id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
382	Observation Impact, OBS_IMPACT_SPLIT	arango	arango	"The observation impact operator for '''W4DPSAS''' and '''W4DVAR''' was further developed to additionally compute the contributions due to initial conditions, surface forcing, and boundary conditions. A new C-preprocessing option, '''OBS_IMPACT_SPLIT''', is introduced to achieve this.  It requires additional integrations of the tangent linear model. This option needs to be used at the same time with '''OBS_IMPACT''' and '''W4DPSAS_SENSITIVITY''' or '''W4DVAR_SENSITIVITY'''.

If '''OBS_IMPACT_SPLIT''' is defined as well, then the contribution
to the observation sensitivities for the increments in the initial
conditions, surface forcing, and boundary conditions are all
computed separately. This is a very nice feature and is very revealing.

Many thanks to Andy Moore for coding and testing this new option."	upgrade	closed	major	Adjoint Based Algorithms	Adjoint	3.3	Done