Sentences with phrase «solar irradiance variability»
We assert that the amount of magnetic energy that remains present (de Wijn et al. 2009) at the surface of a spotless (i.e. quiet) Sun is the main driver of solar irradiance variability on centennial time scales.
https://www.aanda.org/
Magnetic field indices derived from synoptic magnetograms of the Mt. Wilson Observatory, i.e. Magnetic Plage Strength Index (MPSI) and Mt. Wilson Sunspot Index (MWSI), are used to study the effects of surface magnetism on total solar irradiance variability during solar cycles 21, 22 and 23.
The choice of the model for the minimum state of the Sun is a crucial point in our technique because it defines the amplitude of the reconstructed solar irradiance variability.
Citation: Soon, W.H., E.S. Posmentier, and S.L. Baliunas, 1996: Inference of solar irradiance variability from terrestrial temperature changes, 1880 - 1993: An astrophysical application of the Sun - climate connection.
«The forcings for ECHO - G are selected in advance by (1) choosing the strength and time series of solar irradiance variability; (2) choosing the strength and time series of volcanic aerosol variability and converting this to a surrogate time series of solar irradiance reductions, which are then added to (1); and (3) choosing the time series of greenhouse gas concentrations.
No matter how you mirror it, solar irradiance variability has long been one of the unhottest fronts of the Climate Wars because:
«Long - Term Solar Irradiance Variability During Sunspot Cycle 22.»
from «Magnitudes and Timescales of Total Solar Irradiance Variability,» by Greg Kopp.
Jo's scientific interests include radiative transfer in the atmosphere, climate modelling, radiative forcing of climate change and the influence of solar irradiance variability on climate.
Not exact matches
The solar UV irradiance from the thermosphere of Saturn and the solar wind are the most probable sources to account for the long - term variability of the electron radiation belts (Roussos et al. 2014), suggesting that external drivers play indeed an important role in Saturn's magnetospheric dynamics.
The authors also note that they chose a reconstruction with high variability in solar irradiance, so if anything they may have overestimated the natural contribution to the observed warming.
«Even for a reconstruction with high variability in total irradiance, solar forcing contributed only about 0.07 °C (0.03 - 0.13 °C) to the warming since 1950.»
Current understanding of solar physics and the known sources of irradiance variability suggest comparable irradiance levels during the past two solar cycles, including at solar minima.
Typhoon variability was likely modulated further by the state of the East Asia summer monsoon (EASM) pattern, associated with variation in the magnitude of solar irradiance.
Contributions from the following topics (but not exclusively) are invited: • Solar irradiance and energetic particle impacts on the atmosphere • Upper atmospheric dynamical variability and coupling between atmospheric layers • Solar variations and stratosphere - troposphere coupling • Solar influence on climate variability • Solar irradiance (spectral and total irradiance) variations
As examples of work in this category, I would mention Judith Lean's tireless efforts on relating luminosity to sunspot number, the work of Bard and colleagues on developing isotopic solar proxies like 10Be, Shindell's work on response to solar ultraviolet variability, and the work of Foukal et al on factors governing solar irradiance variations.
Recent reduced solar irradiance (Fig. 7) may have decreased the forcing over the past decade by about half of the full amplitude of measured irradiance variability, thus yielding a negative forcing of, say, − 0.12 W / m2.
Thus it appears that, provided further satellite cloud data confirms the cosmic ray flux low cloud seeding hypothesis, and no other factors were involved over the past 150 years (e.g., variability of other cloud layers) then there is a potential for solar activity induced changes in cloudiness and irradiance to account for a significant part of the global warming experienced during the 20th century, with the possible exception of the last two decades.
Current understanding of solar physics and the known sources of irradiance variability suggest comparable irradiance levels during the past two solar cycles, including at solar minima.
... we strongly support Delworth and Knutson's (2000) contention that this high - latitude warming event represents primarily natural variability within the climate system, rather than being caused primarily by external forcings, whether solar forcing alone (Thejll and Lassen, 2000) or a combination of increasing solar irradiance, increasing anthropogenic trace gases, and decreasing volcanic aerosols.
Egorova, T., E. Rozanov, E. Manzini, M. Haberreiter, W. Schmutz, V. Zubov, and T. Peter, 2004: Chemical and dynamical response to the 11 - year variability of the solar irradiance simulated with a chemistry - climate model, Geophys.
This is in contrast to externally forced variability in global mean surface temperature which arises due to changes in atmospheric greenhouse gasses, aerosols, solar irradiance, ect.
Since the solar UV irradiance has no long - term trend, the mechanism for the secular change of TSI must differ from the effect of surface magnetism, as manifested by sunspots, faculae, and network which indeed explain well the intra-cycle variability of both total and spectral irradiance.
If Northern Hemisphere temperatures have been in an overall cooling trend for two millennia due to «orbital forcing» (i.e. reduced solar irradiance), then the burden of proof becomes greater on those who attribute the warmth of recent decades to solar variability rather than rising greenhouse gas concentrations.
The temperature trend since 1998 is understood to result from natural climate variability, combined with reduced solar irradiance during the downward part of the solar cycle after its 2001 maximum.
The field has long been plagued by the lack of an acceptable physical mechanism by which solar variability can affect climate, but the discovery of variability in the Sun's total irradiance (the solar «constant» of meteorology) by spacecraft instruments has pointed to a direct mechanism.
Research suggests that solar variability accounts for up to 68 % of the increase in earths temperatures with strong association between solar sunspots / irradiance and global temperature fluctuations.
Further, our temperature reconstructions, within age uncertainty, can be well correlated with solar irradiance changes, suggesting a possible link between solar forcing and natural climate variability, at least on the northern Tibetan Plateau.»
«From what I can tell, the list was compiled mostly from reviewed scientific articles in which authors proposed or identified various sources of natural variability in climate; in my case solar irradiance and cosmic ray flux.
The response of atmospheric CO2 and climate to the reconstructed variability in solar irradiance and radiative forcing by volcanoes over the last millennium is examined by applying a coupled physical — biogeochemical climate model that includes the Lund - Potsdam - Jena dynamic global vegetation model (LPJ - DGVM) and a simplified analogue of a coupled atmosphere — ocean general circulation model.
Global solar irradiance reconstruction [48 — 50] and ice - core based sulfate (SO4) influx in the Northern Hemisphere [51] from volcanic activity (a); mean annual temperature (MAT) reconstructions for the Northern Hemisphere [52], North America [29], and the American Southwest * expressed as anomalies based on 1961 — 1990 temperature averages (b); changes in ENSO - related variability based on El Junco diatom record [41], oxygen isotopes records from Palmyra [42], and the unified ENSO proxy [UEP; 23](c); changes in PDSI variability for the American Southwest (d), and changes in winter precipitation variability as simulated by CESM model ensembles 2 to 5 [43].
The solar irradiance averaged over the earth averaged over the year doesn't change with orbital variability.
Recent reduced solar irradiance (Fig. 7) may have decreased the forcing over the past decade by about half of the full amplitude of measured irradiance variability, thus yielding a negative forcing of, say, − 0.12 W / m2.
The 11 - year averaging period minimizes the effect of variability due to the 10 — 12 year periodicity of solar irradiance as well as irregular El Niño / La Niña warming / cooling in the tropical Pacific Ocean.
Phase relationships between hemispheric and global climate reconstructions from tree - rings and the solar irradiance time series indicate a lag of ~ 10 years (range, 5 - 20 years), with solar changes leading temperature anomalies, consistent with both climate modeling and other climate and solar variability studies (Eichler et al., 2009; Breitenmoser et al., 2012; Anchukaitis et al., 2017).
Harder, J. W., Fontenla, J. M., Pilewskie, P., Richard, E. C. & Woods, T. N. Trends in solar spectral irradiance variability in the visible and infrared.
Shapiro et al. (2011) and Judge et al. (2012) proposed TSI models based a comparison between solar irradiance reconstructions and sun - like - stellar data that show a TSI secular variability at least 3 - to - 6 times greater than Lean's TSI proxy.
Interdecadal 20th century temperature deviations, such as the accelerated observed 1910 — 1940 warming that has been attributed to an unverifiable increase in solar irradiance (4, 7, 19, 20), appear to instead be due to natural variability.
One more: «Interdecadal 20th century temperature deviations, such as the accelerated observed 1910 — 1940 warming that has been attributed to an unverifiable increase in solar irradiance (4, 7, 19, 20), appear to instead be due to natural variability.
The authors also note that they chose a reconstruction with high variability in solar irradiance, so if anything they may have overestimated the natural contribution to the observed warming.
«Even for a reconstruction with high variability in total irradiance, solar forcing contributed only about 0.07 °C (0.03 - 0.13 °C) to the warming since 1950.»
1992 S.L. Baliunas, et al., «Long - Term Variability of Solar Total Irradiance: Studies of Solar - Type Stars.»
DePreSys (18) takes into account the observed state of the atmosphere and ocean in order to predict internal variability, together with plausible changes in anthropogenic sources of greenhouse gases and aerosol concentrations (19) and projected changes in solar irradiance and volcanic aerosol (20).