[gradsusr] using merra temperatures

[Mike Bosilovich]

Hi Antoine,

The GES DISC serves a constants data file for MERRA that includes the
surface geopotential, which your can get surface altitude.  The data
file is tagged const_2d_asm_Nx.

For future reference, the question on the existence of this data is
more for the MERRA questions help line (or documentation)  :
merra-questions at lists.nasa.gov

The question about altitude corrections fro air temperature
comparisons should be researched through textbooks or journals.
Though, the MERRA air temperature will have biases, as it is derived
from the model forecast, so there is more than correcting the
altitude.

Mike

On Tue, Jul 10, 2012 at 5:43 AM, Antoine Molin <amolin at plenr.fr> wrote:
> Hi,
>
>
>
> For wind energy, I would like to use merra  temperatures T2M from
> single-level diagnostics data.
>
> Is it possible to know the altitudes of the grid points ?
>
>
>
> I tried a point (49°N ; 4.67°E) in France, years 1995-2011 ; mean
> temperature seems ok (284K ; 10.8°C) but extreme temperatures are a little
> bit strange, with max 316K (~43°C) and min 257K (-16°C) ; max should be more
> ~312K, and i think min should be lower, ~252K.
>
> Is there a way to correct these temperatures ?
>
> Best regards.
>
>
>
> Antoine Molin
>
> Etudes de vent PlenR
>
> Tel : 03 20 47 99 76
>
>
>
>
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