# Re: Divergence

From: Dennis Shea <shea_at_nyahnyahspammersnyahnyah>
Date: Wed Jul 24 2013 - 11:01:29 MDT

Yes: g/kg/sec = g kg-1 s-1

On 7/24/13 10:51 AM, Guilherme Martins wrote:
> Thanks,
>
> Now it's ok.
>
> The unit is *[g kg-1 s-1]*?
>
> *According to:*
>
> u = f->uvel(0,0,:,:) ; m/s
> v = f->vvel(0,0,:,:) ; m/s
> q = f->umes(0,0,:,:) ; kg/kg
> *uq = u*(q*1e3) ; kg/kg -> g/kg*
> *vq = v*(q*1e3) ; kg/kg -> g/kg*
>
> dv = uv2dvG(uq,vq) ; divergence - gaussian grid
> dv@long_name = "moisture divergence"
>
>
> Guilherme
>
>
> 2013/7/24 Dennis Shea <shea@ucar.edu>
>
>> 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 11:01:42 2013

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