SEMINAR: MPO Seminar:Dr. Patrick Hogan,Tuesday,March 23 at 11:00 a.m.,Slab Seminar Room S/A 103

[Sandrine Apelbaum <sapelbaum@rsmas.miami.edu>]

MPO Seminar

 

Dr. Patrick Hogan

Open Ocean Processes and Prediction Systems Section

Naval Research Laboratory - Stennis Space Center

 

Title:Predictability of Lagrangian Sonobuoys

 

 Date: Tuesday, March 23 at 11:00 a.m.

Room: Slab Seminar Room, S/A 103

 

 

 

Abstract:

 

Some acoustic sensor systems used by the Navy to protect ships from hostile threats are air-dropped sonobuoys. Recently, new versions of these systems have required an increase in “in-the-water” lifetime from 4-8 hours to 24-48 hours. Thus the new systems greatly benefit from, and in some cases require, accurate knowledge of the ocean currents in order for the buoy field to maintain optimal search coverage. The ocean modeling component of this project includesassimilative regional ocean forecasting (using the NCOM/NCODA system), hydromechanical modeling for specific buoy types, and sonobuoy trajectory analyses such as calculations of relative dispersion. Results from real-time support of two sonobuoy deployment exercises will be discussed. In one exercise (2009), real-time support from forecast systems with progressively finer horizontal resolution (9, 3, 1 km) were provided, and those results demonstrate that an accurate initial state is more important than horizontal resolution for a good sonobuoy trajectory forecast. In the other exercise (2007), which was held in a challenging environment near the Kuroshuio, ensembles have been used to describe the trajectory drift uncertainity. As will be discussed, the “spread” of the ensemble members is relatively small in the area of the Kuroshio north of the Ryukyu Islands where the Kuroshio Current flows consistently towards the northeast. The south side of the Ryukyu’s however is dominated by mesoscale eddies, and as such the variability is much greater and the predictability much more difficult, as evidenced by the large spread in the uncertainty envelope outlined by the individual ensemble trajectories.

 

Sandrine Apelbaum

Meteorology and Physical Oceanography 
Rosenstiel School of Marine and Atmospheric Science
University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149-1098
Tel     (305) 421-4057
Fax     (305) 421-4696

sapelbaum@rsmas.miami.edu