J/ApJ/920/100 Reconstruction of solar irradiance from 1700 to 2019 (Wang+, 2021)
A New Reconstruction of the Sun Magnetic Field and Total Irradiance since 1700.
Wang Y.-M.,Lean J.L.
<Astrophys. J., 920, 100 (2021)>
=2021ApJ...920..100W 2021ApJ...920..100W
ADC_Keywords: Models; Sun; Magnetic fields
Keywords: Interplanetary magnetic fields ; Solar-terrestrial interactions ;
Solar cycle ; Solar dynamo ; Solar magnetic fields ; Solar
faculae ; Ephemeral active regions ; Solar radiation ; Sunspots
; Solar active regions ; Galactic cosmic rays
Abstract:
We model the Sun's large-scale magnetic field and total solar
irradiance (TSI) since 1700 by combining flux transport simulations
with empirical relationships between facular brightening, sunspot
darkening, and the total photospheric flux. The photospheric field is
evolved subject to the constraints that (1) the flux emergence rate
scales as the yearly sunspot numbers, and (2) the polar field strength
at solar minimum is proportional to the amplitude of the following
cycle. Simulations are performed using both the recently revised
sunspot numbers and an average of these numbers and the Hoyt- Schatten
group numbers. A decrease (increase) in the polar field strength from
one cycle to the next is simulated either by increasing (decreasing)
the poleward flow speed, or by decreasing (increasing) the average
axial tilts of active regions; the resulting photospheric field
evolution is very similar whichever parameter is varied. Comparisons
between irradiance data and both the simulated and observed
photospheric field suggest that TSI and facular brightness increase
less steeply with the field strength at solar minimum than at other
phases of the cycle, presumably because of the dominance of small-
scale ephemeral regions when activity is very low. This relative
insensitivity of the irradiance to changes in the large-scale field
during cycle minima results in a minimum-to-minimum increase of annual
TSI from 1700 to 1964 (2008) of 0.2(0.06)W/m2, a factor of 2-3
smaller than predicted in earlier reconstructions where the relation
between facular brightness and field strength was assumed to be
independent of cycle phase.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
fig17.dat 50 320 Reconstruction of TSI from 1700 to 2019
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See also:
J/A+A/625/A69 : Plage area composite series (Chatzistergos+, 2019)
J/A+A/639/A88 : Plage area composite series (Chatzistergos+, 2020)
J/A+A/640/A78 : Sunspot area catalogue revisited (1874-2019) (Mandal+, 2020)
Byte-by-byte Description of file: fig17.dat
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Bytes Format Units Label Explanations
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1- 6 F6.1 yr Year [1700/2020] Besselian year
8- 15 F8.3 W/m2 TSI1 [1360/1362] Total Solar Irradiance (1)
17- 22 F6.3 G Btot1 [0.44/21.5] Total Magnetic Flux averaged over
photosphere (1)
24- 28 F5.3 G Bopen1 [0.26/2.59] Open Magnetic Flux averaged over
photosphere (1)
30- 37 F8.3 W/m2 TSI2 [1360/1362] Total Solar Irradiance (2)
39- 44 F6.3 G Btot2 [0.57/21.8] Total Magnetic Flux averaged over
photosphere (2)
46- 50 F5.3 G Bopen2 [0.33/1.84] Open Magnetic Flux averaged over
photosphere (2)
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Note (1): For annual sunspot number calculated by an average of the SILSO and
HS values.
Note (2): For annual sunspot number based on the revised World Data Center's
Sunspot Index and Long-term Solar Observations (SILSO).
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix [CDS], 03-Mar-2023