Homogenization and assessment of observed near-surface wind speed trends over Spain and Portugal, 1961-2011

Near-surface wind speed trends recorded at 67 land-based stations across Spain and Portugal for 1961-2011, also focusing on the 1979-2008 subperiod, were analyzed. Wind speed series were subjected to quality control, reconstruction, and homogenization using a novel procedure that incorporated the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5)-simulated series as reference. The resultant series show a slight downward trend for both 1961-2011 (-0.016ms-1 decade-1) and 1979-2008 (-0.010ms-1 decade-1). However, differences between seasons with declining values in winter and spring, and increasing trends in summer and autumn, were observed. Even though wind stilling affected 77.8% of the stations in winter and 66.7% in spring, only roughly 40% of the declining trends were statistically significant at the p < 0.10 level. On the contrary, increasing trends appeared in 51.9% of the stations in summer and 57.4% in autumn, with also around 40% of the positive trends statistically significant at the p < 0.10 level. In this article, the authors also investigated (i) the possible impact of three atmospheric indices on the observed trends and (ii) the role played by the urbanization growth in the observed decline. An accurate homogenization and assessment of the long-term trends of wind speed is crucial for many fields such as wind energy (e.g., power generation) and agriculture-hydrology (e.g., evaporative demand). © 2014 American Meteorological Society.The authors wish to acknowledge the editor and three anonymous reviewers for their detailed and helpful comments to the original manuscript. This research was supported by (i) the JAE-DOC043 (CSIC; European Social Fund, FSE) and the JCI-2011-10263 Grants; (ii) A. S.-L. received a postdoctoral fellowship from the Secretaria per a Universitats i Recerca del Departament d’Economia i Coneixement, de la Generalitat de Catalunya i del programa Cofund de les Accions Marie Curie del 7è Programa marc d’R+D de la Unió Europea (2011 BP-B 00078); (iii) Projects CGL2011-27574-C02-02, CGL2011-27536/HID, CGL2011-29263-C02-01, and PSE.120000.2007.14, financed by the Spanish Commission of Science and Technology and FEDER; ACQWA (FP7-ENV- 2008-1-212250), financed by the European Comission; Efecto de los escenarios de cambio climático sobre la hidrología superficial y la gestión de embalses del Pirineo Aragonés, financed by Obra Social La Caixa; CTTP1/12 Creación de un modelo de alta resolución espacial para cuantificar la esquiabilidad y la afluencia turística en el Pirineo bajo distintos escenarios de cambio climático, financed by the Comunidad de Trabajo de los Pirineos; ENAC (PTDC/AAC-CLI/103567/2008), financed by the Portuguese Science Foundation; and (iv) the Climatology Group (2009 SGR 443, Catalan Government). The authors thank the AEMET and the IPMA institutions for the observed wind data and particularly José-Antonio Guijarro (AEMET-Baleares) and Juan-José Vizcaíno (AEMET-Valencia) for their useful comments and information. We thank Ptr Stepanek for providing the AnClim software and the MAR research group of the University of Murcia for providing the MM5-simulated wind speed series, particularly the assistance of Raquel Lorente-Plazas and Juan Pedro Montávez.Peer Reviewe

Estructura y características ambientales de los sabinares de Juniperus turbinata Guss. en la isla de El Hierro (Islas Canarias)

6 p., mapas, tablas -- Comunicación presentada al XIV Colóquio Ibérico de Geografía, celebrado del 11 al 14 de noviembre en Guimarães, Portugal.[ES]En la Reserva de la Biosfera de la isla de El Hierro se encuentran los sabinares de Juniperus turbinata Guss. más extensos de las Islas Canarias, aunque su área de distribución actual es muy inferior a la potencial. El objetivo principal fue estudiar las especies que se encuentran en el sabinar, su estructura y las condiciones ambientales en las que se desarrolla. Los métodos utilizados han sido los inventarios sistemáticos y la toma de datos climáticos en los sabinares actuales. Los resultados obtenidos muestran que hay diferencias florísticas significativas entre los sabinares de diferentes vertientes, pero también existen contrastes en parcelas próximas que fueron gestionados de manera desigual en el siglo XX. Los resultados de esta investigación permiten conocer mejor la biodiversidad del sabinar herreño y por ello la proporción de endemismos, especies mediterráneas y especies introducidas.Peer reviewe

Climate controls on rainfall isotopes and their effects on cave drip water and speleothem growth: the case of Molinos cave (Teruel, NE Spain)

The interpretation of stable isotopes in speleothems in terms of past temperature variability or precipitation rates requires a comprehensive understanding of the climatic factors and processes that influence the δ18O signal in the way through the atmosphere to the cave, where carbonate precipitates acquiring its final isotopic composition. This study presents for the first time in the Iberia Peninsula an integrated analysis of the isotopic composition of rainfall (δ18Op) during 2010–2012 years and, through a detailed monitoring survey, the transference of the primary isotopic signal throughout the soil and epikarst into the Molinos cave (Teruel, NE Spain). Both air temperature and amount of precipitation have an important effect on δ18Op values, clearly imprinting a seasonal variability modulated by an amount effect when rainfall events are more frequent or intense. Air mass history and atmospheric circulation influences are considered through the study of weather types, synoptic-scale climate patterns and large-scale atmospheric circulation indexes (North Atlantic Oscillation and Western Mediterranean Oscillation) revealing a dominant source effect on δ18Op values in this region where tropical North Atlantic and Western Mediterranean are the two moisture source regions. A delay of 2–3 months occurs between the dripwater oxygen isotopic composition (δ18Od) respect to δ18Op values as a consequence of large residence time in the epikarst. Limited calcite precipitates are found from winter to spring when δ18Od values are less negative and dripwater rates are constant. This study suggests that NE Iberian δ18Ocalcite proxy records are best interpreted as reflecting a combination of parameters, not just paleotemperature or paleorainfall and, if extending present-day situation towards the recent past, a biased signal towards winter values should be expected in Molinos speleothem records

Trends in frequency indices of daily precipitation over the Iberian Peninsula during the last century

This study provides the first long-term assessment of changes in precipitation associated with different rainfall categories over the Iberian Peninsula (IP). Using recently digitized data from 27 stations in Portugal and Spain, we have examined trends of precipitation indices for the complete period 1903–2003 and the two subperiods 1903–1953 and 1954–2003. These indices were evaluated seasonally according to five rainfall categories: total rainfall (=0.2 mm), light rainfall (=0.2 an