scholarly journals Association of Supergranule Mean Scales with Solar Cycle Strengths and Total Solar Irradiance

2017 ◽  
Vol 844 (1) ◽  
pp. 24 ◽  
Author(s):  
Sudip Mandal ◽  
Subhamoy Chatterjee ◽  
Dipankar Banerjee
Keyword(s):  
Solar Cycle ◽  
Solar Irradiance ◽  
Total Solar Irradiance

Solar Irradiance: Instrument-Based Advances

2018 ◽  
Vol 14 (A30) ◽  
pp. 354-357
Author(s):  
Greg Kopp
Keyword(s):  
Solar Cycle ◽  
Solar Flares ◽  
Solar Irradiance ◽  
Large Scale ◽  
Total Solar Irradiance ◽  
Climate Forcing ◽  
Solar Cycles ◽  
Climate Stability ◽  
Measurement Results ◽  
Measuring Space

AbstractVariations of the total solar irradiance (TSI) over long periods of time provide natural Earth-climate forcing and are thus important to monitor. Variations over a solar cycle are at the 0.1 % level. Variations on multi-decadal to century timescales are (fortunately for our climate stability) very small, which drives the need for highly-accurate and stable measurements over correspondingly long periods of time to discern any such irradiance changes. Advances to TSI-measuring space-borne instruments are approaching the desired climate-driven measurement accuracies and on-orbit stabilities. I present a summary of the modern-instrument improvements enabling these measurements and present some of the solar-variability measurement results from recent space-borne instruments, including TSI variations on timescales from solar flares and large-scale convection to solar cycles.

Variations in total solar irradiance during solar cycle 22

1996 ◽  
Vol 101 (A6) ◽  
pp. 13541-13548 ◽  
Author(s):  
G. A. Chapman ◽  
A. M. Cookson ◽  
J. J. Dobias
Keyword(s):  
Solar Cycle ◽  
Solar Irradiance ◽  
Total Solar Irradiance

scholarly journals Stratospheric Temperature and Radiative Forcing Response to 11-Year Solar Cycle Changes in Irradiance and Ozone

2009 ◽  
Vol 66 (8) ◽  
pp. 2402-2417 ◽  
Author(s):  
L. J. Gray ◽  
S. T. Rumbold ◽  
K. P. Shine
Keyword(s):  
Solar Cycle ◽  
Solar Irradiance ◽  
Radiative Forcing ◽  
Temperature Response ◽  
Total Solar Irradiance ◽  
Stratospheric Temperature ◽  
Simple Scaling ◽  
Microwave Sounding ◽  
The Difference ◽  
Spectrally Resolved

Abstract The 11-yr solar cycle temperature response to spectrally resolved solar irradiance changes and associated ozone changes is calculated using a fixed dynamical heating (FDH) model. Imposed ozone changes are from satellite observations, in contrast to some earlier studies. A maximum of 1.6 K is found in the equatorial upper stratosphere and a secondary maximum of 0.4 K in the equatorial lower stratosphere, forming a double peak in the vertical. The upper maximum is primarily due to the irradiance changes while the lower maximum is due to the imposed ozone changes. The results compare well with analyses using the 40-yr ECMWF Re-Analysis (ERA-40) and NCEP/NCAR datasets. The equatorial lower stratospheric structure is reproduced even though, by definition, the FDH calculations exclude dynamically driven temperature changes, suggesting an important role for an indirect dynamical effect through ozone redistribution. The results also suggest that differences between the Stratospheric Sounding Unit (SSU)/Microwave Sounding Unit (MSU) and ERA-40 estimates of the solar cycle signal can be explained by the poor vertical resolution of the SSU/MSU measurements. The adjusted radiative forcing of climate change is also investigated. The forcing due to irradiance changes was 0.14 W m−2, which is only 78% of the value obtained by employing the standard method of simple scaling of the total solar irradiance (TSI) change. The difference arises because much of the change in TSI is at wavelengths where ozone absorbs strongly. The forcing due to the ozone change was only 0.004 W m−2 owing to strong compensation between negative shortwave and positive longwave forcings.

scholarly journals Modelling solar irradiance from ground-based photometric observations

2020 ◽  
Vol 10 ◽  
pp. 45 ◽  
Author(s):  
Theodosios Chatzistergos ◽  
Ilaria Ermolli ◽  
Fabrizio Giorgi ◽  
Natalie A. Krivova ◽  
Cosmin Constantin Puiu
Keyword(s):  
Solar Cycle ◽  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Visible Range ◽  
Solar Cycles ◽  
Term Trend ◽  
Photometric Observations ◽  
San Fernando ◽  
Long Term Trend

Total solar irradiance (TSI) has been monitored from space since 1978, i.e. for about four solar cycles. The measurements show a prominent variability in phase with the solar cycle, as well as fluctuations on timescales shorter than a few days. However, the measurements were done by multiple and usually relatively short-lived missions. The different absolute calibrations of the individual instruments and the unaccounted for instrumental trends make estimates of the possible long-term trend in the TSI highly uncertain. Furthermore, both the variability and the uncertainty are strongly wavelength-dependent. While the variability in the UV irradiance is clearly in-phase with the solar cycle, the phase of the variability in the visible range has been debated. In this paper, we aim at getting an insight into the long-term trend of TSI since 1996 and the phase of the solar irradiance variations in the visible part of the spectrum. We use independent ground-based full-disc photometric observations in Ca II K and continuum from the Rome and San Fernando observatories to compute the TSI since 1996. We follow the empirical San Fernando approach based on the photometric sum index. We find a weak declining trend in the TSI of $ {-7.8}_{-0.8}^{+4.9}\times 1{0}^{-3}$ Wm−2 y−1 between the 1996 and 2008 activity minima, while between 2008 and 2019 the reconstructed TSI shows no trend to a marginally decreasing (but statistically insignificant) trend of $ {-0.1}_{-0.02}^{+0.25}\times 1{0}^{-3}$ Wm−2 y−1. The reference TSI series used for the reconstruction does not significantly affect the determined trend. The variation in the blue continuum (409.2 nm) is rather flat, while the variation in the red continuum (607.1 nm) is marginally in anti-phase, although this result is extremely sensitive to the accurate assessment of the quiet Sun level in the images. These results provide further insights into the long-term variation of the TSI. The amplitude of the variations in the visible is below the uncertainties of the processing, which prevents an assessment of the phase of the variations.

scholarly journals Revisiting the Question: The Cause of the Solar Cycle Variation of Total Solar Irradiance

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
N. B. Xiang
Keyword(s):  
Time Series ◽  
Solar Cycle ◽  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Sunspot Area ◽  
Wavelet Coherence ◽  
Solar Cycle Variation ◽  
Cycle Variation ◽  
Magnetic Features

The Mg II index and sunspot area are usually used to represent the intensification contribution by solar bright structures to total solar irradiance (TSI) and sunspot darkening, respectively. In order to understand the cause of the solar cycle variation of TSI, we use extension of wavelet transform, wavelet coherence (WTC), and partial wavelet coherence (PWC), to revisit this issue. The WTC of TSI with sunspot area shows that the two time series are very coherent on timescales of one solar cycle, but the PWC of TSI with sunspot area, which can find the results of WTC after eliminating the effect of the Mg II index, indicates that the solar cycle variation of TSI is not related to sunspots on the solar surface. The coherence of two time series at these timescales should be due to a particular phase relation between sunspots and TSI. The WTC and PWC of TSI with Mg II index show that the solar cycle variation of TSI is highly related to Mg II index, which reflects the relation of TSI with the long-term part of Mg II index that shows the intensification contribution by the small magnetic features to TSI. Consequently, the solar cycle variation of TSI is dominated by the small magnetic features on the solar full disk. Additionally, we also show the combined effects of the sunspot darkening and the intensification contribution represented by Mg II index to TSI on timescales of a few days to several months and indicate that the faculae increase TSI and contribute to its variation at these timescales.

The Fengyun-3E/Joint Total Solar Irradiance Absolute Radiometer: Instrument Design, Characterization, and Calibration

Solar Physics ◽  
2021 ◽  
Vol 296 (3) ◽  
Author(s):  
Baoqi Song ◽  
Xin Ye ◽  
Wolfgang Finsterle ◽  
Manfred Gyo ◽  
Matthias Gander ◽  
...  
Keyword(s):  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Instrument Design

Long-term variations in total solar irradiance

Solar Physics ◽  
1994 ◽  
Vol 152 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Judit M. Pap ◽  
Richard C. Willson ◽  
Claus Fr�hlich ◽  
Richard F. Donnelly ◽  
Larry Puga
Keyword(s):  
Solar Irradiance ◽  
Total Solar Irradiance ◽  
Long Term Variations

scholarly journals Stellar activity, differential rotation, and exoplanets

2010 ◽  
Vol 6 (S273) ◽  
pp. 89-95 ◽  
Author(s):  
A. F. Lanza
Keyword(s):  
Time Series ◽  
Differential Rotation ◽  
Solar Irradiance ◽  
Giant Planet ◽  
Total Solar Irradiance ◽  
Short Term ◽  
Stellar Activity ◽  
Transiting Planets ◽  
Spot Model ◽  
Spot Activity

AbstractThe photospheric spot activity of some of the stars with transiting planets discovered by the CoRoT space experiment is reviewed. Their out-of-transit light modulations are fitted by a spot model previously tested with the total solar irradiance variations. This approach allows us to study the longitude distribution of the spotted area and its variations versus time during the five months of a typical CoRoT time series. The migration of the spots in longitude provides a lower limit for the surface differential rotation, while the variation of the total spotted area can be used to search for short-term cycles akin the solar Rieger cycles. The possible impact of a close-in giant planet on stellar activity is also discussed.

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