I am running a simulation regarding the regional air quality using cmaqv5.2 using one area emission inventory. Just for a test case, so only 1 area emission inventory is used and the temporary allocation factor is the same through the simulation period. While checking the cmaq output, it does not correspond with the area emission inventory. Specifically, the concentration in the emission area is normal at the beginning, but sometimes gets close to 0, as if the emission area has no input. Even if i change the emission inventory, or using cmaqv5.3, the error appears at the same time. I am sure no error exists in the emission inventory. I have atteched the log file below, it will be appreciated if someone give me some suggestions.
(The first picture is my emission inventory，and the second is CTM_CONC_1. )
CTM_LOG_007.v53_gcc_PRD02_20200324.txt (909.6 KB)
First for all, you do need to check your emissions. I do not know where your target region is located, but the magnitude of NO2 emission is pretty high for area sources. Your modeled concentration of NO2 at layer 1 is even over 150 ppb which is too high to be true.
The straightforward way to check your emission inventory is to convert the emission dimension from mole/s into kg/h and sum emissions up from all grid cells over this area. And then check if the total emission make sense for this region.
I hope this helps.
Thank you so much for the prompt reply.
I checked my emissions and run again.But in fact,the problem remains unsolved that the concentration in the emission area sometimes gets close to 0.The following is the pollution situation in the area emission of CTM_ACONC.
I will be appreciated if you could give me some advice.Looking forward to your reply.
I do not see any obvious problems in your log file.
Do you have SO2 emissions in your area source file? What is their magnitude?
Your emissions appear to be speciated for cb6. Are you using a cb6 chemical mechanism?
Thank you for your prompt reply.
First of all, I make sure have SO2 emissions in my area source file and the temporary allocation factor is the same through the simulation period(24h).The following is the emissions of EMISfile.Secondly,I am using a cb6 chemical mechanism for my emissions.
I would appreciate it if you could give me some suggestions to help me.Sincerely looking forward to your reply.
The maximum SO2 emission rate shown in your figure is 1.6e-4 moles per second, or about 0.01 grams per second. That seems quite low to me.
In your first post, you wrote that the concentrations are low, but your graph shows NO2 concentrations of 0.8 ppm, or 800 ppb, which is not low at all.
Please describe the problem you are experiencing as clearly as you can. Instead of just saying that you are sure the emissions inputs are correct, please state what you have done to convince yourself that is the case.
I simulate a temperature inversion episode and I expect that the concentrations in Online simulation were larger than offline simulation, but it didn’t. Could you help me why this happened, please?