The Carbon Cycle Data Assimilation System CCDAS - JULES

1 st derivative (gradient) of
J( p ) to model parameters p :
−∂J( p ) ∂p
yields direction of steepest
descent.
Gradient Method
cost function
J( p )
2 nd derivative (Hessian)
of J( p ):
∂ 2 J( p ) ∂ p 2
yields curvature of J.
Approximates covariance of
parameters.
Model parameter space ( p )
Figure from Tarantola, 1987