Integrated Studies of High Sensitivity Systems

In the complex, non-linear system of the surface ocean and lower atmosphere, the five SOLAS core themes interact and influence each other. Studying these themes collectively will greatly benefit for the understanding of processes of interactions and making predictions of the evolution of the earth system. Integrated SOLAS studies are currently underway and being developed in a number of regional, high-sensitivity, and high priority systems. These are broad topics that overlap, and this list is not exclusive; SOLAS scientists continually identify new topics for integrated studies. In particular, SOLAS would like to encourage more international collaboration on the implications of coral reef ecosystems for air-sea exchange of climatically active substances.

Upwelling Systems


Team leaders

Ivonne Montes (Peru,
Arvind Singh (India,

Team members

Boris Dewitte (Chile,
Marcela Cornejo D'Ottone (Chile,
Véronique Garçon (France,
Arne Körtzinger  (Germany,
Zouhair Lachkar (United Arab Emirates,
Elisa Lovecchio (United Kingdom,
Baye Cheikh Mbaye (Senegal,
Javier Arístegui Ruiz (Spain,

Present understanding

Upwelling systems, both coastal and equatorial, are natural laboratories for studying the impacts of multiple stressors on air sea-exchange processes and marine ecosystem services. These systems are characterised by very high biological productivity closely related to the presence of an extensive oxygen minimum zone (OMZ) and a low pH-high CO2 regime. Active research during recent decades has determined the role of upwelling systems in the exchange of climatically active gases (such as CO2, N2O, and CH4), OMZ variability, and the biogeochemical cycles of nitrogen, carbon, sulphur, halogens and trace metals.



In order to better understand ocean-atmosphere connections in upwelling regions, several temporal (diurnal, intra-seasonal, seasonal, interannual, decadal, and multidecadal) and spatial (submesoscale, mesoscale, local, regional, and global) scales of variability and physical forcing in the system need to be considered. There is still a critical knowledge gap in understanding the driving mechanisms and the connectivity to climate change, the extent and spatiotemporal variability of ocean deoxygenation in upwelling systems, as well as impacts on marine food webs and biogeochemistry. The latter aspects are variously simulated by state-of-the-art Earth System Models (ESMs) preventing a reliable projection of ocean deoxygenation for instance on marine ecosystem services in these upwelling regions. Understanding how land-air-sea interactions control the dynamics behind the OMZs in the eastern boundary upwelling systems and may potentially exacerbate deoxygenation is not just a matter of scientific interest, but also a major societal concern. Given the high socioeconomic importance of coastal upwelling systems, a complete understanding of the complex atmosphere-ocean interaction and physical-chemical-biological coupling in eastern boundary upwelling systems is needed. For SOLAS, this is an ideal research area and requires involvement and interaction of all 5 core themes.

Planned activities

Research programmes on Upwelling

Current national and international programmes investigating upwelling include "Role of Eddies in the Carbon Pump of Eastern Boundary Upwelling Systems" (REEBUS), "Biogeochemical impact of mesoscale and sub-mesoscale processes along the life history of cyclonic and anticyclonic eddies (e-IMPACT)", and SCOR WG 155 on Eastern boundary upwelling systems (EBUS): diversity, coupled dynamics and sensitivity to climate change.


●   SOLAS Summer School 2023, 5-16 June 2023, Mindelo, Cabo Verde, with special sessions on upwelling.
●   WCRP's Open Science Conference, 23-27 October 2023, Kigali, Rwanda.
●   GOOD-OARS-CLAP-COPAS Summer School 2023, 6-12 November 2023, La Serena Chile, with focus on the Humboldt system.
●   FUTURO Large International Field Campaign in Canary Current EBUS, time window: 2027-2029, currently in early planning state
●   3rd GO2NE/GOOD/OARS Summer School, summer 2025, Universiti Sains Malaysia, Penang, Malaysia
●   OceanICU campaign, from South Africa upwelling to the Canary Current Upwelling, Spring 2025

Polar Oceans and Sea Ice


Team leaders

Daiki Nomura (Japan,
Nadja Steiner (Canada,

Team members

Katye Altieri (South Africa,
Markus Frey (United Kingdom,
Santiago Gassó (United States,
Anoop Mahajan (India,
Lisa Miller (Canada,
Peter Minnett (United States,
Jun Nishioka (Japan,
Jacqueline Steffels (The Netherlands,
Lisan Yu (United States,

Present understanding

Changing sea-ice coverage in the polar oceans is impacting air-sea exchanges of chemically, biologically, and climatically active trace gases and particles. The dynamics and consequences of changes in sea-ice characteristics and distribution in the polar oceans are critical to understanding and modelling feedback mechanisms and future scenarios of climate change. Sea ice, including the overlying snowpack, is a very rich and complex system that actively exchanges heat, momentum, and material (i.e., gases and particles) with both the atmosphere and the underlying water, and impacts exchanges in surrounding waters. Sea ice harbors a highly productive ecosystem, which interacts with both the ocean and the atmosphere and supports multiple ecosystem services. Understanding changes to the system is crucial in understanding potential impacts on these ecosystem services. The snowpack on sea ice is a highly reactive environment controlling uptake and release of many photochemically active trace gases, particles and their precursors, interacting with the lower atmosphere and the sea ice underneath. Understanding emission and deposition fluxes above snow on sea ice is critical to assess the impact of a changing sea-ice environment on atmospheric composition (oxidizing capacity, budgets of mercury, halogens, sulfur, nitrogen and organics), aerosol direct and indirect effects, and climate. In addition to changes to sea-ice itself, the transition from permanently ice-covered to seasonally ice-covered leads to drastic changes in ocean stratification, biological activity and exchange processes between ocean and atmosphere.

Much of the current information about sea-ice characteristics, surface temperatures, and clouds in the Arctic is obtained from remote sensing instruments on polar-orbiting earth-observation satellites, of which there are many. Instrument algorithm improvements are expected to continue to result in higher accuracy in the retrieved variables to the benefit of SOLAS polar objectives.



Understand how the structure of sea ice impacts the uptake and release of climatically-active substances to/from the atmosphere and the underlying water. This involves exploring the changing nature of ice, which is generally becoming thinner and warmer. In the Arctic, increasing pack ice mobility and rafting is potentially redistributing sympagic biological communities throughout the ice. Melt ponds, which are becoming increasingly prevalent in spring in the Arctic, may also represent a significant albeit poorly quantified source of gases and particles to the atmosphere. Thinner ice and enhanced snowfall can cause flooding and snow-ice formation, which are common in the Southern Ocean and becoming more so in the Arctic, impacting both ice biology and chemistry. Seasonalities in the amount and phase of precipitation as well as melt onset timing are changing leading to warmer and wetter snowpacks. With a thinner and more brittle ice pack, and more potential for direct air-sea gas exchange and changes in pelagic versus sympagic primary production, as well as more seasonal ice formation. Deeper and wetter snowpacks may dampen or even shut down ice-air trace gas and particle fluxes, whereas increased flooding and saltier first year ice may increase salt loading of the snow column with unknown impact on photochemical processes and air-snow fluxes of trace gases, particles, and their precursors. The question of whether air-sea gas exchange rates are enhanced or dampened in the presence of a broken, mobile ice cover (including leads and polynyas) is still open, and contradictory results from laboratory and field measurements need to be resolved. The extent to which sea-ice brines directly contribute to deep-ocean carbon sequestration is also still unresolved. Answering these questions requires both detailed process studies (lab, field, and numerical) and integrated, large-scale observation systems.


Planned activities

BEPSII (Biogeochemical Exchange Processes at Sea-Ice Interfaces)

A research community co-sponsored by SOLAS, CliC, and SCAR, BEPSII focuses on how the biogeochemistry of sea ice influences both the ocean and the atmosphere. Within sea ice, biotic and abiotic processes interact in changing ways throughout the freeze-melt cycle, and thus, sea ice is an active participant in the biogeochemical cycles of many elements, producing climatically active atmospheric aerosols, modulating the surface ocean ecosystem, contributing to seasonal gas fluxes, and possibly facilitating long-term export and carbon dioxide sequestration in deep waters. Near-future priorities for BEPSII include:

  • A position analysis (PA) on Antarctic sea-ice biogeochemical responses to climate change (An Arctic PA has been published in Nature Climate Change)
  • A policy brief on Antarctic sea-ice biogeochemical responses to climate change, summarizing the Antarctic PA and ecosystem services impacts (An Arctic policy brief has been published in 2021 and presented at the COP26)
  • 1-D model intercomparison
  • Expert contribution to the analysis of sea-ice biogeochemistry, ecosystem, and modelling components of the MOSAiC project
  • A coordinated 2nd Ice Algae Model intercomparison Project (IAMIP2)
  • SCOR working group (Cice2Clouds ##163)

BEPSII will hold their 2023 meeting in La Jolla, USA, just after the Gordon Conference on Polar Marine Science. Website:

CATCH (the Cryosphere and ATmospheric CHemistry)

Cosponsored by SOLAS and IGAC, the CATCH mission is to facilitate atmospheric chemistry research within the international community, with a focus on natural processes specific to cold regions of the Earth. Cold regions include areas that are seasonally or permanently covered by snow and ice, from the high mountains to the polar ice sheets and sea ice zones, as well as regions where ice clouds are found. Upcoming and ongoing activities and priorities for CATCH include:

  • Planning of a CATCH focused Faraday Discussion  Conference in 2024/25
  • Model Intercomparison Project - bromine in polar (Arctic) regions
  • Special issue/ review of chemical fluxes between ocean, sea ice, snow and atmosphere
  • SCOR working group (Cice2Clouds ##163)
  • Monthly CATCH newsletter
  • CATCH seminar series (1-2 months)
  • Session on Polar and Wintertime Atmospheric Chemistry at AGU 2022
  • Session on Surface Exchange Processes in the Polar Regions: Physics, Chemistry, Isotopes, and Aerosols at EGU 2023


Coordinating research programmes on Polar Oceans

PICCAASO (Partnerships for Investigating Clouds and the biogeoChemistry of the Atmosphere in Antarctica and the Southern Ocean).

PICCAASO's mission is to amplify the scientific discovery of the many upcoming projects occurring in the Antarctic and Southern Ocean region by facilitating global collaboration and coordination. PICCASO's specific focus is on the scientific questions surrounding the link between biogeochemistry and atmospheric processes in this pristine region. PICCAASO evolved from a CATCH working group into an independent initiative since 2021. At the outset of this initiative, we have identified 16 long-term stations in the region, together with 21 intensive research projects, either fully funded or proposed, occurring before the end of 2025.

Positioning paper submitted in 2022 to Elementa. Find out more at

CRiceS (Climate Relevant interactions and feedbacks: the key role of Sea ice and Snow in the polar and global climate system)

The objective of CRiceS is to deliver improved understanding of chemical, biogeochemical, and physical interactions within the ocean-ice/snow-atmosphere system in order to quantify their role in polar and global climate, including feedbacks and teleconnections, to predict the consequences and impacts of change.

The specific objectives of CRiceS are to:

  • Quantify key uncertain processes that control the polar ocean-ice/snow-atmosphere system, using existing and planned observations including in-situ data, satellite observations and data services for both poles
  • Deliver improved descriptions of key ocean-ice/snow-atmosphere processes in process models and climate models/ESMs that operate on seasonal to climate timescales and local to global spatial scales
  • Systematically quantify polar-global teleconnections in both hemispheres, how they are modified by natural and anthropogenic drivers of climate change and their governing physical processes and feedbacks
  • Deliver improved projections that directly feed into regional and global climate change assessments relevant for EU policy development that can be used to quantify climate impacts relevant for society
Cice2Clouds (Coupling of ocean-ice-atmosphere processes: from sea-Ice biogeochemistry to aerosols and Clouds)

Cice2Clouds a joint SCOR working group (#163) was developed from the BEPSII and CATCH communities to investigate feedbacks between atmospheric chemistry and sea-ice biogeochemistry. The CIce2Clouds mission is to bring the sea-ice and atmospheric communities together to resolve open questions about the impacts of the marine cryosphere on atmospheric chemistry in polar ocean environments.

CIce2Clouds objectives are to:

  • Prioritize key coupled biological and chemical systems that drive atmospheric reactive trace gas, aerosol, and cloud properties in polar ocean environments
  • Identify similarities and differences in controls on exchange processes between the Arctic and Antarctic O-SI-S-A systems
  • Develop a conceptual model of exchange processes in O-SI-S-A systems, focusing on prioritized key reactive trace gas and aerosol species
  • Develop interdisciplinary campaign planning recommendations to guide future studies and address model and measurement gaps
  • Facilitate community and capacity building opportunities for sustainable multidisciplinary science at the O-SI-S-A interface

A hybrid online-in person meeting was held in Cape Town in 2022 before the SOLAS OSC and online meetings are held on a continuing basis for various subgroups.

Indian Ocean


Team leaders

Zouhair Lachkar (United Arab Emirates,
Tanya Marshall (South Africa,
Lisan Yu (USA,

Team members

Hermann Bange (Germany,
Sheryl Oliveira Fernandes (India,
Christa Marandino (Germany,
Parvadha Suntharalingam (United Kingdom,
Susann Tegtmeier (Canada,
Guiling Zhang (China,
Lisan Yu (United States,

Present understanding

There have been significant advances in our ability to describe and model the Indian Ocean in recent years. For example, observations and modelling studies have confirmed that the Indian Ocean is warming faster than any other ocean besides the Arctic Ocean. The marginal seas around the Indian Ocean, such as the Red Sea and the Persian Gulf, also show high rates of warming suggesting a region-wide amplification effect. Observations also show considerable changes in deoxygenation, acidification, eutrophication, dynamics and productivity in the Indian Ocean. Due to increasing anthropogenic activities, the atmospheric composition and the ocean-atmosphere exchange over the Indian Ocean are also changing.

However, our understanding of oceanic and atmospheric processes in the Indian Ocean region is still rudimentary in many respects. This is largely because the Indian Ocean remains under-sampled in space and time, especially compared to the Atlantic and Pacific Oceans. The lack of sustained observation programs across the basin limits our understanding, which is currently based on episodic projects. The Indian Ocean is a dynamically complex and highly variable system, which is different from the other oceans because it shows a strong influence of and on the monsoon system. The air masses over the Indian Ocean change drastically in terms of continental influence depending on the season. With fast changes being observed, many uncertainties remain regarding how oceanic and atmospheric processes affect climate, extreme events, marine biogeochemical cycles, atmospheric chemistry, meteorology, ecosystems, and human populations in and around the Indian Ocean. Anthropogenic impacts of various pollutants lead to water quality deterioration and can have far-reaching detrimental ecosystem effects. There are growing concerns about food security, considering that countries with large populations surround the Indian Ocean. Thus, a detailed study of the Indian Ocean is needed in the context of the ongoing environmental changes to quantify the impacts of anthropogenic stressors on coastal environments and fisheries sustainability, especially in light of ocean utilisation projects planned by various countries in this region.



The biogeochemical cycles and ecosystems of the Indian Ocean appear to be particularly vulnerable to anthropogenic impacts (including climate change, eutrophication, atmospheric pollution and aerosol load), the effects of which appear to be amplified as compared to other ocean basins. There are several global and regional phenomena, such as the Indian Ocean Dipole (IOD), Madden Julian Oscillation (MJO), and El Niño–Southern Oscillation (ENSO), which affect the Indian Ocean. This, in turn, affects the ocean-atmosphere exchange, which is still not well understood. It is essential to understand the underlying processes and drivers of these changes to predict the future of the Indian Ocean.

Major research questions to be addressed with high priority are:

  • Which processes determine the natural variability of the biogeochemical cycles, ecosystems and atmospheric chemistry over the Indian Ocean?
  • What are the effects of human-induced stressors (e.g., air pollution, extraneous nutrient input) on ocean biogeochemistry, ecosystems, atmospheric chemistry and climate, and why are these effects amplified in the Indian Ocean?
  • How are ecosystem and basin-wide changes affecting monsoon circulation?
  • How, in turn, are these changes affecting human populations?
  • What role does the southern basin play in air-sea exchange, carbon cycling and climate?

Planned activities

  • BIOCAN Cruise to the Arabian Sea - Birgit Gaye Chief Scientist on board German R/V Sonne (January/February 2024)
  • BIOCAT Cruise to the Bay of Bengal - Hermann Bange Chief Scientist on board German R/V Sonne (April/May 2024)
  • Deep Madagascar Basin (DMB) Experiment - cruise-based, March 2023, southwest Indian Ocean, Viviane Menezes and Heather Furey as Chief Scientists, the project welcomes piggy-back projects.
  • IIOE-2 (2015-2025, cruises in the Indian Ocean, for an overview see (
  • ISESO (January 2023 - every two years, cruise-based, Southern Indian Ocean)