id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
499	Problems with Met Office backgrounds	Ian Culverwell	Ian Culverwell	"ROM SAF Helpdesk Eqn 341 has highlighted an embarrassment: there is no documented way of generating background data (i.e. level 2b/2d) in  ROPP format.  The enquirer wanted to convert Unified Model (UM) 'fieldsfiles' into ROPP format.  There is no more-or-less automated way to do this, unlike for ECMWF data, which can be converted into ROPP format using either '''grib2bgrasc''' or '''bgrasc2ropp'''.

We should probably look at introducing a tool to do this conversion.  This is not just code work, however: there are real questions about precisely which UM fields should populate the ROPP file. {{{geop_sfc}}} and {{{press_sfc}}} appear to be particularly problematic.  See Enq 341 (http://www.romsaf.org/view_admin_enquiry.php?id=341) for more.

While we're at it, Sec 3.67 of the ROPP FM UG needs attention: Fig 3.4 has mislabelled levels (I think it should be rho/A and theta/B), and there is no mention of the fact that ZA is calculated from ZB (by linear interpolation), not given.



 "	enhancement	new	normal	Whenever	ropp_fm	8.0		UM