Precipitation reconstructions for Paris based on the observations by Louis Morin, 1665-1713 CE

This paper presents a precipitation reconstruction that is based on the continuous observations by Louis Morin in Paris from 1665–1713. Morin usually recorded precipitation intensity and duration three times each day (sometimes up to six times) when it snowed or rained. The continuity of his observations can be calculated considering all measurements and observations (e.g., temperature, cloud cover), where on 98.7% of all days between February 1665 and July 1713 at least one entry per day is noted. To convert these observations to common units, we calibrated them with a multiplicative interacting model using Philippe and Gabriele-Philippe de la Hire’s instrumental measurements from Paris. The two series of measurements by de la Hire (father and son) and observations by Morin overlap from 1688–1713. To test the quality of the reconstruction, we analyzed it with the de la Hire’s measurements, proxy data, an internal analysis of Morin’s measurements of different climate variables, and modern data. Thus, we assess the reliability of the precipitation reconstructions based on Morin’s data as follows. We have moderate confidence regarding the exact quantities of daily, seasonal, and annual precipitation totals. We have low confidence regarding exceptionally high precipitation amounts, but we have high confidence in the indices of an impact analysis (i.e., dry days, wet days, consecutive dry days, consecutive wet days); in monthly frequencies of rainfall; and in interannual, interseasonal, and interdecadal variability. Rainy seasons with precipitation totals greater than 250mm occurred in MAM 1682, JJA 1682, SON 1687, JJA 1697, and JJA 1703. Furthermore, compared to other DJF seasons, the winter of 1666/1667 slightly stands out with a precipitation total of 214.6 mm. Dry seasons with precipitation totals less than 60mm occurred in SON 1669, DJF 1671/1672, and DJF 1690/1691. An impact analysis shows no abnormalities regarding consecutive dry days or wet days in MAM. In JJA a longer dry period of 31 days appeared in 1686 and a dry period of 69 d appeared in DJF 1671/1672.