CCTM initial concentrations in output


#1

Hello Comunity:
Several days ago I am asking, how CCTM process to obtain the initial concentrations in any simulation.

I ran the data example for a single day, the SE52BENCH case and I observed the relation between Black carbon emission (PEC) and the output concentration obtained.
Since the initial hour, the AECJ and AECI (elemental carbon in output) concentrations are around 4 ug/m3. I saw the initial concentration made in ICON module and AECJ and AECI are not defined, so CCTM starts with 1*E-30 by default.

The question for me is why when I want to work with another case (in hemispheric domain), using the same initial concentration (AECJ and AECI not defined in ICON and BCON) I obtained concentrations about 1*E-22 ug/m3.

Is there any modification or change to do in the run script ?? How CCTM gets those initial values?

Please if you can help me, I will thank forever.


#2

Ernesto,
I am not sure I understand. For the SE52BENCH case, there are some grid cells and hours where the value of AECJ (but not AECI) exceeds 4 ug/m3. For me, the peak concentration in the ACONC file is 8.6 ug/m3 for AECJ and 0.88 ug/m3 for AECI.

Is your question why are these peak values so high, or is your question why the peak values in a hemispheric simulation so low? Do you have PEC emissions in your hemispheric simulation?


#3

Hello Chris.
My question is related to how CCTM process the initial condition and the emissions. If you start with zero concentration of any species (for example AECI and AECJ), in log files, you will see CCTM set to 1E-30. But in SE52BENCH case, since the first hour, you will see concentrations higher than 1E-30.
IN my case, in the hemispheric domain, I have emissions of PEC ( the equivalent of AECI and AECJ), but considering the same scenario (zero concentrations as initial condition), CCTM output concentrations about 1E-22. Why CCTM does not start with 1E-30 since first hour of simulation?
What step makes the diference between the set initial value (1E-30) and the first hour of simulation (1E-22 or 4E*0)
That´s my question.

In other way, The analysis in a 108 km size grid is the same as in the 27 km? The output concentration is considered the same in the size of the grid? Or is there any formulae to obtain concentrations wich could be compared to a monitoring station.
That´s one of my doubt when I work with hemispheric domain, because, I would like to compare real monitoring data (one point) with the output of CCTM. Is that comparable in an hemispheric domain?

Thanks for your help and time


#4

The concentration in the CONC file at the beginning of the file (2011-07-01_00:00:00) is exactly the value in the ICON file. For the SE52BENCH case, that maximum is 1.677 ug/m3.

If there is no value for AECJ in your hemispheric ICON file, then the CCTM will assume 1.0E-30. The log file should indicate this (“No IC found for species … in INIT_AERO_1; set to 1.00E-30”).


#5

Thanks Chris for your reply:
I did not observed the value you mentioned as initial condition. In my case, I did not put an initial value( observing the message you sent me), and the registry in the ACONC file for the first time is 1.00E-22 for AECJ.
That´s why I´m concerned about how CCTM obtain the first concentration.
Right now I´m also asking if CCTM process my emission file, in two posts in this forum. I don´t have evidence of this process.

Thanks again


#6

The ACONC file gives you the average concentration over the output time step (which is usually an hour). Assuming you are starting your simulation at 00 UTC with a 1-h output time step, then the first time step in the ACONC file represents the average concentration between 0:00 and 1:00.

If you have no AECJ in your ICON file, then the initial value (at 0:00) should be set to 1.0E-30. If you have no emissions and no BCON for this species, then concentrations should stay very small. 1E-22 is indeed small, but perhaps bigger than we want. Is that the concern you are having?

Or, if you have PEC emissions in your file, and you think your model concentrations of AECJ should be higher, then check your run script and CTM_LOG_000 file and you should be able to tell if the emissions are being read. Post them if you can’t tell and want someone to review.


#7

Hello again:
This message is very confussed for me:

—>> WARNING in subroutine GET_AERO_EMIS on PE 000
Could not read PEC from EMIS_1
M3WARN: DTBUF 12:07:30 Jan. 1, 2014 (2014001:120730)
Bad argument LAY1= 49

Wath´s the meaning of this??

This is the info about EMISS file

“EMIS_1” opened as OLD:READ-ONLY
File name “/home/epino/CMAQ_BLD_NLHPC/data//SMOKE/enero_febre2.ncf”
File type GRDDED3
Execution ID “???”
Grid name “GRIDOUT_POLAR01_”
Dimensions: 177 rows, 177 cols, 1 lays, 44 vbles
NetCDF ID: 786432 opened as READONLY
Starting date and time 2014001:000000 (0:00:00 Jan. 1, 2014)
Timestep 010000 (1:00:00 hh:mm:ss)
Maximum current record number 1777
Checking header data for file: EMIS_1

As you can see, I only have one layer in the emission file processed in SMOKE4.5

The other message that confussed me is this:

 Value for CTM_EMLAYS not defined; returning default:  49
 Number of emission layers                                                       
 Environment variable not set or empty ... Using default:                                                                        0

      Number of Emissions Layers:          49
      out of total Number of Model Layers: 49
 Value for CTM_LTNG_NO:  N returning FALSE

 Aerosol Emissions Processing in Vertical diffusion ...
 
 >>--->> WARNING in subroutine map_pmemis on PE 000
 Could not find the following species in emissions file 
      PH2O 
      POC 
      POC 
      POC 
      POC 
      POC

Why does it say Number of emission layers Environment variable not set or empty … Using default: 0

How can I change this statement??

Thanks


#8

That is a bit strange. Does your simulation start at noon? It is weird that it is trying to read emissions at 12:07:30. Is PEC in your gridded emissions file (EMIS_1)? Are you also using PT3D emissions, and is PEC in those files?


#9

Ernesto,
Since your problem now has nothing to do with the original subject, please start a new thread.