id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
479	Specify units for forward model gradients in ROPP FM UG	Ian Culverwell	Ian Culverwell	"Joe Nielsen (DMI) points out that the forward model gradient fields, generated when '''ropp_fm_bg2ro_1d''' is run without the {{{-f}}} option, are calculated in 'ropp_fm' units (eg N-unit/K, N-unit/(kg/kg), N-unit/Pa, rather than 'ropp_io' units (eg N-unit/K, N-unit/(g/kg), N-unit/hPa).  With the log p/q option, or with (eg) Met Office background files, the units would be different again.  And the unit conversion routines in ropp_utils couldn't cope with units literally given as 'N-unit/K, N-unit/(kg/kg), N-unit/Pa', for example.  So we have to live with dN/dx having a unit in the output file of 'N-unit'.

The ROPP FM documentation doesn't spell this out, and probably should.  Secs 4.8.6, 4.9.6 and E.3 would be good places to note it.

"	enhancement	new	minor	Whenever	ropp_fm	8.0		Gradient