The role of the land-surface model for climate change projections over the Iberian Peninsula

Copyright 2012 by the American Geophysical Union. This study received support from the Spanish Ministry of Environment (projects ESCENA, reference 20080050084265, and SALVA-SINOBAS), the Spanish Ministry of Science and Technology (project INVENTO-CGL2005-06966-C07-04/CLI), the Regional Agency for Science and Technology of Murcia (Fundación Séneca, reference 00619/PI/04) and the "Instituto Euromediterráneo del Agua". P. Jiménez Guerrero thanks the Ramón y Cajal Program of the Spanish Ministry of Science and Innovation. J. J. Gómez Navarro thanks the Spanish Ministry of Education for his Doctoral scholarship (AP2006-04100). Finally, the authors gratefully acknowledge the contribution of anonymous reviewers which helped us to improve the quality and clarity of the manuscript.
The importance of land-surface processes within Regional Climate Models for accurately reproducing the present-day climate is well known. However, their role when projecting future climate is still poorly reported. Hence, this work assesses the influence of the land-surface processes, particularly the contribution of soil moisture, when projecting future changes for temperature, precipitation and wind over a complex area as the Iberian Peninsula, which, in addition, shows great sensitivity to climate change. The main signals are found for the summer season, when the results indicate a strengthening in the increases projected for both mean temperature and temperature variability as a consequence of the future intensification of the positive soil moisture-temperature feedback. The more severe warming over the inner dry Iberian Peninsula further implies an intensification of the Iberian thermal low and, thus, of the cyclonic circulation. Furthermore, the land-atmosphere coupling leads to the projection of a wider future daily temperature range, since maximum temperatures are more affected than minima, a feature absent in non-coupled simulations. Regarding variability, the areas where the land-atmosphere coupling introduces larger changes are those where the reduction in the soil moisture content is more dramatic in future simulations, i.e., the so-called transitional zones. As regards precipitation, weaker positive signals for convective precipitation and more intense negative signals for non-convective precipitation are obtained as a result of the soil moisture-atmosphere interactions. These results highlight the crucial contribution of soil moisture to climate change projections and suggest its plausible key role for future projections of extreme events.
Ministerio de Medio Ambiente y Medio Rural y Marino, España
Ministerio de Ciencia y Tecnología (MCYT), España
Agencia Regional de Ciencia y Tecnología de la Región de Murcia
Instituto Euromediterráneo del Agua
Ministerio de Educación, Cultura y Deporte (MECD), España
Ministerio de Ciencia e Innovación ((MCI), España
Fundación Séneca, Murcia
Proyecto ESCENA
Proyecto SALVÁ-SINOBAS
Depto. de Física de la Tierra y Astrofísica
Fac. de Ciencias Físicas
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