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Copy file name to clipboardExpand all lines: docs/ais/ais_emissions.md
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## Data Exploration
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AIS data is extracted by Exclusive Economic Zones (EEZ) from 2019 to May 2024. The charts below show the number of unique vessels per month for each economic zone.
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AIS data is extracted by Exclusive Economic Zones (EEZ) from 2009 to latest available data. The charts below show the number of unique vessels per month for each economic zone.
For each vessel journey, we calculate the total emissions of various GHG components. The below summarizes monthly CO2 emissions by type of vessel (Cargo, Tanker, Fishing, Passenger, or Other). Toggle the area of interest to explore emissions by country.
We also calculate emissions for other GHG and pollutants, including Particulate Matter and Methane. Each line in this chart represents total monthly emissions for a specific pollutant.
Copy file name to clipboardExpand all lines: docs/ais/ais_hhi.md
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# Market concentration of vessel operators
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Market concentration among vessel operators in Pacific Island countries can be analyzed using the Herfindahl-Hirschman Index (HHI):
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$$
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HHI = \sum s_i^2
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$$
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```{math}
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HHI = \sum s_i^2
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```
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Where $s_i$ is the market share of operator $i$. HHI value close to 0 indicates near perfect competition, while HHI value close to 1 indicates monopoly.
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Here, the market share is defined by the share of port calls from an operator. We use the [port calls data](ais_trade.md) derived from AIS, and the operator information from ship register data. Note that this excludes all vessels not registered with the IMO which is ~12% of port calls from cargo, tanker, and passenger vessels.
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## HHI ranked by country/vessel category 2024
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The following interactive graph displays yearly HHI values for each country by vessel category. To use this graph:
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The following graph displays the latest HHI values for each country and vessel category in 2024. The countries are ranked from highest (most concentrated) to lowest (most competitive) HHI.
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1.**Compare two years**: Select different years in both fields to see how market concentration changed between them.
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2.**View a single year**: Select the same year in both fields to see a snapshot of that year's data.
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3.**Change vessel category**: Use the category selector to view HHI values for different vessel types.
Copy file name to clipboardExpand all lines: docs/ais/ais_trade.md
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We get the difference between the departure and arrival displacements to get the estimate of volume of cargo loaded/unloaded. If the net displacement is positive, it is assumed that the cargo for exports, and for imports otherwise.
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