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What is the solar influence on climate?


Nouska

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Posted
  • Location: Surrey and SW France.
  • Location: Surrey and SW France.

A look at the most recent research on solar effects on climate and moving beyond the traditional concept of TSI.

Some of this research will be of interest for the stratosphere thread.

 

http://www.progearthplanetsci.com/content/1/1/24

 

 

 

What is the importance of spectral variations to solar influences on climate?

Solar influence on climate is now accepted as an important contribution to climate variability, particularly on regional scales. Reflecting this, the main focus has moved from TSI towards understanding SSI variations and their impact as well as shifting from the global responses to more regional responses. With better understanding of SSI, the importance of the top-down stratospheric UV mechanism has been widely accepted. Improved measurements of both TSI and SSI became available leading to more reliable solar cycle variation estimates, and a new value for the solar constant (TSI) was recommended for the IPCC AR5 climate simulations.

What is the effect of energetic particle forcing on the whole atmosphere and what are the implications for climate?

Direct effects of particles to both ionisation rates and chemical changes are now better understood for EPP. Strong indirect effects were observed in the stratosphere with further potential impacts on the troposphere. More studies are required to understand the EPP indirect effects on the tropospheric and surface climate. SPE events have a large impulsive impact on polar chemistry, but simulation studies found little long-term (beyond a year) effects of statistical significance. CR provide the main source of ionisation in the troposphere with the ionisation peaking at 13 to 14 km altitude. No trend in GCR was observed in neutron monitor data in the last 50 years.

How well do models reproduce and predict solar irradiance and energetic particle influences on the atmosphere and climate?

Climate models include the TSI solar cycle, and TSI was included in the Fifth IPCC Assessment Report. New observations are urgently needed to assess the true solar cycle variation in SSI. Currently, only the so-called high-top models include solar cycle EPP variation (electron precipitation parameterisation + observed SPEs). Models are beginning to include GCR ionisation, but understanding the interactions with aerosols remains an important question. It is now recognised that both bottom-up and top-down mechanisms are needed to reproduce the observed solar signals, although many open questions still remain. Models now include better EPP ionisation rates and have improved calculations of the EPP chemical effects. In general, all processes are now better represented in models, but improvements are still needed.

It is clear that much progress was gained in all questions. However, one of the big remaining unknowns for future is how the different solar forcing terms will now develop. With some predictions suggesting a potential near future grand solar minimum and new evidence pointing to large abrupt changes in atmospheric dynamics, closely linked to regional-scale climate, associated to grand minima in the past, it is now evident that we need to better understand the role of the Sun and all forms of solar forcing on continental- and subcontinental-scale climate.

 

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Posted
  • Location: Ireland, probably South Tipperary
  • Weather Preferences: Cold, Snow, Windstorms and Thunderstorms
  • Location: Ireland, probably South Tipperary

A look at the most recent research on solar effects on climate and moving beyond the traditional concept of TSI.

Some of this research will be of interest for the stratosphere thread.

 

http://www.progearthplanetsci.com/content/1/1/24

 

And with respect to climate change ( as well as variability), here's another good paper.

 

SOLAR INFLUENCES ON CLIMATE

 

ABSTRACT

Understanding the influence of solar variability on the Earth’s climate requires knowledge of solar variability, solarâ€terrestrial interactions, and the mechanisms determining the response of the Earth’s climate system. We provide a summary of our current understanding in each of these three areas. Observations and mechanisms for the Sun’s variability are described, including solar irradiance variations on both decadal and centennial time scales and their relation to galactic cosmic rays. Corresponding observations of variations of the Earth’s climate on associated time scales are described, including variations in ozone, temperatures, winds, clouds, precipitation, and regional modes of variability such as the monsoons and the North Atlantic Oscillation. A discussion of the available solar and climate proxies is provided. Mechanisms proposed to explain these climate observations are described, including the effects of variations in solar irradiance and of charged particles. Finally, the contributions of solar variations to recent observations of global climate change are discussed.

 

 

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  • 3 weeks later...

Hi Nouska. Great topic.

As you started the thread I feel that you already believe that the complex role played out by solar influences has been too readily swept beneath the carpet by modern climatology. Please correct my assumptions where necessary.

As, I am sure you are aware, solar energy is 99.99% of the energy on Earth. With around 0.71 of the incident flux thermalised by discrete radiation/matter interaction we have to be indeed very careful that natural spectral variation, only detectable from space, does not weight the portion thermalised beyond expected parameters.

The atmosphere's absorptivity of direct solar shortwave is indeed spectrally sensitive. High altitude thermalisation of extreme UV and soft X-rays energise the upper atmosphere affecting both its temperature and extension into space (this storing energy which cannot be lost without being thermalised by collapse). The extent of inflation produces differential rotation. This can only be rectified by turbulent mixing through the atmospheric layers until finally dissipated upon the lithosphere, modulating fundamental surface wind patterning in the process.

I'm afraid of making this too much too early in the discussion but look forward to any replies.

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  • 3 weeks later...
Posted
  • Location: York
  • Weather Preferences: Long warm summer evenings. Cold frosty sunny winter days.
  • Location: York

Hi Nouska. I can assume only two scenarios. The firsts being that you choose, as is your right, apparently, to ignore me, or you are not monitoring this post. Thanks to Nick L for making this clear and concise.

 

This post makes little or no sense?

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Posted
  • Location: Cheddington, Buckinghamshire
  • Weather Preferences: Winter: Cold & Snowy, Summer: Just not hot
  • Location: Cheddington, Buckinghamshire

Hi Nouska. I can assume only two scenarios. The firsts being that you choose, as is your right, apparently, to ignore me, or you are not monitoring this post. Thanks to Nick L for making this clear and concise.

 

I have explained this via PM already, but ok. Nouska hasn't been online for over 2 weeks. People have lives outside of weather forums believe it or not. There is no need for posts like this.

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