How to use Ingestion options to process v01 version S5P O3 data

HARP
,
1

I used the following code to calculate the monthly mean of ozone for March 2022 in my previous research:

input_files=r"D:\Downloads\S5P\1903_O3_S5P\xx\S5P*.nc"
export_path=r"D:\Downloads\S5P\monthly mean\1903_O3_GZ1.nc"
Converted_NO2_2022 = harp.import_product(input_files,
operations= “latitude >= 22.5[degree_north] ; latitude <= 24[degree_north] ;
longitude>=112.8 [degree_east];longitude<=114.2[degree_east];O3_column_number_density_validity>50;
bin_spatial(155,22.5, .01, 145 , 112.8, .01);
derive(latitude {latitude}); derive(longitude {longitude});
keep(latitude,longitude,O3_column_number_density,weight)”,
post_operations=“bin(); squash(time, (latitude,longitude))”
)
harp.export_product(Converted_HCHO_2022, export_path,file_format=“netcdf”)

Now I want to calculate the monthly mean of ozone for March 2019. But after reading the PRF-O3-NRTI and PRF-O3-OFFL in the User Documents of L2__O3____, I found that for the NRTI and OFFL data of v01 version before July 16, 2020, the following selection rules:
‘ozone_total_vertical_columnn out of [0 to 0.45] ;
ozone_effective_temperature out of [180 to 260] ;
fitted_root_mean_square larger than 0.01’
and
‘ozone_total_vertical_column out of [0 to 0.45];
ozone_effective_temperature out of [180 to 260];
ring_scale_factor out of [0 to 0.15];
effective_albedo out of [-0.5 to 1.5]’
should be used instead of qa_value.

I found an Ingestion options named qa_filter in the S5P_L2_O3 of ingestion definitions, which can be used to process the ozone data of v01.x.x instead of qa_value. So I want to know two questions. First, how can I apply this Ingestion options to my code. Second, does this Ingestion options have different selection rules when processing NRTI and OFFL data?

2

To enable that filter you just need to add an options="qa_filter=custom" argument to your harp.import_product() function. This will set the qa_value to either 100 or 0 depending on whether the selection rules match or not. Be aware that we only implemented the rules for OFFL, not for NRTI.

You should generally not be using NRTI for monthly mean analysis anyway, unless you are actually performing validation/verification analysis. But even then, since there is already a V2 version of the processor, I am not sure that looking at NRTI data from processor V1 will be of much use at this point.

Also be aware that there is a new full reprocessed dataset for O3 available (produced with processor V2, having collection id 3, so you can use normal qa flag filtering). Unless you have a very good reason to still look at the old V1 data, your are strongly advised to use this new reprocessed dataset.

3

Thank you very much for your reply, sander. I have solved the code problem. I did use the OFFL data in my research. But I still have a question about data acquisition. I did not find the data for March 2019 produced with processor V2 on the websites “s5phub.copernicus.eu” and “dataspace.copernicus.eu”. I would like to know where I can get this new full reprocessed O3 dataset if possible. Thank you again for your help!

4

The collection 3 data is available from the dataspace system. You have to search for RPRO/Reprocessing though:

cdse-o3-rpro
cdse-o3-rpro1462×1162 133 KB

HARP treats RPRO products the same as OFFL for S5P.

5

I will download the data as you said. Thank you again for sharing these useful informations with me！