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Former-commit-id:a02aeb236c[formerly9f19e3f712] [formerlya02aeb236c[formerly9f19e3f712] [formerly06a8b51d6d[formerly 64fa9254b946eae7e61bbc3f513b7c3696c4f54f]]] Former-commit-id:06a8b51d6dFormer-commit-id:8e80217e59[formerly3360eb6c5f] Former-commit-id:377dcd10b9
69 lines
No EOL
2.5 KiB
Python
69 lines
No EOL
2.5 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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import IsenStability
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import Vorticity
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##
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# Calculate the isentropic potential vorticity through a layer.
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#
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# @change: Adapted from calcpv.f 2008-18-06
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# User Notes:
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#
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# 1. Stability is defined as -dP/d(theta). We calculate this through
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# the layer from the isentropic surface 'n' to the surface above it,
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# 'n+1'.
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#
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# 2. Since we are dealing with a layer, we calculate a mean absolute
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# vorticity using the winds at the upper and lower layers.
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#
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# 3. The PV is then [mean abs. vort.]/[stability]
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#
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# @param p_up: Pressure on upper isentrope (mb)
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# @param p_lo: Pressure on lower isentrope (mb)
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# @param o_up: Upper isentrope (K) (usually scalar)
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# @param o_lo: This (lower) isentrope (K) (usually scalar)
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# @param Wind_up: tuple(U,V) of winds on upper isentrope (m/s)
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# @param Wind_lo: tuple(U,V) of winds on lower isentrope (m/s)
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# @param dx: Spacing between data points in X direction (m)
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# @param dy: Spacing between data points in Y direction (m)
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# @param coriolis: Coriolis parameters (/s)
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# @return: isentropic potential vorticity array
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#
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def execute(p_up, p_lo, o_up, o_lo, vector_up, vector_lo, dx, dy, coriolis):
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"Calculate the isentropic potential vorticity through a layer."
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u_up, v_up = vector_up[2], vector_up[3]
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u_lo, v_lo = vector_lo[2], vector_lo[3]
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# Calculate the absolute vorticity at each isentropic surface.
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avort1 = Vorticity.execute(u_up, v_up, coriolis, dx, dy)
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avort2 = Vorticity.execute(u_lo, v_lo, coriolis, dx, dy)
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# Calculate the isentropic stability through the layer.
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pvort = IsenStability.execute(p_up, p_lo, o_up, o_lo)
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# Calculate isentropic potential vorticity
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result = avort1 + avort2
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result *= 0.5
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result /= pvort
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return result |