The solar radiation is 63 Megawatts/m2
on the surface of the Sun. On the energy emitted by the
Sun it comes perpendicularly on average at the top of the
atmosphere between the Equator and the tropics 1368.W/m2.
Therefore in overall average the energy received
on the top of the atmosphere of the Earth is 1368/4.W/m2,
342.W/m2. This value
is modulated annually by variation of the Earth-Sun distance
(elliptic orbit of the Earth). The maximum value of the
solar radiation is approximately 1415 W/m² at the winter
solstice in January and the minimum value of 1326 W/m²
at the summer solstice is in June (we must add an uncertainty
of 10 W/m²).
The Sun knows four types
of activities that are more or less significant depending
on the duration of this activity. The variations in solar
activity have been studied according to the analysis of C14
(carbone 14). This isotope is formed by the action of cosmic
rays on atmospheric nitrogen. The more the Sun is active the
more the solar wind prevents these cosmic
rays to enter the Earth's atmosphere. Therefore
This solar cycle lasting
from 8 to 13 years for an average of 11 years is the best
known of the four variations of solar activity. The amateur,
Heinrich Schwabe (1789-1875) discovered this cycle by observing
the appearance of sunspots. With
satellites astronomers were able to directly measure the flow
of energy emitted by the Sun during the most recent cycles.
The flux decreases to 0,10.%
between the maximum and minimum of this cycle.
But this solar activity is more or less significant depending
on the three other solar cycles.
As shown in the diagram
below the temperature evolution follows the evolution of the
solar constant. From 1645 to 1715, during the Maunder minimum,
both the solar constant as the temperature was low. The solar
constant had dropped by 0,25.%.
This it is reproduced from 1795 to 1830 during the Dalton
The evolution from 1611 to 1980 of the
solar constant and the temperature of the
northern hemisphere according to the average of 1960-1990
average. NOAA data.
We find the same result with the number of
sunspots which is a good indicator for this solar cycle as
you can see by comparing the above diagram with that of below.
This cycle with a duration
of 80 to 90 years was discovered by Gleissberg in 1958. It
has effects on the amplitude of the 11-years schwabe solar
cycle. However, the ten-year
cycles only being identified over a period of three centuries
by using the sunspots, accurate extraction of this period
presents some difficulties. This is why other data are used
(carbone 14). This period was also found in the secular variation
of the solar diameter. Evaluating minimums and maximums eras
per Gleissberg was based on data of auroral activity (Schove,
1955). The Gleissberg maximum around 1984 is the first in
a long sequence of maximum associated with zero phase in the
cycle of 166 years. Next Gleissberg the maximums should occur
around 2069, 2159 and 2235.
OR VRIES CYCLE
The data of the carbon
14 concentration also indicate a period of about 150-200 years.
Date of beginning
and end of Oort, Wolf, Spörer, Maunder and Dalton minimums
The dates of Oort,
Wolf, Spörer, Maunder and Dalton Minimum, presented in
the table above, suggest a periodicity of the order of about
one to two centuries.. It leads to variability in the amplitude
of the cycle of Schawbe, for example when comparing the solar
cycle of 1715 with that of 1958.
The red curve
represents the evolution of the temperature according to the
average of 1960-1990 and the blue curve
the solar constant from 843 to 1980
This must have links with
the rotation of the gaseous planets which have an effect on
the variation of the speed of the momentum of the Sun around
the barycenter of the solar system as explained further in
CAUSE OF LONG CYCLES.
This period was found in the analysis
of carbon-14 concentration and climate data. Its origin
isn't elucidated. Some think it is of solar origin, others
believe that it is a natural mode of oscillation of the
ocean-atmosphere system. This cycle would be a period of
2.300 years and its maximum
should be reached around the year 2.800
and the next minimum around 3.950.
Variation of hallstattzeit Solar cycle
according to the evolution
of carbon 14 and deleting Gleissberg and Suess cycles
(Damon and Sonett, 1991)
EVOLUTION OF THE ROTATION
AND THE DIAMETER OF THE SUN
EVOLUTION OF THE SOLAR DIAMETER
The Sun has an oscillation of the diameter
of amplitude of 0,5 arc second with a period of about 900
days or 27 months of the same phase.
But following solar activity this oscillation
is more or less important. When solar activity is at its maximum
the oscillation of its diameter is less significant than whether
solar activity is at a minimum. What makes the variation of
the diameter of the Sun varies opposite to the variation of
solar activity as shown in the diagram below.
Variation of the solar diameter and
solar activity from 1978 to 1998. Solar activity
is represented by the number of sunspots (in
red). The variation of the semi-diameter
of the sun in arc second is represented by the blue
circles. The oscillation of
diameter has a anti-correlation with the 11-years cycle. (F.
Mouton (1659-1661), Picard and Richer (1666-1672)
and La Hire (1683-1718) and his son (1719) were among the
first to measure the diameter of the sun depending on the
day of the year and also according to solar eclipses. Ribes
et al. (1987) examined again in 1987 the data with the withdrawal
of the variation of the solar diameter depending on the Earth-Sun
distance according to the seasons and they concluded that
measures of Picard and La Hire are similar. By comparing the
values achieved from 1666 to 1719 we find that during the
Maunder Minimum the semi-diameter of the Sun was bigger approximately
0,5 arcsecond compared to the end of the Maunder Minimum.
Because during the Maunder Minimum (1683) the Sun had a semi-diameter
of 962,5 arcseconds against a semi-diameter of 961,78 arcseconds
at the end of Maunder Minimum in 1715. And according to the
data recorded by the European satellite Picard during his
mission from 06/15/2010 until 04/04/2014, now that the Sun
has an even stronger activity, his semi-diameter is smaller
as it oscillates between 959,2 and 959,8 arcseconds during
the 11-years cycle (150 km). A difference of about 3 arcseconds
compared to the Maunder Minimum, representing 2,000.km
more than the current value of the average diameter.
Variation of the solar diameter, 1860-1940.
maximum of sunspots. (From ASO-X6 in The Sun and Solar System
The variation in the diameter of the Sun causes
the variation of the solar constant. That is what exactly
has an effect on the climate as it affects the thermal
and dynamic structure of the stratosphere that after
causes changes in the troposphere and thus a slight
variation of the temperature of the Earth.
According to the equation W=(DR/R)/(DS/S)
where there is the solar radius (R) and the solar constant
(S) can be calculated relative change ratio of R and
S. Following that W=0,2. According to measurements
of the solar diameter during the Maunder Minimum, which
had varied about 1 arcsecond it can be inferred that
the solar constant the solar constant was lower of 3,5W/m2.
And this is the reason why there is a variation in contrast
between the temperature and the diameter of the Sun
as shown in the diagram to the right.
Temperature anomalies and evolution of the solar
radius from 1650 to 1990 (data of Jones and al., 1999)
as a function of time. Over 300 years, the climate trend
correlates with the evolution of the solar ray.
EVOLUTION OF ROTATION OF THE SUN ON ITSELF
In addition to this variation, the differential
rotation of the Sun on itself follows the evolution of the
oscillation of the diameter of the Sun. The observation of
the movement of sunspots since the early 17th centuries
allowed to follow the evolution of its diameter during the
last four centuries.
During the Maunder minimum either when solar
activity was very low and the Sun's diameter was bigger that
currently, the speed of rotation was 3% lower than the current
speed. Furthermore, the observation of sunspots during the
last centuries was used to assess the differential rotation.
It observed around the Maunder minimum, when there were sunspots,
was more pronounced that currently due to a latitudinal gradient
of speed greater than now.
In addition to changing the diameter and
differential rotation of the Sun on itself according to solar
activity, the luminosity also varies. During the low active
period of the Sun therefore to the Maunder Minimum it is estimated
that its luminosity had declined between 0,2 and 0,3%.
Régnier helped me correct mistakes, please you to
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