# Re: Divergence

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Wed Jul 24 2013 - 10:20:52 MDT

I think what you want is

uq = u*q
vq = v*q
dv = uv2dvG(uq,vq)
dv@long_name = "moisture divergence"

On 7/24/13 10:00 AM, Guilherme Martins wrote:
> My question is: The values using the function uv2dvG make sense? I multiply
> "divg" by "humidity specific" because I want humidity divergence.
>
> f = addfile("uvq.1000hpa.nc","r") ; gaussian grid
>
> u = f->uvel(0,0,:,:) ; m/s
> v = f->vvel(0,0,:,:) ; m/s
> q = f->umes(0,0,:,:) ; kg/kg
> dv = uv2dvG(u,v) ; divergence - gaussian grid
>
> divg = dv * q
>
> Thanks,
>
> Guilherme.
>
>
>
> 2013/7/24 Dennis Shea <shea@ucar.edu>
>
>> Not sure what you want.
>>
>> The units of divergence are 1/sec
>> --
>> Embedded in the long_name ... units are m/s
>>
>> float uvel ( time, lev, lat, lon )
>> long_name : ZONAL WIND (U) (M/Sec
>> )
>>
>> float vvel ( time, lev, lat, lon )
>> long_name : MERIDIONAL WIND (V) (M/Sec
>> )
>>
>> float umes ( time, lev, lat, lon )
>> long_name : SPECIFIC HUMIDITY (No Dim
>> )
>>
>> If the largest values of 'umes' are (say) 20 then the
>> units are g/kg; if the largest values are (say) 0.002
>> they are kg/kg (ie unitless)
>>
>> ====
>> The code you sent indicates this already
>>
>> u = f->uvel(0,0,:,:) ; m/s
>> v = f->vvel(0,0,:,:) ; m/s
>> q = f->umes(0,0,:,:) ; kg/kg
>> dv = uv2dvG(u,v) ; divergence - gaussian grid
>>
>>
>>
>>
>>
>> On 7/24/13 9:10 AM, Guilherme Martins wrote:
>>
>>> Hi all,
>>>
>>> I'm calculating the divergence, but I'm not sure about the units of the
>>> variables. Can anyone help me?
>>>
>>> The files are in attach.
>>>
>>> Thanks,
>>>
>>> Guilherme.
>>>
>>>
>>>
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>
>
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Received on Wed Jul 24 10:20:59 2013

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