Aerosol optical thickness

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They are provided on the NEO web site as 1-day measurements and 8-day and 1-month composites. There are many applications for aerosol optical thickness data: " 1 Atmospheric correction of remotely sensed surface features 2 Monitoring of sources and sinks of aerosols 3 Monitoring of volcanic eruptions and forest fire 4 Radiative Transfer Model 5 Air Quality 6 Health and Environment 7 Earth Radiation Budget 8 Climate Change" 1 "Aerosol particles are important to scientists because they represent an area of great uncertainty in their efforts to understand Earth's climate system. Depending upon their size, type, and location, aerosols can either cool the surface, or warm it. They can help clouds to form, or they can inhibit cloud formation. And if inhaled, aerosols can be harmful to people's health. This data can be used to teach or learn the following topics and skills in introductory Earth science:.

Aerosol optical thickness

Tiny solid and liquid particles suspended in the atmosphere are called aerosols. Windblown dust, sea salts, volcanic ash, smoke from wildfires, and pollution from factories are all examples of aerosols. Depending upon their size, type, and location, aerosols can either cool the surface, or warm it. They can help clouds to form, or they can inhibit cloud formation. And if inhaled, some aerosols can be harmful to people's health. Satellite measurements of aerosols, called aerosol optical thickness, are based on the fact that the particles change the way the atmosphere reflects and absorbs visible and infrared light. An optical thickness of less than 0. High aerosol amounts are linked to different process in different places and times of year. High aerosol amounts occur over South America from July through September. This pattern is due to land clearing and agricultural fires that are widespread across the Amazon Basin and Cerrado regions during the dry season.

Statistical Bureau of Jiangsu. Aerosol optical depth retrieval from visibility in China during — Therefore, this network can not be used operationally to correct the satellite images over large areas, aerosol optical thickness.

This post contains formulas! Aerosols play a great role in the atmospheric effects. Aerosols are particles suspended in the atmosphere, which can be of several types: sand or dust, soot from combustion, sulfates or sea salt, surrounded by water… Their size ranges between 0. Their quantity is also extremely variable : rain can suddenly reduce their abundance known as « aerosol optical thickness ». The abundance variations result in great variations of observable reflectances from one day to the next, and it is therefore necessary to know the quantity and type of aerosols, in order to correct their effects.

Tiny solid and liquid particles suspended in the atmosphere are called aerosols. Windblown dust, sea salts, volcanic ash, smoke from wildfires, and pollution from factories are all examples of aerosols. Depending upon their size, type, and location, aerosols can either cool the surface, or warm it. They can help clouds to form, or they can inhibit cloud formation. And if inhaled, some aerosols can be harmful to people's health. Satellite measurements of aerosols, called aerosol optical thickness, are based on the fact that the particles change the way the atmosphere reflects and absorbs visible and infrared light. An optical thickness of less than 0. High aerosol amounts are linked to different process in different places and times of year. High aerosol amounts occur over South America from July through September. This pattern is due to land clearing and agricultural fires that are widespread across the Amazon Basin and Cerrado regions during the dry season.

Aerosol optical thickness

The aerosol quantity determined by most instruments is the aerosol optical depth AOD. This is related to the amount of light aerosols scatter or absorb in a column through the atmosphere specifically, it is the vertically-integrated aerosol extinction , and is also sometimes referred to as aerosol optical thickness AOT. AOD depends on wavelength; a common reference wavelength reported by satellite data products is nm. This is related to the aerosol particle size. Roughly speaking , values less than 1 suggest an optical dominance of coarse particles e. For health purposes, people are often interested in the mass of aerosols of a certain size at ground level. This is often referred to by the term 'particulate matter' PM and separated by size. Terms such as PM 1 , PM 2.

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Faraday Discuss. Depending upon their size, type, and location, aerosols can either cool the surface, or warm it. They generally tend to work better on vegetated areas rather than in arid areas. References Kaufman, Y. Abdou, W. Over the land, the dynamic aerosol models will be derived from ground-based sky measurements and used in the net retrieval process. Remote Sens. However, most regions with low correlation can be either desert areas with very bright surfaces or areas with complex surface elements, which leads to lower correlations between two aerosol products due to their lower sensitivity to aerosol properties on bright surfaces 28 , 58 , Mishchenko, M. May and June were excluded from deseasonalized analysis, because they were the period of active dust storms, affected the whole Asian continent 13 , 36 , 44 , Google Scholar Zhang, J. Figure 3. NEO offers a variety of data exploration and analysis tools including simple visual exploration, visualization of graphical displays of the data, mathematical combinations of two or three data sets, and time-series animation. Aerosols play a great role in the atmospheric effects. As a rule, monthly standard deviation SD in anomalies constitutes 0.

In the maps shown here, dark brown pixels show high aerosol concentrations, while tan pixels show lower concentrations, and light yellow areas show little or no aerosols. Black shows where the sensor could not make its measurement. Aerosol optical depth is the degree to which aerosols prevent the transmission of light by absorption or scattering of light.

Multi Temporal Method In most cases, the reflectance of the land surface changes slowly over time, while the aerosol optical properties vary rapidly from one day to another. Generally, we observe a gradual decrease of aerosol load on the territory of the country, which may be associated with a consistent state policy in the field of environment protection, aimed not only at control and development of methods to decrease atmosphere pollution, but the improvement of the total ecological situation of the country. Cheng, T. For all regions, with the exception of North China Plain in which the maximum occurs in summer 0. Show Related Maps. Early versions used the following equations:. Such good results may be characterized by unique features in MISR instrument, which make it possible to ensure a better view and study of spectral response characteristics to obtain aerosol optical properties over various surfaces due to the use of its polygonal and multispectral view capabilities. The method named « Dark Dense Vegetation » DDV is based on assumptions about relationships between surface reflectances of the dense vegetation exploiting the fact that the spectrum of dense green vegetation is quite constant. Recently, satellite remote sensing and ground-based observations have become widely used to monitor the spatial and temporal distributions of aerosols on a global and local scale 23 , 24 , 25 , 26 , Enregistrer mon nom, mon e-mail et mon site dans le navigateur pour mon prochain commentaire.