Re: [ferret_users] long time series climate data

[Jaison Kurian <jaison@xxxxxxxxxxxxxxxxxx>]

Hi Qunying Luo,
                 In general, there are two ways to solve your problem : 
(1) Write a descriptor file so that you can open all the NetCDF files
in Ferret as a single dataset & (2) Combine individual NetCDF files to
create a bigger NetCDF file.

 To suggest a method, you have to provide little more details about your
dataset :
 
   1. Are the monthly files on the same Lat-Lon (XY) grid ?
   2. Does the time sampling is constant for all monthwise files
        (two times a day)
   3. How big is one months data ?  
   4. How does the filenames look like (myfile1.nc, myfile2.nc.....)
   5. Are variable names consistent between the files ?

With Regards,

Jaison



On Tue, 15 Aug 2006, Qunying Luo wrote:

> Dear ferret users
> 
> I am a beginner of ferret. Hope to get your support!
> 
> I got some netCDF files for two time slices (1961-1990, 2065-2094). One
> file comprises 1 month's data (1 sample file attached). There are 60
> years. This resulted in 720 (60*12) netCDF files. The content of netCDF
> files are solar radiation, maximum temperature, minimum temperature and
> rainfall at a frequency of half day for a spatial area. The task I am
> going to undertake is to put the daily data for these 4 variables in a
> sequence order for specific locations for further analysis (for example,
> to derive changes in wet/dry spells). The final dataset should be in the
> following format
> Year Day  Radiation  MaxT  MinT  Rainfall
> 1961 1    19         34    17     0
> 1961 2
> ...
> 1961 365
> ...
> 2094 1
> 2094 2
> ...
> 2094 365 
>  
> It would be very appreciated if you could help me out on this. I have
> explored the user's guide for some days and found there are too much
> info and do not know where to start. I am using ferret V5.53, operating
> system: Windows 2000. Other three affiliated questions associated with
> these procedures are
> (1) Not sure if intermediate processes needed to calculate the daily
> value as there are two outputs per day
> (2) How ferret handle multiple netCDF files?
> (3) How to extract point based data rather than spatial data
> 
> I am looking forward to hearing from you!
> 
> Thanks with anticipation!
> 
> 
> Sincerely yours
> Qunying Luo
> 
>