[RegCNET] Cloud liquid water path and postproc

[Fabien SOLMON]

Hello

Talking about cloud variables, one should be also aware that cloud
liquid water path (CLWP in the RAD. output) is not correctly
interpolated when using the pressure grid interpolation option of
postproc. The reason for this is that CLWP depends explicitly of the
layer thickness (CLWP is an extensive variable), which changes when
going from sigma grid to a new pressure grid. CLWP on a pressure grid
should be recalculated from interpolated cloud water mixing ratio on the
same pressure grid. There is a similar issue when interpolating AEXT
variable in the CHE. output .

All the best.

Fabien


Prodromos Zanis a écrit :
> Dear Gao
> In order to calculate total column fraction cloud cover you can use
> the farctional cloud cover from each model level with the following way:
> Total column FC
> =1-[(1-fc(z=1))*(1-fc(z=2))*(1-fc(z=3))*(1-fc(z=4))*(1-fc(z=5))*(1-fc(z=6))*(1-fc(z=7))*(1-fc(z=8))*(1-fc(z=9))*(1-fc(z=10))*(1-fc(z=11))]
> In this examble 11 model levels are assumed.
>
> You should NOT do simply sum of FC in the model levels to calculate
> Total column FC.
>
> Best wishes
> Prodromos
>
>     ----- Original Message -----
>     *From:* gaoxj at cma.gov.cn <mailto:gaoxj at cma.gov.cn>
>     *To:* regcnet at lists.ictp.it <mailto:regcnet at lists.ictp.it>
>     *Sent:* Wednesday, February 03, 2010 5:34 AM
>     *Subject:* [RegCNET] cloud coverage
>
>     Dear all,
>     The cloud coverage in RegCM is caculated and output in each
>     vertical layers. Then if I want to know the total cloud cover,
>     should I pick the maxima among the layers, or should I do average
>     of the layers?
>     Thanks ahead for your reply.
>     Best regards,
>     Gao
>
>     ------------------------------------------------------------------------
>     _______________________________________________
>     RegCNET mailing list
>     RegCNET at lists.ictp.it
>     https://lists.ictp.it/mailman/listinfo/regcnet
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> RegCNET mailing list
> RegCNET at lists.ictp.it
> https://lists.ictp.it/mailman/listinfo/regcnet