Extremely low ozone concentrations at night

[whr]

Dear all,

In my simulations for East Asia, I found that daytime ozone concentrations were normal (~80 ppb), but nighttime ozone concentrations were very low (~0 ppb). The first figure shows the daytime ozone distribution and the second figure shows the nighttime ozone distribution. The simulation dates are from 2 June 2020 to 10 June 2020 and the emission inventory is from MEIC.I have noticed that the same question has been raised by a user in the forum and their solution was to add biological emissions. After I tried this solution, I noticed a significant improvement in the daytime ozone concentration (up about 30 ppb). However, at night the ozone concentration is still equal to about 0 ppb. I was confused for weeks and tried some other methods during that time but they do not work. Scripts and logs have been uploaded. If anyone can make some suggestions, I would be very very grateful.

run_cctm_Bench_2018_12NE3.csh (35.4 KB)
run_cctm_Bench_2018_12NE3.log.txt (107.2 KB)

Haorui Wang
2024.9.2

[gsarwar]

@whr

In my simulations for East Asia, I found that daytime ozone concentrations were normal (~80 ppb), but nighttime ozone concentrations were very low (~0 ppb). The first figure shows the daytime ozone distribution and the second figure shows the nighttime ozone distribution. The simulation dates are from 2 June 2020 to 10 June 2020 and the emission inventory is from MEIC.I have noticed that the same question has been raised by a user in the forum and their solution was to add biological emissions. After I tried this solution, I noticed a significant improvement in the daytime ozone concentration (up about 30 ppb). However, at night the ozone concentration is still equal to about 0 ppb. I was confused for weeks and tried some other methods during that time but they do not work. Scripts and logs have been uploaded. If anyone can make some suggestions, I would be very very grateful.

Dear Haorui Wang,

Very low night-time ozone concentrations can occur due to high NO concentrations. Please check your night-time NO concentrations. High NO concentration can occur for many reasons including high NOx emissions and/or low night-time PBL heights.

Thanks,

Sarwar

[whr]

Dear Sarwar,

Thanks so much for your help. I did notice high NO concentrations (roughly 400-800 ppb) at night. I visualized and believe the emission inventory to be reasonable. I then checked the nighttime PBL heights again and found some areas below 10m (I’m not sure this is reasonable or not). Anyway, I will re-run the WRF and see if I can get reasonable nighttime PBL heights. Thanks again!

Haorui Wang