Picture: Antarctic sea ice. Credit: Pixabay (Pexels).
Direct observations of the atmosphere are few and scattered in the remote ocean region around Antarctica, so most studies of change in this region rely on ‘reanalysis’ datasets – these are best-guess estimates of the state of the atmosphere made from combining observations and models, similar to a daily weather map.
However, multiple reanalysis products have very different surface trends in this region over the last 40 years of satellite observations, so which one should we use?
This study is based the well-established fact that sea ice cover is very closely related to surface air temperature, so that we can use trends in Antarctic sea ice as an independent validation for the reanalysis trends. This simple approach works beautifully, and we are able to show not only which reanalysis products have the ‘best’ trends overall (at least in terms of their agreement with sea ice), but we can also highlight regions where the products are more or less reliable.
This will be invaluable information for Antarctic and Southern Ocean researchers who come across the old problem of ‘what data should I use?’.
- Paper: Hobbs, W. R., A. R. Klekociuk, and Y. Pan, 2020: Validation of reanalysis Southern Ocean atmosphere trends using sea ice data. Atmos. Chem. Phys. Discuss., 2020, 1-17, 10.5194/acp-2020-580.