Extrapolation of Subsurface Current Observations to the Sea Surface: Applicability and Limitations of Basic Algorithms

摘要

Information about near-surface currents provided in near-real-time is required in a variety of applications. However, direct measurements of near-surface currents are scarce. In the Gulf of Mexico, the oil industry has been collecting current profiles from deepwater rigs, platforms, and moorings in accordance with BSEE Notices to Lessees (NTLs) since 2005. On the rigs and some platforms, these profiles are usually collected with long-range ADCPs positioned beneath the rig/platform keel, so the measured current profiles typically extend from 70-80m below the surface to as deep as 1000m. Unfortunately, only a few stations are equipped to provide good-quality near surface current data. This study assesses the validity and limitations of some simplistic current profile extrapolation algorithms, including approximation of the near surface current by "slab" flow and profile extrapolation algorithms derived from the shape of the measured subsurface profile or from a generic current profile shape.