Black carbon seems to be a really potent source of climatic changes. But I haven't really found many papers on the remote sensing of it. There are some papers dealing with detecting it in snow and ice in the polar regions. But I am interested into detecting and quantifying it as long it is still airborne. I am aware that there are many different sorts of aerosols in the atmosphere and that many studies have been finished on the general aerosol remote sensing. But are there any specific studies related also to satellite remote sensing of black carbon?
The incomplete combustion of fossil fuels or biomass
leads to the formation of carbon-rich residues and soot which are collectively called elemental carbon (EC, used in atmospheric sciences) or black carbon (BC, used in soil
and sediment sciences), seem to be ubiquitous in the atmosphere, soil, and water. [Watson et al., 2005]. It has a direct effect on Earth’s radiative heat balance and visibility. According to estimates found in literature, >80% of BC produced ends up in the soil, where it can reside for hundreds to thousands of years, Black carbon (BC) particles emitted from incomplete combustion of fossil fuel and biomass, are transported and if they get deposited on the snow, darken the surface, and reduce the albedo. The direct snow albedo effect of BC has previously been modeled . But the question is related to Elemental carbon EC content monitoring by remote sensing. It is well known that Aerosols are being monitored effectively by remote sensing techniques. It is observed that fossil fuel plus biofuel BC dominate from emission measurements. Good amount of data and analysis is available in the Report from the international workshop:
Black carbon in snow – sampling, albedo effects and climate impact Tromsø, Norway, 13–14 August 2009...KORTRAPPORT/BRIEF REPORT SERIES 017 NORSK POLARINSTITUTT 2010
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150000357.pdf
Ken
This was not in response to your reply but to the original question. As for Iyyanki's reply: that is not a reply to the original question. Because what goes up must come down: all BC ends up on the "ground". He gives a generic incomplete idea of the lif cycle of BC/EC
Ken
Also when it is above snow it decrease the albedo; similarly when it is above low clouds but even over a surface with a low reflectivity because BC is completely absorptive. This in total is the effect of Black Carbon on the radiation balance of the atmosphere and this effect is an order of magnitude larger than the effect of BC deposited in/on snow. Summarised in IPCC AR5 fig 8.8
https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/drafts/fgd/WGIAR5_WGI-12Doc2b_FinalDraft_Chapter08.pdf
PAGE 8.110
Ken
You referring to figure 8.2?
In fig 8.8 it is shown that BC in/on ice is a minor effect compared to BC in the atmosphere
The standard measurement of aerosols such as from MODIS or VIIRS measures the aerosol optical depth due to scattering, and as such is insensitive to aerosol absorption, which characterize black carbon or soot. The Aerosol Index (AI) (from TOMS or OMI) measures the UV absorption optical depth and is proportional to the amount of black carbon. However, other types of aerosols, such as mineral dust or volcanic ash, are weak absorbers of UV. So a positive AI value does not uniquely identify the aerosol as black carbon. Backward trajectory analysis can often help identify the source of the aerosol. Also black carbon more strongly absorbs UV light than mineral dust or volcanic ash, so larger values of AI are generally associated with smoke. However, AI increases with the height of the absorbing layer, so information on the height of the layer can help identify it.
Thank you all for your answers and thank you Harry for both links. And I am sorry to reply you with such a delay, but the "problem" is that I have just started my holidays yesterday.
The reason I am interested into black carbon is 1) its impact on the radiative forcing and 2) because I have recently started a new job where I am supposed to generate ideas for future CubeSat missions. One idea is to identify sources of pollutions. For this, you would need a better spatial resolution than OMI , because we actually want to identify the factories and power plants emitting the BC. The institute I am working at now has an expertise in formation of small satellites so we could provide different instruments or the same instruments observing the same spot at the same time. This would give us the possibility to consider also the effect of geomtry on the observations. So the way I see it from the discussion we should focus on UV instruments.
Is there any specific spectral signature that really distinguishes BC from other aerosols? As Eric writes above, at the moment we cannot be sure what we really see -is this an issue of the instruments currently available or the limitations of physics?
Thank you all again and have a nice evening!
Amirr
read the entry by Eric on ABSORPTION and you can also google-search for OMI plus Absorption Index
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