1A3di_Oil_Tanker_Loading only in USA, only for BC/OC?

[jkikstra]

For use in CMIP7, it is key to harmonize and grid future data in a similar fashion as historical data is gridded.

One of the sectors that we aggregate CEDS data into for harmonization (and subsequent gridding) is 'International Shipping'

That would intuitively be both "1A3di_International-shipping" and "1A3di_Oil_Tanker_Loading".

In v_2024_07_08:
As expected, "1A3di_International-shipping" only has global (=international) data.
Unexpectedly, "1A3di_Oil_Tanker_Loading" has data only for the USA, and only for BC and OC.

Question is: how to best deal with this?

• How is this dealt with for historical gridding?
• If it is important to grid it separately, that would be an argument for not gridding it using an 'International Shipping' pattern-scaling. However, if it is indeed important, then why is there only data for "usa" and not for other countries?

Or is it maybe a mistake in this version of the data?
Reading the 'Data_and_Assumptions', I would have thought that it should only be in the "global" region?
See for instance section 6.7 (Miscellaneous Process Emissions) and section 9.1 (CEDS Gridding Sectors).

Curious to hear more about this.

@ssmithClimate

[ssmithClimate]

Thanks @jkikstra! There shouldn't be any BC emissions for this sector - we will fix that in the next release (they are very small- so isn't causing any distortion of global patterns or trends). So you can ignore that.

Note there are VOC emissions in the global iso for this sector, that's the only emission species that should be in this sector currently. Its folded into the shipping sector gridding (using the RCP-era pattern).

[jkikstra]

Thanks @jkikstra! There shouldn't be any BC emissions for this sector - we will fix that in the next release (they are very small- so isn't causing any distortion of global patterns or trends). So you can ignore that.

Note there are VOC emissions in the global iso for this sector, that's the only emission species that should be in this sector currently. Its folded into the shipping sector gridding (using the RCP-era pattern).

Hi @ssmithClimate, I downloaded version v_2025_03_11, but it looks like it still has this issue.
i.e., I still get:
non-zero values for BC and OC in 1A3di_Oil_Tanker_Loading in country=usa.
note that country=global is zero.

In 2023, its 7.09 ktC BC (= 0.1% of global), and 135.6 ktC OC (= 0.4% of global)

(fyi @znichollscr)