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Clarification Needed for the PRECIS generated SO2 data http://forum.precisrcm.com/viewtopic.php?f=3&t=19 |
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Author: | prasanta [ Tue Apr 22, 2014 5:14 pm ] |
Post subject: | Clarification Needed for the PRECIS generated SO2 data |
I am Prasanta Kumar Bal, Scientist Centre for Climate Change and Adaptation research , Anna University, Chennai, India. I have completed the PRECIS model runs for AR4 simulations by using HadCM3Q LBC data. I need some clarifications to analyze SO2 data. I have collected observation data for the Chennai city, Tamil Nadu which is in mg/m3 (observation data is ambient so2 data i.e after the emission, how much so2 is remained in the atmosphere. This is not the stack emission data from the industry ) so which parameter I need to select from the PRECIS output which are listed as below to validate with the observational data? The output is in kg/m2/sec. How to convert kg/m2/sec to mg/m3? Stash code Description Units 58 sulpher dioxide emmisions kg/m2/sec 101 so2 mass mixing ratio kg/kg 121 natural so2 emissions kg/m2/sec 126 high level so2 emissions kg/m2/sec Please can you provide me the description about the each stash code. Regards Prasanta Kumar Bal |
Author: | dmhg [ Tue Apr 22, 2014 5:17 pm ] |
Post subject: | Re: Clarification Needed for the PRECIS generated SO2 data |
Dear Prasanta, I relay the response from Simon, who is quoting another colleague at the Met Office: Quote: Given what the observational data are, it looks like STASH code 00-101 ("SO2 MASS MIXING RATIO AFTER TSTEP") from the lowest model layer would be the obvious thing to compare against. Notes: (1) As the name says, this is mass mixing ratio, so would need to be multiplied by air density to convert to kg/m3 (and then to mg/m3). (2) As with all sulphur-cycle variables, this one is mass mixing ratio of S-in-SO2, i.e. only the mass of the sulphur atom is considered. If the observations are of the mass of SO2 (which is likely), then as well as multiplying by air density, 00-101 will need to be multplied by the ratio of the atomic weights of SO2 and S (which, conveniently enough, in this case is just a multiplication by 2: S=32, O=16, so SO2/S = (32+16+16)/32 = 2) Thank you, David on behalf of Simon T and the PRECIS team |
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