long netcdf names

[Geert Jan van Oldenborgh]

I get netcdf variable names longer than 15 characters in files I extract
from the opendap server at data.ecmwf.int.

When I try to plot these in 1.9b4 I get the error message

ga-> d sea_water_potential_temperature
Syntax Error:  Invalid Operand
  'sea_water_potenti' not a variable or function name
  Error ocurred at column 1

but truncating to 15 characters is no problem

ga-> d sea_water_poten
Contouring: 273 to 303 interval 3

Why is the variable name truncated to 17 characters in the first case?  If
it would be truncated to 15 it would work automagically.

Greetings from finally sunny Holland,

             Geert Jan van Oldenborgh