Getting wrong mean values when dividing two netcdf files
Added by ankit bhandari about 4 years ago
Dear sir
When I am dividing my two netcdf files in cdo I am obtaining following results.
cdo div spatail_bias.nc CWD_timmean.nc div.nccdo infon div.nc
-1 : Date Time Level Gridsize Miss : Minimum Mean Maximum : Parameter name
1 : 2009-03-31 18:00:00 0 5325 2780 : _ -5.9778 0.011248 0.57895 : cons_ecutive_wet_days_index_per_time_period
2 : 2009-03-31 18:00:00 0 5325 3506 : -5.0000 0.14879 1.0000 : number_of_cwd_periods_with_more_than_5days_per_time_period
As cdo infon CWD_timmean.nc
-1 : Date Time Level Gridsize Miss : Minimum Mean Maximum : Parameter name
1 : 2009-03-31 18:00:00 0 5325 2780 : 1.5000 6.2843 16.750 : consecutive_wet_days_index_per_time_period
2 : 2009-03-31 18:00:00 0 5325 2780 : 0.0000 1.0671 3.5000 : number_of_cwd_periods_with_more_than_5days_per_time_period
cdo infon spatail_bias.nc
-1 : Date Time Level Gridsize Miss : Minimum Mean Maximum : Parameter name
1 : 2009-03-31 18:00:00 0 5325 2780 : -13.450 0.16330 6.4500 : consecutive_wet_days_index_per_time_period
2 : 2009-03-31 18:00:00 0 5325 2780 : -2.7000 0.14513 1.8500 : number_of_cwd_periods_with_more_than_5days_per_time_period
But when divide it manually 0.16330/6.2843=0.025985392 this mean value should be obtained. Where is the mistake?.As I am getting 0.011248 value in results. And both min and max value are not giving correct results.
Wait for a reply
| spatail_bias.nc (86.7 KB) spatail_bias.nc | bias | ||
| CWD_timmean.nc (86.6 KB) CWD_timmean.nc | histocial |
Replies (1)
RE: Getting wrong mean values when dividing two netcdf files - Added by kunal bali about 4 years ago
Hi Ankit,
The mean value from div files is showing the mean of divided values of each grid of the given area. So, You can't just take the average value of each file using cdo info directly, such as 0.16330/6.2843=0.025985392.
If you have a doubt then, extract point location data from your file and then divide both the files. It will give you a better idea.
This could be the one reason.