[gradsusr] mysterious bug with merra-2 data

[Antoine Molin]

Hi,

 

I am using merra-2 data U&V wind speeds at 50m, for wind energy studies in
France ; very good data
..

 

Getting « MERRA2_400.tavg1_2d_slv_Nx.%y4%m2%d2.SUB.nc4»  daily files, data
are obtained with grads, using xdfopen and enclosed data descriptor files.

 

I really don’t understand why i get different values with different
descriptor files, for same point and time :

 

As an example, at point (49°N ; 4.375°E) and time  2017-12-01 at 0h,  i get
U50m=5.31 m/s using « merra2_dec2017.ctl »  (lat = 49, lon = 4.375, t = 1),
and U50m=5.22 m/s using « merra2_2017.ctl »  (lat = 49, lon = 4.375,
t=8017)
..

 

Why ????????????????

 

Thanks !

 

 

Antoine Molin

Etudes de vent PlenR

Tel : 03 20 47 99 76

 

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