Sentences with phrase «irradiance variations in»

Krivova, N. A., Solanki, S. K., Fligge, A. & Unruh, Y. C. Reconstruction of solar irradiance variations in cycle 23: is solar surface magnetism the cause?

Tying those factors together in order to estimate solar irradiance variations in the past is crucial for attributing past climate changes, particularly in the pre-industrial.

Not exact matches

11 Duration, in years, of a typical solar cycle, natural variations in the number of sunspots and flares that affect solar irradiance levels on Earth.

The «equilibrium» sensitivity of the global surface temperature to solar irradiance variations, which is calculated simply by dividing the absolute temperature on the earth's surface (288K) by the solar constant (1365Wm - 2), is based on the assumption that the climate response is linear in the whole temperature band starting at the zero point.

On the other hand, Esper's data appear to be in close agreement with variations in cosmogenic isotopes whose production rates are indicators of variation in solar irradiance, and thus, global temperatures on Earth.

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.

Flood layer frequency in the Ammersee sediment record depicts distinct multi-decadal variations and significant correlations to a total solar irradiance reconstruction (r = − 0.4, p < 0.0001) and 14C production rates (r = 0.37, p < 0.0001), reflecting changes in solar activity.

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.

Important manifestations of such external forcing from space to the atmosphere are the variations in different solar parameters such as the solar irradiance (including solar UV) and solar particle fluxes, which can induce changes in the atmosphere both at local and global scales, and can influence over a large range of altitudes.

Changes in insolation are also thought to have arisen from small variations in solar irradiance, although both timing and magnitude of past solar radiation fluctuations are highly uncertain (see Chapters 2 and 6; Lean et al., 2002; Gray et al., 2005; Foukal et al., 2006).

Jim Cross (268)-- Somewhere I came across a paper showing that variations in solar irradiance proxies, sunspots and Be10, for other than the sunspot pseudoperiodic «cycle», are best explained as random events.

We only have direct observations of total solar irradiance (TSI) since the beginning of the satellite era and substantial evidence for variations in the level of solar activity (from cosmogenic isotopes or sunspot records) in the past.

While the later is useful, as it is all that we have earlier than 1978 or so, direct measurements of irradiance show that the variation is at best 1 part in 1300 over the last forty or so years

In the May issue of Astronomy & Astrophysics, Shapiro et al. present a new long - term reconstruction of the solar irradiance that implies much greater variation over the last 7000 years than any previous ly reconstruction.

See e.g. this review paper (Schmidt et al, 2004), where the response of a climate model to estimated past changes in natural forcing due to solar irradiance variations and explosive volcanic eruptions, is shown to match the spatial pattern of reconstructed temperature changes during the «Little Ice Age» (which includes enhanced cooling in certain regions such as Europe).

Recent sun - cloud connections have a decreasing correlation with CRF, but a good correlation between (low) clouds and solar irradiance, see figure 1 in http://folk.uio.no/jegill/papers/2002GL015646.pdf Also in the 6 May 2005 Science, there is an article which finds a long - term link between solar intensity (based on 14C variations) and monsoon intensity over the past 9000 years...

[Response: In the 19 models studied in Santer et al (2005)(Table 1), 11 models have historical variations in solar irradiance, 7 don't, and one was uncertaiIn the 19 models studied in Santer et al (2005)(Table 1), 11 models have historical variations in solar irradiance, 7 don't, and one was uncertaiin Santer et al (2005)(Table 1), 11 models have historical variations in solar irradiance, 7 don't, and one was uncertaiin solar irradiance, 7 don't, and one was uncertain.

The IPCC 2001 report states «Several recent reconstructions estimate that variations in solar irradiance give rise to a forcing at the Earth's surface of about 0.6 to 0.7 Wm - 2 since the Maunder Minimum and about half this over the 20th century... All reconstructions indicate that the direct effect of variations in solar forcing over the 20th century was about 20 to 25 % of the change in forcing due to increases in the well - mixed greenhouse gases.»

Title: «Shortwave forcing of the Earth's climate: Modern and historical variations in the Sun's irradiance and Earth's reflectance» Author, P.R. Goode, E. Pallé Journal: Journal of ATMOSPHERIC and SOLAR - TERRESTRIAL PHYSICS DoP: Sept 2007 DOI: 10.1016 / j.jastp.2007.06.011

The clear seasonal pattern in generation rates reflects variation in solar irradiance, which is higher in the summer and lower in the winter.

Increasing CO2 does increase the greenhouse effect, but there are other factors which determine climate, including solar irradiance, volcanism, albedo, orbital variations, continental drift, mountain building, variations in sea currents, changes in greenhouse gases, even cometary impacts.

When reconstructing Earth's climate history, it can't be explained without including all the various influences, including solar irradiance, volcanism, albedo, orbital variations, continental drift, mountain building, variations in sea currents, changes in greenhouse gases, even cometary impacts.

CO2 concentrations are meaningless — it's water in all it's phases reacting to variations in solar irradiance brought on by various solar cycles and orbital cycles that controls climate — PERIOD!

However, it is not the variation in the TSI (total solar irradiance) which is causing the change.

The Holy Grail of climatology has always been to ascertain whether, and if so how, the sun might affect the Earth's energy budget to cause the climate swings observed throughout history despite the apparent inadequacy of the tiny variations in Total Solar Irradiance (TSI) that occur from one series of solar cycles to another.

These warming trends are consistent with the response to increasing greenhouse gases and sulphate aerosols and likely can not be explained by natural internal climate variations or the response to changes in natural external forcing (solar irradiance and volcanoes).

Oceanic oscillations are sufficient to cancel out or enhance the effects of natural variations in solar irradiance or other forms of solar input to the heat budget of the Earth for variable periods of time.

«Holocene Climatic Change, 14c Wiggles and Variations in Solar Irradiance.»

The solar effect on climate has been discounted by the climate modellers because the variation in total solar irradiance...

Whatever wide - ranging coherence one finds at multi-decadal frequencies is more likely the result of global - scale variations in cloud - regulated thermalization of solar irradiance and the lagged advection of heat from the tropics by winds and ocean currents.

A third example would be the research on how incoming solar irradiance influences China's thermometer temperature records, showing that over periods of many decades the variations in total solar irradiance in the upper atmosphere are matched by variations at the surface.

These include solar - related chemical - based UV irradiance - related variations in stratospheric temperatures and galactic cosmic ray - related changes in cloud cover and surface temperatures, as well as ocean oscillations, such as the Pacific Decadal Oscillation and the North Atlantic Oscillation that significant affect the climate.

Parsimony is not a grounds for ignoring the now mountain of evidence that solar activity does somehow drive climate much more powerfully than can be explained by the tiny variation in solar irradiance, and the implications of a solar explanation for 20th century warming are much different than for an internal - variation explanation.

This high climate sensitivity is not alone due to variations in total solar irradiance - related direct solar forcing, but also due to additional, so - called indirect solar forcings.

«Since irradiance variations are apparently minimal, changes in the Earth's climate that seem to be associated with changes in the level of solar activity — the Maunder Minimum and the Little Ice age for example — would then seem to be due to terrestrial responses to more subtle changes in the Sun's spectrum of radiative output.

Soon, W., 2005: Variable solar irradiance as a plausible agent for multidecadal variations in the Arctic - wide surface air temperature record of the past 130 years, Geophysical Research Letters32: doi.10.1029 / 2005GL023429.

Regarding your statement, «Perhaps it is known that the natural variations in surface temperature are all due to unforced mechanisms, otherwise it is simply an assertion», I assume by «natural variations» you mean ENSO, PDO, AMO, etc., because obviously natural changes in solar irradiance or volcanic aerosols are recognized as forcing mechanisms.

Shortwave forcing of the Earth's climate: modern and historical variations in the Sun's irradiance and the Earth's reflectance, P.R. Goode, E. Palle, J. Atm.

We also show that a non-thermal solar component is necessarily present, indicating that the total solar contribution to the 20th century global warming, of ∆ Tsolar = 0.27 ± 0.07 ◦ C, is much larger than can be expected from variation in the total solar irradiance alone.

In the summary of Chapter 7, one can read that the effects of variation in solar radiation are negligible You seem to miss the whole point.: «The Chapter 7 authors are admitting strong evidence («many empirical relationships») for enhanced solar forcing (forcing beyond total solar irradiance, or TSI), even if they don't know what the mechanism is.&raquIn the summary of Chapter 7, one can read that the effects of variation in solar radiation are negligible You seem to miss the whole point.: «The Chapter 7 authors are admitting strong evidence («many empirical relationships») for enhanced solar forcing (forcing beyond total solar irradiance, or TSI), even if they don't know what the mechanism is.&raquin solar radiation are negligible You seem to miss the whole point.: «The Chapter 7 authors are admitting strong evidence («many empirical relationships») for enhanced solar forcing (forcing beyond total solar irradiance, or TSI), even if they don't know what the mechanism is.»

There could also be other unknown mechanisms driven by solar changes that exaggerate the effect of small variations in total solar irradiance.

«Over the 11 - year solar cycle, small changes in the total solar irradiance (TSI) give rise to small variations in the global energy budget.

Second, their temperature reconstructions were not based exclusively on TSI changes as the sole source of temperature variation, but included associated changes in spectral irradiance that would be expected to amplify TSI effects, changes in UV being one example.

Shortwave forcing of the earth's climate: Modern and historical variations in the sun's irradiance and the earth's reflectance.

In order to reliably interpret surface temperature variations we need a good idea of all the causal factors, including El Niño, solar irradiance, volcanic eruptions, observational biases, changes in ocean circulation and possible long term oscillationIn order to reliably interpret surface temperature variations we need a good idea of all the causal factors, including El Niño, solar irradiance, volcanic eruptions, observational biases, changes in ocean circulation and possible long term oscillationin ocean circulation and possible long term oscillations.

We conclude that variations in mean zonal winds are modulated by the solar activity cycle through variations in irradiance, solar wind or cosmic ray intensity.

Sceptical scientists and climate realists, contest natural variation; solar magnetic effects, volcanic eruptions, solar irradiance, ozone depletion, ocean currents PDO / AMO, clouds, all play a much more significant role in the climate system.

Although we focus on a hypothesized CR - cloud connection, we note that it is difficult to separate changes in the CR flux from accompanying variations in solar irradiance and the solar wind, for which numerous causal links to climate have also been proposed, including: the influence of UV spectral irradiance on stratospheric heating and dynamic stratosphere - troposphere links (Haigh 1996); UV irradiance and radiative damage to phytoplankton influencing the release of volatile precursor compounds which form sulphate aerosols over ocean environments (Kniveton et al. 2003); an amplification of total solar irradiance (TSI) variations by the addition of energy in cloud - free regions enhancing tropospheric circulation features (Meehl et al. 2008; Roy & Haigh 2010); numerous solar - related influences (including solar wind inputs) to the properties of the global electric circuit (GEC) and associated microphysical cloud changes (Tinsley 2008).

http://www.agci.org/docs/lean.pdf «Global (and regional) surface temperature fluctuations in the past 120 years reflect, as in the space era, a combination of solar, volcanic, ENSO, and anthropogenic influences, with relative contributions shown in Figure 6.22 The adopted solar brightness changes in this scenario are based on a solar surface flux transport model; although long - term changes are «50 % larger than the 11 - year irradiance cycle, they are significantly smaller than the original estimates based on variations in Sun - like stars and geomagnetic activity.

Just how effective this driver is has remained relatively uncertain, however, partly due to missing knowledge on the exact variation of the Sun's irradiance over time in different parts of the solar spectrum.