Intercomparison Tests Related to the Application of Drift Buoy Systems for Lagrangian Current Measurements in the Yellow Sea

Abstract

Based on the success of the torpedo drifter (Cresswell et al. 1978; Fig. 1) developed and used by Cresswell of CSIRO in the Indian Ocean, the Tasman Sea, and in eddys off the east Coast of Australia, (Cresswell and Vaudrey, 1977; Cresswell and Wood, 1977) and the Ferranti ORE version (Smith et al 1984; Fig. 2) used by Luyten in the Agulhas current off Africa (Luyten and Smith, 1985), the ORE torpedo drifter was planned for use in the Yellow Sea Experiment, a joint USA-PRC coastal processes study to be conducted in 1986. However, a test performed at the Scripps Institution of Oceanography (p.p. Niiler, personal communication) indicated that despite the advantages of the torpedo shape in reducing wind and wave drag force errors in major ocean current areas, in regions having low velocity current regimes these errors might still be significant. Therefore, an intercomparison experiment was conducted using the ORE torpedo drifter, small spherical drifters, and the Scripps spherical drifter-drogue system. Various drogues were used with the torpedo and the small spherical drifters. While wind and sea conditions at the time of the experiment were not extreme enough to conclusively answer the question raised by the Scripps observations, it is believed an important aspect of the use of drogued drifters was revealed.