by University of Oulu, March 18, 2020
Changes in space climate driven by long-term changes in solar activity have a significant impact on Earth’s atmosphere and climate. Understanding the complex system requires cooperation between space physics and climate science.
On the right, a picture of the Sun taken at the wavelength of visible light, i.e. like a regular camera at very short shutter speed, visible sunspot groups. The time series in the image illustrate a few long series of data used in space air research.
On green: approximately 40 years of direct satellite measurements, a combination of energetic electrons coming into the Earth’s atmosphere.
In red: from geomagnetic measurements reconstructed estimate of the speed of the solar wind in the last hundred years.
With purple: the longest unified time series for geomagnetic activity (the so-called AA index), starting from 1868 and continuing to the present day.
In blue: 400 year series of sunspots. This set of data is the longest indicator of solar activity based on direct measurements.
by K. Richard, October 3, 2019 in NoTricksZone
In the last few years, hundreds of peer-reviewed scientific papers have been published linking changes in solar activity to Earth’s climate (2016, 2017, 2018). The evidence for a robust Sun-Climate connection continues to accumulate in 2019.
When it comes to the Sun’s influence on climate, one conclusion is certain: there is no widespread scientific agreement as to how and to what extent solar activity and its related parameters (i.e., galactic cosmic rays, geomagnetic activity, solar wind flux) impact changes in the Earth’s temperature and precipitation.
The disagreement is so chasmic and the mechanisms are so poorly understood that scientists’ estimates of the influence of direct solar irradiance forcing between the 17th century and today can range between a negligible +0.1 W m-2 to a very robust +6 W m-2 (Egorova et al., 2018; Mazzarella and Scafetta, 2018).
“There is no consensus on the amplitude of the historical solar forcing. The estimated magnitude of the total solar irradiance difference between Maunder minimum and present time ranges from 0.1 to 6 W/m2 making uncertain the simulation of the past and future climate.” (Egorova et al., 2018)
“According to the IPCC (2013), solar forcing is extremely small and cannot induce the estimated 1.0–1.5 °C since the LIA. However, thesolar radiative forcing is quite uncertain because from 1700 to 2000 the proposed historical total solar irradiance reconstructions vary greatly from a minimum of 0.5 W/m2 to a maximum of about 6 W/m2 (cf..: Hoyt and Schatten 1993; Wang et al. 2005; Shapiro et al. 2011). Moreover, it is believed that the sun can influence the climate also via a magnetically induced cosmic ray flux modulation (e.g.: Kirkby 2007) or via heliospheric oscillation related to planetary resonances (e.g.: Scafetta 2013, 2014b; Scafetta et al. 2016, and others). Since solar and climate records correlate quite significantly throughout the Holocene (cf: Kerr 2001; Steinhilber et al. 2012; Scafetta 2012, 20104b), the results shown herein may be quite realistic, although the exact physical mechanisms linking astronomical forcings to climate change are still poorly understood.” (Mazzarella and Scafetta, 2018)”
by Zherebtsov G.A. et al., April 2019 in J.Atm&SolarTerrestrialPhysics
La géologie, une science plus que passionnante … et diverse