Determination of wind force and present weather terms:: The Dutch case

The Dutch wind force terms in the CLIWOC period (1750-1854) consist for 59% of descriptors and for 41% of regular Beaufort numbers. In total, over 1600 different descriptors are encountered. An attempt is made to transform the wind force descriptors into wind speed via the Beaufort scale of wind force. Nearly two-third of the descriptors refer to the use of sails. Despite the huge amount of descriptors, it was possible to condense 99% of the wind force reports into the 13-point Beaufort scale. Quality checks against ICOADS indicate that the quality of the post-1800 Dutch CLIWOC wind data surpasses that of the pre-1800 Dutch data, while for the pre-1800 data the quality seems comparable with that from the other countries within CLIWOC. Weather terms other than wind are denoted in 15% of the reports by special symbols, of which the meaning was lost. A key to these symbols is reconstructed.