Hi,
I was trying to download a single day simulation CMAQ5.2.1 benchmark data. But I can see only the input data for 9.12.17 folder and only the output data for the 9.5.17 folder. Or maybe I am missing anything or not in the right folder. Could anyone suggest me where I can the data of both input and output for a specific day?
Hi,
Could anyone please help me getting the output file for single day simulation of CMAQ5.2.1 benchmarking? Thanks in advance.
Sadia
Yes, I had the same question - I cannot see the CMAQ one day and two week benchmark test case data from CMAS Center website Downloads page.
The CMAQv5.2.1 benchmark relies on the CMAQv5.2 benchmark data.
This information is available thru the CMAS Center when you go to the CMAQ v5.2.1 download site.
Data Download
Input datasets are available for CMAQv5.2, and these will work with the CMAQv5.2.1 code. These test datasets may be used to test the installation of the model and to benchmark new software installations. Single-day and multi-day test cases are available for CMAQv5.2 from the link below. See the CMAQ Quick Start Guide for instructions on installing and running the single day test case.
The output data isn’t available at this time. We are preparing for a new release of CMAQ, and this release will have input and output datasets available.
Got the instructions, and currently downloading following the instructions. Thanks a lot!
Hi, skunwar. I see you’ve got the input data, could you please share me the lightning input data? The CMAQ5.2 Data Download Site isn’t accessible for me.
I want to use the observed lightning data to calculate the LNO with CMAQ5.2(LNO option1). I’m not quite sure about the format of the input. Thanks a lot.
apple@stu2020.jnu.edu.cn
Hi @Axueaha , if I understand correctly, NLDN (hourly lightning strikes) file contains proprietary data and so has to be purchased. The other option of using LTNG file for input into CMAQ is being distributed for free. Were you seeking NLDN file?
Thanks for your reply. I’ve seen the LTNG file. About In-line lightning NOx options using hourly NLDN strike, can I replace the NLDN data with my own lightning strike data? In Dr. Kang’s article, it is mentioned how to convert the observed raw data into the format of the input file. But I haven’t worked it out completely. According to this method, there is no need for a lightning parameter file, right? Thanks a lot.
Hi @Axueaha Of course you can replace your own lightning strike data as long as it is gridded hourly into your modeling domain. But you still need a lightning parameter file to provide the ratios between CG (Cloud to Ground) strikes to CC strikes (Cloud to Cloud) and the ocean masks. The CG2CC ratios are needed because the ground-based lightning detection networks are generally only detect CG strikes more accurately, the climatological CG2CC ratios are used to account for CC strikes and they are provided in the lightning parameter file. The ocean mask is used to account for the differences of lightning NOx production efficiency between land and ocean grid cells.
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@Axueaha If you are unable to access the Google Drive with the lightning parameter file and the ocean mask we can share these with you via ftp.
Thank you for your reply, Dr. Kang. I have some other doubts. Regarding applying the lightning data in the model, I see that the unit used in your article is flashes, but my original data is stroke, I mean the multiplicity (number of strokes per flash) of this lightning, as well as the subsequent calculation of LNOPE Is this value corresponding to flash? So I also need to classify my original stroke data as flash? I read your article about “The lightning NOx production rate over land-based grid cells is set to 350 moles/stroke” in the western mountainous area, what does this stroke mean? Also in data preprocessing for the LNO production, the Fortran program NLDN_2D , and the Ocean_factor, Strike_factor, and ICCG R scripts are all configured in the model, right? Just input the gridded lightning data and parameter files? Sorry for so many questions. Thanks for your answer.
Hi @Axueaha, there exist some confusions in terms of the terminology used in lightning. Generally, a flash is a strike (another obscure name) that between cloud and ground. A flash may contain some return strokes within the same channel. In general, the ground-based networks only capture the CG flashes well, but the detection of strokes may not be accurate. Satellite observed lightning imagery can provide more detailed information. Depending on the data you have, you may want to group them into flashes to use the CMAQ inline LNOx module. The lightning NO production rate given in the earlier article was not correct, it should be 350 moles/flash. In terms of the LNO preprocessing, you are right that all the steps are now implemented in the parameter files and you only need the gridded lightning flash data and a parameter file to produce lightning NOx emissions in CMAQ. Hope this answers some of your questions. Good luck!
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Dr. Kang, I’ve made my own lightning data into a gridded hourly file within my modeling domain. The NLDN_STRIKES file is available. According to the above answer that these three parameters including the ICCG_SUM, ICCG_WIN and OCNMASK are available now. But still reported the error that these parameters (SLOPE, INTERCEPT, SLOPE_lg, INTERCEPT_lg) are requested, how should this be made. I checked other posts your reply, you already have the parameter file of the US region, but I am in the Pearl River Delta, I don’t know how to make these parameters, can you help me answer. I’m using CMAQ5.3.1&WRF4.0.
@Axueaha Thanks for reporting this problem. Since you are using the lightning flash data, the parameters (SLOPE, INTERCEPT, SLOPE_lg, INTERCEPT_lg) are not used, but unfortunately the program still reads the parameters as a redundant request. When we use the parameter file in U.S., I based through the parameters there and neglected the situations that these parameters are not needed. We will fix the problem for next release. For your case, you can either create the variables with dumb values (for instance put 1) in your parameter file or you can go to the centralized_io_module.F file to comment out the “EXTRACT3” statements that contain these variables. The easier method would be to add the dumb values in your parameter file without touching the model code. Hope this will help.
- Daiwen Kang
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Dr. Kang, I have run out the CCTM_LTNGCOL and CCTM_LTNGHRLY file through the above steps, I want to check whether the concentration of NOx in the CCTM_CONC or CCTM_ACONC file output contained the LNOx when open the CTM_LTNG, or if it is just a separate output of LNOx emission file. Then I need to add the CCTM_LTNGCOL file to my original emission source again to run the CCTM. Then the CCTM_CONC file will include the LNOx. Can you help me？Thanks a lot.
Sorry answer so lately. I’ve got my own lightning parameter file according to the template. Thanks a lot.
@Axueaha The lightning NOx is one of the NOx emissions like any other emissions, when it is generated online, it has already merged with other emissions and gone through the same chemistry/photochemistry and transport processes. Therefore, its impact has been fully integrated into the model results, i.e., the CONC/ACONC or any other CMAQ output variables have reflected the lightning NOx effects. The LTNGCOL and LTNGHRLY are just optional diagnostic files for users to check if the lightning NOx emissions are generated properly or want to do analysis regarding lightning NOx emissions. If you add the diagnostic emissions back into the “original” emission source again, you will double count the lightning NOx emissions. I don’t think that you want to do that.
Thank you for the meticulous answer. I understand. Can I ask you some additional questions, Dr.Kang. In fact, I want to analyze the effect of LNOx on surface concentrations, but the phenomenon is not obvious. Looking at the literature, I learned that LNOx yield may be related to the intensity of lightning, so I was wondering if there was any way to add intensity information. I don’t know if this idea is correct or not. Thanks a lot.
Lightning NOx estimation is associated with various uncertainties, and we do what we can do with the best knowledge we have. As for the present CMAS versions, we don’t use information other than the flashes to estimate lightning NOx. But we do in the process to incorporate (as a research project) the detected energy property associated with lightning events that are available in satellite GLM data. As for now, we can’t add the intensity information. The impact of lightning NOx on surface air quality is indeed limited and it depends on many other contributing factors such as anthropogenic and soil NOx emissions and vary greatly over geographic regions. But in general, the largest impact occurs in the middle to upper troposphere. To analyze the impact of lightning NOx, you need at least to perform two simulations, one with lightning NOx turned on, and the other without. You have probably already done that.
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