Solar Cycle Signals in the Pacific and the Issue of Timings

Roy, Indrani; Haigh, Joanna D.

doi:10.1175/jas-d-11-0277.1

Cited by 47 publications

(51 citation statements)

References 21 publications

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“…The following processes, however, need further clarification: (i) the role of ocean fronts and atmospheric baroclinic eddies in the downward extension of zonal mean zonal winds from the stratosphere, and (ii) the role of tropical convection in interactions between the stratospheric mean meridional circulation and the Hadley circulation. Concerning the La Niña-like SST anomaly, Roy and Haigh (2012) confirmed a tendency for La Niña to occur more frequently during the peak year of the solar cycle as previously suggested by van Loon et al (2007). However, their peak year is only 1 year among 11 years of a solar cycle.…”

Section: Connection With the Stratospheresupporting

confidence: 82%

How can we understand the global distribution of the solar cycle signal on the Earth's surface?

Kodera

Thiéblemont²,

Yukimoto

et al. 2016

Atmos. Chem. Phys.

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Abstract. To understand solar cycle signals on the Earth's surface and identify the physical mechanisms responsible, surface temperature variations from observations as well as climate model data are analysed to characterize their spatial structure. The solar signal in the annual mean surface temperature is characterized by (i) mid-latitude warming and (ii) no overall tropical warming. The mid-latitude warming during solar maxima in both hemispheres is associated with a downward penetration of zonal mean zonal wind anomalies from the upper stratosphere during late winter. During the Northern Hemisphere winter this is manifested by a modulation of the polar-night jet, whereas in the Southern Hemisphere, the upper stratospheric subtropical jet plays the major role. Warming signals are particularly apparent over the Eurasian continent and ocean frontal zones, including a previously reported lagged response over the North Atlantic. In the tropics, local warming occurs over the Indian and central Pacific oceans during high solar activity. However, this warming is counterbalanced by cooling over the cold tongue sectors in the southeastern Pacific and the South Atlantic, and results in a very weak zonally averaged tropical mean signal. The cooling in the ocean basins is associated with stronger cross-equatorial winds resulting from a northward shift of the ascending branch of the Hadley circulation during solar maxima. To understand the complex processes involved in the solar signal transfer, results of an idealized middle atmosphere-ocean coupled model experiment on the impact of stratospheric zonal wind changes are compared with solar signals in observations. Model integration of 100 years of strong or weak stratospheric westerly jet condition in winter may exaggerate long-term ocean feedback. However, the role of ocean in the solar influence on the Earth's surface can be better seen. Although the momentum forcing differs from that of solar radiative forcing, the model results suggest that stratospheric changes can influence the troposphere, not only in the extratropics but also in the tropics through (i) a downward migration of wave-zonal mean flow interactions and (ii) changes in the stratospheric mean meridional circulation. These experiments support earlier evidence of an indirect solar influence from the stratosphere.

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Section: Connection With the Stratospheresupporting

confidence: 82%

How can we understand the global distribution of the solar cycle signal on the Earth's surface?

Kodera

Thiéblemont²,

Yukimoto

et al. 2016

Atmos. Chem. Phys.

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“…At the equator, where the Sun's radiative input is largest, there has been much recent debate about the pattern and timing of the 11 year solar signal in the observed tropical Pacific sea surface temperatures (SSTs), and whether or not 11 year solar irradiance variability at the Earth's surface can act as a trigger for El Niño-Southern Oscillation (ENSO) variability [e.g., van Loon et al, 2007;Meehl et al, 2008Roy and Haigh, 2010;Zhou and Tung, 2010;Haam and Tung, 2012;Roy and Haigh, 2012].…”

Section: à2mentioning

confidence: 99%

A lagged response to the 11 year solar cycle in observed winter Atlantic/European weather patterns

et al. 2013

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[1] The surface response to 11 year solar cycle variations is investigated by analyzing the long-term mean sea level pressure and sea surface temperature observations for the period 1870-2010. The analysis reveals a statistically significant 11 year solar signal over Europe, and the North Atlantic provided that the data are lagged by a few years. The delayed signal resembles the positive phase of the North Atlantic Oscillation (NAO) following a solar maximum. The corresponding sea surface temperature response is consistent with this. A similar analysis is performed on long-term climate simulations from a coupled ocean-atmosphere version of the Hadley Centre model that has an extended upper lid so that influences of solar variability via the stratosphere are well resolved. The model reproduces the positive NAO signal over the Atlantic/European sector, but the lag of the surface response is not well reproduced. Possible mechanisms for the lagged nature of the observed response are discussed.

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“…However, when the focus is on Period B, the relationship not only reversed but even showed significant up to 95% level. It is noteworthy that Roy and Haigh [2012], focusing on a similar period of analysis, also observed the preferential alignment of the negative phase of ENSO during active phases of the solar cycle (i.e., when SSN >80) during northern winter. Updating that record with current data (upto 2015) also confirmed such observation (Fig.…”

Section: Influence Of Enso (Column Iii)mentioning

confidence: 62%

“…4. The ENSO suggested cold phase not only during peak solar years of active cycles, but that also followed 1 to 2 years after the peak (Roy, 2014, Roy andHaigh, 2012). Overruling all speculations, the last solar peak year of 2014 again suggested the cold phase of ENSO ).…”

Section: Influence Of Enso (Column Iii)mentioning

confidence: 82%

“…Regarding energy output, only a 0.1 % change between maximum to minimum of the solar 11-year cycle [Lean and Rind, 2001], which is too negligible to influence climate. However, studies identified significant regional impacts which are felt seasonally (Gray et al 2010;Roy and Haigh, 2010;van Loon and Meehl, 2007) and also depend on overall period chosen (Roy and Haigh, 2012;Roy, 2014). In understanding climate variability and in interpreting signals of climate change it is important to ascertain the actual role of natural factors so that any human influence may be more accurately identified.…”

Section: Introductionmentioning

confidence: 99%

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The Role of Natural Factors on Major Climate Variability in Northern Winter

Roy¹

2017

Preprint

Self Cite

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Abstract. The role of natural factors mainly solar eleven-year cycle variability, and volcanic eruptions on two major modes of climate variability the North Atlantic Oscillation (NAO) and El Niño Southern Oscillation (ENSO) are studied for around last 150 years period. The NAO is the primary factor to regulate Central England Temperature (CET) during winter throughout the period, though NAO is impacted differently by other factors in various time periods. Solar variability indicates a strong positive influence on NAO during 1978-1997, though suggests opposite in earlier period. Solar NAO lag relationship is also shown sensitive to the chosen times of reference and thus points towards the previously proposed mechanism/ relationship related to the sun and NAO. The ENSO is influenced strongly by solar variability and volcanic eruptions in certain periods. This study observes a strong negative association between the sun and ENSO before the 1950s, which is even opposite during the second half of 20th century. The period 1978-1997, when two strong eruptions coincided with active years of strong solar cycles, the ENSO, and volcano suggested a stronger association, and we discussed the important role played by ENSO. That period showed warming in central tropical Pacific while cooling in the North Atlantic with reference to the later period (1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015)(2016)(2017) and also from chosen earlier period. Here we show that the mean atmospheric state is important for understanding the connection between solar variability, the NAO and ENSO and associated mechanism. It presents a critical analysis to improve knowledge about major modes of variability and their role in climate. We also discussed the importance of detecting the robust signal of natural variability, mainly the sun.

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Solar Cycle Signals in the Pacific and the Issue of Timings

Cited by 47 publications

References 21 publications

How can we understand the global distribution of the solar cycle signal on the Earth's surface?

How can we understand the global distribution of the solar cycle signal on the Earth's surface?

A lagged response to the 11 year solar cycle in observed winter Atlantic/European weather patterns

The Role of Natural Factors on Major Climate Variability in Northern Winter

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