Reconstruction of the precipitation in the Canary Islands for the period 1600-1815. A NAO proxy?

Ricardo Garcia Herrera
Dept. of Atmospheric Sciences, University of Madrid, Spain

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Abstract

Historical documentary sources from cereal taxes collected in the Canary Islands have been used to construct a complete and reliable wheat and barley production series for the period 1595-1836. These series have been applied to generate a proxy for the islands' rainfall. The cereal growth period in this region spans the months between October and March, covering essentially the whole rainy season in the islands, making these crops adequate to characterize the precipitation at annual scales. The close relationship between cereal production and precipitation has been assessed by using two independent series for drought and wet years, obtaining very good concordance. The spectral analysis, shows a strong non stationary behaviour, with two active phases a 50-60 year and 8-14 years, with a trend to longer period to the end of the series. The relationship between Canarian rainfall and the North Atlantic Oscillation (NAO) during the instrumental period suggests the use of the reconstructed precipitation series as a NAO proxy. The comparison with the only instrumental NAO series back to 1824 shows a strong agreement but limited to the 13-year common period. Comparison with proxies available support the value of the crop production in the Canaries to add new information to the NAO behaviour, specially regarding to its Southern centre of action.

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6 Dec, 2001
2 PM/ DSRC 1D 403
(Coffee at 1:50 PM)
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