Download time series WRONG!

Datasets and Usage CAMS - Datasets and Usage
1

When I download The CAMS Global Fire Assimilation System Datasets by month, I inputed the whole month like 2023-09-01 to 2023-09-30, and submit message shows the same period,but the .nc file shows a time period of 2023-09-02 to 2023-10-01 with xarray after I downloaded the file. It’s really confused, maybe the server processed wrong data?

2

Hi,
The new netCDF converter chooses the end of the 24-hour averaging period rather than the start as the validity time, hence the 24-hour shift you’re seeing.

Thanks

3

Thanks for your reply!
I’m glad you can answer my question. So that means I need to input 2023-08-31 to 2023-09-29 to download the 2023 September’s fire emission data?

Have a nice day! :slight_smile:

4

Hi,

I was also confused by this. The data you originally downloaded is for the correct input window but is labelled by the end of the averaging period, as @Michela says.

This means you should continue to input 2023-09-01 to 2023-09-30 when downloading the data for September 2023. If you want to view the correct date within the netcdf file, you should subtract one day (for the start of the averaging period) or 12 hours (for the middle of the averaging period).

This is a little clearer when reading the CAMS data documentation guidlines, but it is still very unintuitive for new users. I ended up downloading the grib and netcdf versions and comparing them day-by-day to be certain of what was going on.

I hope this helps :slight_smile: