Earthdata Forum

Follow-up: you do not need to send the images to the Help Desk. When I save the image to my system, I can view it at full resolution.

I have inquired about this question to the MERRA-2 group. They are examining it.

Thank you Jim,

Have you already received a response? The main questions I have are the following:

-(How) can MERRA-2 be used to assess the impact of the large scale reduction in anthropogenic aerosol, notably SOx emissions (amongst others from IMO 2020 regulation)?
-Is MERRA-2 data reliable enough to produce an indication of the relative change of SOx concentrations over ocean and land?
-Is there any ongoing research on the atmospheric and climatic effects of IMO 2020 shipping regulation (which is estimated to reduce the sulphur burden from shipping with 8.5 million metric tons and will likely cause an increase in Black Carbon emissions from shipping).

Find attached the MERRA-2 SO2 ocean surface mass concentration of Jan-Oct 2020 and the comparison with the same period of 2019.

Leon,

I have not received a specific response; I will follow-up with my previous message. Currently many of the experts are involved with the ongoing AGU Fall Meeting, which is in a virtual format this year, so I am unsure of their availability.

Thank you Jim. Have you already heard back?

As 2020 has come to an end, the average annual concentrations will come available soon. It will be great to have more insight into the details behind the data.

I worked on analysis of the Anthropogenic SO2 Emissions (M2TMNXADG v5.12.4), comparing different base periods to available data from 2020, but something seems off. There is no (notable) change between comparing base period 2011-2015 or 2016-2019 to the average of 2020 (Jan-Oct). Also there is no visibility of the reduction in anthropogenic SO2 emissions from shipping, while the annual reduction of approximately 8.5 million metric tonnes of SOx should be clearly visible. See attached analyses.

There is a visible change from shipping (and land emissions) when comparing 2006-2010 with 2020 (see also below). Also note the two orders of magnitude difference when comparing emissions change between the earlier period (-5x10^-14 to 5x10^-14 kg/m²/s) in stead of when comparing the more recent periods (-5x10^-16 to 5x10^-16 kg/m²/s) to 2020. Of course the comparisons of the more recent periods should show changes much more clearly because of this.

Leon,

I have not received a reply on your question. However, I did find an article you may find of interest that utilized Giovanni. The reference is below.

Wang, Q., Liu, H., Wang, P., Dai, W., Zhang, T., Zhao, Y., Tian, J., Zhang, W., Han, Y. and Cao, J. (2020) Optical source apportionment and radiative effect of light-absorbing carbonaceous aerosols in a tropical marine monsoon climate zone: the importance of ship emissions. Atmospheric Chemistry and Physics, 20(24), 15537-15549, doi:10.5194/acp-20-15537-2020.
https://acp.copernicus.org/articles/20/15537/2020/