Droughts derive from a precipitation deficit and can also be temperature driven. They are dangerous natural hazards for human societies. Documentary data from the pre-modern and early modern times contain direct and indirect information on precipitation that allow for the production of reconstructions using historical climatology methods. For this study, two drought indices – the drought index of Bern (DIB) and the drought index of Rouen (DIR) – have been created on the basis of documentary data produced in Bern, Switzerland, and Rouen, France, respectively for the period from 1315 to 1715. These two indices have been compared to a third supra-regional drought index (SDI) for Switzerland, Germany, France, the Netherlands, and Belgium that was synthesised from precipitation reconstruction based on historical climatology. The results of this study show that the documentary data from Bern mainly contain summer droughts, whereas the data from Rouen rather allow for the reconstruction of spring droughts. The comparison of the three above-mentioned indices shows that the DIB and the DIR most probably do not contain all of the actual drought events; however, they detect droughts that do not appear in the SDI. This fact suggests that more documentary data from single locations, such as historical city archives, should be examined in the future and should be added to larger reconstructions in order to obtain more complete drought reconstructions.

中文翻译：

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根据文献证据，从14世纪到18世纪初，伯尔尼和鲁昂的干旱

干旱源于降水不足，也可能是温度驱动的。它们是人类社会的危险自然灾害。来自近现代和近代早期的文献数据包含有关降水的直接和间接信息，这些信息允许使用历史气候学方法进行重建。在本研究中，根据分别在瑞士伯尔尼和法国鲁昂产生的文献数据，创建了两个干旱指数-伯尔尼干旱指数（DIB）和鲁昂干旱指数（DIR）。从1315年到1715年。这两个指数已与瑞士，德国，法国，荷兰和比利时的第三次超地区干旱指数（SDI）进行了比较，该指数是根据历史气候学从降水重建中得出的。这项研究的结果表明，伯尔尼的文献资料主要包含夏季干旱，而鲁昂的资料则可以重建春季干旱。对上述三个指数的比较表明，DIB和DIR最有可能没有包含所有实际的干旱事件。但是，他们检测到SDI中未出现的干旱。这一事实表明，将来应检查来自单个位置的更多文献数据，例如历史城市档案，并应将其添加到较大的重建物中，以获得更完整的干旱重建。对上述三个指数的比较表明，DIB和DIR最有可能没有包含所有实际的干旱事件。但是，他们检测到SDI中未出现的干旱。这一事实表明，将来应检查来自单个位置的更多文献数据，例如历史城市档案，并应将其添加到较大的重建物中，以获得更完整的干旱重建。对上述三个指数的比较表明，DIB和DIR最有可能没有包含所有实际的干旱事件。但是，他们检测到SDI中未出现的干旱。这一事实表明，将来应检查来自单个位置的更多文献数据，例如历史城市档案，并应将其添加到较大的重建物中，以获得更完整的干旱重建。