BIOGEOCHEMICAL BUDGET THROUGH THE STRAIT OF GIBRALTAR, A MODELLING STUDY

BIOGEOCHEMICAL BUDGET THROUGH THE STRAIT OF GIBRALTAR, A MODELLING STUDY

Macas, D. (1),, Bruno, M.(2) , Echevarra, F. (1,3), Vzquez, A.(2),Garca, C.M. (1)

(1) Biology Department. University of Cdiz(2) Applied Physics Department. University of Cdiz

(3) Centro Andaluz de Ciencia y Tecnologa Marinas (CACYTMAR)

AREA OF STUDY

1/15

AREA OF STUDY

1/15

AREA OF STUDY

14 km250 m

2/15

ALONG STRAIT CIRCULATION

TWO LAYER FLUX OVER THE SILL

3/15

ALONG STRAIT CIRCULATION

INTERNAL WAVE GENERATION

TIDE RISING IN THE ATLANTIC

INTERFACIAL MIXINGBUDGETS ALTERATION 4/15

DIMENSION OF THE PHENOMENON

-200

-150

-100

-50

-200

-150

-100

-50

-200

-150

-100

-50

Salinidad (p.s.u.)

Temperatura (C)

Clorofila (mg/m3)

35

35.6

36.2

36.8

37.4

38

38.6

1313.51414.51515.51616.517

00.651.31.952.63.253.94.55

a)

b)

c)

HW+6 HW-4 HW-2 HW HW+2 HW+4 HW+6 HW-4 HW-2 HW HW+2 HW+4

1 2 3 4 5 6 7 8 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

1 2 3 4 5 6 7 8 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

HW+6 HW-4 HW-2 HW HW+2 HW+4 HW+6 HW-4 HW-2 HW HW+2 HW+4

1 2 3 4 5 6 7 8 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37

HW+6 HW-4 HW-2 HW HW+2 HW+4 HW+6 HW-4 HW-2 HW HW+2 HW+4

Complicate patterns on the spatio-temporal distribution of physical and biogeochemical variables

Undetermined effect of interfacial mixing on the element budgets between Mediterranean and Atlantic basins.

NECESITY OF APPROPIATED MODELS TO REPRESENT TIDAL FORCINGS AND MIXING EVENTS !!

5/15

6/15

PHYSICAL MODEL

-6 -5.8 -5.6 -5.4 -5.2 -5

35.6

35.8

36

36.2

36.4

Gibraltar

Tarifa

CeutaTanger

Data of:* Upper layer velocity* Lower layer velocity* Upper layer thickness

START POINT: 2 layer-2D hydrodynamical model (Izquierdo et al, 2001)

Main problems:* Two-layered model* Hydrostatic (no w velocities)

THREE LAYER APPROACH

Sigmoid fitting

Velocity

h1

Dep

th

u1u2

1

2

Velocity

h1

Dep

th

u1u2

1

2

3

u3

h3

The interfacial layer is the region where a steep change in the vertical velocity profile occurs (3).

PHYSICAL MODELIMPROVEMENTS OF THE MODEL

7/15

8/15

Interface

Dep

th

Along strait distance

W E

Upper layer velocity

Lower layer velocity

Density

h1

Interface

/2

/21 m

Nbefore

Ndeep

( )( )

25.0*)()(

)1(0

221

12