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Project details
| Title: | Southern Ocean Winter Cloud Interactions processes (SOWCLIP) |
| Id: | 2647 |
| Acronym: | SOWCLIP |
| Investigator(s): | Alain Protat
Bureau of Meteorology [details] |
| Description: | Cloud microphysical properties produced from the competition between supercooled liquid and ice particles for water vapour in subfreezing cumulus clouds over the Southern Ocean and off the coast of Antarctica have been directly linked to errors in absorbed solar radiation at the sea surface, which have been further linked to uncertainty in predicting global climate sensitivity under CO2 warming and sea surface temperature biases in climate models. Strikingly, the latest climate simulations using improved knowledge gained on the frequency of occurrence of supercooled liquid water from earlier voyages (IN2015_V02, IN2016_V02, IN2018_V01, IN2018_V02, IN2022_V03, IN2023_V03) indicate the existence of two distinct large surface shortwave radiation biases of opposite sign north or south of about 55°S latitude. From the IN2018_V01 and most recent IN2024_V01 observations collected closer to the coast of Antarctica, we have gathered evidence that emissions of aerosol precursors from over Antarctica produce very high concentrations of aerosols and different cloud properties from further north and from when air masses bring pristine air from the open ocean. However, our number of samples remain quite limited to draw statistically significant conclusions. Past voyages have further revealed a change in the thermodynamic profile of the atmosphere across the 55°S latitude, i.e., the Antarctic Ocean polar front. At high latitudes the upper air soundings reveal that the free troposphere has a greater relative humidity supporting multiple cloud layers. The surface heat fluxes also vary strongly across this divide with suppressed sensible and latent heat fluxes across the high latitudes. Our main objective is to collect a suite of aerosol, cloud, surface radiation and precipitation observations during IN2025_V02. This new dataset will be combined with the existing ones collected in the period 2016 - 2024 to continue to build a comprehensive understanding of the relationship between ocean productivity, aerosol formation, cloud microphysics, cloud dynamics, and link that understanding to rainfall properties and surface radiation. If at all possible, we would like to contribute to the early calibration effort of the cloud radar and lidar launched in space as part of the European Space Agency EarthCARE mission by collecting cloud radar – lidar and precipitation observations under the satellite track. We will use orbital predictions to identify potential opportunities without interfering with the SOTS operations. We will launch radiosondes with an expected frequency of twice a day (with an option to add one more in interesting situations pending confirmation of budget). If suitable for the SOTS and ship crew, we’d suggest 8am / 8 pm local time as preferred launch times. |
| Years: | 2025 |
List of surveys that this project was on. Click on column header to sort.
Use [details] link to view survey details (map, reports, metadata etc) including links to download data.
| Survey | Investigator | Description |
|---|---|---|
| IN2025_V03 [details] |
Ruhi Humphries | The World Meteorological Organization’s (WMO) Global Atmosphere Watch (GAW) program consists of an observational network charged with understanding the increasing influence of human activity on the global atmosphere. The kennaook / Cape Grim Baseline Air Pollution Station (KCGBAPS), measuring the Southern Ocean’s atmosphere from the northwest tip of Tasmania, is one of three premier global GAW stations. By utilising the mobility of the RV Investigator (RVI), the world’s first mobile GAW station, both stations can be compared directly and data quality improved and validated. This high-quality observational data feeds directly into improving both regional and global climate, air quality and Earth System models. This project aims to: 1. Directly compare two world-leading WMO-GAW stations, the RVI and the KCGBAPS – a global first. This will include validating the RVI’s full suite of atmospheric measurements and sampling systems against complementary measurements at the KCGBAPS, improving data quality for all locations visited by the vessel. 2. Validate how representative measurements of atmospheric composition and boundary layer structure at the KCGBAPS is of the broader Southern Ocean. 3. Provide improved characterisation of atmospheric structure and composition to inform and improve earth system, climate, air quality and smoke forecasting models. 4. Determine the best boundary conditions for air quality modelling over Australia by improving our understanding of Southern Ocean and Cape Grim baseline concentrations of a range of trace atmospheric constituents. |
| IN2025_V02 [details] |
Elizabeth Shadwick | The primary objective is to first deploy a new set of SOTS moorings (SOFS-14 and SAZ-27) and then recover the existing SOTS moorings (SOFS-13, and SAZ-26). Each of the SOTS moorings deliver to specific aspects of the atmosphere-ocean exchanges: • the SAZ sediment trap mooring collects samples to quantify the transfer of carbon and other nutrients to the ocean interior by sinking particles and investigate their ecological controls. • the Southern Ocean Flux Station (SOFS) mooring measures meteorological and ocean properties important to air-sea exchanges, ocean stratification, waves, currents and biological productivity and ecosystem structure. Water samples are collected for more detailed nutrient and plankton investigations after recovery. Ancillary work will obtain supporting information on atmospheric and oceanographic conditions using CTD casts, and underway measurements. 1. Deploy SOFS-14 meteorology/biogeochemistry mooring 2. Deploy SAZ-27 sediment trap mooring 3. Recover SOFS-13 meteorology/biogeochemistry mooring 4. Recover SAZ-26 sediment trap mooring 5. CTD sampling (3 cast to 4550m, 2 to 600m) at the SOTS site, including collecting samples for nutrients, oxygen, dissolved inorganic carbon, alkalinity, and eDNA analyses 6. Ship meteorological observations at SOFS buoys for comparisons 7. Deployment of BGC-Argo Float (with additional UVP sensor recently refurbished after the SOLACE float was recovered). 8. Recovery of ACC-SWOT mooring at 55S site (deployed on the FOCUS IN2023_V07 voyage). 9. Deployment of BoM drifters at site of ACC-SWOT mooring recovery; CTD cast for post-calibration of recovered sensors. 10. Carry out underway air and water sampling and sensor measurements, including bio-optics and bio-acoustics |