Preprints
https://doi.org/10.5194/egusphere-2022-939
https://doi.org/10.5194/egusphere-2022-939
 
15 Nov 2022
15 Nov 2022
Status: this preprint is open for discussion.

Forcing and impact of the Northern Hemisphere continental snow cover in 1979–2014

Guillaume Gastineau1, Claude Frankignoul1, Yongqi Gao2,, Yu-Chiao Liang3, Young-Oh Kwon4, Annalisa Cherchi5,6, Rohit Ghosh7,8, Eliza Manzini7, Daniela Matei7, Jennifer Mecking9, Lingling Suo2, Tian Tian10, Shuting Yang10, and Ying Zhang11 Guillaume Gastineau et al.
  • 1UMR LOCEAN, Sorbonne Université/IRD/MNHM/CNRS, IPSL, Paris, 75005, France
  • 2Nansen Environmental and Remote Sensing Center and Bjerknes Center for Climate Research, Bergen 5006, Norway
  • 3Department of Atmospheric Sciences, National Taiwan University
  • 4Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, U.S.A.
  • 5National Research Council of Italy, Institute of the Atmospheric Science and Climate (CNR-ISAC), Bologna, Italy
  • 6Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy
  • 7Max Planck Institute for Meteorology, Hamburg, Germany
  • 8Department of Meteorology, University of Reading, United Kingdom
  • 9National Oceanography Centre, Southampton, United Kingdom
  • 10Danish Meteorological Institute, Copenhagen, Denmark
  • 11Nansen-Zhu International Research Center, Institute of Atmospheric Physics, Chinese Academy of Sciences, 100029 Beijing, People’s Republic of China
  • Deceased, July 23rd 2021

Abstract. The role of surface ocean anomalies for the continental Northern Hemisphere snow cover is investigated, together with the interactions between snow cover and atmosphere. Four observational datasets and two large multi-model ensembles of atmosphere-only simulations are used, with prescribed sea surface temperature (SST) and sea ice concentration (SIC). A first ensemble uses observed interannually varying SST and SIC conditions for 1979–2014, while a second ensemble is identical except for SIC where a repeated climatological cycle is used.

SST and external forcing typically explain 10 to 25 % of the snow cover variance in model simulations, with a dominant forcing from the tropical and North Pacific SST, while no robust influence of the SIC is found. In observations, the Ural blocking is the main driver of the November and April snow cover over Eastern Eurasia, while the North Atlantic Oscillation (NAO) dominates the snow cover forcing in January. In November and more robustly in January, dipolar anomalies of snow cover over Eurasia, with positive anomalies over Europe and negative anomalies over Southern Siberia, also precede the Arctic Oscillation (AO) by one month. In models, snow cover over western Eurasia in January also precedes by one or two months a negative AO phase. The detailed outputs from one of the models suggest that both the western Eurasia snow cover and polar vortex are generated by Ural blocking, and that both snow cover and polar vortex anomalies act to generate the AO one or two months later.

Guillaume Gastineau et al.

Status: open (until 10 Jan 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • CC1: 'Comment on egusphere-2022-939', Joaquin Munoz-Sabater, 23 Nov 2022 reply

Guillaume Gastineau et al.

Guillaume Gastineau et al.

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Short summary
Snow cover variability is important for many human activities. This study aims to understand the main drivers of snow cover in observations and models, in order to better understand it and guide the improvement of forecasting systems. Analyses reveal a dominant role for sea surface temperature in the Pacific. Winter snow cover is also found to have important two-way interactions with the troposphere and stratosphere.