[gradsusr] unit conversion -

[Júlio Barboza Chiquetto]

Dear Arlindo,

Thank you for your answer.

I thought there were more complicated calculations involved in this
procedure and that it would be necessary to write an equation in GrADS,
that's why I sent an email to the list.

Thank you,




Júlio B. Chiquetto,
Doutorando em Climatologia pelo Programa de Pós-Graduação em Geografia
Física da Universidade de São Paulo.

PhD Student in Climatology at the Post-Graduation Program in Physical
Geography of the University of Sao Paulo.


On 21 May 2014 21:42, Arlindo da Silva <dasilva at alum.mit.edu> wrote:

> On Wed, May 21, 2014 at 6:48 PM, Júlio Barboza Chiquetto <
> julio22 at gmail.com> wrote:
>
>> Hello dear users,
>> I have a tropospheric ozone time series in micrograms/m3, but I need to
>> display it in ppm. I know it's a simple issue, but I don't have much
>> experience in writing formulas in GrADS and I was wondering if other users
>> might have already needed a script that does this unit conversion when
>> displaying a variable.
>>
>
> Consult the wikipedia to learn about the part-per notation:
>
>                     http://en.wikipedia.org/wiki/Parts-per_notation
>
> Notice that ppm (parts per million) implies mass mixing ratio (ppmv is
> used for volume mixing ratio). All you have to do is to divide your ozone
> density time series by the air density which in principle depends on
> pressure and temperature:
>
>         rho = p / (RT)
>
> If you express the air density in micrograms/m3 as your ozone density you
> will have your mixing ratio in Kg/Kg. Mutiply it by 1,000,000 to have ppm.
>
>     Arlindo
>
> --
> Arlindo da Silva
> *dasilva at alum.mit.edu <dasilva at alum.mit.edu>*
>
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>
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