The Atmospheric Pressure Observations 1856-1858 by Father Louis Furet, at Naha, Japan

Abstract

Father Louis Théodore Furet (1816⊖1900) was a missionary of the Société des Missions étrangères de Paris (Paris Foreign Missions Society) who was posted in the Far East from 1853 to 1869. The discovery of his manuscript of meteorological observations undertaken at Naha, Okinawa, Ryukyu Islands, Japan, opens up new perspectives on the historical climatology of 19 th century Japan. Furet arrived at Naha (spelled Nafa in the 19 th century literature) , the main port of Okinawa, on 26 February 1855. From December 1856 to September 1858, he carried out meteorological observations five times a day: at 6 and 10 am, 1, 4 and 10 pm. The hydrological engineer Alexandre Delamarche (1815⊖1884) calibrated the meteorological instruments entrusted to Father Furet by the French Dépôt de la Marine. The observations were carried out following the meteorological procedures in use in France in the 1850s. The atmospheric pressure data are given by the barometer readings, the barometer-temperature readings and the computed temperature-corrected atmospheric pressure. The pressure data are controlled and corrected, where necessary, using the Delcros and Haeghens formula which was in use in the 1850s. The historical atmospheric pressure observations are compared to the present-day long-term averages at Naha. During his observation period a typhoon was witnessed by Father Louis Furet on 18 May 1857. Other low atmospheric pressure observations probably correspond to extra-tropical storms. In such an event, the Dutch ship van Bosse was wrecked near the island Tarama but the captain, his wife and the whole crew survived. They were helped by the inhabitants of the island and were later transferred to Naha, Okinawa, where they met the three French missionaries and finally got a passage from the Dutch trading post at Decima to Batavia (present-day Jakarta) .

Overview of the Special Issue “Meteorological Disasters and Climate Variations in Historical Times”

“…These data give important clues for understanding the climate of Southwest Japan in the mid-19th century. Demarée et al (2018) focused on the barometric observations conducted five times a day during the period 1856⊖1858 by Father Furet mentioned above. Barometric air pressure data were corrected for sea level and temperature, and monthly mean values were calculated and graphed in comparison with present average values.…”