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def initialize_bps (V , pixelsperkm , timestep , p_pert_par = (10.88 ,0.23 ,- 7.68 ),
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p_pert_perp = (5.76 ,0.31 ,- 2.72 ), randstate = np .random , seed = None ):
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- """Initialize the motion field perturbator described in Bowler et al.
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- 2006: STEPS: A probabilistic precipitation forecasting scheme which merges
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- an extrapolation nowcast with downscaled NWP. For simplicity, the bias
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- adjustment procedure described in the above reference has not been
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+ """Initialize the motion field perturbator described in :cite:`BPS2006`.
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+ For simplicity, the bias adjustment procedure described there has not been
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implemented. The perturbator generates a constant field whose magnitude
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- depends on lead time, see generate_motion_perturbations_bps .
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+ depends on lead time.
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Parameters
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----------
@@ -42,12 +40,12 @@ def initialize_bps(V, pixelsperkm, timestep, p_pert_par=(10.88,0.23,-7.68),
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Tuple containing the parameters a,b and c for the standard deviation of
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the perturbations in the direction parallel to the motion vectors. The
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standard deviations are modeled by the function f_par(t) = a*t^b+c, where
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- t is lead time. The default values are taken from Bowler et al. 2006 .
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+ t is lead time. The default values are taken from :cite:`BPS2006` .
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p_pert_perp : tuple
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Tuple containing the parameters a,b and c for the standard deviation of
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the perturbations in the direction perpendicular to the motion vectors.
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The standard deviations are modeled by the function f_par(t) = a*t^b+c,
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- where t is lead time. The default values are taken from Bowler et al. 2006 .
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+ where t is lead time. The default values are taken from :cite:`BPS2006` .
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pixelsperkm : float
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Spatial resolution of the motion field (pixels/kilometer).
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timestep : float
@@ -62,6 +60,11 @@ def initialize_bps(V, pixelsperkm, timestep, p_pert_par=(10.88,0.23,-7.68),
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out : dict
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A dictionary containing the perturbator that can be supplied to
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generate_motion_perturbations_bps.
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+
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+ See also
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+ --------
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+ pysteps.noise.motion.generate_bps
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+
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"""
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if len (V .shape ) != 3 :
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raise ValueError ("V is not a three-dimensional array" )
@@ -117,6 +120,11 @@ def generate_bps(perturbator, t):
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out : ndarray
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Array of shape (2,m,n) containing the x- and y-components of the motion
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vector perturbations, where m and n are determined from the perturbator.
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+
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+ See also
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+ --------
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+ pysteps.noise.motion.initialize_bps
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+
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"""
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vsf = perturbator ["vsf" ]
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p_par = perturbator ["p_par" ]
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