A 250-Year Annual Precipitation Reconstruction and Drought Assessment for Cyprus from Pinus Brutia Ten

INTERNATIONAL JOURNAL OF CLIMATOLOGY Int. J. Climatol. (2013) Published online in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/joc.3869 A 250-year annual precipitation reconstruction and drought assessment for Cyprus from Pinus brutia Ten. tree-rings Carol Griggs,a* Charlotte Pearson,b Sturt W. Manninga and Brita Lorentzena a The Malcolm and Carolyn Wiener Laboratory for Aegean and Near Eastern Dendrochronology, Cornell University, Ithaca, NY, USA b LTRR, University of Arizona, Tucson, AZ, USA ABSTRACT: Precipitation around Cyprus, a relatively small island, is generally consistent in year-to-year variation in all dimensions except amplitude, with the higher elevations in the west generally receiving more precipitation. An annual record of precipitation was found in tree-rings of the predominant pine species, Pinus brutia Ten., which grows from the lower foothills up to 1400 m in altitude across the island. Tree-ring chronologies from four sites in west-central Cyprus are used here to reconstruct the annual September to August precipitation and a drought record for AD 1830–2006, with the drought reconstruction extending back to 1756. A minimum of 40% of the variance in annual precipitation and drought occurrence is explained by the variance in the tree-ring widths in all cases. Our drought assessment indicates that, on average, annual droughts occur once every 5 years and sustained droughts, 2–6 years in length, have occurred in small clusters of time, from 1806–1824, 1915–1934 and 1986–2000, when the winter North Atlantic Oscillation was in a predominantly positive phase. These results suggest that a sustained drought period has a mean return time probability of one in 70–100 years. This study provides the first long-term annual precipitation reconstruction and drought assessment at low to mid-elevations for Cyprus and will aid in future plans for drought mitigation. KEY WORDS annual precipitation reconstruction; drought record; dendroclimatology; Pinus brutia (Ten.); Cyprus; Troodos Massif; North Atlantic Oscillation Received 25 February 2013; Revised 8 October 2013; Accepted 12 October 2013 1. Introduction elevation 1951 m) in the southwest and the Pentadaktylos (Kyrenia) range (maximum height 1000 m) along the Past climate parameters have been reconstructed from northern coast, which give Cyprus high topographical many proxy records developed to understand palaeocli- variability (Price et al., 1999). mate conditions over time around the world. The nature Cyprus has a Mediterranean climate regime consisting and quality of the reconstruction depend on the origin of hot, dry summers with clear skies from June to of the data sets employed. For the time series in a den- September, and cool, wet winters from November to droclimatological reconstruction the general principle is March (Figure 2). The short autumn and spring seasons that trees primarily respond to certain climate parameters in October, April and May are characterized by high during their growing season months, particularly precip- variability and rapid changes in precipitation and temper- itation in any drier region of the range of the studied ature (Price et al., 1999). The minimal cloud cover and species, and temperature at high latitudes or altitudes high temperatures in summertime are largely influenced (Hughes et al., 2011; Fritts, 1976). However, in Cyprus, by the combination of subsidence from the northward the amount of precipitation occurring year round criti- shift of the subtropical high and the Persian trough, a cally influences water availability throughout the growing shallow low-pressure trough extending from the Asian season, so the trees contain an annual precipitation record monsoon depression centred over Pakistan, which leads that is unusual and of considerable importance in acquir- to summertime northwesterly winds. When summer ing a more complete understanding of long-term climate rainfall does occur, it is usually in the form of isolated change in Cyprus and the northeastern Mediterranean thunderstorms and contributes less than 5% of the total region. ◦ ◦ annual rainfall. Winter weather is generally influenced Cyprus is located at approximately 35 N and 33 E, at by unsettled small low pressure systems crossing the the east end of the Mediterranean Sea, and is ∼224 km sea from between the continental anticyclone of Eurasia WSW to ENE, and ∼97 km NNW–SSE with a land area and the persistent low pressure belt over North Africa. of approximately 9250 km2 (Figure 1). The island has These depressions produce the majority of the island’s two mountain ranges – the Troodos Massif (maximum annual precipitation, with the average precipitation from December to February being about 60% of the annual total (Price et al., 1999) (Figure 2). * Correspondence to: C. Griggs, The Malcolm and Carolyn Wiener Unequal heating of the sea surface and island interior Laboratory for Aegean and Near Eastern Dendrochronology, B48 Gold- win Smith Hall, Ithaca, NY 14853, USA. E-mail: [email protected] plus a large variation in the island’s topography create 2013 Royal Meteorological Society C. GRIGGS et al. ◦ Figure 1. Map of Cyprus showing study sites and weather stations on the Island. The cross-hair shows the centre of the 4 CRU 0.5 grids at ◦ ◦ 33.0 E, 35.0 N. Figure 2. Mean monthly precipitation totals and average temperature for Cyprus. Data is from the Cyprus Meteorological Service and the Climate Research Unit (CRU). substantial seasonal and daily temperature differences depths (ca. 1–1.5 m) on the high northern slopes, while between these sites, resulting in localized climate varia- snowfall is rare in the Kyrenia range and lowland areas tion. The central Troodos Massif, and, to a lesser degree, (Pashiardis, 2000). However, despite variations in ampli- the Kyrenia range also play an important role in defining tude, precipitation across the island is fairly consistent in the weather conditions of Cyprus. Mean annual precip- year-to-year anomalies (Figure 2, Table 1) which allows itation increases up the south windward slopes to the for a stable precipitation reconstruction across the island. top of the Troodos range from 45 cm to nearly 110 cm, Over the last half of the 20th century AD, available while on the leeward slopes amounts decrease steadily meteorological data indicate a general increase in tem- to the north and east to around 30–35 cm (Price et al., perature and a slight decrease in precipitation with a 1999; Pashiardis and Michaelides, 2008). In the winter corresponding increase in drought (Price et al., 1999; months snow may lie for several weeks at considerable Pashiardis and Michaelides, 2008). We show here that 2013 Royal Meteorological Society Int. J. Climatol. (2013) A 250-YEAR PRECIPITATION AND DROUGHT RECORD FROM TREE-RINGS FOR CYPRUS Table 1. October-September P correlations between stations for over 500 years (Tsintides et al., 2002). Touchan et al. and the average of 4 grids (CRU) for 1918–2008, with the (2005) report finding P. brutia at elevations ranging from exception of Agios Epifanios, at 1957–2008. 1483 to 1646 m at Armiantos, Cyprus, with lifespans of over 400 years. Our collection indicates a range of Agios Epifanios 150–300 years is more normal for the species at the mid Troodos 0.693 Troodos and lower elevations, and Boydak (2004) reports a simi- Pedoulas 0.697 0.866 Pedoulas lar age range (250–305 years) for P. brutia mainly at the Pano Panagia 0.569 0.841 0.843 Pano Panagia Peristerona 0.779 0.570 0.592 0.561 Peristerona middle elevation range in southwestern Turkey. In both Avg 4 grids 0.793 0.649 0.754 0.670 0.697 areas human activity is a major factor, but climate condi- (CRU) tions are also more stressful to tree growth than at higher elevations. Immediately apparent in our exploratory analysis was the number of droughts and the extreme level of annual the clear response of P. brutia ring-growth to annual precipitation during the droughts have not significantly precipitation. This response is similar to a study by changed, but the variability and number of moderate to Sarris et al. (2007) that showed evidence of significantly very wet years is considerably reduced, especially in the lower annual precipitation from 1985 to 2000 recorded in 1970s–1980s. This exacerbates the effect of droughts P. brutia on the island of Samos, Greece. The drought when they occur due to little or no groundwater replen- years of the Samos meteorological data correlate very ishment from current and previous years. In the late 20th well with the Cypriot drought years, taking into account to early 21st centuries, drought in Cyprus has caused their use of January to December precipitation rather than problems ranging from support of a growing population our use of the precipitation from September to December and tourist industry to sustaining the agricultural sector of the year before growth and January to August of (especially viniculture). The severe drought of 2007/2008 the year of growth. Touchan et al. (2005) reconstructed reduced reservoir supplies to just 3% of capacity (Dav- May to August precipitation on a much larger scale in enport, 2008). Mitigation and management strategies are the northeastern Mediterranean region, including Cyprus, needed, but such planning is inhibited by the fact that using many genera and species of conifers, including most of the ∼150 weather station records on the island P. brutia. However, it is not an annual record, and the begin around 1960 or later, with less than 25 extending drought years indicated by both the meteorological data back to the early 1900s and even fewer having the unifor- and their reconstruction do not match many of the annual mity necessary for a valid assessment. Our reconstruction Cypriot drought years in our data sets. The results of extends the meteorological record by 160 years, nearly Kienast et al. (1987) indicate variability in the climate tripling the information necessary for planning drought response of trees growing along altitudinal transects, with mitigation strategies.

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