Ubiquitous low-level liquid-containing Arctic clouds: New observations and climate model constraints from CALIPSO-GOCCP

G. Cesana (1, 2) , J.E. Kay (2) , H. Chepfer (1) , J.M. English (2) , G. de Boer (3, 4, 5)

1 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
2 CGD - Climate and Global Dynamics Division [Boulder]
3 CIRES - Cooperative Institute for Research in Environmental Sciences
4 ESRL - NOAA Earth System Research Laboratory
5 LBNL - Lawrence Berkeley National Laboratory [Berkeley]

Ground-based observations show that persistent liquid-containing Arctic clouds occur frequently and have a dominant influence on Arctic surface radiative fluxes. Yet, without a hemispheric multi-year perspective, the climate relevance of these intriguing Arctic cloud observations was previously unknown. In this study, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observations are used to document cloud phase over the Arctic basin (60-82N) during a five-year period (2006-2011). Over Arctic ocean-covered areas, low-level liquid-containing clouds are prevalent in all seasons, especially in Fall. These new CALIPSO observations provide a unique and climate-relevant constraint on Arctic cloud processes. Evaluation of one climate model using a lidar simulator suggests a lack of liquid-containing Arctic clouds contributes to a lack of "radiatively opaque" states. The surface radiation biases found in this one model are found in multiple models, highlighting the need for improved modeling of Arctic cloud phase. © 2012. American Geophysical Union. All Rights Reserved.

Domaines: Climatologie

G. Cesana, J.E. Kay, H. Chepfer, J.M. English, G. de Boer. Ubiquitous low-level liquid-containing Arctic clouds: New observations and climate model constraints from CALIPSO-GOCCP. Geophysical Research Letters, 2012, 39 (20), pp.L20804. ⟨10.1029/2012GL053385⟩. ⟨hal-01116274⟩