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These are the intended use-case/justification for one or multiple variable groups. Opportunities are linked to relevant experiment groups. Identifying opportunities helps to provide a structure to map variables against requirements. Each opportunity description will convey why this combination of variables and experiments is important and how they contribute to impact.
| Attribute | Value |
|---|---|
| description | The Southern Ocean and Antarctic represent the best region on the planet to study near ‘pre-industrial’ conditions in terms of aerosol-cloud-climate interactions. It is also one of the most poorly modelled regions on the planet in terms of aerosol and cloud interactions; has been identified as a region of great uncertainty with respect to cloud feedbacks and aerosol-cloud radiative forcing that contribute to uncertainties in climate equilibrium; and is a difficult region to evaluate models due to sparse observations. We are proposing this opportunity to better coordinate modelling efforts in this region to understand how natural aerosol in this region impact clouds and radiation. This opportunity will cross disciplines and experiments, taking advantage of already proposed MIPs and centralizing information for efficient use by end users. This opportunity aligns with a current initiative to consolidate observational efforts in the Southern Ocean to understand these same issues (Mallet et al. 2023: https://doi.org/10.1525/elementa.2022.00130). |
| expected_impacts | CMIP models have had a long-standing radiative bias over the Southern Ocean, which has been attributed in part to challenges in simulating the commonly occurring and radiatively important low-level clouds that contain both ice and liquid phases. One reason for this is the lack of Southern Ocean/Antarctic informed parameterisations relating clouds to aerosol and aerosol to biogeochemistry. As models become more aerosol-aware, the interaction of biogeochemistry, aerosol and cloud becomes more important to understand and evaluate. This combination of aerosol (including their precursors) and cloud data will allow us to evaluate this system in a holistic way. By taking advantage of pre-proposed experiments, we can understand how this system might respond to different forcings. One such example would be to specifically look at the cloud-radiative feedback over the Southern Ocean, which has been identified as one of the most uncertain on the globe. Aerosol originating from the Southern high latitudes contribute to the overall Southern Ocean aerosol population that drive the cloud-radiative feedback and in turn have likely impacts on the ice extent and biology along the marginal ice zone. By considering the aerosol-cloud system as a whole, evaluating processes from aerosol flux through to the radiative balance to the cryosphere, we may gain a better understanding of what may be likely or unlikely in the future. |
| justification_of_resources | Aerosol-cloud interaction has been identified in previous CMIPs as one of the most uncertain aspects of the global-radiative balance. The Southern Ocean, which makes up over 15% of the globe's surface area, contributes in large part to this uncertainty, both due to its size and its difficulty to accurately simulate. Having a concentrated effort on understanding this system will be of great benefit to both understanding the past, present and future of our planet, as well as for future model development. This opportunity will reduce barriers to end users who are investigating this system, who often work in interdisciplinary teams and are not necessarily modelers themselves. We have aimed to reduce the burden on data resources by requesting new variable groups only for the Southern Ocean and Antarctic, limiting the number of fields that use full model height, and only requesting monthly means. |
| lead_theme | Atmosphere |
| minimum_ensemble_size | 1 |
| name | Southern Ocean Biogeochemistry to Clouds |
| opportunity_id | 61 |
| technical_notes | Requested southern ocean domain (south of 30 deg), but when it comes to harmonisation, if all other groups want same variables globally that is fine for us |
| data_request_themes | Atmosphere, Ocean & Sea-Ice, Earth System |
| experiment_groups | picontrol, deck, fast-track, scenarios, historical |
| mips | DCPP |
| time_subsets | 80ac3156-a698-11ef-914a-613c0433d878 |
| variable_groups | SO_BGC-cloud_atmos_composition_monthly, SO_BGC-cloud_BGC_monthly, SO_BGC-cloud_cloudvars_monthly, SO_BGC-cloud_met_monthly, SO_BGC-cloud_ocean_monthly |