Re: EP-Flux near real time

Hi,
I am sorry, i meant Elliasen Palm Flux in QG (quasi-geostrophic) spherical
coordinates. But what you have coded its at least give me a bit clue. My
problem for coding EP Flux is the problem in scale factor and handling the
dates. For instance if a 7-day average spans two different years and
requires accessing two different yearly data files.

Thanks for your help.
WH

On Mon, Jun 11, 2012 at 7:17 PM, Dennis Shea <shea@ucar.edu> wrote:

> The Subject 'EP-Flux near real time' is not clear.
> What is meant by "near real time" ?
>
> Eddy flux quantities are (say) u't' which require
> a mean quantity (uavg, tavg). There are many EP flux forms.
> The following should help you write the code.
>
> U(time,lev,lat,lon), T(time,lev,lat,lon)
> 0 1 2 3
>
>
> Say you have one month U,T at 6hrly times
> --------
> Without meta data
>
> uavg = dim_avg_n(U, 0) ; 3D
> tavg = dim_avg_n(T, 0)
> up = U-conform(U, uavg, (/1,2,3/) ) ; 4D
> tp = T-conform(T, uavg, (/1,2,3/) )
> uptp = up*tp
> uptp_avg = dim_avg_n(uptp, 0) ; 3D
> --------
> With meta data (recommended) and printing variable overviews
>
> uavg = dim_avg_n_Wrap(U, 0) ; (lev,lat,lon)
> tavg = dim_avg_n_Wrap(T, 0)
> printVarSummary(uavg)
> printVarSummary(tavg)
>
> up = U-conform(U, uavg, (/1,2,3/) )
> copy_VarMeta(U, up)
> up@long_name = "u'"
> printVarSummary(up) ; (time,lev,lat,lon)
>
> tp = ...
>
> uptp = up*tp
> copy_VarCoords(U, uptp)
> uptp@long_name = "u't'"
> uptp@units = "(m/s)-K"
> printVarSummary(uptp) ; (time,lev,lat,lon)
>
> uptp_avg = dim_avg_n_Wrap(uptp, 0)
> uttp_avg@long_name = "monthly avg u't'"
> printVarSummary(uptp_avg) ; (lev,lat,lon)
>
> Note: **all** non-linear quantities must be computed
> **at each time step**
>
>
> On 6/11/12 9:25 AM, Wilhelm Haygen wrote:
>
>> Hi,
>> Does anybody has experience in calculating/computing EP-Flux by using NCL?
>> Especially based on variable U, V and T (Theta)?
>> Thanks for your sharing,
>>
>> WH,
>>
>>
>>
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Received on Mon Jun 11 12:36:31 2012