A 500-year multi-proxy drought reconstruction for the Czech Lands

Abstract. Any proxy archive related to climate has inherent advantages and disadvantages. What have become known as the multi-proxy approaches therefore constitute the cutting edge of paleoclimatology, as they are capable of providing more complete pictures of past climatic changes. This contribution combines tree-ring width chronologies, grape harvest dates and documentary-based precipitation indices from the territory of the Czech Republic to reconstruct inter-annual to multi-decadal drought variability, as expressed by Z-index, back to AD 1501. Using Principle Component Analysis and simple linear regression, the multi-proxy record explains 70 % of April–July drought variability between 1805 and 1854. It is demonstrated that the relatively short calibration period of early instrumental measurements, from 1805 to 1854, does not influence the quality of this reconstruction, and that the regression approach does not underestimate drought extremes. While reflecting a considerable amount of inter-annual spring-summer drought variability, the new Z-index reconstruction does not capture any long-term trends beyond the multi-decadal domain. The driest (1616) and the wettest (1713) years match previously published hydroclimate reconstructions from the same region, whereas the driest and wettest 30-year periods occurred in 1998–2017 and 1890–1919 respectively. Thus central Europe has recently experienced the most severe decadal-scale late spring–early summer drought of the past 500 years. The new multi-proxy drought reconstruction demonstrated progress beyond previous single-proxy attempts at establishing the strength of hydroclimate signal.