations (e.g., wind components, water vapor density, and air temperature) can be made accurately. However, accurate observations of meteorological variables depend on removal of shipmotion contaminations and appropriate placement of sensors onboard. Vertical and lateral wind components suffer more disturbances than longitudinal wind in consequence of ship motion. Wind stream approaching towards bow gets deflected due to the presence of ship's superstructure that causes error in the wind measurements. It has been reported that underestimation in wind speed owing to the ship's superstructure is ∼7% for bow-on wind and overestimation is ∼10% for relative wind direction of 900 [1]. Mean wind speed reduction of ∼8.5% were estimated due to the cylindrical mast when wind flows was parallel to the horizontal plane and excess of ∼9% for the wind flow normal to the plane. It has been observed that the effect of flow distortion on wind is less for relative wind direction of α450 relative to the major axis of the ship [2]. In this article, instrumentation used for measuring high-frequency components of meteorological parameters onboard Indian Research Vessel “Sindhu Sankalp” and correction of wind for ship motions is considered.