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I have a .nc file that contains data every 1 hour of precipitation for 1 full year, my interest is to calculate the daily precipitation and compare with observed data. I have some doubts about the units that the CMIP6 output has since it shows me the same in Kg/m2.sec and when I add the 24 hourly data to transform them into a daily, the values are very small. How could I correct these values so that they are displayed in mm/day?

Thank you!

Fernando Primo Forgioni
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    take the average and multiply by 86400, or take the sum and multiply by 3600 ? – ClimateUnboxed Apr 13 '23 at 21:01
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    What do you mean by “doubts”? Occasionally the units in CMIP6 data files are incorrect. This is because the units used by the model itself are not the same as those required by CMIP6 and a mistake has been made during the conversion. I’ve seen this happen, only rarely, with temperature. If what @AdrianTompkins suggests does not fix the problem this might be a mistake in the data file – Robert Wilson Apr 14 '23 at 07:10
  • I suspect this is just a case to convert the units though, OP should have tried a simple unit conversion first (seconds to days!) and *then* post if it doesn't work. – ClimateUnboxed Apr 14 '23 at 07:16

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kg/m^2 exactly gives you mm, so actually you have mm/sec. You can multiply your data with 3600 and and take the daily sum. You can do this by

cdo -daysum -mulc,3600 infile.nc outfile.nc
Jeremy Caney
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zekican demiralay
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