Climate variability in Andalusia (southern Spain) during the period 1701–1850 based on documentary sources: evaluation and comparison with climate model simulations

Abstract

Abstract. In this work, a reconstruction of climatic conditions in Andalusia (southern Iberian Peninsula) during the period 1701-1850, as well as an evaluation of its associated uncertainties, is presented. This period is interesting because it is characterized by a minimum in solar irradiance (Dalton Minimum, around 1800), as well as intense volcanic activity (for instance, the eruption of Tambora in 1815), at a time when any increase in atmospheric CO 2 concentrations was of minor importance. The reconstruction is based on the analysis of a wide variety of documentary data. The reconstruction methodology is based on counting the number of extreme events in the past, and inferring mean value and standard deviation using the assumption of normal distribution for the seasonal means of climate variables. This reconstruction methodology is tested within the pseudoreality of a high-resolution paleoclimate simulation performed with the regional climate model MM5 coupled to the global model ECHO-G. The results show that the reconstructions are influenced by the reference period chosen and the threshold values used to define extreme values. This creates uncertainties which are assessed within the context of climate simulation. An ensemble of reconstructions was obtained using two different reference periods (1885-1915 and 1960-1990) and two pairs of percentiles as threshold values (10-90 and 25-75). The results correspond to winter temperature, and winter, spring and autumn rainfall, and they are compared with simulations of the climate model for the considered period. The mean value of winter temperature for the period 1781-1850 was 10.6 ± 0.1 • C (11.0 • C for the reference period . The mean value of winter rainfall for the period 1701-1850 was 267 ± 18 mm (224 mm for . The mean values of spring and autumn rainfall were 164 ± 11 and 194 ± 16 mm (129 and 162 mm for 1960-1990, respectively). Comparison of the distribution functions corresponding to 1790-1820 and 1960-1990 indicates that during the Dalton Minimum the frequency of dry and warm (wet and cold) winters was lower (higher) than during the reference period: temperatures were up to 0.5 • C lower than the 1960-1990 value, and rainfall was 4 % higher.

Droughts in Portugal in the 18th century: A study based on newly found documentary data

“…A good correspondence was found between the main drought periods in Portugal in the 18th century and droughts previously detected for southwestern Spain in the same periods (Domínguez-Castro et al, 2012;Rodrigo et al, 2012).…”

Degradation of buried ice and permafrost in the Veleta cirque (Sierra Nevada, Spain) from 2006 to 2013 as a response to recent climate trends

“…These stillsurviving remains of frozen bodies are the heir of the Little Ice Age period (14th-19th centuries), although their formation may have started earlier, even during the Medieval Warm Period (Oliva and Gómez-Ortiz, 2012). Evidence of this cold phase is found in historical documents Rodrigo et al, 2012), palynological studies (Esteban-Amat, 1996) and sedimentological records (Oliva and Gómez-Ortiz, 2012;Oliva et al, 2011). Sierra Nevada was dominated by a climate regime different from today's, especially in its temperatures, which are calculated as at least 0.93 • C lower than now (Oliva and Gómez-Ortiz, 2012), which would mean that a greater altitude range was under cryonival conditions than today.…”

The climate of Granada (southern Spain) during the first third of the 18th century (1706–1730) according to documentary sources

“…There is a third problem of a statistical nature: the calibration of indices is normally done using a regression procedure between proxy data (indices) and instrumental data during an overlapping period. From a statistical point of view, the consequence is the loss of variance in the reconstructed series, a problem that is normally solved using an "inflation factor" to correct the reconstructed series (Rutherford et al, 2005). With this method, in principle, it is not necessary to introduce this mathematical artifact.…”