More about the CLIWOC project
The principal objective of the project was to prepare a database that could be used by scientists to gain a better understanding of the climates over the ocean in the pre-instrumental period. This was achieved at a global level as far back as the mid-18th century, and more locally for the North Atlantic, back to the mid-17th century. The CLIWOC project focused on 1750–1850, thereby linking with the instrumental, oceanic records that had already been abstracted, but extending the record back a further 100 years.
For climatologists this is an important period. It marks the closing decades of the so-called 'Little Ice Age'; a time when European weather was cooler, wetter and stormier than it is today. It marks also a period when climatic change cannot be seen as a possible consequence of world-wide industrialization and the release of greenhouse gases into the atmosphere.
Although the data was non-instrumental and did not include temperatures, air pressure nor any of the other standard observations that make up such a big part of present-day observational systems, they were important in two respects:
- The logbooks provided information on the important elements of wind strength and direction, which helped to provide a picture of the behaviour of major weather systems.
- The data was very detailed, in the sense that the observations were made several times each day.
Mariners were also quick to note other weather elements such as lightning, rain, snow, fog and cloud. They also recorded of the state of the sea, and any sightings of icebergs (or ice-islands as they were often known). All of these observations help scientists to reconstruct the nature of day-to-day weather, and longer term climate and climatic change at sea at those periods.
Unlike many 'proxy' sources of climatic data, the logbook data allowed the database to be constructed at a daily level so that researchers were able to examine not only the long-term shifts in climate, the wind belts and pressure systems, but were also able to interrogate the database, requesting data from specific days.