Strange values in the CMAQ-adjoint model

CMAQ-Adjoint
1

Hi,

I am running the CMAQv5.0-adjoint model to calculate the sensitivity of O3 to NOx. However, I encountered strange values at some time points when I run the model backwardly. Please see the enclosed figures. The sensitivity at this time point suddenly became such a large value (-10*10^10). May I know what could be the reason for this?
image

Thank you very much.
Jie

2

Hi Jie,

This does not look right. Can you please tell me more about your backward run including your cost function/receptor, model resolution, etc? How did the sensitivities look like up to this point? Could you please double check if your sensitivities to NOX calculations are all right?

Thanks,
Shunliu

3

Hi Shunliu,

Thanks for your response. I set the receptor region as the whole of Malaysia, and the cost function is the hourly O3 concentration. The model resolution is 30km. I tried to set different receptor regions but still encountered the problem at this time step. Enclosed is the O3 (ppmv) sensitivity to NO2 with 2 hours time interval. The sensitivity seems to be correct at hours 23, 21, and 19, but when the model runs backwards at hour 17, it shows a strangely large value (white colour) compared with the background. This value increases explosively when the models run backwards. I checked the emission and the WRF output but I didn’t find any abnormal data. Can you help me find the reason? Thank you very much.

image
image1510×778 230 KB

Thanks,
Jie

4

Hi Jie,

Sorry for the delay in getting back to you. Can you please share the input data and the detailed setup with me via email so that I can do a test run on my end? It would greatly help if I can duplicate your problem. And we can start from there.

Thanks,
Shunliu

5

Hi Shunliu,

Thanks for your reply. I will I compile the input data with the setup files and send to your email soon. Thanks again for your help.

Best regards,
Hu Jie