id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
287	Handling of missing values in input phase	kmk	Stig Syndergaard	"This sprang from the testing of ROPP on the ROSA data.

There are two elements to it. 
First: the code uses the dividing point between GO and WO to double as also the dividing line between two different ways of handling low-quality L2 data. Below 25 km low-quality (or missing) L2 data is replaced by a synthetic L2 signal extrapolated from L1. Above 25 km low-quality L2 data is replaced by a heavily-smoothed version of the input L2 signal. It is not very clear or reasonable that this dividing line between two regimes for handling L2 should always be the same as the GO-WO dividing line. The two don't have much to do with each other.
Secondly, and probably more seriously, we discovered during ROSA data processing that the code does not correctly catch and handle missing values in the L2 excess phase. On the contrary they are treated as valid data with the value -9999. In the WO regime this will not cause drastic problems, because a missing value will be flagged as bad L2 data and L2 will be replaced by a synthetic L2. Also for GRAS data this will be caught as data gaps in the special GRAS preprocessing routine. However without a special preprocessing routine data in the GO regime will go crazy because the L2 signal will merely be replaced by a heavily smoothed version of the same signal – still including the -9999 value(s). 

I think Dave's attittude was that ROPP should maybe more stringently prohibit data input from an unknown source. Right now it just throws a warning "	defect	assigned	major	DMI ROPP developments	ropp_pp	6.0