# [ncl-talk] help

Alan Brammer abrammer at albany.edu
Wed Feb 3 10:00:01 MST 2016

```ok, I’ll bite and attempt to answer.

Assuming you mean this:
Power Dissipation Index (PDI) for a tropical cyclone is defined as, "the sum of the maximum one-minute sustained wind speed cubed, at six-hourly intervals, for all periods when the cyclone is at least tropical storm strength”.

so calculate wind speed. 		https://www.ncl.ucar.edu/Document/Functions/Contributed/wind_speed.shtml
find maximum  				https://www.ncl.ucar.edu/Document/Functions/Built-in/local_max.shtml
cube the maximum value.  		x^3

What your units are and whether they match Emanuels or others is a problem you’ll have to work out.

##############################
Alan Brammer,
Post-Doc Researcher

Department of Atmospheric and Environmental Sciences,
University at Albany, State University of New York, Albany, NY, 12222
abrammer at albany.edu
##############################

> On 3 Feb 2016, at 09:19, Dennis Shea <shea at ucar.edu> wrote:
>
> Please do not post the same question.
>
> The reason for no answer is that no one knows what you mean by "power dissipation". Hence, there is no function.
>
> On Tue, Feb 2, 2016 at 4:06 PM, Key Tone <keytone25 at gmail.com <mailto:keytone25 at gmail.com>> wrote:
> Hi,
>
> I was wondering what code/script to use when calculating the power dissipation of this vector plot below?
>
> <image.png>
>
> Here is the code for the plot: <image.png>
>
> Thanks!
>
> _______________________________________________
> ncl-talk mailing list
> ncl-talk at ucar.edu <mailto:ncl-talk at ucar.edu>
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk <http://mailman.ucar.edu/mailman/listinfo/ncl-talk>
>
>
> _______________________________________________
> ncl-talk mailing list
> ncl-talk at ucar.edu
> List instructions, subscriber options, unsubscribe:
> http://mailman.ucar.edu/mailman/listinfo/ncl-talk

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20160203/671326af/attachment.html
```