Contents
What is top of atmosphere reflectance?
Top of Atmosphere (TOA) Reflectance is a unitless measurement which provides the ratio of radiation reflected to the incident solar radiation on a given surface. It that can be computed from satellite measured spectral radiance using the mean solar spectral irradiance and the solar zenith angle.
Which is the hottest layer of the atmosphere?
The thermosphere
The thermosphere is often considered the “hot layer” because it contains the warmest temperatures in the atmosphere. Temperature increases with height until the estimated top of the thermosphere at 500 km. Temperatures can reach as high as 2000 K or 1727 ºC in this layer (Wallace and Hobbs 24).
How is the dark object subtraction method used?
The Dark Object Subtraction (DOS) method is an image-based technique to cancel out the haze component caused by additive scattering from remote sensing data (Chavez Jr, 1988). This method is found to be data dependent and well accepted by the geospatial community to correct light scattering in remote sensing data (Song et al. 2000).
Which is the module top of atmosphere reflectance?
Module Top of Atmosphere Reflectance / SAGA-GIS Module Library Documentation (v2.1.3) SAGA-GIS Module Library Documentation (v2.1.3) Modules A-ZContentsImagery – Tools Module Top of Atmosphere Reflectance Calculation of top-of-atmosphere radiance or reflectance and temperature (TOAR) for Landsat MSS/TM/ETM+.
Why does a black object have a nonzero reflectance?
The concept is simple: if you have a completely black object, and therefore does not reflect light at all, this object should have a value of reflectance equal to zero, will have a nonzero value at the satellite sensor. This value will be the reflectance due to the particles present in the atmosphere.
Which is the best tool for Atmospheric correction?
ENVI offers several atmospheric correction tools. See the following sections: Use Dark Subtraction to remove the effects of atmospheric scattering from an image by subtracting a pixel value that represents a background signature from each band.