Hi Gao

As Filippo said, we calculate the total cloud cover using the random overlaping assumption considering all the levels. From the RAD files, you have for each level of the model its fc(i). The total cloud cover for n levels is given by:

cl=1-[(1-fc(1))(1-fc(2))(1-fc(3).....(1-fc(n))]

If you want, you can multiply cl by 100 to have it in percentage like in the CRU.

Cheers

***************************************************
Mouhamadou Bamba SYLLA
Post-Doc Position, PWC/ESP
International Centre for Theoretical Physics
Strada Costiera 11, 34100 Trieste, Italy
Office tel: 0039 040 2240 225
Cell: 0039 34 71 94 06 55
emails: msylla@ictp.it, syllabamba@yahoo.fr
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De : "gaoxj@cma.gov.cn" <gaoxj@cma.gov.cn>
À : regcnet@lists.ictp.it
Envoyé le : Mer 3 Février 2010, 4 h 34 min 38 s
Objet : [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