Hello everyone, I'm very new to these issues yet.
I downloaded "Total column water vapor" data for each hour and each month for 2019 and 2020 from the database of "ERA5 hourly data on single levels from 1979 to present" in NetCDF format. I tried to open it with various programs. (Panoply, HDFview, R) But I couldn't understand the data. When I read the file it says 21 longitude, 9 latitude and time size 15550.
When I convert it to text and CSV format and open it, there is no clock data and it says "1043177" instead of a date in the time column. In addition, there is a value of 148576, not 15550. I really can't understand the data. Can you help me? It is very necessary for my thesis.
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Kevin Marsh
Hi Gizem,
I think the values like "1043177" are an offset from the reference time in the netCDF file.
This page may help you convert the files to CSV
How to convert NetCDF to CSV
Thanks,
Kevin
Gizem Boztas
Hello Kevin, thanks for your answer. How do you think I can see the time and date? Can I also change it to "1043177" normal date?
Kevin Marsh
Hi Gizem,
The python script in the page
How to convert NetCDF to CSV
will export the netcdf data to a CSV and convert the times to a standard form, i.e it will write the data as a table with 4 columns: time, latitude, longitude, value.
Also this page may help:
What are NetCDF files and how can I read them
Thanks,
Kevin
Gizem Boztas
Hello Kevin, yes I saw that script. But I haven't worked at Phyton before, I always work on R. So I will try to convert it to R script with "addins" in R. I could not try it because there was a problem with my computer. I write the result.
Gizem Boztas
Hello everyone, I downloaded ERA-5 data in python. I want to convert the Netcdf file to CSV. I follow the steps on How to convert NetCDF to CSV page. I use the following command to open the netcdf file in python, but this command shouldn't have an output? So I need to see the inside of the file but nothing is visible. Am I doing something wrong, I couldn't understand. By the way, the file is downloading successfully.
# Open netCDF4 file
f = netCDF4.Dataset (file_location)
Secondly, I don't understand what the code below means. Could you help?
# Extract variable
t2m = f.variables ['t2m']