Southern Ocean Solar Reflection Biases in CMIP6 Models Linked to Cloud Phase and Vertical Structure Representations - Archive ouverte HAL Access content directly
Journal Articles Geophysical Research Letters Year : 2022

Southern Ocean Solar Reflection Biases in CMIP6 Models Linked to Cloud Phase and Vertical Structure Representations

(1, 2) , (3, 4) , (5) , (6)
1
2
3
4
5
6

Abstract

Over the Southern Ocean (SO, 40°S–70°S), climate models have consistently underestimated solar reflection. Here we evaluate the relationship between cloud profiles, cloud phase and radiation over the SO in Coupled Model Intercomparison Project Phase 6 (CMIP6) models against Clouds and the Earth's Radiant Energy System and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations. We find that the lack of solar reflection is slightly improved in CMIP6 models compared to CMIP5's, attributable to a better representation of cloud fraction and phase. We show that clouds have a different vertical structure and radiative effect south and north of where the 0°C isotherm meets the surface (∼55°S). Although the models capture the greater vertical extent of clouds south of 55°S, they fail to reproduce the observed increase in solar reflection, which we pinpoint to cloud phase biases. Increasing CMIP6 supercooled liquid cloud opacity should help reduce their persistent shortwave biases.
Embargoed file
Embargoed file
0 4 29
Year Month Jours
Avant la publication

Dates and versions

insu-03872791 , version 1 (04-01-2023)

Identifiers

Cite

Grégory V. Cesana, Théodore Khadir, Hélène Chepfer, Marjolaine Chiriaco. Southern Ocean Solar Reflection Biases in CMIP6 Models Linked to Cloud Phase and Vertical Structure Representations. Geophysical Research Letters, 2022, 49 (22), pp.e2022GL099777. ⟨10.1029/2022GL099777⟩. ⟨insu-03872791⟩
0 View
0 Download

Altmetric

Share

Gmail Facebook Twitter LinkedIn More