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# coding: utf-8 |
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# Copyright (c) 2020 Stefan Bender |
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# |
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# This file is part of pyeppaurora. |
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# pyeppaurora is free software: you can redistribute it or modify |
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# it under the terms of the GNU General Public License as published |
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# by the Free Software Foundation, version 2. |
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# See accompanying LICENSE file or http://www.gnu.org/licenses/gpl-2.0.html. |
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"""Atmospheric recombination rate parametrizations |
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Atmospheric recombination rate parametrizations as described |
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in [1]_, [2]_, and [3]_. |
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.. [1] Vickrey et al., J. Geophys. Res. Space Phys., 87, A7, 5184--5196, |
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doi:10.1029/ja087ia07p05184 |
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.. [2] Gledhill, Radio Sci., 21, 3, 399-408, doi:10.1029/rs021i003p00399 |
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.. [3] https://ssusi.jhuapl.edu/data_algorithms |
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""" |
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import numpy as np |
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__all__ = [ |
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"alpha_vickrey1982", |
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"alpha_gledhill1986_aurora", |
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"alpha_gledhill1986_day", |
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"alpha_gledhill1986_night", |
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"alpha_ssusi", |
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] |
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def alpha_vickrey1982(h): |
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u""" Vickrey et al. 1982 [#]_ |
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Parameters |
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---------- |
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h: float or array_like |
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Altitude in [km] |
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Returns |
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------- |
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alpha: float or array_like |
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The recombination rate [cm³ s⁻¹]. |
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References |
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---------- |
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.. [#] Vickrey et al., J. Geophys. Res. Space Phys., |
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87, A7, 5184--5196, doi:10.1029/ja087ia07p05184 |
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""" |
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return 2.5e-6 * np.exp(-h / 51.2) |
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def alpha_gledhill1986_aurora(h): |
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""" Gledhill 1986, Aurora parameterization [#]_ |
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Parameters |
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---------- |
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h: float or array_like |
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Altitude in [km] |
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Returns |
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------- |
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alpha: float or array_like |
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The recombination rate [cm³ s⁻¹]. |
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References |
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---------- |
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.. [#] Radio Sci., 21, 3, 399-408, doi:10.1029/rs021i003p00399 |
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""" |
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return 4.3e-6 * np.exp(-2.42e-2 * h) + 8.16e12 * np.exp(-0.524 * h) |
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def alpha_gledhill1986_day(h): |
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u""" Gledhill 1986, day-time parameterization [#]_ |
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Parameters |
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---------- |
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h: float or array_like |
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Altitude in [km] |
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Returns |
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------- |
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alpha: float or array_like |
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The recombination rate [cm³ s⁻¹]. |
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References |
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---------- |
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.. [#] Radio Sci., 21, 3, 399-408, doi:10.1029/rs021i003p00399 |
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""" |
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return 0.501 * np.exp(-0.165 * h) |
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def alpha_gledhill1986_night(h): |
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""" Gledhill 1986, night-time parameterization [#]_ |
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Parameters |
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---------- |
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h: float or array_like |
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Altitude in [km] |
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Returns |
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------- |
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alpha: float or array_like |
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The recombination rate [cm³ s⁻¹]. |
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References |
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---------- |
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.. [#] Radio Sci., 21, 3, 399-408, doi:10.1029/rs021i003p00399 |
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""" |
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return 652 * np.exp(-0.234 * h) |
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def alpha_ssusi(z, alpha0=4.2e-7, scaleh=28.9, z0=108., z1=None): |
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u""" Recombination rate from the SSUSI algorithm [#]_ |
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Implements section 2.6.2.15 from [#]_, |
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more details are also in [#]_. |
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Parameters |
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---------- |
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z: float, array_like |
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Profile altitude [km]. |
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alpha0: float, optional |
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Predetermined peak effective recombination coefficient. |
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Default: 4.2e-7 |
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scaleh: float, optional |
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Predetermined scale height [km] of the effective recombination coefficient. |
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Default: 28.9. |
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z0: float, optional |
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Predetermined altitude [km] of the peak effective recombination coefficient. |
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Default: 108. |
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z1: float, optional |
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Use :func:`alpha_vickrey1982()` above z1 [km]. |
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Default: None |
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Returns |
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------- |
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alpha: float or array_like |
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The recombination rate [cm³ s⁻¹]. |
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References |
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---------- |
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.. [#] https://ssusi.jhuapl.edu/data_algorithms |
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.. [#] https://ssusi.jhuapl.edu/docs/algorithms/Aurora_LID_c_Version_2.0.pdf |
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.. [#] https://ssusi.jhuapl.edu/docs/algorithms/SSUSI_DataProductAlgorithms_V1_13.doc |
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""" |
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alpha = np.zeros_like(z) |
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alpha[z < z0] = alpha0 |
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alpha[z >= z0] = alpha0 * np.exp(-(z[z >= z0] - z0) / scaleh) |
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if z1 is not None: |
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# use Vickrey et al. above z1 |
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alpha[z >= z1] = 2.5e-6 * np.exp(-z[z >= z1] / 51.2) |
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return alpha |
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st-bender /
pyeppaurora
