Climate Science: Simulations of the combined effect of long solar cycles and multidecadal ocean oscillations (original) (raw)
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Modelling the Climatic Response to Solar Variability [and Discussion]
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1990
The Sun, the primary energy source driving the climate system, is known to vary in time both in total irradiance and in spectral composition in the ultraviolet. According to solar interior evolution models, the solar luminosity has increased steadily by 25-30% over the past 4 x 10 9 years. Periodic variations are also suspected with characteristic timescales of 11 or 22 years, 80-90 years and possibly longer periods. The ultraviolet radiation below 300 nm also exhibits significant changes over the 27-day solar rotation period as well as the 11-year solar cycle. Variations in the solar constant are expected to produce both direct and indirect (feedback) perturbations in the global surface temperature. A hierarchy of zero- to three-dimensional models have been used to study the complex couplings involved by such effects. The response of a zonally averaged model to possible total irradiance changes associated with the Gleissberg cycle is investigated and compared with measurements of t...
Potential Role of Solar Variability as an Agent for Climate Change
1999
Numerical experiments have been carried out with a two-dimensional sector averaged global climate model in order to assess the potential impact of solar variability on the Earth's surface temperature from 1700 to 1992. This was done by investigating the model response to the variations in solar radiation caused by the changes in the Earth's orbital elements, as well as by the changes intrinsic to the Sun. In the absence of a full physical theory able to explain the origin of the observed total solar irradiance variations, three different total solar irradiance reconstructions have been used. A total solar irradiance change due to the photospheric effects incorporated in the Willson and Hudson (1988) parameterization, and the newly reconstructed solar total irradiance variations from the solar models of Hoyt and Schatten (1993) and Lean et al. (1995). Our results indicate that while the influence of the orbital forcing on the annual and global mean surface temperature is negligible at the century time scale, the monthly mean response to this forcing can be quite different from one month to another. The modelled global warming due to the three investigated total solar irradiance reconstructions is insufficient to reproduce the observed 20th century warming. Nevertheless, our simulated surface temperature response to the changes in the Sun's radiant energy output suggests that the Gleissberg cycle (≈88 years) solar forcing should not be neglected in explaining the century-scale climate variations. Finally, spectral analysis seems to point out that the 10-to 12-year oscillations found in the recorded Northern Hemisphere temperature variations from 1700 to 1992 could be unrelated to the solar forcing. Such a result could indicate that the eleven-year period which is frequently found in climate data might be related to oscillations in the atmosphere or oceans, internal to the climate system.
Climate Dynamics, 1997
Two simulations with a global coupled oceanatmosphere circulation model have been carried out to study the potential impact of solar variability on climate. The Hoyt and Schatten estimate of solar variability from 1700 to 1992 has been used to force the model. Results indicate that the near-surface temperature simulated by the model is dominated by the long periodic solar fluctuations (Gleissberg cycle), with global mean temperatures varying by about 0.5 K. Further results indicate that solar variability and an increase in greenhouse gases both induce to a first approximation a comparable pattern of surface temperature change, i.e., an increase of the landsea contrast. However, the solar-induced warming pattern in annual means and summer is more centered over the subtropics, compared to a more uniform warming associated with the increase in greenhouse gases. The observed temperature rise over the most recent 30 and 100 years is larger than the trend in the solar forcing simulation during the same period, indicating a strong likelihood that, if the model forcing and response is realistic, other factors have contributed to the observed warming. Since the pattern of the recent observed warming agrees better with the greenhouse warming pattern than with the solar variability response, it is likely that one of these factors is the increase of the atmospheric greenhouse gas concentration.
A simple model of solar variability influence on climate
Advances in Space Research, 2004
We present a simple dynamic model of solar variability influence on climate, which is truncated from the stratospheric wavezonal flow interaction dynamics over a b-plane. The model consists of three ordinary differential equations controlled by two parameters: the initial amplitude of planetary waves and the vertical gradient of the zonal wind. The changes associated with the solar UV variability, as well as with seasonal variations, are introduced as periodic modulations of the zonal wind gradient. Influence of the Quasi-Biennial Oscillation is included as a periodic change of the width of the latitudinal extent of the b-plane. The major climate response to these changes is seen through modulation of the number of cold and warm winters.
Simulation of the role of solar and orbital forcing on climate
Advances in Space Research, 2006
The climate system is excited by changes in the solar forcing caused by two effects: (a) by variations of the solar radiation caused by dynamical processes within the Sun, and (b) by changes in the orbital parameters of the Earth around the Sun.
Long-term solar activity variations as a stimulator of abrupt climate change
Russian Journal of Earth Sciences, 2007
Analysis of solar forcing of climate on long time scales has shown that it is necessary to take into consideration the influence of long-term solar cyclicity, such as 200 and 2300-2400-year cycles, on climate. Even in the relatively warm climate of the last 10,000 years, a tendency to climate cooling at deep minima of long-term solar cyclicity is observed. Along with this, a long-term solar forcing of climate manifests itself not only as an external factor due the influence of solar irradiance variations on the atmosphere-ocean system, but also as a stimulator of internal processes in the climatic system, which, in turn, can lead to abrupt climate change. Large-scale abrupt climate oscillations-warmings and subsequent coolings (Dansgaard-Oeschger cycles)-have been revealed in cores of Greenland ice for the interval 60,000-10,000 years BP. They are attributed to the ice-rafting events in the North Atlantic. A comparative analysis of the development of Dansgaard-Oeschger events and solar activity variations (variations in the 10 Be concentration in Greenland ice) has shown that these climatic and solar processes developed simultaneously. It is evident that ice-rafting events were stimulated by an increasing ambient temperature and, hence, they are associated with a high solar activity level. A similar effect of solar activity has been revealed for the time interval of the Holocene. Thus, not only a low, but also a high level of solar activity was in the past a stimulator of abrupt climate changes.
Evidence of solar 11-year cycle from Sea Surface Temperature (SST)
Academia Letters, 2021
The solar contribution to variation in mean temperatures of the earth during the past has been long debated. The reason for this is evident: a direct sun's influence on global climate parameters would undoubtedly confirm the primary role of the sun in driving the climate in the past, present, and allow us to forecast the future. Once assessed the primary sun's role, other forcings like CO2 or other GHG gases concentration, or other anthropogenic contributions, would need to be reconsidered. Indeed many scientific studies have shown that changes in solar activity have impacted climate over the whole Holocene period (approximately the last 10,000 years) [1 and references therein],[2]. The high solar activity was the main cause of the well-known Medieval Warm Period, around the year 1000 AD, and the subsequent low levels of solar activity produced the following cold period, now called The Little Ice Age (1300-1850 AD). The sun's role in earth's climate is rationally highlighted in a recent reports of the GWPF [3] and in one recent (2020), very interesting book [1]. Other GWPF reports demonstrate that ocean and natural cycles, and not human activities, may be behind most observed climate changes [4,5] Even if from 1979 satellite global temperature records are available, direct evidence of the 11-years cycle of solar activity on global temperatures of the last decades has been however rather elusive, although thoroughly investigated. Nicola Scafetta [6] analyzed in 2009 the cyclic solar contribution to global mean air surface temperature. He employed an empirical bi-scale climate model characterized by both fast and slow time responses to solar forcings : and or. Only a fable 11-year solar cycle signature was evidenced in the major temperature patterns covering years from 1950 to 2009, even if surface temperatures were subtracted by volcano and ENSO signatures.
Solar-induced and internal climate variability at decadal time scales
International journal of …, 2005
Statistical analyses of long-term instrumental and proxy data emphasize a distinction between two quasi-decadal modes of climate variability. One mode is linked to atmosphere-ocean interactions ('the internal mode') and the other one is associated with the solar sunspots cycle ('the solar mode'). The distinct signatures of these two modes are also detected in a high-resolution sediment core located in the Cariaco basin. In the oceanic surface temperature the internal mode explains about three times more variance than the solar mode. In contrast, the solar mode dominates over the internal mode in the sea-level pressure and upper atmospheric fields. The heterogeneous methods and data sets used in this study underline the distinction between these decadal modes and enable estimation of their relative importance. The distinction between these modes is important for the understanding of climate variability, the recent global warming trend and the interpretation of high-resolution proxy data.
The Cyclical Sine Model Explanation for Climate Change
The global warming/climate change underway on earth today is a totally natural occurrence caused by solar cycles with solid scientific and historical support. Earth temperatures are controlled by three solar cycles of nominally 1,000, 70, and 11 years. A supporting 73-year cycle within measured earth temperatures is documented in this work. The earth is currently in the upswing part of its normal temperature cycle. Very warm (Medieval Warming) and very cold (Little Ice Age) temperature epochs have been historically documented on earth for at least the last 3,000 years. The primary 1,000-year solar cyclicity was first estimated to be approximately every 1,500 ± 500 (1,000 - 2,000) years from many, diverse scientific studies [1]. The explanation for the earth’s temperature increases since 1850 is captured in a mathematical model called the Cyclical Sine Model. This model fits measured temperatures since 1850, past climate epochs, and correlates closely with the thousand year cyclicity of solar activity from 14C/12C ratio studies [2], Bond Atlantic drift ice cycles [3,4], sunspot history [5], the Atlantic Multidecadal Oscillation [6], and the Pacific Decadal Oscillation [7]. In addition, this model quantitively presents an explanation for the time span 1945-1975 when an impending new ice age was feared [8]. This work shows that the temperature and climate conditions currently on earth today are very similar to the earth in about 930 when the maximum temperature of the Medieval Warming epoch was still about 210 years away. The Cyclical Sine Model predicts that we are also currently 210 years away from the next maximum temperature on earth. Measured earth temperatures for the next several years will validate either the Cyclical Sine Model or the UNIPCC model which conjectures that greenhouse gasses are controlling future earth temperatures. The near-term predictions for future temperatures of these two models are significantly different. The Figure 1 below will demonstrate which model best fits these future measured values. A full explanation for this Figure 1 is detailed in the rest of this paper. Currently 2021 and 2022 earth temperatures are very similar and fit the Cyclical Sine Model best.
Decadal climate variability in a coupled atmosphere-ocean climate model of moderate complexity
Journal of Geophysical Research, 1999
In this study we determined characteristic temporal modes of atmospheric variability at the decadal and interdecadal timescales. This was done on the basis of 1000 year long integrations of a global coupled atmosphere-ocean climate model of moderate complexity including the troposphere, stratosphere, and mesosphere. The applied model resolves explicitely the basic features of the large-scale long-term atmospheric and oceanic variables. The synoptic-scale processes are described in terms of autocorrelation and crosscorrelation functions. The paper includes an extended description and validation of the model as well as the results of analyses of two 1000 year long model integrations. One model run has been performed with the fully coupled model of the atmosphere-ocean system. The performed time-frequency analyses of atmospheric fields reveal strong decadal and interdecadal modes with periods of about 9, 18, and 30 years. To quantify the influence of the ocean on atmospheric variations an additional run with seasonally varying prescribed sea surface temperatures has been carried out, which is characterized by strong decadal modes with periods of about 9 years. The comparison of both runs suggests that decadal variability can be understood as an inherent atmospheric mode due to the nonlinear dynamics of the large-scale atmospheric circulation patterns whereas interdecadal climate variability has to be regarded as coupled atmosphere-ocean modes. Paper number 1999JD900836. 0148-0227 / 99 / 1999 JD 900836509.00 leoclimate proxy data analysis. To address the problem of internal low-frequency variability anyway, long-term integrations of appropriate models are one possible way to get hints on the real atmospheric behavior on the decadal and interdecadal timescales. The study of the internal low-frequency variability generation in simple low-order and complex atmospheric and coupled atmosphere-ocean circulation models started with the work by James and James [1989]. They used a primitive equation model of the atmosphere to produce pronounced internal climate variability on the interannual and decadal timescales. The decadal climate variability was associated with fluctuations of the unstable baroclinic waves in midlatitudes [James and James, 1992]. In the work of James et al. [1994] it was shown that the atmospheric low-frequency variability was caused not only by stochastic contributions but also by the low-dimensional nonlinear dynamics. The influence of nonlinear dynamics on the long-term climate variability in simple atmospheric low-order models was investigated by Pielke and Zeng [1994] and Kurgansky et al. [1996]. The role of orographic, thermal, and synoptic influences in producing the long-term climate variability was investigated by Dethloff et al. [1998] using an atmosphere-like, dynamical low-order system which has 27,253 27,254 HANDORF ET AL.: DECADAL CLIMATE VARIABILITY [1991] and Petoukhov et al. [1998]. It is based on modules for atmospheric, oceanic, sea ice, and land surface processes, linked through fluxes of energy, momentum, and water.