In case of whole world we can calculate that how much CO2 are released (net released) based on the information of increased CO2 concentration. Using 5.137 x 10^18 kg as the mass of the atmosphere we know that 1 PPMV CO2=7.81 Gt CO2. Can we apply this information at local area level? If we can do this is it logical to use the ratio of the surface area of AOI (Area of Interest) to World Surface area (as we can't use the atmospheric weight of the world in case of a local area)?
Florian Obersteiner
thanks for your answer. Actually, I am not going to downscale the world emission to a local area. My question is if we have two consecutive years' column average concentration (CAC) of CO2 for an area can we calculate the net emission from that area. Say for example an area of 1000 sq.km has the CAC of two consecutive years which are 403 ppm and 402 ppm then can we calculate the yearly net emission of that area?
The question about the emission in a given area based on the measured concentration of a particular trace species is an example of a classic inverse problem. Formally, the correct approach is based on the solution of an adjoint transport equation to obtain the influence function. The emission is then calculated from the Lagrange duality relation. The main problem with this approach is that the inverse problem is ill conditioned and it is not always possible to find a solution.
A general overview of techniques used to solve inverse problems for CO2 is presented by Enting; I have attached a file with a number of very useful suggestions that are relevant to your problem.
And finally, in order to answer the original question directly, I would suggest to avoid a simplistic approach. This method will lead to a very poor estimate of CO2 emission due to ignoring the specific pattern of atmospheric transport.
Muhammad Salaha Uddin,
The answer to your question is "unfortunately not!" CO2 in the atmosphere is well mixed, so any change in concentration over one year would tend to follow the global trend.
Of course you could compare the local trend against the global trend and prove me wrong.
Although CO2 is relatively well mixed, there are still significant deviations from uniformity. This fact is illustrated by computer animation
https://youtu.be/x1SgmFa0r04
Janusz Pudykiewicz
Yes, but measuring the CO2 anomaly in one place does not tell you whether it originates there or has been advected from an adjacent site.
You can't discover that by taking one reading at the start of the year and another at the end of the year. To find out how much CO2 is produced there you would need to surround the site with stations measuring all the inputs and outputs.
Alastair Bain McDonald
For this reason you have to solve the inverse tracer transport problem in order to obtain the influence function as suggested in my first answer.
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