legacy/src/main/java/ucar/nc2/NetcdfFileWriteable.java
public Attribute addGlobalAttribute(String name, Array values) {
    return addGlobalAttribute( new Attribute(name, values));
  }
public Attribute addGlobalAttribute(String name, Array values) {
    return addGlobalAttribute( new Attribute(name, values));
  }
Add a Global attribute of type Array to the file. Must be in define mode.

@param name   name of attribute.
@param values Array of values
@return the created attribute