Third IMO Greenhouse Gas Study 2014

Annex 3
Details for Section 1.4:
bottom-up QA/QC
Activity estimate quality of spatial coverage
It can be seen from Table 5 that the amount of messages per year usable for the bottom-up emissions study
is the largest in 2012, including sets from two different satellite sources (Kystverket, exactEarth) and several
terrestrial sources. The total number of AIS-messages successfully processed (all years) is over 8.3 billion.
However, this number may include duplicate messages, especially near European coastal regions. The annual
number of messages is significantly smaller for 2007–2009 and for these years there were no S-AIS sources
available.
The effect of the increase in messages is that coverage increases both temporally and geographically from
2007 to 2012. This section focused specifically on the geographical coverage.
Figure 10 and Figure 12 show the coverage of the AIS and LRIT data sets respectively with the same scale
to facilitate comparability through the period. Most noticeable is that from 2010 to 2012 there are marked
improvements, particularly over ocean regions owing to the inclusion of S-AIS. Europe is very well covered in
all years, but particularly from 2010 onwards. Marine Traffic and IHS are global coverage terrestrial AIS sources,
with the former substituting for the latter from 2010 onwards, resulting in what appears to be consistently
improved shore-based message reception.
The 2012 and 2011 AIS data set provides good global coverage, with shipping routes clearly noticeable at this
scale.