Quick plots with Ferret

Ferret is an interactive computer visualization and analysis environment designed to meet the needs of oceanographers and meteorologists analyzing gridded data sets. It is very useful to create quick plots to check what is going with the data. Below a few very basic examples are given how to quickly visualize data with Ferret.

In order to use Ferret on Mistral, load it via

module load ferret

Start Ferret by

ferret

in the shell command prompt and the ferret command prompt will look like

yes? 

Ferret expects gridded data, i.e. on a longitude-latitude-height-time grid. As an example, say you have a gridded (0.05°x0.05°; this is high resolutiob) file of surface temperature from the ICON dpp0016 simulation. You can load this file into ferret via:

yes? use dpp0016_ts_005x005.nc

You can inspect the data via:

yes? show data
 
currently SET data sets:
    1> ./dpp0016_ts_005x005.nc  (default)
 name     title                             I         J         K         L         M         N
 TS       surface temperature              1:7200     1:3600     ...       1:297     ...       ...

You can see the longitude (7200 data points), latitude (3600) and time (297 days).

To make a plot of the tropical Atlantic averaged over the entire time period, do (it make take some time because the file is large):

yes? shade TS[x=60W:20E,y=30S:30N,t=@ave]
yes? go land

To make a plot of a timeseries of surface temperature over a spatial mean of some region in the tropical Atlantic, do:

yes? plot TS[x=30W:10E@ave,y=5S:5N@ave]

Exit ferret via

yes? q