e2ecdcfe33
Former-commit-id:a02aeb236c[formerly9f19e3f712] [formerlya02aeb236c[formerly9f19e3f712] [formerly06a8b51d6d[formerly 64fa9254b946eae7e61bbc3f513b7c3696c4f54f]]] Former-commit-id:06a8b51d6dFormer-commit-id:8e80217e59[formerly3360eb6c5f] Former-commit-id:377dcd10b9
126 lines
4.2 KiB
Python
126 lines
4.2 KiB
Python
##
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# This software was developed and / or modified by Raytheon Company,
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# pursuant to Contract DG133W-05-CQ-1067 with the US Government.
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#
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# U.S. EXPORT CONTROLLED TECHNICAL DATA
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# This software product contains export-restricted data whose
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# export/transfer/disclosure is restricted by U.S. law. Dissemination
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# to non-U.S. persons whether in the United States or abroad requires
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# an export license or other authorization.
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#
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# Contractor Name: Raytheon Company
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# Contractor Address: 6825 Pine Street, Suite 340
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# Mail Stop B8
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# Omaha, NE 68106
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# 402.291.0100
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#
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# See the AWIPS II Master Rights File ("Master Rights File.pdf") for
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# further licensing information.
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###
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## @file VorticityAdv.py
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from numpy import empty, shape, NaN
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##
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# Calculate vorticity advection.
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# This is currently only used in the calculation of PIVA; it was included here because it
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# was originally part of g2gkinematics.f, and is similar to more commonly-used functions
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# derived from that file like vorticity and divergence.
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#
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# @param Vector: A 2-tuple (U,V) of vector components. U and V must have the same shape,
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# be rank 2 or more, and have a shape of 3 or more in the first two dimensions.
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# @param coriolis: The coriolis adjustment of the grid accessor. This must be an array with
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# the same dimensions as U and V.
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# @param dx: The spacing between adjacent data points in the X direction. This can be an array
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# with the same dimensions as U or a scalar.
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# @param dy: The spacing between adjacent data points in the Y direction. This can be an array
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# with the same dimensions as U or a scalar.
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# @return: The vorticity advection array.
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# @rtype: An array of at least rank 2 with a shape of 3 or more in the first two dimensions.
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# The outer edges of the returned cannot be calculated and are set to NaN.
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def execute(U, V, dx, dy, coriolis):
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"""Calculate vorticity advection.
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Parameters:
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Vector - a tuple(U,V) of arrays, at least 3x3.
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coriolis - coriolis factor: an array the same shape as U
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dx - X dimension spacing: an array the same shape as U or a scalar
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dy - Y dimension spacing: an array the same shape as U or a scalar
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Returns:
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Vorticity advection: An array the same shape as U
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"""
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# coriolis, dx, and dy are generated values, not data.
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# Assume they never have invalid values to mask away.
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# If dx and dy are matrices, we never use the outer edge,
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# so strip it off so we don't have to use slice notation in the math.
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# If they're actually scalars or 1-element matrices, we can't
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# slice them so don't try.
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shapedx = shape(dx)
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if len(shapedx) < sum(shapedx):
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dx = dx[1:-1,1:-1]
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shapedy = shape(dy)
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if len(shapedy) < sum(shapedy):
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dy = dy[1:-1, 1:-1]
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# create an array to hold the result of calculation.
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result = empty(shape(U), dtype=U.dtype)
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result[0,:] = NaN
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result[-1,:] = NaN
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result[1:-1,0] = NaN
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result[1:-1,-1] = NaN
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# coriolis horizontal diff * U at pt / dx
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ans = coriolis[1:-1,0:-2] - coriolis[1:-1,2:]
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ans *= U[1:-1,1:-1]
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ans /= dx
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# coriolis vertical diff * V at pt / dy
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coriB = coriolis[0:-2,1:-1] - coriolis[2:,1:-1]
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coriB *= V[1:-1,1:-1]
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coriB /= dy
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# average coriolis terms
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ans += coriB
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ans /= 2
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# U difference of diagonal neighbors / 4
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term1 = U[2:,2:] + U[0:-2,0:-2]
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term1 -= U[0:-2,2:]
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term1 -= U[2:,0:-2]
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term1 /= 4
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# add 2*V at pt - V horizontal neighbors
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term1 += V[1:-1,1:-1] * 2
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term1 -= V[1:-1,2:]
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term1 -= V[1:-1,0:-2]
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# multiply by U at pt
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term1 *= U[1:-1,1:-1]
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# V difference of diagonal neighbors / 4
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term2 = V[2:,2:] + V[0:-2,0:-2]
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term2 -= V[0:-2,2:]
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term2 -= V[2:,0:-2]
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term2 /= 4
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# add 2*U at pt - U vertical neighbors
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term2 += U[1:-1,1:-1] * 2
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term2 -= U[2:,1:-1]
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term2 -= U[0:-2,1:-1]
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# multiply by V at pt
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term2 *= V[1:-1,1:-1]
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# find diff of terms
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term1 -= term2
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# divide by dx * dy
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term1 /= dx * dy
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# add to average of coriolis terms
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ans += term1
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result[1:-1,1:-1] = ans
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return result
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