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Application of the Monte Carlo method to describe the radiative transfer within a spatially non-uniform forest canopyтезисы доклада
- Авторы: Levashova Nataliya, Gandilyan David, Olchev Alexander
- Сборник: American Geophysical Union (AGU) 2020 Fall Meeting
- Том: 2020
- Тезисы
- Год издания: 2020
- Издательство: AGU Publications
- Местоположение издательства: Вашингтон
- Номер статьи: B009-11
- Аннотация: Solar radiation is a key factor determining the climate and weather conditions in different regions of the Earth. It influences the surface energy budget, water vapor and carbon dioxide exchange at the vegetation - atmosphere interface, and thereby affecting not only the plant functioning and growth, but also the concentrations of greenhouse gases (GHG) in the atmosphere. Over the last decades many experimental and modeling studies of spatial and temporal variability of solar radiation were provided within different ecological and meteorological studies. Numerous radiative transfer models of different scales and complexity, from the simplest 1D to more sophisticated 3D models, were developed and applied to describe the solar radiation reflection and absorption in various plant ecosystem types. In the present study a 3D Monte Carlo model of radiative transfer within a spatially non-uniform forest canopy is suggested. The developed model allows to describe the reflection, absorption and transmission of solar radiation within a spatially heterogeneous forest canopy taking into account the multiple scattering from plant elements and soil surface. The radiation transfer is simulated as a random Markov chain of sunlight photon interaction with plant elements (leaves, branches) and soil. The spatial vegetation structure in the model is derived using the methods of fractal geometry. A fractal broadleaf tree is built using the self-similarity principle by sequential applying the branching algorithm using the Wolfram Mathematica computing system. At the first step, we specify the coordinates of each tree location, length of tree trunk and first-order branches, number of first-order branches, and their zenith and azimuth angles. In the next steps we simulate the second- and higher-order branches and leaves. The length of tree branches is assumed to be a multiple of the golden ratio φ≈0.61803. Namely, we use a scale factor that is equal φ–1 for the first-order branches, φ–2 - for the second-order branches, etc. The results of numerical simulation are well agreed with reflection and transmission estimations provide by a 3D radiative transfer model based on steady-state transport equations.
- Добавил в систему: Левашова Наталия Тимуровна