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Radiation range
Image

Radiation is divided into that from the sun (mostly visible) and that from the earth (mostly infrared). When represented as a function of wavelength, it appears as follows:



Typical satellite measurements, such as those from the MODIS project, are taken in different channels.

The visible part is measured with three channels:

Channels Ranges [µm] Relative Weights
Blue 0.459-0.479 0.4364
Green 0.545-0.565 0.2366
Red 0.620-0.670 0.3265



The infrared part is estimated with the following channels:

Channels Ranges [µm] Relative Weights
NIR 0.841-0.876 0.5447
1.2 1.230-1.250 0.1363
1.6 1.628-1.652 0.0469
2.1 2.105-2.155 0.2536

The results from the first group are referred to as VIS, while those from the second group are referred to as NIR, although part of the observed spectrum falls within the visible range.To understand why the separation is made around 750 nm instead of 3 microns, as is normally defined for the infrared range, one must consider the behavior of the albedo. It shows a substantial increase for wavelengths around 750 nm and above, not just from 3 microns onwards (see the albedo chart as a function of wavelength).

ID:(9921, 0)


Solar radiation flow over the ocean surface
Model

Variables
Symbol
Text
Variable
Value
Units
Calculate
MKS Value
MKS Units
$a_e$
a_e
Albedo of the planet's surface
-
$a_{VIS}$
a_VIS
Albedo Visible (VIS)
-
$\gamma_v$
g_v
Atmosphere coverage for VIS radiation
-
$I_p$
I_p
Average earth intensity
W/m^2
$I_r$
I_r
Reflected Intensity
W/m^2
$I_{ev}$
I_ev
VIS intensity absorbed by the ground
W/m^2
$I_{sev}$
I_sev
VIS intensity reaching the earth's surface
W/m^2
$I_{sav}$
I_sav
VIS intensity that interacts with the atmosphere
W/m^2

Calculations

First, select the equation:   to ,  then, select the variable:   to 
Symbol
Equation
Solved
Translated

Calculations

Symbol
Equation
Solved
Translated

 Variable   Given   Calculate   Target :   Equation   To be used


Equations

Examples

The radiations reaching the surface of the ocean or emitted from it can be summarized in the following graph:

In summary:- $I_{sev}$: Net solar radiation.- $I_e$: Radiation emitted by the Earth.- $I_H$: Exchange due to droplet input/output.- $I_E$: Exchange due to water evaporation/condensation.- $I_c$: Exchange due to conduction.This graph provides a concise overview of the different forms of radiation interacting at the ocean's surface and the associated energy exchanges.

(ID 13497)

Radiation is divided into that from the sun (mostly visible) and that from the earth (mostly infrared). When represented as a function of wavelength, it appears as follows:



Typical satellite measurements, such as those from the MODIS project, are taken in different channels.

The visible part is measured with three channels:

Channels Ranges [ m] Relative Weights
Blue 0.459-0.479 0.4364
Green 0.545-0.565 0.2366
Red 0.620-0.670 0.3265



The infrared part is estimated with the following channels:

Channels Ranges [ m] Relative Weights
NIR 0.841-0.876 0.5447
1.2 1.230-1.250 0.1363
1.6 1.628-1.652 0.0469
2.1 2.105-2.155 0.2536

The results from the first group are referred to as VIS, while those from the second group are referred to as NIR, although part of the observed spectrum falls within the visible range.To understand why the separation is made around 750 nm instead of 3 microns, as is normally defined for the infrared range, one must consider the behavior of the albedo. It shows a substantial increase for wavelengths around 750 nm and above, not just from 3 microns onwards (see the albedo chart as a function of wavelength).

(ID 9921)

ID:(1540, 0)