2 research outputs found

    Atlantic and Mediterranean synoptic drivers of central Spanish juniper growth

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    Atlantic and Mediterranean air masses influence the climate over the Iberian System mountain range. The relatively short instrumental records in central Spain though limit any long-term assessment of these synoptic systems. We here evaluate the potential to analyze such changes using ring width data from Juniperus thurifera trees growing in the northwestern and southeastern regions of the Iberian System, exposed to Atlantic and Mediterranean cyclonic activity, respectively. Comparison of tree rings with regional precipitation, temperature, and Palmer Drought Severity Index (PDSI) data indicates that juniper trees contain information on late spring and early summer drought conditions. Calibration trials using spatially resolved, gridded climate data reveal that the northwestern sampling site is predominantly controlled by Atlantic weather, while the southeastern site mainly reflects Mediterranean climate patterns. The strength and position of the blocking Azores high during spring to early summer is of particular importance for the distinct growth reactions in the Iberian System. The climate signal is remarkably strong in the southeastern site, where we developed the longest and best-replicated juniper tree ring record of the Iberian Peninsula. Data from this site allowed the reconstruction of May-June PDSI variability back to the early eighteenth century, indicating severe drought (PDSI < ¿9) in southeastern Spain in 1782, 1828, 1869, 1981, and 2005. The new PDSI record coheres well with historical rogation ceremony data from eastern Spain, indicating that common information on past drought events is inherent in both proxy archives. © 2014, Springer-Verlag Wien.We thank G. Sangüesa-Barreda and R. Hernández for the help in the field. This study was supported by the Mainz Geocycles Research Center. JJC received support from ARAID and projects CGL2011-26654 (Spanish Ministry of Economy) and 387-2011 (OAPN). FDC received support from the Prometeo Project, Secretariat of Higher Learning, Science, Technology and Innovation (Ecuador Government). UB received support from the Operational Program of Education for Competitiveness of Ministry of Education, Youth and Sports of the Czech Republic (Project: Building up a multidisciplinary scientific team focused on drought, No. CZ.1.07/2.3.00/20.0248).Peer Reviewe
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