Tsunami Ghost Boat Drift According to OSCURS - March 27, 2012

By Curtis C. Ebbesmeyer, Beachcombers’ Alert,

curtisebbesmeyer@comcast.net

Jim Ingraham, DriftBusters Co.,

jim.ingraham@wavecable.com

Please report flotsam to:

www.flotsametrics.com

            On March 20, 2012, Canada’s Department of National Defense spotted a derelict vessel on the order of 100-feet long off the Queen Charlotte Islands (Figure 1).  Subsequent investigation traced the vessel to northern Japan where the great tsunami of March 11, 2011, washed it out to sea. 

            Using the computer model known as OSCURS (Ocean Surface CURrent Simulator; see other blogs at this website for descriptions of OSCURS), Jim Ingraham reconstructed the drift of the vessel ending on February 29, 2012, the last date for which daily weather data is available from the US Navy via NOAA (National Oceanic and Atmospheric Administration; Figure 2). 

Jim achieved a reasonable simulation of the vessel’s drift using a wind factor of 2.1.  Jim will receive the daily March weather from the US Navy via NOAA in the first few days of April.  This will allow him to update OSCURS for March showing where and when the vessel might come ashore.  We will update the vessel’s drift in a subsequent blog.

            Judging from the devastation in Japan, we believe additional vessels set free by the tsunami are drifting toward America.  Figure 3 shows the OSCURS simulation we believe indicates where these other vessels may be heading.   The destinations range from the Gulf of Alaska south to waters between California and Hawaii.  Some vessels may loop around the Gulf of Alaska and the Great Garbage Patch located between California and Hawaii.

            We urge mariners to be vigilant.  Please report derelict vessels to Curt at www.flotsametrics.com.

Figure 1.  Aerial photo of the Japanese fishing vessel discovered adrift off the Queen Charlotte Islands.  Photo credit: Canada’s Department of National Defense.



Figure 2.  OSCURS drift for Japanese Boat No. 1 using wind factor 2.1 ending on February 29, 2012.  The trajectory (wiggly line) from the start-point proceeds day by day according to the weather data at the location of the vessel. The trajectory ends on February 29, 2012, the last date for which daily weather data are available from the US Navy.  Jim Ingraham OSCURS simulation.

Figure 3.  Possible locations of other derelict vessels based on OSCURS drift for wind factors 2-3 ending on February 29, 2012.  Vessels may be in the vicinity of the colored circles at the end of the trajectories.  All totaled, this computer run shows 36 drift tracks, i.e., flotsam with six wind factors starting on March 11, 2011, at six coastal locations.  Start-points are stars along the tsunami coast.  The colors of the 6 start-points from north to south are: black, red, green, blue, light purple, and gray.  All trajectories (wiggly lines) from each start-point are the same color of that start-point.  To represent various wind factors, six trajectories begin at each start point according to wind factors spaced at 0.2 intervals: 2.0, 2.2, 2.4, 2.6, 2.8 and 3.0.  End-points are the circles of the same color.  Most of the time, the end-points are distributed by the fastest (largest magnitude) wind factor leading the way -- as seen in the black trajectories.  Each trajectory ends on February 29, 2012.  Jim Ingraham OSCURS simulation.