Презентация The laws of extinction онлайн

Содержание слайда: The laws of SR extinction in the atmosphere Suppose a monochromatic flux of radiation falls on a point A1 at the top of the atmosphere. Radiation flux at point B’ is and at point B is The value is extinction of the radiation flux as it passes from B’ to B. According to Bouguer’s law

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Содержание слайда: Optical mass of the atmosphere

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Содержание слайда: Optical depth and optical mass relationship

Содержание слайда: Transmission coefficient For better understanding attenuation process it is worth introducing one more notion transmission coefficient (коэф.прозрач.)of the atmosphere (Pλ).

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Содержание слайда: The total flux of solar radiation For practical purposes we need to know total (integrated) flux of SR but monochromatic. Due to very intricate dependence of the transmission coefficient on wavelength, it is not easy to take this integral. The only way to make necessary calculation is to use average values of P and We may do it because in this case transmission coefficient P also shows the fraction of SR that reaches Earth’s surface when the Sun is in zenith: However, in this case P value depends on the optical mass m.

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Содержание слайда: The atmosphere turbidity factor Optical depth of the atmosphere can be presented as a sum of three items. is the optical depth of the ideal atmosphere. is the optical depth formed by variable constituents (CO2, H2O ) is the optical depth formed by aerosols. is turbidity factor. As we know

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Содержание слайда: Direct solar radiation (DSR) The solar radiation coming on an observation point as a bundle of parallel rays is called DSR. Fluxes of I and depends on the following factors: Solar constant. Distance between the Earth and the Sun. Physical state of the atmosphere over the point. Altitude of the Sun. Values of I and I’ have well-defined diurnal and annual variations. Maximal values is observed at the local noon. They are also influenced by turbidity of the atmosphere. They increase with increasing altitude of a locality (in this case optical mass decreases). It is why in mountain areas these quantities are larger than over planes.

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Содержание слайда: Scattered (diffused) radiation (DR) Amount of scattered radiation coming on a unit of area in a unit of time is named SCATTERED RADIATION FLUX (i). It depends on Altitude of the Sun Transparency of the atmosphere Cloudiness The DR flux reaches its maximum value at medium and high level clouds. At some cases it can be 2-3 times more intensive than the clear sky does. The maximal value of DR is observed at local noon when the Sun altitude is the highest for the given day.

Содержание слайда: Relationship between DSR and DR

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