pydda.cost_functions.calculate_model_gradient

pydda.cost_functions.calculate_model_gradient(u, v, w, weights, u_model, v_model, w_model, coeff=1.0)[source]

Calculates the cost function for the model constraint. This is calculated simply as twice the differences between the model wind field and the analysis wind field for each u, v. Vertical velocities are not factored into this cost function as there is typically a high amount of uncertainty in model derived vertical velocities. Therefore, the gradient for all of the w’s will be 0.

Parameters
u: Float array

Float array with u component of wind field

v: Float array

Float array with v component of wind field

w: Float array

Float array with w component of wind field

weights: list of 3D float arrays

Weights for each point to consider into cost function

u_model: list of 3D float arrays

Zonal wind field from model

v_model: list of 3D float arrays

Meridional wind field from model

w_model: list of 3D float arrays

Vertical wind field from model

coeff: float

Weight of background constraint to total cost function

Returns
y: float array

value of gradient of background cost function