[gradsusr] hdivg function

[Yaqiang Wang]

The correct one should be:

define du = cdiff(u,x)
define dx = cdiff(lon,x)*3.1416/180
define dv = cdiff(v*cos(lat*3.1416/180),y)
define dy = cdiff(lat,y)*3.1416/180
display (du/dx+dv/dy)/(6.37e6*cos(lat*3.1416/180))

Yaqiang

Chinese Academy of Meteorological Sciences
yaqiang.wang at gmail.com

On Mon, Nov 15, 2010 at 12:47 PM, Yaqiang Wang <yaqiang.wang at gmail.com> wrote:
> Thanks for Jeff's reply! But it seems that in GrADS the hdivg function
> was calculated as following. Please mention the last sentence.
>
> define dv = cdiff(v,x)
> define dx = cdiff(lon,x)*3.1416/180
> define du = cdiff(u*cos(lat*3.1416/180),y)
> define dy = cdiff(lat,y)*3.1416/180
> display (du/dy+dv/dx)/(6.37e6*cos(lat*3.1416/180))
>
> Yaqiang
>
> Chinese Academy of Meteorological Sciences
> yaqiang.wang at gmail.com
>
> On Mon, Nov 15, 2010 at 11:56 AM, Jeffrey Duda <jdduda at iastate.edu> wrote:
>> Yaqiang,
>> You are exactly correct.
>>
>> Jeff Duda
>>
>> On Sun, Nov 14, 2010 at 9:22 PM, Yaqiang Wang <yaqiang.wang at gmail.com>
>> wrote:
>>>
>>> The GrADS documentation said that the cdiff function may be used to
>>> duplicate the calculation done by the hcurl function:
>>>
>>> define dv = cdiff(v,x)
>>> define dx = cdiff(lon,x)*3.1416/180
>>> define du = cdiff(u*cos(lat*3.1416/180),y)
>>> define dy = cdiff(lat,y)*3.1416/180
>>> display (dv/dx-du/dy)/(6.37e6*cos(lat*3.1416/180))
>>>
>>> But there is no description of hdivg function. I guess hdivg function
>>> could be duplicated using cdiff function as following. Please anybody
>>> tell me if it is correct or not. Thanks!
>>>
>>> define dv = cdiff(v,x)
>>> define dx = cdiff(lon,x)*3.1416/180
>>> define du = cdiff(u*cos(lat*3.1416/180),y)
>>> define dy = cdiff(lat,y)*3.1416/180
>>> display (du/dx+dv/dy)/(6.37e6*cos(lat*3.1416/180))
>>>
>>> Yaqiang Wang
>>>
>>> Chinese Academy of Meteorological Sciences
>>> yaqiang.wang at gmail.com
>>> _______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>>
>>
>> --
>> Jeff Duda
>> Iowa State University
>> Meteorology Graduate Student
>> 3134 Agronomy Hall
>> www.meteor.iastate.edu/~jdduda
>>
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>>
>