Cliwoc
Encyclopedia
The Climatological database for the world's oceans (CLIWOC) was a research project to convert ships' logbooks into a computerised database. It was funded by the European Union
, and the bulk of the work was done between 2001 and 2003. The database draws on British
, Dutch
, French
and Spanish
ships' logbook
records for the immediate pre-instrumental period, 1750 to 1850.
CLIWOC established early ships' logbooks as another source for those seeking to understand climate change
, to be used alongside proxy and instrument data. The observations were made at local noon every single day, and cover most of the world's oceans - only the Pacific Ocean
lacks detailed coverage. This volume of data was not available by any other means.
Though each book used consistent terms to refer to wind speeds, these values were not always consistent between logbooks. The researchers chose to standardise the terms into their Beaufort scale
equivalents. The vocabulary used also differed between the national sources - British mariners used a relatively narrow range of terms, while sailors from the Netherlands, Spain, and France used a wider set of descriptions. Researchers found that the majority of wind force entries were accounted for by twelve or so terms, allowing the group to prepare a dictionary defining most wind force terms in use. This multi-lingual dictionary has also been published.
or travelling in close company. These voyages often lasted several weeks, giving large samples. The research showed that there was a consistently high degree of correlation
in recorded wind forces and recorded wind directions.
On a number of occasions, the records showed small but persistent differences between absolute wind force records prepared on ships of different sizes. This was adjudged not to materially influence the scientific outcome of the project, but remains a matter for further investigation.
It was also necessary to correct the data to modern norms, both for wind speed and for wind direction - some books recorded data by reference to magnetic north, rather than true north
. Precise navigational methods were not widely used until late in the study period, so it was necessary to correct latitude
and longitude
using specifically designed software.
and via the CLIWOC website. The data structure is based on the International Maritime Meteorological Archive (IMMA) format.
The database includes information on date and time of each observation, the latitude and longitude of the recording vessel, its country of origin. wind direction and wind force. Where available - usually only towards the end of the survey period - instrumental observations are also included.
The CLIWOC database is also being used as an extension of the instrument-based records contained in the I-COADS dataset.
The database was used to feed wind force and direction into statistical models, which in turn produced monthly pressure field reconstructions for the Indian
and the South and North Atlantic Ocean
s. These models provide information for researchers into climate change over the oceans in the century from 1750. It also allows estimates of such measures as the North Atlantic Oscillation
and Southern Oscillation indices for this period.
By the time the project closed in 2003, the Spanish logbooks have been almost completely studied. Over 50 per cent of Dutch and over 90 per cent of British and French logbooks remained unexamined - each of these sources contains around 100,000 observations. All sources include many observations taken at times other than local noon; these observations have not been studied in any depth.
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
, and the bulk of the work was done between 2001 and 2003. The database draws on British
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
, Dutch
Netherlands
The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...
, French
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
and Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
ships' logbook
Logbook
A logbook was originally a book for recording readings from the chip log, and is used to determine the distance a ship traveled within a certain amount of time...
records for the immediate pre-instrumental period, 1750 to 1850.
Logbooks in review
Logbooks from the eighteenth and early nineteenth century had previously been used in case studies of individual events of historic or climatic interest.CLIWOC established early ships' logbooks as another source for those seeking to understand climate change
Climate change
Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...
, to be used alongside proxy and instrument data. The observations were made at local noon every single day, and cover most of the world's oceans - only the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
lacks detailed coverage. This volume of data was not available by any other means.
Interpreting the data
In researching the data, CLIWOC staff found that the data need to be treated with caution, and subjected to careful scrutiny. The range of information - wind force terms and directions, and general weather descriptions - is consistent between the different national sources. The data was primarily based on observations made by experienced officers.Though each book used consistent terms to refer to wind speeds, these values were not always consistent between logbooks. The researchers chose to standardise the terms into their Beaufort scale
Beaufort scale
The Beaufort Scale is an empirical measure that relates wind speed to observed conditions at sea or on land. Its full name is the Beaufort Wind Force Scale.-History:...
equivalents. The vocabulary used also differed between the national sources - British mariners used a relatively narrow range of terms, while sailors from the Netherlands, Spain, and France used a wider set of descriptions. Researchers found that the majority of wind force entries were accounted for by twelve or so terms, allowing the group to prepare a dictionary defining most wind force terms in use. This multi-lingual dictionary has also been published.
Data verification
In order to establish the reliability of logbook records, the researchers looked at readings taken where ships were in convoyConvoy
A convoy is a group of vehicles, typically motor vehicles or ships, traveling together for mutual support and protection. Often, a convoy is organized with armed defensive support, though it may also be used in a non-military sense, for example when driving through remote areas.-Age of Sail:Naval...
or travelling in close company. These voyages often lasted several weeks, giving large samples. The research showed that there was a consistently high degree of correlation
Correlation
In statistics, dependence refers to any statistical relationship between two random variables or two sets of data. Correlation refers to any of a broad class of statistical relationships involving dependence....
in recorded wind forces and recorded wind directions.
On a number of occasions, the records showed small but persistent differences between absolute wind force records prepared on ships of different sizes. This was adjudged not to materially influence the scientific outcome of the project, but remains a matter for further investigation.
It was also necessary to correct the data to modern norms, both for wind speed and for wind direction - some books recorded data by reference to magnetic north, rather than true north
True north
True north is the direction along the earth's surface towards the geographic North Pole.True geodetic north usually differs from magnetic north , and from grid north...
. Precise navigational methods were not widely used until late in the study period, so it was necessary to correct latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...
and longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
using specifically designed software.
The database
An initial version of the database was released in late 2003, as a CD-ROMCD-ROM
A CD-ROM is a pre-pressed compact disc that contains data accessible to, but not writable by, a computer for data storage and music playback. The 1985 “Yellow Book” standard developed by Sony and Philips adapted the format to hold any form of binary data....
and via the CLIWOC website. The data structure is based on the International Maritime Meteorological Archive (IMMA) format.
The database includes information on date and time of each observation, the latitude and longitude of the recording vessel, its country of origin. wind direction and wind force. Where available - usually only towards the end of the survey period - instrumental observations are also included.
Achieving CLIWOC's objectives
After the CLIWOC project ended in 2003, the researchers claimed a number of successes. According to the project's website, these included:- Established a freely-available database of calibrated climatic data that will be of value in climatic studies;
- Confirmed by objectiveObjectivity (science)Objectivity in science is a value that informs how science is practiced and how scientific truths are created. It is the idea that scientists, in attempting to uncover truths about the natural world, must aspire to eliminate personal biases, a priori commitments, emotional involvement, etc...
means the reliability of logbook data; - Provided a dictionary of terms that allows other scientists to decipher more readily the descriptions contained in logbooks
- Developed a statistical algorithmAlgorithmIn mathematics and computer science, an algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Algorithms are used for calculation, data processing, and automated reasoning...
by which fields of collated logbook data can be used to reconstruct atmospheric pressureAtmospheric pressureAtmospheric pressure is the force per unit area exerted into a surface by the weight of air above that surface in the atmosphere of Earth . In most circumstances atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point...
fields over the oceans
The CLIWOC database is also being used as an extension of the instrument-based records contained in the I-COADS dataset.
The database was used to feed wind force and direction into statistical models, which in turn produced monthly pressure field reconstructions for the Indian
Indian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
and the South and North Atlantic Ocean
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
s. These models provide information for researchers into climate change over the oceans in the century from 1750. It also allows estimates of such measures as the North Atlantic Oscillation
North Atlantic oscillation
The North Atlantic oscillation is a climatic phenomenon in the North Atlantic Ocean of fluctuations in the difference of atmospheric pressure at sea level between the Icelandic low and the Azores high. Through east-west oscillation motions of the Icelandic low and the Azores high, it controls the...
and Southern Oscillation indices for this period.
By the time the project closed in 2003, the Spanish logbooks have been almost completely studied. Over 50 per cent of Dutch and over 90 per cent of British and French logbooks remained unexamined - each of these sources contains around 100,000 observations. All sources include many observations taken at times other than local noon; these observations have not been studied in any depth.
Participants
Participating institutions included:- Universidad Complutense de Madrid
- University of SunderlandUniversity of SunderlandThe University of Sunderland is located in Sunderland, north east England. The university has more than 17,500 students, including 7,000-plus international students from some 70 countries....
- University of East AngliaUniversity of East AngliaThe University of East Anglia is a public research university based in Norwich, United Kingdom. It was established in 1963, and is a founder-member of the 1994 Group of research-intensive universities.-History:...
- Royal Netherlands Meteorological Institute
- Instituto de Nivología, Glaciología y Ciencias Ambientales
- National Maritime MuseumNational Maritime MuseumThe National Maritime Museum in Greenwich, England is the leading maritime museum of the United Kingdom and may be the largest museum of its kind in the world. The historic buildings forming part of the Maritime Greenwich World Heritage Site, it also incorporates the Royal Observatory, Greenwich,...
- Netherlands Institute for Scientific Information Services
- the US National Oceanic and Atmospheric Administration
See also
- International Comprehensive Ocean-Atmosphere Data SetInternational Comprehensive Ocean-Atmosphere Data SetThe International Comprehensive Ocean-Atmosphere Data Set, or ICOADS, is a digital database of 261 million weather observations made by ships, weather ships, and weather buoys spanning the years 1667 to 2007. The database was initially constructed in 1985 and continues to be expanded upon and...
- Temperature recordTemperature recordThe temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time. The most detailed information exists since 1850, when methodical thermometer-based records began. There are numerous estimates of temperatures since the end of the...
- Temperature record of the past 1000 yearsTemperature record of the past 1000 yearsThe temperature record of the 2nd millennium describes the reconstruction of temperatures since 1000 CE on the Northern Hemisphere, later extended back to 1 CE and also to cover the southern hemisphere. A reconstruction is needed because a reliable surface temperature record exists only since about...
External links
- www.ucm.es/info/cliwoc CLIWOC website - also contains an FTPFile Transfer ProtocolFile Transfer Protocol is a standard network protocol used to transfer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and utilizes separate control and data connections between the client and server...
version of the database. - ICOADS dataset
- Climate of the Past: Seasonal mean pressure reconstruction for the North Atlantic (1750-1850) based on early marine data