- •The Sun and Solar constant
- •Some particularities of the solar atmosphere
- •Two successive photos of a solar flare phenomenon evolving on the sun. The
- •Solar spots
- •http://en.wikipedia.org/wiki/File:Solar-cycle-data.png
- •Total spectrum of the solar radiation
- •http://en.wikipedia.org/wiki/File:Atmospheric_Transmission.png
- •Notion of OPTICAL WINDOW
- •Solar constant
- •Temperature of the Sun emitting surface
- •Difference between the insolation in Northern and southern hemispheres is explained by the
- •Distribution of the Sun energy in various areas of the spectrum
- •Solar radiation distribution over the globe
- •Insolation
- •The Q values in summer of the Southern hemisphere are bigger than corresponding
Temperature of the Sun emitting surface
Average distance between the Sun and the Earth
|
|
r 149,5 106 km |
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
0 |
|
|
|
|
|
|
|
a 696,6 103 km |
|
|||||
|
|
And the radius of the sun is |
r |
||||||||||||||
|
|
r0 |
|
Every m2of the sphere of the radius |
|||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0 |
|
|
|
|
in one second receives the energy |
|
||||||||||||
|
|
|
|
I0* 1,37 kW m2 . The Whole sphere receives |
|
||||||||||||
|
|
|
|
all the energy emitted by the Sun |
|
||||||||||||
|
|
4 a2 B 4 r2 I* |
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
r |
2 |
|
* |
|
|
B |
T |
4 |
|
|
|||||
|
|
s |
|
0 0 |
B |
|
0 |
|
I |
|
|
|
|
|
|
||
|
|
|
|
|
s |
|
a |
|
|
0 |
|
|
s |
s |
|
|
|
T 4 |
B |
5805k |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
s |
s |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
This temperature is also called effective (radiation) temperature of the Sun.
For practical purposes it adopted to be 6000 K
11
12
Difference between the insolation in Northern and southern hemispheres is explained by the eccentricity of the EARTH ORBIT
22 June (Aphelion) r 1,52 108 km
22 December (Perihelion) r 1,47 108 km
r 5000 000km
13
Distribution of the Sun energy in various areas of the spectrum
UV ( |
0,39 |
) – 9% |
Visible Light ( 0,39 0,75 ) – 47% |
||
IR ( |
0,76 |
) – 44% |
99% of the energy falls to the area 0,1 – 4,0 μ.
Conclusion: The Sun emits Short wave radiation.
100% of the terrestrial radiation (Earth’s radiation) falls to the area 3 – 120 μ (maximal 10μ).
Conclusion: The Earth emits Long wave radiation.
14
Solar radiation distribution over the globe
We’ll consider the distribution over the upper “boundary of the atmosphere”, where the astronomical factors only may be accounted for
•Rotation of the Earth about the Sun.
•The tilt to ecliptic of the earth spinning axis.
•The Earth spinning.
At an arbitrary chosen moment of time the distance between the Sun and the Earth is not necessarily equal to the average one, i. e.
r r |
4 r |
2 |
I |
|
4 r |
2 |
I |
* |
|
|
|
|
I0* |
|
|
|
0 |
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
|
|
|
0 |
0 |
|
0 |
|
I0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
r |
r |
2 |
|||||||
|
|
|
|
|
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0 |
|
15
Insolation
The flux of solar radiation falling on a horizontal surface is called
INSOLATION
|
B |
|
I0 AB I0' AC |
|
|
|||
|
ξ |
|
' |
|
||||
|
C |
AB AC sin |
I0 I0 sin |
|
||||
|
|
|
|
|||||
|
A |
|
|
|
||||
|
denotes altitude of the Sun above horizon (or just SUN ALTITUDE) |
|||||||
sin sin sin cos cos cos |
2 |
t |
Here, φ is latitude, δ is declination |
|||||
|
||||||||
|
|
|
|
|
of the Sun, П=86400 s is duration |
|||
|
|
|
|
|
|
|||
|
of the one spin of the earth, 2 t is hour angle, and t is time being counted |
|||||||
|
from the noon. |
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
Let us determine amount of SR Q arriving to one m2of a horizontal surface |
||||||||
|
during a day time at the top of the atmosphere, i. e. diurnal insolation. |
16
|
|
|
|
|
|
|
|
t0 Denotes time of sunrise |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||||
|
|
|
|
t0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||
|
Q I0' dt |
t |
0 |
Denotes time of sunset |
|
|
At |
t0 sin 0 |
|
|
|
|
|
|||||||||||||||||||
|
|
|
|
t0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
|
|
|
|
|
|
|
|
|
|
|
sin sin sin cos cos cos |
2 |
t0 0 |
|
|
|
|
|
||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
2 |
|
|
|
|
|
cos |
2 |
t0 tg tg |
|
|
|
||||||||||||||
|
|
|
sin sin cos cos cos |
|
|
t0 |
|
|
|
|
|
t0 t0 , |
||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||||||||
|
|
|
|
I0* |
|
|
|
' |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||||||||
|
|
|
|
|
|
|
I0 sin |
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||
I0 |
|
|
|
|
|
|
|
I0 |
|
|
|
|
I0* |
|
|
|
|
|
|
|
|
|
2 |
|
|
|||||||
|
|
|
|
2 |
|
|
' |
|
|
|
|
|
|
|
|
|
|
|||||||||||||||
|
|
|
|
r |
|
|
|
|
|
|
|
|
|
|
I0 |
|
|
|
|
|
|
sin sin cos cos cos |
|
t |
|
|||||||
|
|
|
r |
|
|
|
|
|
|
|
|
|
r |
|
|
2 |
|
|
||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
r |
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
* |
|
|
|
t0 |
t0 |
2 |
|
|
|
I0 |
|
|
|
|
||||
Q |
|
|
|
|
|
sin sin |
dt cos cos cos |
|
tdt |
|
|
r |
|
|
2 |
|
|||||
|
r |
|
|
t0 |
t0 |
|
||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0 |
|
|
|
|
|
|
|
17
|
|
|
* |
|
|
|
t0 |
t0 |
2 |
|
|
|
|
I0 |
|
|
|
|
|||||
Q |
|
|
|
|
|
sin sin |
dt cos cos cos |
|
tdt |
||
|
r |
|
|
2 |
|
||||||
|
|
|
|
t0 |
t0 |
|
|||||
|
|
|
r |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||
|
|
|
0 |
|
|
|
|
|
|
|
|
sin sin |
t0dt |
2t |
0 |
sin sin |
|
cos axdx 1 sin ax |
|||||||||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
a |
|
|
|
|
||||
|
|
|
|
|
t0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||
t0 |
2 |
|
|
|
|
|
|
|
|
|
2 |
|
|
|
|
2 |
|
|
|
|
|
2 |
|
|
|
|
|
|
|||
cos |
|
dt |
|
|
sin |
|
|
|
t0 |
sin |
|
t0 |
2 |
|
sin |
|
t0 |
|
|
|
|
|
|||||||||
|
|
|
|
|
|
2 |
|
|
|
|
|
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
||||||||||||||||||||||||
t0 |
|
|
|
2 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
||||
|
Q |
|
2I0* |
t |
|
sin sin |
|
|
cos cos sin |
2 |
t |
|
|
|
|||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||||||||
|
|
r |
|
|
2 |
0 |
|
2 |
|
0 |
|
|
|||||||||||||||||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||||||||
|
|
|
|
r |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|||||
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Calculation made from this formula allowed obtaining following distribution of the insolation over the globe.
18
19
The Q values in summer of the Southern hemisphere are bigger than corresponding values for the Northern hemisphere. This is due to the Earth is close to its orbit aphelion during the Northern hemisphere mid-summer (the distance from the Sun is about 1.52*10 8 km), while at the midsummer
of the Southern hemisphere the Earth is close to its orbit perihelion (the distance from the Sun is about 1.47 * 10 8 km).
Because of the eccentricity e the seasons duration at Southern hemisphere is different from that of Northern hemisphere. Therefore, mean diurnal insolation values at Northern hemisphere differ from those of Southern hemisphere.
In summer, the Southern hemisphere atmosphere top receives a bit more radiation than that in Northern hemisphere. In winter, one can observe the vice versa.
20
21