Climate Dynamics

, Volume 32, Issue 1, pp 75–93

Contribution of realistic soil moisture initial conditions to boreal summer climate predictability

Article

DOI: 10.1007/s00382-008-0375-9

Cite this article as:
Conil, S., Douville, H. & Tyteca, S. Clim Dyn (2009) 32: 75. doi:10.1007/s00382-008-0375-9

Abstract

Seasonal climate forecasts mainly rely on the atmospheric sensitivity to its lower boundary conditions and on their own predictability. Besides sea surface temperature (SST), soil moisture (SM) may be an additional source of climate predictability particularly during boreal summer in the mid-latitudes. In this work, we investigate the role of SM initial conditions on near-surface climate predictability during ten boreal summer seasons using three complementary ensembles of AMIP-type simulations performed with the Arpège-Climat atmospheric general circulation model. First we have conducted an assessment of the SM predictability itself through a comparison of simple empirical SM models with Arpège-Climat. The statistical and dynamical models reveal similar SM prediction skill patterns but the Arpège-Climat reaches higher scores suggesting that it is at least suitable to explore the influence of SM initialization on atmospheric predictability. Then we evaluate the relationships between SM predictability and some near surface atmospheric predictability. While SM initialization obviously improves the predictability of land surface evaporation, it has no systematic influence on the precipitation and near surface temperature skills. Nevertheless, the summer hindcast skill is clearly improved during specific years and over certain regions (mainly north America and eastern Europe in the Arpège-Climat model), when and where the SM forcing is sufficiently widespread and strong. In this case, a significant impact is also found on the occurrence of heat waves and heavy rains, whose predictability at the seasonal timescale is a crucial challenge for years to come.

Keywords

Soil Moisture predictability Land–atmosphere interactions Boreal summer predictability Severe climate events 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  1. 1.LPAT-GEOL, Département de Physique, UFR SENUniversité des Antilles et de la GuyanePointe-à-Pitre Cedex, GuadeloupeFrance
  2. 2.CNRM/GMGEC/UDC, Météo FranceToulouseFrance

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