Improving wind-based upwelling estimates off the west coasts of North and South America

• Main Author: Pickett, Mark H.
• Other Authors: Schwing, Franklin B.
• Published: Monterey, California. Naval Postgraduate School 2012
• Online Access: http://hdl.handle.net/10945/9830

Approved for public release; distribution is unlimited === Weekly upwelling was estimated at 25 sites off the North and South American west coasts from August 1999 to December 2001 using geostrophically derived winds, model-derived winds from the U.S. Navy's global atmospheric (NOGAPS) model, and QuikSCAT satellite-measured winds. Satellite-measured winds, verified with 15 U.S. west coast buoys, were within 1.3 m s-1 and 26ﾰ RMS. Upwelling estimates derived from geostrophic winds using the Pacific Fisheries Environmental Laboratory (PFEL) technique were compared to those derived from both satellite-measured winds and modelderived winds. Upwelling estimates from model-derived winds agreed with satellite-based estimates at all 14 North American sites and 9 of 11 South American sites. Estimates from geostrophic winds agreed with satellite-based estimates at 12 of 14 North American sites and 7 of 11 South American sites. These comparisons showed that upwelling estimates based on the Navy's global model winds were accurate in more regions than those based on geostrophic winds. A fine-scale upwelling investigation using the Navy's high-resolution atmospheric model (COAMPS) revealed narrow near-shore bands of strong wind-stress and wind-stress-curl missed in the above upwelling estimates. Improvements in the depiction of coastal upwelling will require wind data and upwelling estimates with at least a 10 km resolution.