Gökay KarakaşGökay Karakaş11 Patrick MarchesielloPatrick Marchesiello22 Stephan FrickenhausStephan Frickenhaus1 1

Nicolas NowaldNicolas Nowald33 Reiner SchlitzerReiner Schlitzer11

11Alfred-Wegener-Institute for Polar and Marine Research (AWI), BremerhavenAlfred-Wegener-Institute for Polar and Marine Research (AWI), Bremerhaven22Institut de Recherche pour le Developpement (IRD), BrestInstitut de Recherche pour le Developpement (IRD), Brest

33Center for Marine Environmental Sciences (MARUM)Center for Marine Environmental Sciences (MARUM), Bremen, Bremen

Modelling Particle Fluxes in the Modelling Particle Fluxes in the Coastal Upwelling Zone off NW AfricaCoastal Upwelling Zone off NW Africa

• Uni-Bremen, AWI, MPI, MARUM, ZMT• aims to investigate geoscientifically the ocean margins, the transitional zones between the oceans and the continents• within the Center the scientific work focuses on four main research fields:

A - Paleoenvironment

B - Biogeochemical Processes

C - Sedimentation Processes

D - Use Impact Research

• The research subjects span from environmental changes in the Tertiary to the impact of recent coastal constructions, and from microbial degradation in the sediment to large scale sediment mass wasting along continental margins

www.rcom-bremen.de

Research Center Ocean Margins - RCOMResearch Center Ocean Margins - RCOM

B - Biogeochemical ProcessesB - Biogeochemical Processes• Project B1:

Oxygen minimum zones in high-productivity regimes: Biogeochemical cycling and geological documentation • Project B2:

Origin, reactivity, and transformation of particulate organic material in the benthic boundary layer in high productivity systems

• Project B3:Lateral and vertical transport of particles produced in the surface layer on their way down to the deep ocean and into the sediment

• Project B4:Biogenic silica in the Southern Ocean and adjacent ocean margin sediments: Biogeochemical processes, budgets, and temporal variations

Sub-project B3: Particle TransportSub-project B3: Particle Transport• How does the material transfer run into the open ocean from the productive zone? Could it be

simulated?

• Which effects have spacious climatic variations on the dynamics of the coastal lift?

• What is the significance of different ballast minerals (e.g. quartz dust, carbonate) for the export and the decay of organic material?

• Which larger particles are important for vertical transport and what is their composition?

• Which processes control concentrations and size distributions of particles in the water column?

• How is the remineralisation in micro environments of pellets and aggregates as a function of size and sinking velocity?

- Modelling the transport of particles in the coastal upwelling system off NW Africa- Various transport scenarios with particle types, concentrations, sizes and sinking rates incorporated - Validation with both particle fluxes from field work (sediment traps, optical measurements) as well as surface ocean data derived

from remote sensing datasets

- Investigations on main and trace elements

- Experimental microbiological studies on pellets and aggregates

- Field Campaigns

B3 – Particle TransportB3 – Particle Transport

A new insight into export budgets of carbon in this major upwelling system of the world ocean

- Deep Sea Particle Camera, ParCa

- In-situ particle data from optical systems

- Quantify the in-situ

distribution, size, orientation

and shape of marine

particulate matter

Field CampaignsField Campaigns

- Data extraction from the pictures is provided by a digital, image analysis software - Attached in a profiler or Remotely Operated Vehicle (ROV)

Field CampaignsField Campaigns

- Remotely Operated Vehicle (ROV)- In-situ sampling of marine aggregates

- Diving up to 1000m

Field CampaignsField Campaigns

Kameraprofil

GeoB 7411

GeoB 8630

GeoB 7415

Kap Blanc

Fallenverankerung

seit 1988

Kameraprofil

GeoB 7404

http://seawifs.gsfc.nasa.gov/SEAWIFS.html

Arbeitsgebiet

18° 18°

20° 20°

22° 22°

24° 24°

26° 26°

-22°

-22°

-20°

-20°

-18°

-18°

-16°

-16°

-14°

-14°

CB_13

CB_I

GeoB_8628GeoB_8629 GeoB_8630

GeoB_8631_1

GeoB_8631_12

GeoB_8632

GeoB_8633_3GeoB_8633_8

GeoB_8634

GeoB_8635

GeoB_8636

GeoB_8637

GeoB_8638GeoB_8639

7929

7930

79317932

79337934

7935

7937

7938

7920

7927

GeoB_7408

GeoB_7410

GeoB_7411

GeoB_7412

GeoB_7413

GeoB_7415

GeoB_7421

GeoB_7422

GeoB_7423

GeoB_7425

GeoB_7428

GeoB_7429

GeoB_7430

POS 272M53 1cM 58 2b500 m1000 m2000 m3000 m4000 m

Source: GEBCO.

Stations from different cruises

• Test various hypotheses on particle transport with simple, idealised scenarios

• Roms_Agrif

Nested Model Setup

• Etopo2 bathymetry• Parent grid 1/12°• Child grid 1/36°• 32 vertical levels

Modelling Particle TransportModelling Particle Transport

• Initialisation and climatology fields from WOA (2001)

• Model started from rest with the January climatology

• Wind and thermodynamic forcing fields from monthly mean COADS (1994)

Modelling Particle TransportModelling Particle Transport

January wind stress July wind stress

• Geostrophic and Ekman velocities along the lateral open boundaries

• Sponge/Nudging with WOA climatology

POS 272 – April 2001 M58/2b – Mai 2003

0 100 200 300

GeoB 7411

P a rtic le Abundance (n/l)

1400

1200

1000

800

600

400

200

0

De

pth

(m

)

0 4 8 12 16 20 24

GeoB 7404 (CB Trap Location)

P artic le Abundanc e (n/l)

4000

3500

3000

2500

2000

1500

1000

500

0

De

pth

(m

)

0 100 200 300

GeoB 8630P a rtic le Abundance (n/l)

1400

1200

1000

800

600

400

200

0

De

pth

(m

)

See map for Station sites Sub-surface peaks…?

# define NWAfrica

!! Parallelization

# define OPENMP

! Embedding

# define AGRIF

!

! Model configuration

# define SOLVE3D

# define UV_COR

# define UV_ADV

# if defined SSH_TIDES || defined UV_TIDES

# undef TIDERAMP

# endif

! Mode Splitting

# define M2FILTER_COSINE

# if defined SSH_TIDES || defined UV_TIDES

# define M2FILTER_FLAT

# endif

! Grid configuration

# define CURVGRID

# define SPHERICAL

# define MASKING

! Input/Output

# undef AVERAGES

! Equation of State

# define SALINITY

# define NONLIN_EOS

# define SPLIT_EOS

! Surface Forcing and Climatology

# define ZCLIMATOLOGY

# define UCLIMATOLOGY

# define ZNUDGING

# define M2NUDGING

# define SPONGE

Modelling Particle TransportModelling Particle Transport!

# ifdef SOLVE3D

# define QCORRECTION

# define SFLX_CORR

# define DIURNAL_SRFLUX

# define TCLIMATOLOGY

# define TNUDGING

# define M3NUDGING

# define ANA_BSFLUX

# define ANA_BTFLUX

# endif

! Lateral Mixing

# define UV_VIS2

# define MIX_GP_TS

# ifdef SOLVE3D

# define TS_DIF2

# define MIX_GP_UV

# ifdef TCLIMATOLOGY

# define CLIMAT_TS_MIXH

# endif

# endif

! Vertical Mixing

# ifdef SOLVE3D

# define LMD_MIXING

# endif

# if defined LMD_MIXING

# define LMD_SKPP

# define LMD_BKPP

# define LMD_RIMIX

# define LMD_CONVEC

# endif

!

! Open Boundary Conditions

# define OBC_WEST

# define OBC_NORTH

# define OBC_SOUTH

!

# if defined SSH_TIDES || defined UV_TIDES

# define OBC_M2FLATHER

# else

# define OBC_M2ORLANSKI

# define OBC_VOLCONS

# endif

# define OBC_TORLANSKI

# define OBC_M3ORLANSKI

! Embedding conditions

# ifdef AGRIF

# undef AGRIF_STORE_BAROT_CHILD

# ifdef AGRIF_STORE_BAROT_CHILD

# define AGRIF_FLUX_BC

# else

# define AGRIF_POLY_DUAVG

# endif

# define AGRIF_LOCAL_VOLCONS

# ifdef OBC_M2FLATHER

# define AGRIF_RAD2D

# endif

# define AGRIF_2WAY

# endif

!

! Applications:

! Sediments

!

# define SEDIMENT

# ifdef SEDIMENT

# define ANA_SEDIMENT

# define BED_ARMOR

# define LINEAR_CONTINUATION

# endif

Modelling Particle TransportModelling Particle Transport

0.00E+00

2.00E-04

4.00E-04

6.00E-04

8.00E-04

1.00E-03

1.20E-03

1.40E-03

0 200 400 600 800 1000

days

kin

etic

en

ergy

• Spinup for 2 years

• Continuous seeding of particles along the shelf (depths less than 135 m) in the bottommost 3 layers at a rate of ~ 1000mg/l/day from the third year

• Two-size classes of particles: 0.5 mm and 0.01 mm with settling velocities of 17.3 m/day and 4.3 m/day respectively

4 Aug 16 Nov

4 Aug 16 Nov

4 Aug 16 Nov

4 Aug 16 Nov

4 Aug 16 Nov

16 Nov4 Aug

4 Aug

16 Nov

4 Aug

16 Nov

4 Aug

16 Nov

4 Aug

16 Nov

4 Aug

16 Nov

4 Aug

16 Nov

Silt and sand concentrations - 4 Aug

Silt and sand concentrations - 16 Nov

Poseidon 271/272 - ParCa Profilstationen

Pos 271 - ParCa Profile

Pos 272 - ParCa Profile

7405 7406

7403

7404 7407

7415

7408

74117410

7412

7413

74237422

7421

74257428

74297430

271-8 271-12

271-9 271-11

271-10

CB

CI

Dachla

Cap Bojador

Cap Blanc

Final RemarksFinal Remarks• Mesoscale dynamics in the region has clear implications on cross-shore particle transport

• Vigorous transport of particles by eddies and jets

• Fluxes and off-shore plume extent are maximal in the Cape Blanc region

• The model simulations suggest that sub-surface particle clouds frequently seen in the particle camera data may derive from sources on the shelf

• Various release scenarios and particle size classes are to be simulated

• How do aggregation processes affect the particle fluxes?