Naval Postgraduate School
Dudley Knox Library
NPS Dudley Knox Library
View Item 
  •   Calhoun Home
  • Faculty and Researchers
  • Faculty and Researchers' Publications
  • View Item
  •   Calhoun Home
  • Faculty and Researchers
  • Faculty and Researchers' Publications
  • View Item
  • How to search in Calhoun
  • My Accounts
  • Ask a Librarian
JavaScript is disabled for your browser. Some features of this site may not work without it.

Browse

All of CalhounCollectionsThis Collection

My Account

LoginRegister

Statistics

Most Popular ItemsStatistics by CountryMost Popular Authors

Observation and prediction of flotsam

Thumbnail
Download
IconCollins_Observation and prediction of flotsam.pdf (3.432Mb)
Download Record
Download to EndNote/RefMan (RIS)
Download to BibTex
Author
Gates, Dallas C.
Collins, Curtis A.
Margolina, Tetyana
Rago, Thomas A.
Date
2021-04-01
Metadata
Show full item record
Abstract
Surface drift of eighty-nine undrogued RAFOS floats in the California Current System (CCS) has been studied to describe patterns of flotsam drift, its seasonal variability and predictability limitations. The floats were launched in the California Undercurrent during 1992–2010 and were tracked by the ARGOS system when they surfaced at the end of their subsurface missions. The duration of surface trajectories varied from as short as 11 to as long as 280 days. The surface drift of these floats was typically equatorward in the California Current. However, some floats moved poleward into the Subpolar Gyre, and others drifted westward into the North Equatorial Current. Usually, observations of surface currents use drifters which are coupled to the surface layer by drogues located at 15 m depth. While drogued observations are useful for studies of circulation of the upper layer of the ocean, a more typical operational problem involves trying to find flotsam that has fallen off the deck of a ship or to predict the path of an abandoned vessel. To better understand the behavior of these surface drifting objects, observations of the surface drifts of RAFOS floats in the California Current system were used to compare the floats’ motions to wind-induced drift and to evaluate the drift prediction by three ocean models: Ocean Surface Current Simulator (OSCURS), Global Navy Coastal Model (gNCOM) and Hybrid Coordinate Ocean Model (HYCOM). Cross-Calibrated Multi-Platform Ocean Surface Wind Vector L3.0 First-Look Analysis wind data were used to analyze the surface drift of the RAFOS floats. The best correlation between float drift speed and wind speed was observed during summer and fall months, when the wind regime over the Northeast Pacific is dominated by the North Pacific High. The predominant winds associated with this regime are steady and contribute to the surface drift in the same direction as the large-scale geostrophic component of the California Current. Evaluation of the drift prediction by three ocean models was conducted by comparing observed drifter trajectories with model-simulated trajectories at 7-day time scales. The model-simulated trajectories were initially collocated with RAFOS positions and restarted every 15 days. The OSCURS model was the only one of three analyzed models which allowed for tuning based on the surface RAFOS trajectories. Two main parameters, Wind Angle Deflection (WAD) and Geostrophic Current Factor (GCF), were adjusted to minimize the separation between observed and modeled trajectories. At shorter time scales, from weeks to several months, the tuned OSCURS model outperformed gNCOM and HYCOM models in reproducing the observed surface drift. For seasonal and longer time scales, both gNCOM and HYCOM can reproduce the seasonal variability, flow direction, and eddy-like structures in the California Current system, which may be useful for long-term forecasts of the Northeast Pacific circulation.
Description
17 USC 105 interim-entered record; under temporary embargo.
URI
http://hdl.handle.net/10945/68926
Collections
  • Faculty and Researchers' Publications

Related items

Showing items related by title, author, creator and subject.

  • Thumbnail

    Behavior of Flotsam in the California Current System Utilizing Surface Drift of RAFOS Floats 

    Gates, Dallas Cody (Monterey, California. Naval Postgraduate School, 2012-09);
    The patterns of surface drift of eighty-nine undrogued RAFOS floats in the California Current System have been studied. The floats were launched in the California Undercurrent during 19922010 and were tracked by the ARGOS ...
  • Thumbnail

    Seasonal variability in the California Current, a DIECAST model study 

    Donato, Joseph R. (Monterey, California. Naval Postgraduate School, 1998-12);
    The high resolution DIECAST ocean model, with improved physics, is used to simulate the annual cycle of mesoscale variability in the California coastal region. Model improvements include reduced numerical dispersion, an ...
  • Thumbnail

    High frequency subsurface Lagrangian measurements in the California Current with RAFOS floats 

    Benson, Kirk R. (Monterey, California. Naval Postgraduate School, 1995-09);
    This study presents float observations from four RAFOS floats that were deployed off central California for a twenty-three day period as part of a Tomography Demonstration Experiment. These floats, which sampled hourly, ...
NPS Dudley Knox LibraryDUDLEY KNOX LIBRARY
Feedback

411 Dyer Rd. Bldg. 339
Monterey, CA 93943
circdesk@nps.edu
(831) 656-2947
DSN 756-2947

    Federal Depository Library      


Start Your Research

Research Guides
Academic Writing
Ask a Librarian
Copyright at NPS
Graduate Writing Center
How to Cite
Library Liaisons
Research Tools
Thesis Processing Office

Find & Download

Databases List
Articles, Books & More
NPS Theses
NPS Faculty Publications: Calhoun
Journal Titles
Course Reserves

Use the Library

My Accounts
Request Article or Book
Borrow, Renew, Return
Tech Help
Remote Access
Workshops & Tours

For Faculty & Researchers
For International Students
For Alumni

Print, Copy, Scan, Fax
Rooms & Study Spaces
Floor Map
Computers & Software
Adapters, Lockers & More

Collections

NPS Archive: Calhoun
Restricted Resources
Special Collections & Archives
Federal Depository
Homeland Security Digital Library

About

Hours
Library Staff
About Us
Special Exhibits
Policies
Our Affiliates
Visit Us

NPS-Licensed Resources—Terms & Conditions
Copyright Notice

Naval Postgraduate School

Naval Postgraduate School
1 University Circle, Monterey, CA 93943
Driving Directions | Campus Map

This is an official U.S. Navy Website |  Please read our Privacy Policy Notice  |  FOIA |  Section 508 |  No FEAR Act |  Whistleblower Protection |  Copyright and Accessibility |  Contact Webmaster

Export search results

The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

A logged-in user can export up to 15000 items. If you're not logged in, you can export no more than 500 items.

To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.