Model simulation of dye dispersion

Bob Houghton, LDEO

Changsheng Chen & Qichun Xu, Umass D

FieldExperimentGLOBEC IIIMay 1999

Pre-injection

Cross tidal front

Hydrographic

sections

Observations

Temperature variation of dye patch (seasonal heating ~0.034 oC/day)

Inferred cross-front velocity v=(dT/dt)/(dT/dy)

4km grid 2km grid

`

0.25 km grid0.5 km grid

From simulated model calculations

Data assimilation fromScanfish surveys of dye patch

Trajectory of a near-

bottom particle

Trajectory of a near-surface particle

Trajectory of the center of the vertically averaged model dye concentration.

Simulated 0.5 km Assimilation 0.5 km

Simulated Assimilation

2

1: 3:59 GMT, 23 May 2: 11: 43 GMT, 23 May3: 15:22 GMT, 23 May4: 19:24 GMT, 23 May5: 21:34 GMT, 23 May6: 00:53 GMT, 25 May

ObservedSimulated Assimilation with T and S

1

34

5

6

Observed dye patch temperature

Patch temperature from assimilation model

Data assimilation

Integrated dye on 30 m Temperature

A B

C D

5-23 6000 5-23 18000

5-24 18000

5-26 18000

Integrated dye on 30 m density

A B

C D

5-26 180005-24 18000

5-23 180005-23 6000

Diabatic event

C D

o

o

A B

o o

600 hr 800 hr

1000 hr 1200 hr