Precipitation reconstruction for Northwestern Tunisia from tree rings

An October-June precipitation reconstruction was developed from a Pinus halepensis regional tree-ring chronology from four sites in northwestern Tunisia for the period of 1771-2002. The reconstruction is based on a reliable and replicable statistical relationship between climate and tree-ring growth and shows climate variability on both interannual and interdecadal time scales. Thresholds (12th and 88th percentiles) based on the empirical cumulative distribution of observed precipitation for the 1902-2002 calibration period were used to delineate dry years and wet years of the long-term reconstruction. The longest reconstructed drought by this classification in the 232-year reconstruction is 2 years, which occurred in the 19th century. Analysis of 500 mb height data for the period 1948-2002 suggests reconstructed extreme dry and wet events can provide information on past atmospheric circulation anomalies over a broad region including the Mediterranean, Europe and eastern Asia.