Southern Ocean Cloud Project
The biases observed in climate models over the Southern Ocean in surface radiation and sea surface temperature are larger than anywhere else in the world. They have a fundamental impact on the ability of these models to predict global climate. Evidence suggests that errors in the representation of the mixed phase clouds found over the high latitudes of the Southern Ocean are responsible for these biases. Southern Ocean Clouds (SOC) Is a major project that aims to investigate high latitude mixed phase clouds and their representation in climate models by:
i) Investigating the source and composition of the cloud forming nuclei responsible for these clouds
ii) Investigating the cloud microphysical processes –such as secondary ice production –that are important in these mixed phase clouds
iii) Using the new observations to identify and partition the various sources of aerosols found in this region
iv) In conjunction with our new field data, developing new microphysical parameterisations for use in climate models
v) Conducting a series of global-scale model experiments, using our new microphysical parameterisations, to assess the impact of Southern Ocean clouds on the global climate system and so reduce the climate sensitivity due to clouds.
Objectives
To address our overall aims, we have a number of specific objectives:
- Identify the composition and sources of cloud-forming nuclei that play a major role in the formation of clouds in the Southern Ocean.
- Identify the detailed processes involved in secondary ice production (SIP) in clouds over the Southern Ocean and the role that SIP plays in cloud formation.
- Use the detailed observations of aerosols made during this project to validate and improve models of aerosol production over the Southern Ocean.
- Improve the representation of clouds in climate models of the Southern Ocean by developing and evaluating parameterizations based on our observational findings
- Evaluate the impact of these new parameterizations on model simulations of the climate system.
Observations
- We have been taking ground based measurements of aerosol size, composition, CCN and INP numbers at Rothera station since January 2022. Although funding for Southern Ocean Cloud project runs out soon we have obtained funding to continue these measurements for the foreseeable future. We also run a Micropulse lidar at Rothera.
- We have had two airborne campaigns using our instrumented Twin Otter aircraft based from Rothera in February 2023 and November/December 2024. The second campaign took place at the same time as a cruise on the Sir David Attenborough (see below). The aircraft campaigns concentrated of measuring the in situ cloud microphysical properties associated with the ground based observations.
- We have competed a cruise on the Sir David Attenborough during November and December 2024 measuring aerosol size, composition and INP numbers. The cruise visited Rothera, Signy, the South Shetland Islands, Bird Island and South Georgia. It had international participants from Portugal, Spain and the US as well researchers from UK universities.
Platforms:
- Rothera station
- Bird Island research station
- RRS Sir David Attenborough
- RRS James Clerk Ross
Location: Antarctic Peninsula and surrounding oceans
Timing: February 2022 – December 2024
Contact: Tom Lachlan-Cope (tlc<@>bas.ac.uk)
Links:
- https://www.bas.ac.uk/project/southern-ocean-clouds/#about
- https://cloudsense.ac.uk/
- follow us on Twitter: @CloudSenseNERC
Instruments: