precipitation in CAM

[huihuojia@163_com]

There are many variables regarding precipitation: PRECL, PRECC, PRECT, PRECCav, PRECLav

1. What is the difference between PRECL and PRECCav? If my output interval is 6 hours, is PRECCav the averaged PRECC within the 6 hour interval? and could I say if I output "PRECC:A", it is same as PRECCav?
2. The unit of both PRECC and PRECCav is m/s. But when I try to compare the daily rainfall with satelite, for which the unit of precipitation is mm, how could I transform these variables and units?

Thanks

 

[hannay]

It depends on you averaging flag. By default averaging flag for precipitation is "A". It means that it is averaged over the time-period between 2 outputs.So in your example, if you output every 6 hour, it is the average over the 6-hour interval preceeding your output. 

In CAM:
PRECT=PRECC+PRECL
PRECT= total precipitation
PRECC=convective precipitation
PRECL=large-scale precipitation I am not familiar with PRECCav and PRECLav but I looked in the code:PRECC=PRECCav
PRECL=PRECLavHowever, the information about PRECCav and PRECLav in the metadata is not correct.Currently, the metadata are specified in the addfld call   call addfld ('PRECCav ','m/s     ',1,    'A','Average large-scale precipitation (liq + ice)'                      ,phys_decomp)                                                          
   call addfld ('PRECLav ','m/s     ',1,    'A','Average convective precipitation  (liq + ice)'                      ,phys_decomp)    
                                                      This is INCORRECT. There is an inversion between teh description of PRECCav and PRECCav.However, the variable itself is output correctly.That said I would stick to PRECT, PRECL, and PRECC. These are defined and output correctly.