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    <entry>
      <title>辐射传输方法</title>
      <link href="/2024/07/14/fu-she-chuan-shu-fang-fa/"/>
      <url>/2024/07/14/fu-she-chuan-shu-fang-fa/</url>
      
        <content type="html"><![CDATA[<blockquote><p>大气辐射传输学习总结</p></blockquote><h2 id="1-引言"><a href="#1-引言" class="headerlink" title="1 引言"></a>1 引言</h2><p>大气辐射传输的基本原理是将气体、气溶胶和云等大气介质的辐射特性参数化后求解辐射传输方程。辐射传输的物理过程由微分-积分方程来描述，在一定的条件下可以获得解析解。本章主要介绍近些年来我们发展的辐射传输算法。5.1节主要概述常用的辐射传输算法。5.2节集中介绍二流辐射传输算法。二流辐射传输算法主要包括矩阵算子算法和 Eddington近似。5.3节从辐射传输的四个不变性原理出发，建立四流累加辐射传输理论，并形成了四流离散纵坐标累加辐射传输算法和四流球谐函数展开累加辐射传输算法。5.4节介绍最新发展的二流四流混合算法。</p><h2 id="2-总的方法介绍"><a href="#2-总的方法介绍" class="headerlink" title="2 总的方法介绍"></a>2 总的方法介绍</h2><p>辐射传输方程的求解是大气辐射学的重要组成部分。有些方法直接对辐射传输方程进行离散化处理（离散纵坐标法和球谐函数展开法），有些基于直观的物理过程进行考虑（倍加-累加法、逐次散射法和蒙特卡洛求解法）（石广玉，2007）。<br>离散纵坐标法是Chandrasekhar（1950）为了应用于行星大气辐射传输而提出的一种独具 匠心的方法。Liou（1973）证明了离散纵坐标可以有效地用于大气辐射计算。Stamnes等（1988）利用离散纵坐标方法开发了DISORT程序包，目前DISORT高流方案计算的结果一般可以作为辐射传输计算的参考标准，用来衡量其他辐射传输算法的精度。目前在气候模式中广泛采用的是二流离散纵坐标法。</p><h2 id="3-6S辐射传输模式"><a href="#3-6S辐射传输模式" class="headerlink" title="3 6S辐射传输模式"></a>3 6S辐射传输模式</h2><p><strong><em>Second Simulation of the Satellite Signal in the Solar Spectrum</em></strong>&nbsp;(known, understandably, as 6S) is a Radiative Transfer Model which is widely used within remote sensing. It is an advanced radiative transfer code designed to simulate the reflection of solar radiation by a coupled atmosphere-surface system for a wide range of atmospheric, spectral and geometrical conditions. It belongs to the group of procedures called&nbsp;<a href="https://en.wikipedia.org/wiki/Atmospheric_correction" title="Atmospheric correction">Atmospheric correction</a>&nbsp;for the process of removing the effects of the&nbsp;<a href="https://en.wikipedia.org/wiki/Atmosphere" title="Atmosphere">atmosphere</a>&nbsp;on the reflectance values of images taken by&nbsp;<a href="https://en.wikipedia.org/wiki/Satellite" title="Satellite">satellite</a>&nbsp;or airborne sensors. The code operates on the basis of an SOS (successive orders of scattering) method and accounts for the&nbsp;<a href="https://en.wikipedia.org/wiki/Polarization_(waves)" title="Polarization (waves)">polarization</a>&nbsp;of radiation in the atmosphere through the calculation of the Q and U components of the&nbsp;<a href="https://en.wikipedia.org/wiki/Stokes_vector" title="Stokes vector">Stokes vector</a>. It is a basic code for the calculation of look-up tables in the&nbsp;<a href="https://en.wikipedia.org/wiki/MODIS" title="MODIS">MODIS</a>&nbsp;atmospheric correction algorithm.<br>It simulates the effect of the atmosphere on light passing through it, and can basically answer two questions:</p><ol><li>What intensity of light would be received at a satellite or airborne sensor under a specific set of atmospheric and ground reflectance conditions?</li><li>What would the ground reflectance have been, given the measurement of light intensity at a sensor and the atmospheric conditions? (that is, the reverse of the previous question)</li></ol><p>Although these questions may seem relatively simple, they’re actually quite complicated to answer. They’re also very important. Radiative Transfer Models like 6S are often used to&nbsp;<em>atmospherically correct</em>&nbsp;satellite images (the standard atmospheric corrections for data from the MODIS and Landsat satellites are based upon 6S), and they also have a key role to play in research (for example, assessing the sensitivity of a method to atmospheric contamination.).<br>6S was originally developed by a team led by Eric Vermote, and is fully described in&nbsp;<a href="http://www.geog.ucl.ac.uk/~mdisney/teaching/PPRS/papers/vermote_etal_IEEE_1997.pdf">Vermote et al. (1997)</a>&nbsp;and the&nbsp;<a href="http://6s.ltdri.org/6S_code2_thiner_stuff/6s_ltdri_org_manual.htm">original manuals</a>.</p><table><thead><tr><th>Name</th><th>References</th><th align="center">UV</th><th>Visible</th><th>Near IR</th><th>Thermal IR</th><th>mm/sub-mm</th><th>Microwave</th><th>line-by-line/band</th><th>Scattering</th><th>Polarised</th><th>Geometry</th><th>License</th><th>Notes</th><th>Website</th></tr></thead><tbody><tr><td><a href="https://en.wikipedia.org/wiki/6S_(radiative_transfer_code)" title="6S (radiative transfer code)">6S/6SV1</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#kotchenova1997">Kotchenova et al. (1997)</a><br></td><td align="center">No</td><td>Yes</td><td>Yes</td><td>No</td><td>No</td><td>No</td><td>band</td><td>?</td><td>Yes</td><td></td><td></td><td>non-Lambertian surface</td><td><a href="http://6s.ltdri.org/">http://6s.ltdri.org/</a></td></tr><tr><td><a href="https://en.wikipedia.org/wiki/ARTS_(radiative_transfer_code)" title="ARTS (radiative transfer code)">ARTS</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#eriksson2011">Eriksson et al. (2011)</a><br><br><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#buehler2018">Buehler et al. (2018)</a></td><td align="center">No</td><td>No</td><td>No</td><td>Yes</td><td>Yes</td><td>Yes</td><td>line-by-line</td><td>Yes</td><td>Yes</td><td>spherical 1D, 2D, 3D</td><td><a href="https://en.wikipedia.org/wiki/GPL" title="GPL">GPL</a></td><td></td><td><a href="http://www.radiativetransfer.org/">http://www.radiativetransfer.org/</a></td></tr><tr><td><a href="https://en.wikipedia.org/wiki/DISORT" title="DISORT">DISORT</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#stamnes1988">Stamnes et al. (1988)</a><br><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#lin2015">Lin et al. (2015)</a></td><td align="center">Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td><em>radar</em></td><td></td><td>Yes</td><td>No</td><td>plane-parallel or pseudo-spherical (v4.0)</td><td>free with restrictions</td><td>discrete ordinate, used by others</td><td><a href="http://lllab.phy.stevens.edu/disort/">http://lllab.phy.stevens.edu/disort/</a></td></tr><tr><td><a href="https://en.wikipedia.org/wiki/LBLRTM" title="LBLRTM">LBLRTM</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#clough2005">Clough&nbsp;<em>et al.</em>&nbsp;(2005)</a></td><td align="center">Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>line-by-line</td><td>?</td><td>?</td><td></td><td></td><td></td><td><a href="http://rtweb.aer.com/lblrtm.html">http://rtweb.aer.com/lblrtm.html</a></td></tr><tr><td><a href="https://en.wikipedia.org/w/index.php?title=LibRadtran&amp;action=edit&amp;redlink=1" title="LibRadtran (page does not exist)">libRadtran</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#mayer2005">Mayer and Kylling (2005)</a></td><td align="center">Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>No</td><td>No</td><td>band or line-by-line</td><td>Yes</td><td>Yes</td><td>plane-parallel or pseudo-spherical</td><td><a href="https://en.wikipedia.org/wiki/GPL" title="GPL">GPL</a></td><td></td><td><a href="http://www.libradtran.org/doku.php">http://www.libradtran.org/doku.php</a></td></tr><tr><td><a href="https://en.wikipedia.org/wiki/MODTRAN" title="MODTRAN">MODTRAN</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#berk1998">Berk et al. (1998)</a></td><td align="center"><a href="https://en.wikipedia.org/wiki/Kayser_unit" title="Kayser unit">ṽ</a>&lt;50,000&nbsp;cm−1&nbsp;(eq. to λ&gt;0.2&nbsp;µm)</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>band or line-by-line</td><td>Yes</td><td>?</td><td></td><td>proprietary commercial</td><td>solar and lunar source, uses DISORT</td><td><a href="http://www.modtran.org/">http://www.modtran.org/</a></td></tr><tr><td><a href="https://en.wikipedia.org/wiki/RTTOV_(radiative_transfer_code)" title="RTTOV (radiative transfer code)">RTTOV</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#saunders1999">Saunders&nbsp;<em>et al.</em>&nbsp;(1999)</a></td><td align="center">λ&gt;0.4&nbsp;µm</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>Yes</td><td>band</td><td>Yes</td><td>?</td><td></td><td>available on request</td><td></td><td><a href="http://research.metoffice.gov.uk/research/interproj/nwpsaf/rtm/">http://research.metoffice.gov.uk/research/interproj/nwpsaf/rtm/</a></td></tr><tr><td><a href="https://en.wikipedia.org/w/index.php?title=SBDART&amp;action=edit&amp;redlink=1" title="SBDART (page does not exist)">SBDART</a></td><td><a href="https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes#ricchiazzi1998">Ricchiazzi&nbsp;<em>et al.</em>&nbsp;(1998)</a></td><td align="center">Yes</td><td>Yes</td><td>Yes</td><td>?</td><td>No</td><td>No</td><td></td><td>Yes</td><td>?</td><td>plane-parallel</td><td></td><td>uses DISORT</td><td><a href="https://web.archive.org/web/20100708003803/http://arm.mrcsb.com/sbdart/">https://web.archive.org/web/20100708003803/http://arm.mrcsb.com/sbdart/</a></td></tr></tbody></table><h2 id="Second-Simulation-of-a-Satellite-Signal-in-the-Solar-Spectrum-vector-code"><a href="#Second-Simulation-of-a-Satellite-Signal-in-the-Solar-Spectrum-vector-code" class="headerlink" title="Second Simulation of a Satellite Signal in the Solar Spectrum vector code"></a><a href="https://salsa.umd.edu/6spage.html">Second Simulation of a Satellite Signal in the Solar Spectrum vector code</a></h2><hr><h2 id="Introduction"><a href="#Introduction" class="headerlink" title="Introduction"></a>Introduction</h2><p>The 6S code is a basic RT code used for calculation of lookup tables in the MODIS atmospheric correction algorithm. It enables accurate simulations of satellite and plane observation, accounting for elevated targets, use of anisotropic and lambertian surfaces and calculation of gaseous absorption. The code is based on the method of successive orders of scatterings approximations and its first vector version (6SV1), capable of accounting for radiation polarization. It was publicly released in May, 2005.</p><p>• Scalar (ignoring the effects of polarization).</p><p>• Fixed number of scattering angles (83), used for the specification of an aerosol phase function.</p><p>• 10 node wavelengths.</p><p>• Fixed number of calculation layers (26) and angles (48).</p><p>• Default exponential vertical aerosol profile.</p><p>• Several new subroutines, simulating measurements of the ALI, ASTER, ETM, HYPBLUE, VGT, and VIIRS instruments, have been integrated into the the vector 6S. The spectral response curves for all these instruments can be found in the 6S manual, version 3. The new subroutines were developed by Dr. T. Miura, University of Hawaii at Manoa, Honolulu, USA. </p><hr><h2 id="Authors"><a href="#Authors" class="headerlink" title="Authors"></a>Authors</h2><p>•&nbsp;<strong>Eric F. Vermote</strong>&nbsp;and&nbsp;<strong>Jean-Claude Roger</strong>, NASA GSFC Terrestrial Information Systems Laboratory, Code 619, Greenbelt, USA.<br>•&nbsp;<strong>S.Y. Kotchenova</strong>, Department of Earth and Environment Boston University, Boston, USA<br>•&nbsp;<strong>D. Tanre</strong>&nbsp;,<strong>J.L. Deuze</strong>&nbsp;and&nbsp;<strong>M. Herman</strong>, Laboratoire d’Optique Atmosphérique Université des Sciences et Techniques de Lille | U.E.R. de Physique Fondamentale, France.<br>•&nbsp;<strong>J.J. Morcrette</strong>, European Center for Medium - Range Weather Forecasting Shinfiels Park, United Kingdom<br>•&nbsp;<strong>Raffaella Matarrese</strong>, 6S Interface Credit, Italian National Research Council | CNR, Institute of Water Research IRSA.</p><hr><h2 id="Publications"><a href="#Publications" class="headerlink" title="Publications"></a>Publications</h2><ol><li>Vermote, E.F., Tanré, D., Deuzé, J.L., Herman, M., &amp; Morcrette, J.-J. (1997),&nbsp;<a href="https://ieeexplore.ieee.org/document/581987">Second Simulation of the Satellite Signal in the Solar Spectrum, 6S: An Overview</a>, IEEE Transactions on Geoscience and Remote Sensing, Vol. 35, No. 3, p. 675-686.</li><li>Svetlana Y. Kotchenova, Eric F. Vermote, Raffaella Matarrese, and Frank J. Klemm, Jr (2006).<a href="https://doi.org/10.1364/AO.45.006762">“Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part I: Path radiance”</a>, Optical Society of America, APPLIED OPTICS, Vol. 45, Issue 26, pp. 6762-6774</li><li>Svetlana Y. Kotchenova and Eric F. Vermote (2007).&nbsp;<a href="https://doi.org/10.1364/AO.46.004455">“Validation of a vector version of the 6S radiative transfer code for atmospheric correction of satellite data. Part II. Homogeneous Lambertian and anisotropic surfaces”</a>, Optical Society of America, APPLIED OPTICS, Vol. 46, Issue 20, pp. 4455-4464</li><li>Svetlana Y. Kotchenova, Eric F. Vermote, Robert Levy, and Alexei Lyapustin (2008).&nbsp;<a href="https://doi.org/10.1364/AO.47.002215">“Radiative transfer codes for atmospheric correction and aerosol retrieval: intercomparison study”</a>, Optical Society of America, APPLIED OPTICS, Vol. 47, Issue 13, pp. 2215-2226</li></ol><p><a href="https://www.py6s.rtwilson.com/docs.html">Py6S</a>: As described on the&nbsp;<a href="https://www.py6s.rtwilson.com/features.html">Features page</a>, Py6S is simply a wrapper around the original 6S code. It did not write any of the original 6S code and cannot answer detailed questions about the way that 6S itself works. </p>]]></content>
      
      
      
        <tags>
            
            <tag> 大气辐射传输 </tag>
            
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    <entry>
      <title>Hello World</title>
      <link href="/2024/07/13/hello-world/"/>
      <url>/2024/07/13/hello-world/</url>
      
        <content type="html"><![CDATA[<p>Welcome to <a href="https://hexo.io/">Hexo</a>! This is your very first post. Check <a href="https://hexo.io/docs/">documentation</a> for more info. If you get any problems when using Hexo, you can find the answer in <a href="https://hexo.io/docs/troubleshooting.html">troubleshooting</a> or you can ask me on <a href="https://github.com/hexojs/hexo/issues">GitHub</a>.</p><h2 id="Quick-Start"><a href="#Quick-Start" class="headerlink" title="Quick Start"></a>Quick Start</h2><h3 id="Create-a-new-post"><a href="#Create-a-new-post" class="headerlink" title="Create a new post"></a>Create a new post</h3><pre class="language-bash" data-language="bash"><code class="language-bash">$ hexo new <span class="token string">"My New Post"</span></code></pre><p>More info: <a href="https://hexo.io/docs/writing.html">Writing</a></p><h3 id="Run-server"><a href="#Run-server" class="headerlink" title="Run server"></a>Run server</h3><pre class="language-bash" data-language="bash"><code class="language-bash">$ hexo server</code></pre><p>More info: <a href="https://hexo.io/docs/server.html">Server</a></p><h3 id="Generate-static-files"><a href="#Generate-static-files" class="headerlink" title="Generate static files"></a>Generate static files</h3><pre class="language-bash" data-language="bash"><code class="language-bash">$ hexo generate</code></pre><p>More info: <a href="https://hexo.io/docs/generating.html">Generating</a></p><h3 id="Deploy-to-remote-sites"><a href="#Deploy-to-remote-sites" class="headerlink" title="Deploy to remote sites"></a>Deploy to remote sites</h3><pre class="language-bash" data-language="bash"><code class="language-bash">$ hexo deploy</code></pre><p>More info: <a href="https://hexo.io/docs/one-command-deployment.html">Deployment</a></p>]]></content>
      
      
      
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