Maritime traffic density - results of PASTA MARE project

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The studies are subject to a disclaimer and copyright. The studies have been carried out by external organisations for the European Commission and express the opinions of the organisations having undertaken them. The views have not been adopted or in any way approved by the European Commission and should not be relied upon as a statement of the European Commission's views, nor do they anticipate its policy in this field. The European Commission does not guarantee the accuracy of the information given in the studies, nor does it accept responsibility for any use made thereof. Copyright in these studies is held by the European Union. Persons wishing to use the results of these studies (in whole or in part) may do so so but must acknowledge the European Commission 's copyright .

Data Sources

ne single unique data source to compute a vessel density map at global level does not exist. Instead, to cope with the global scope of the vessel density map two different types of data are used:

1. AIS from space-based sensors (s-AIS) Orbcomm and Pathfinder 2 cover vast open sea areas, outside the reach of terrestrial AIS station network or regions where t-AIS stations do not exist or data are not accessible. These data cover the period from 1 January 2010 – 31 March 2010.
2. AIS from terrestrial sensors (t-AIS) data put at disposal by IALA.net covering high density areas of the North Sea and the Baltic Sea. t-AIS provides an almost complete vessel traffic picture over these coastal areas. In these regions space based AIS data detection capabilities are limited. The plots are based on data provided by the Danish Maritime Safety Administration (DAMSA) for the period 10 Feb 2010 - 16 Feb 2010. The used data comprises all data from DAMSA's 18 own base stations as well as from two receivers located in the North Sea operated by Maersk Oil & Gas, all data from the Finnish AIS network and data from the Swedish AIS network, for the area covering 56°N - 64°N, 15°E - 21°E.

Method

The generation of vessel density maps is based on different assumptions:

1. It is assumed that the total number of class A-vessels is currently about 62.000 (Source: Lloyds MIU Handbook of Maritime Security), i.e. the spatial pattern of these 62.000 vessels needs to be mapped at a global scale.
2. Representativity of the S-AIS sample: S-AIS does not capture at once the location of all 60.000 vessels. Instead, it requires several orbits throughout a longer time window to identify a maximum number of ships. Various tests indicate that within a time window of 8 days around 22.000 individual ships (unique MMSI’s) can be identified. Any extent of the time window does not yield in a substantial increase of the number of ships. It is assumed that the ships captured by S-AIS during the 8 days periods are a valid sample of the total class A ship population, representing the true density global vessel pattern. In order to account for the total number of ships, each 8 day subset is multiplied by a weighting factor for reaching 60.000 vessels
3. Spatially representativity: It is assumed that in every part of the world vessels are identified. In high density areas (EU waters) S-AIS capture a smaller fraction of vessels. Thus those areas are not underrepresented (undersampled) in the S-AIS but compensated through the integration of the above mentioned terrestrial AIS data.
4. It is assumed that there is no seasonality in the global vessel pattern, meaning that there is no daily/weekly/monthly change in the distribution of the global vessel traffic. This assumption is only partly true as the results indicate.

Density maps in pdf

1. all ships
2. types of ship
   1. cargo vessels
   2. fishing vessels
   3. fishing vessels (excluding DAMSA)
   4. tankers
   5. tankers (excluding DAMSA)
   6. other vessels
   7. passenger vessels
3. vessel status
   1. moored vessels
   2. moving vessels

Report describing method in more detail

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