Evaluation of Southern Ocean cloud in the HadGEM3 general circulation model and MERRA-2 reanalysis using ship-based observations

Kuma, Peter; McDonald, Adrian J.; Morgenstern, Olaf; Alexander, Simon P.; Cassano, John J.; Garrett, Sally; Halla, Jamie; Hartery, Sean; Harvey, Mike J.; Parsons, Simon; Plank, Graeme; Varma, Vidya; Williams, Jonny

doi:https://doi.org/10.5194/acp-20-6607-2020

Articles | Volume 20, issue 11

https://doi.org/10.5194/acp-20-6607-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/acp-20-6607-2020

© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 20, issue 11

Research article

|

05 Jun 2020

Research article |

| 05 Jun 2020

Evaluation of Southern Ocean cloud in the HadGEM3 general circulation model and MERRA-2 reanalysis using ship-based observations

Peter Kuma, Adrian J. McDonald, Olaf Morgenstern, Simon P. Alexander, John J. Cassano, Sally Garrett, Jamie Halla, Sean Hartery, Mike J. Harvey, Simon Parsons, Graeme Plank, Vidya Varma, and Jonny Williams

Data sets

Hadley Centre Sea Ice and Sea Surface Temperature data set (HadISST) N. A. Rayner, D. E. Parker, E. B. Horton, C. K. Folland, L. V. Alexander, D. P. Rowell, E. C. Kent, and A. Kaplan https://www.metoffice.gov.uk/hadobs/hadisst/

Modern-Era Retrospective Analysis for Research and Applications, Version 2 R. Gelaro, W. McCarty, M. J. Suárez, R. Todling, A. Molod, L. Takacs, C. A. Randles, A. Darmenov, M. G. Bosilovich, R. Reichle, K. Wargan, L. Coy, R. Cullather, C. Draper, S. Akella, V. Buchard, A. Conaty, A. M. da Silva, W. Gu, G.-K. Kim, R. Koster, R. Lucchesi, D. Merkova, J. E. Nielsen, G. Partyka, S. Pawson, W. Putman, M. Rienecker, S. D. Schubert, M. Sienkiewicz, and B. Zhao https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/

Model code and software

Automatic Lidar and Ceilometer Framework (ALCF) P. Kuma, A. J. McDonald, O. Morgenstern, R. Querel, I. Silber, and C. J. Flynn https://doi.org/10.5281/zenodo.3779518

CFMIP Observation Simulator Package A. Bodas-Salcedo and D. Swales https://github.com/CFMIP/COSPv1

cl2nc P. Kuma https://github.com/peterkuma/cl2nc

CERES Energy Balanced and Filled (EBAF) TOA Monthly means data in netCDF Edition4.1 D. Doelling https://doi.org/10.5067/TERRA-AQUA/CERES/EBAF-TOA_L3B004.1

Near-Real-Time DMSP SSM/I-SSMIS Daily Polar Gridded Sea Ice Concentrations, Version 1 J. Maslanik https://doi.org/10.5067/U8C09DWVX9LM

Short summary

We evaluate clouds over the Southern Ocean in the climate model HadGEM3 and reanalysis MERRA-2 using ship-based ceilometer and radiosonde observations. We find the models underestimate cloud cover by 18–25 %, with clouds below 2 km dominant in reality but lacking in the models. We find a strong link between clouds, atmospheric stability and sea surface temperature in observations but not in the models, implying that sub-grid processes do not generate enough cloud in response to these conditions.