# [ncl-talk] Partial derivative along a coordinate

gibies george gibiesgeorge at gmail.com
Mon Apr 17 10:17:48 MDT 2017

```Thank you so much Dr. Dennis, this is exactly what I was looking for.

Regards

On Apr 17, 2017 8:29 PM, "Dennis Shea" <shea at ucar.edu> wrote:

> Please look at the documentation for:
>
> http://www.ncl.ucar.edu/Document/Functions/Built-in/
> center_finite_diff_n.shtml
>
> Cheers
>
>
> On Mon, Apr 17, 2017 at 8:54 AM, gibies george <gibiesgeorge at gmail.com>
> wrote:
>
>>
>> But the SST case I discussed is just an example.
>>
>> My actual problem is to get zonal, meridional and vertical gradient of
>> ocean temperature profile (4D data with time).
>>
>> I also have to get time tendency of temperature.
>>
>> That is why I put a generalized mail initially.
>>
>> Thank and regards
>>
>> On Apr 17, 2017 6:46 PM, "Dennis Shea" <shea at ucar.edu> wrote:
>>
>>> NCL has functions to calculate gradients (derivatives).
>>>
>>> Your original post did not show that  you wanted gradients of SST.
>>> Presumably, these have missing values (land).
>>>  *ftcurvd *will compute gradients but, as noted in the documentation,
>>> it does not allow missing values.
>>>
>>> NCL has other functions for gradients:
>>>
>>>
>>> Some use spherical harmonics which are "highly accurate"  but, again, do
>>> not allow for missing values.
>>>
>>> --
>>> The following 6.4.0 function does allow for missing values.
>>>
>>> latlon_cfd.shtml
>>>
>>> Read the documentation. This returns a variable of type 'list.' The list
>>> (container) consists of two variables the zonal and meridional gradients.
>>> ---
>>> The following is essentially Example 2:
>>>
>>>    sst  = f->SST                        ; assume a rectilinear grid
>>>
>>>
>>> ; for clarity, explicitly extract the variables within the list
>>>
>>> accessing elements of a list
>>>
>>>    print("---")
>>>
>>>
>>> Good luck
>>>
>>> On Mon, Apr 17, 2017 at 4:01 AM, gibies george <gibies at tropmet.res.in>
>>> wrote:
>>>
>>>>
>>>> Suppose if I have to calculate zonal gradient of SST(time|:,lat|:,lon|:)
>>>>
>>>> xcoord=confirm(*dimsizes*
>>>> <https://www.ncl.ucar.edu/Document/Functions/Built-in/dimsizes.shtml>
>>>> (SST),SST&lon,2)
>>>> dsst_dx = *ftcurvd*(xcoord,SST,SST&lon)
>>>>
>>>> Is this correct ?
>>>>
>>>>
>>>>
>>>>
>>>> *Dr. Gibies George,*
>>>> *Project Scientist C,*
>>>> *Monsoon Mission,*
>>>>
>>>> *Indian Institute of Tropical Meteorology,Dr. Homi Bhabha Road, *
>>>> *NCL Post Office, *
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> *Pashan, Pune 411008, India.Office Teleph  : +912025904423
>>>> <+91%2020%202590%204423>Office mail      : gibies at tropmet.res.in
>>>> <gibies at tropmet.res.in>____________________________________________Vettikuzhiyil
>>>>
>>>>
>>>>
>>>> *Puthencruz-682308, Kochi, India.Mobile number :  +919028523910
>>>> <+91%2090285%2023910>, +919420407392 <+91%2094204%2007392>, Personal mail :
>>>> gibiesgeorge at gmail.com
>>>>
>>>>
>>>> print this e-mail unless you really need. Because every 3000 pages cost a
>>>> tree. *
>>>> *Save Trees, Save mother Earth." *
>>>>
>>>>
>>>> On 13 April 2017 at 20:31, Andy <awmiller at mit.edu> wrote:
>>>>
>>>>> Yes, you can use ftcurvd.
>>>>>
>>>>> Andy
>>>>>
>>>>> Andy Miller
>>>>> MIT PAOC PhD Candidate
>>>>>
>>>>> 77 Massachusetts Ave | 54-1715
>>>>> Cambridge, MA 02139
>>>>>
>>>>> Phone: 617-253-3715 <(617)%20253-3715>
>>>>> Email: awmiller at mit.edu
>>>>>
>>>>> On 04/13/2017 02:46 AM, gibies george wrote:
>>>>>
>>>>> Dear friends,
>>>>>
>>>>> Is there a function available to find partial derivative of a variable
>>>>> along one of its coordinate (say, lonx, laty, levz, time, etc ) ?
>>>>>
>>>>> thanks and regards
>>>>>
>>>>>
>>>>> *Dr. Gibies George,*
>>>>> *Project Scientist C,*
>>>>> *Monsoon Mission,*
>>>>>
>>>>> *Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, *
>>>>> *NCL Post Office, *
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> *Pashan, Pune 411008, India. Office Teleph  : +912025904423
>>>>> <020%202590%204423> Office mail      : gibies at tropmet.res.in
>>>>> <gibies at tropmet.res.in> ____________________________________________
>>>>> Vettikuzhiyil House, Ezhakkaranadu South **Post Office,*
>>>>>
>>>>>
>>>>>
>>>>> * Puthencruz-682308, Kochi, India. Mobile number :  +919028523910
>>>>> <090285%2023910>, +919420407392 <094204%2007392>,  Personal mail :
>>>>> gibiesgeorge at gmail.com <gibiesgeorge at gmail.com>
>>>>>
>>>>>
>>>>> not print this e-mail unless you really need. Because every 3000 pages cost
>>>>> a tree. *
>>>>> *Save Trees, Save mother Earth." *
>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
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