Egypt Air Flight 990 - Floating Debris Dispersion

Predicted Debris Paths
Temperature and Velocity Fields

October 31 - November 9, 1999

A.R. Robinson, P.J. Haley, Jr., P.F.J. Lermusiaux, W.G. Leslie, C.J. Lozano

Division of Applied Sciences
Department of Earth and Planetary Sciences
Cambridge, Massachusetts



Using the Harvard Ocean Prediction System, the potential paths of floating debris for the period 31 October - 9 November have been estimated and forecast. The results presented here were completed at 6 November 0340 EST. If available information and needs dictate, this forecast will continue to be updated daily.

For this application, a modeling domain with a horizontal resolution of .045 degrees (~5km) and 42 vertical sigma (terrain following) levels is utilized. The simulation assimilates sea surface temperature from satellite observations and is forced by Fleet Numerical Meteorology and Oceanography Center (FNMOC) winds. The simulation is for the period 28 October - 9 November.

Potential Debris Paths

The figures below depict the potential drift paths of floating debris for the period 31 October - 9 November. The gray circle indicates an area 10km in radius from the presumed impact point of Egypt Air Flight 990. Particles located within the gray circle at the time of impact (0700 GMT 31 October) are tracked for the duration of the simulation period. The paths of these particles are plotted for every model time step. 12 hour intervals are indicated by the asterisks. Bottom contours are labeled in feet.

The left figure corresponds to an impact point located at 40.20N, 69.75W, while the figure to the right corresponds to an impact point located at 40.35N, 69.75W. The impact points have been estimated based on differing reports from the news media.

Impact point at 40.20N, 69.75W
Impact point at 40.35N, 69.75W
Floating Debris Drift Tracks
Floating Debris Drift Tracks

Potential paths of floating debris: 31 October - 9 November.

(Click on each image for larger size version)

Overall, the trajectories of the floating debris are dependent upon the winds (strength, direction and pattern) and the internal ocean dynamics (meandering shelfbreak front, westward sluggish shelf currents and eddies, and Gulf Stream warm-core rings).

As shown above, the initial trajectories of the potential debris are influenced by the location of the area of possible impact site with respect to an oceanic front, the shelfbreak front. The surface currents of the front are westward-southwestward, meandering approximately along the path of the 300 foot isobath.

    Southern impact point (40.20N, 69.75W; left image) - This impact point is slightly to the north of the shelfbreak front. During the relatively calm wind period, from Oct 31 0700 GMT up to Nov. 2, the motions of the floating debris depend on their position with respect to the front. The debris which are initially trapped in the front are advected by the currents westward. However, the debris which are to the north and south of the front move sluggishly.

    Beginning around Nov. 2, 1200 GMT, the winds pick up in strength, towards the north, becoming very strong on Nov. 3, 1200 GMT. During this period, all simulated debris are moving rapidly primarily northward, turning in the north-northeast direction, and away from the shelfbreak frontal area.

    Starting late on Nov. 3 up to Nov. 5 1200 GMT, the wind changes direction to the east and weakens to strong-moderate winds. All simulated debris are then predicted to deviate east-southeast. On Nov. 6 0000 GMT, the winds briefly strengthen and change direction to the northeast, explaining the "kinks" in the debris patterns to the east-northeast By Nov. 7, 1200 GMT, the forecast winds return to the southeast, and the debris start to move south-southeast. On Nov 8, 1200 GMT, the forecast winds are to the south-southeast and weakening, the debris tracks turn to the south-southwest as they are driven by the winds and entrained by the general slow shelf circulation to the west-southwest. By Nov 9, 1200 GMT the forecast winds are especially weak and the debris follow the local currents, either the shelf circulation or the shelfbreak front.

    Northern impact point (40.35N, 69.75W; right image) - This impact point is located further from the influence of the shelfbreak front and the potential trajectories respond primarily to the effects of wind forcing. Initially the particles follow the main shelf circulation, moving a relatively short distance, as calm winds conditions exist. Subsequently the winds increase and the general pattern of the trajectories is mainly wind-driven, as was described for the southern impact point.

Go to the previous forecast (released 4 November)

Go to the previous forecast (released 3 November)

Temperature and Velocity Fields

The images below illustrate the 4-dimensional (space and time) simulation which was utilized to produce the potential floating debris paths shown above. Daily plots over the duration of the forecast period are included. Each image shows the temperature values at the 5 meter depth, overlaid with velocity vectors at the same depth. The temperature scale is in Celsius and the velocity scale arrow shown is 50 cm/s. Vectors are not plotted if the velocity is below 5 cm/s. Note that the forecast period begins on 2 November.

31 October (5m Temp./Vel.)
1 November (5m Temp./Vel.)
Temperature on 31 October
Temperature on 1 November
2 November (5m Temp./Vel.)
3 November (5m Temp./Vel.)
Temperature on 2 November
Temperature on 3 November
4 November (5m Temp./Vel.)
5 November (5m Temp./Vel.)
Temperature on 4 November
Temperature on 5 November
6 November (5m Temp./Vel.)
7 November (5m Temp./Vel.)
Temperature on 6 November
Temperature on 7 November
8 November (5m Temp./Vel.)
9 November (5m Temp./Vel.)
Temperature on 8 November
Temperature on 9 November

Harvard Ocean Prediction System (HOPS)

HOPS is a flexible, portable and generic system for inter-disciplinary nowcasting, forecasting and simulations. HOPS can rapidly be deployed to any region of the world ocean, including the coastal and deep oceans and across the shelfbreak with open, partially open or closed boundaries. Physical, and acoustical, real time and at sea forecasts have been carried out for more than fifteen years at numerous sites and coupled at sea biological forecasts were initiated in 1997. The present system is applicable in waters from 10m depth to several thousand meters and the heart of the system is a primitive equation physical dynamical model.

This page has been accessed at least several times since 3 November 1999. This page was last revised at 2200 7 November 1999.

Return to top of document