symbol 
definition 

vector of nondimensional control variables 

vector of dimensional control variables 

misfit and control cost function multipliers (1 by default) 

data error covariance matrix (
are weights) 

a set of modeldata differences 

observational data vector 

model counterpart to


postprocessing operator (e.g., a smoother) 

forward model dynamics operator 

diagnostic computation operator 

averaging/subsampling operator 

Preprocessing operator 

Preconditioning operator 