[gradsusr] Vertical gradient of the saturation mixing ratio

[Morwakoma Matabane]

Good day,

I have managed to compute the saturation vapor pressure of two levels, say z-1 and z+1. And after computing the mixing ratios for the respective levels, I cannot seem to be able to calculate the dQs/dz (the vertical gradient of the mixing ratios). All I get whenever I attempt to compute the dQs/dz is an ERROR.
...

'set z 3'

*At temperature t1=t(z+1)

'define qs1=0.622*es1/lev'

*At temperature t2=t(z-1)

'define qs2=0.622*es2/lev'

'define dq=(qs1-qs2)/(lev(z+1)-le(z-1))'

'd dq'

OUTPUTS AN ERROR

How can I avoid the erroneous situation? Your help is highly appreciated.


Regards
Morwakoma
South African Weather Service (SAWS) Scientist

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