Insights from the SO-CHIC Expedition:

Insights from the SO-CHIC Expedition:

what have we done and where are we now?

Marcel du Plessis, University of Gothenburg SO-CHIC panel discussion

SCAR Meeting

9 August 2022

Cruise objectives

Cruise plan: Perform the largest high-resolution mapping of the Maud Rise region

Outcome: Progress in the understanding of polynya formation and air-sea-ice interactions,

improve model capability

Cruise objectives

Cruise plan: Perform the largest high-resolution mapping of the Maud Rise region

Cruise plan: Deploy instruments to collect a first-time full annual cycle of upper ocean bio- physics in the Southern Ocean at sub-daily high-resolution

Outcome: Progress in the understanding of polynya formation and air-sea-ice interactions, improve model capability

Outcome: Fill seasonal gaps of high-resolution observations in key regions of air-sea fluxes of heat and carbon to improve the uncertaintly in climate models, reveal how the ocean

responses to the processes that force it – storms, eddies, mixing (parameterised in models)

Cruise objectives

Cruise plan: Perform the largest high-resolution mapping of the Maud Rise region

Cruise plan: Deploy instruments to collect a first-time full annual cycle of upper ocean bio- physics in the Southern Ocean at sub-daily high-resolution

Data analysis only just starting… and there is still lots to do!

Outcome: Progress in the understanding of polynya formation and air-sea-ice interactions, improve model capability

Outcome: Fill seasonal gaps of high-resolution observations in key regions of air-sea fluxes of heat and carbon to improve the uncertaintly in climate models, reveal how the ocean

responses to the processes that force it – storms, eddies, mixing (parameterised in models)

17 Scientific Personal

11 days dedicated to SO-CHIC cruise (6-16, 23 Jan 2022)

Research Vessel S.A. Agulhas II

SO-CHIC cruise overview

SO-CHIC cruise overview

Maud Rise

Maud Rise Polynya

Maud Rise Polynya

CTD sections: Nadine Steiger

Maud Rise Polynya

CTD sections: Nadine Steiger

Maud Rise Polynya

CTD sections: Nadine Steiger

High-resolution mapping of the Maud Rise region

Ocean:

pCO

₂

Temperature

Salinity

Currents

Swart et al. (in prep) Deep Convection (WP4)

Glider transects mapping the Maud Rise

Swart et al. (in prep)

190 km

Deep Convection (WP4)

Glider transects mapping the Maud Rise

Frölicher et al. (2015), Nicholson et al. (2022)

40 - 50% of the total mean annual ocean uptake of anthropogenic CO

₂

(~1 Pg C yr

⁻¹

)

Mean outgassing region of the Southern Ocean

Surfacing of deep waters with high concentrations of dissolved inorganic carbon and cold ocean temperatures

CO

₂

outgassing CO

₂

uptake

Subpolar Southern Ocean: region of rich CO2 outgassing

Ocean:

pCO

₂

Temperature Salinity Currents

Annual cycle of high-resolution upper ocean biophysical interactions

Boutin et al. (in prep) Air-sea fluxes (WP1)

Glider transects mapping the Maud Rise

Boutin et al. (in prep)

Oxygen increase

Carbon drawdown

Air-sea fluxes (WP1)

Glider transects mapping the Maud Rise

Boutin et al. (in prep)

Oxygen increase

Carbon drawdown

Biological growth

Air-sea fluxes (WP1)

Glider transects mapping the Maud Rise

Boutin et al. (in prep)

Mixing up high carbon waters

from below Oxygen increase

Carbon drawdown

Biological growth

Air-sea fluxes (WP1)

Glider transects mapping the Maud Rise

Deep Convection (WP4)

ADCP deployments to study frontal mixing across the Maud Rise flank

Image: Alberto Naveira Garabato

Air-sea fluxes (WP1)

Saildrones to study air-sea interactions on the winter mixed layer

Image: Saildrone