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

This work studies 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) 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 different time periods. Solar variability has a positive influence on NAO during 1978-1997, which is opposite before that period. Solar NAO lag relationship is also sensitive to the chosen times of reference. Such analyses raise a question about previously proposed mechanism and relationship related to the sun and NAO. The ENSO is seen to be influenced strongly by solar variability and volcanic eruptions in certain periods. This study observes a strong negative association between solar variability 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 volcanic eruptions suggested the stronger association. Here we show that the mean atmospheric state is important for understanding the connection between solar variability, the NAO and ENSO and associated mechanism.

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

10.20944/preprints201608.0025.v2 ◽

2017 ◽

Cited By ~ 2

Author(s):

Indrani Roy

Keyword(s):

Climate Variability ◽

North Atlantic ◽

Southern Oscillation ◽

Volcanic Eruptions ◽

Solar Variability ◽

The Sun ◽

The North ◽

Natural Factors ◽

The North Atlantic

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 (1999-2017) 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.

Major Climate Variability and Natural Factors in Boreal Winter

Pure and Applied Geophysics ◽

10.1007/s00024-020-02522-z ◽

2020 ◽

Vol 177 (10) ◽

pp. 4983-5005 ◽

Cited By ~ 1

Author(s):

Indrani Roy

Keyword(s):

Climate Variability ◽

North Atlantic ◽

Southern Oscillation ◽

Volcanic Eruptions ◽

Solar Variability ◽

Boreal Winter ◽

The Sun ◽

The North ◽

Natural Factors ◽

The North Atlantic

Abstract The role of natural factors, mainly solar 11-year cyclic 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 about the 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 during 1978–1997 indicates a strong positive in-phase connection with NAO, which is different in the period prior to that. Such connections were further explored by known existing mechanisms. Solar NAO lagged relationship is also shown not unequivocally maintained but sensitive to the chosen times of reference. It thus points towards the previously known mechanism/relationship related to the Sun and NAO. This study discussed the important roles played by ENSO on global temperature; while ENSO is influenced strongly by solar variability and volcanic eruptions in certain periods. A strong negative association between the Sun and ENSO is observed before the 1950s, which is positive though statistically insignificant during the second half of the twentieth 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. That period showed warming in the central tropical Pacific while cooling in the North Atlantic with reference to various other anomaly periods. It indicates that the mean atmospheric state is important for understanding the connection between solar variability, the NAO and ENSO and associated mechanisms. It presents critical analyses to improve knowledge about major modes of variability and their roles in climate and reconciles various contradictory findings. It discusses the importance of detecting solar signal which needs to be robust too.

Sub-decadal- to decadal-scale climate cyclicity during the Holsteinian interglacial (MIS 11) evidenced in annually laminated sediments

Climate of the Past ◽

10.5194/cp-7-987-2011 ◽

2011 ◽

Vol 7 (3) ◽

pp. 987-999 ◽

Cited By ~ 23

Author(s):

A. Koutsodendris ◽

A. Brauer ◽

H. Pälike ◽

U. C. Müller ◽

P. Dulski ◽

...

Keyword(s):

Time Series ◽

Southern Oscillation ◽

Laminated Sediments ◽

Solar Cycles ◽

The North ◽

Decadal Scale ◽

Time Series Analyses ◽

Diatom Blooms ◽

Winter Time ◽

Abstract. To unravel the short-term climate variability during Marine Isotope Stage (MIS) 11, which represents a close analogue to the Holocene with regard to orbital boundary conditions, we performed microfacies and time series analyses on a ~3200-yr-long record of annually laminated Holsteinian lake sediments from Dethlingen, northern Germany. These biogenic varves comprise two sub-layers: a light sub-layer, which is controlled by spring/summer diatom blooms, and a dark sub-layer consisting mainly of amorphous organic matter and fragmented diatom frustules deposited during autumn/winter. Time series analyses were performed on the thickness of the light and dark sub-layers. Signals exceeding the 95% and 99% confidence levels occur at periods that are near-identical to those known from modern instrumental data and Holocene palaeoclimatic records. Spectral peaks at periods of 90, 25, and 10.5 yr are likely associated with the 88-, 22- and 11-yr solar cycles, respectively. This variability is mainly expressed in the light sub-layer spectra, suggesting solar influence on the palaeoproductivity of the lake. Significant signals at periods between 3 and 5 yr and at ∼6 yr are strongest expressed in the dark sub-layer spectra and may reflect an influence of the El Niño-Southern Oscillation (ENSO) and the North Atlantic Oscillation (NAO) during autumn/winter. Our results suggest that solar forcing and ENSO/NAO-like variability influenced central European climate during MIS 11 similarly to the present interglacial, thus demonstrating the comparability of the two interglacial periods at sub-decadal to decadal timescales.

Influence of Modes of Climate Variability on Global Temperature Extremes

Journal of Climate ◽

10.1175/2008jcli2125.1 ◽

2008 ◽

Vol 21 (15) ◽

pp. 3872-3889 ◽

Cited By ~ 139

Author(s):

Jesse Kenyon ◽

Gabriele C. Hegerl

Keyword(s):

North America ◽

Climate Variability ◽

Large Scale ◽

Southern Oscillation ◽

Temperature Extremes ◽

Modes Of Variability ◽

The North ◽

The Pacific ◽

The North Atlantic Oscillation ◽

Modes Of Climate Variability

Abstract The influence of large-scale modes of climate variability on worldwide summer and winter temperature extremes has been analyzed, namely, that of the El Niño–Southern Oscillation, the North Atlantic Oscillation, and Pacific interdecadal climate variability. Monthly indexes for temperature extremes from worldwide land areas are used describe moderate extremes, such as the number of exceedences of the 90th and 10th climatological percentiles, and more extreme events such as the annual, most extreme temperature. This study examines which extremes show a statistically significant (5%) difference between the positive and negative phases of a circulation regime. Results show that temperature extremes are substantially affected by large-scale circulation patterns, and they show distinct regional patterns of response to modes of climate variability. The effects of the El Niño–Southern Oscillation are seen throughout the world but most clearly around the Pacific Rim and throughout all of North America. Likewise, the influence of Pacific interdecadal variability is strongest in the Northern Hemisphere, especially around the Pacific region and North America, but it extends to the Southern Hemisphere. The North Atlantic Oscillation has a strong continent-wide effect for Eurasia, with a clear but weaker effect over North America. Modes of variability influence the shape of the daily temperature distribution beyond a simple shift, often affecting cold and warm extremes and sometimes daytime and nighttime temperatures differently. Therefore, for reliable attribution of changes in extremes as well as prediction of future changes, changes in modes of variability need to be accounted for.

Forcing Climate

Climate, Catastrophe, and Faith ◽

10.1093/oso/9780197506219.003.0002 ◽

2021 ◽

pp. 27-42

Author(s):

Philip Jenkins

Keyword(s):

Southern Oscillation ◽

Climate Science ◽

Volcanic Eruptions ◽

Primary Factor ◽

Ice Age ◽

The North ◽

The North Atlantic ◽

The North Atlantic Oscillation ◽

Controversial Nature

This chapter examines the various factors that drive climate, the “forcings.” These include volcanic eruptions, solar energy (as measured by sunspots), and oceanic changes, especially the El Niño–Southern Oscillation. In the Atlantic world, one primary factor is the North Atlantic Oscillation (NAO). Volcanic eruptions in particular have often been implicated in changing climate worldwide, with far-reaching political and religious effects. These different factors are often closely intertwined, influencing each other intimately. This chapter also traces the modern emergence of climate science and the often controversial nature of historical debate over phenomena such as the Medieval Warm Period and Little Ice Age.

North Atlantic climate variability: The role of the North Atlantic Oscillation

Journal of Marine Systems ◽

10.1016/j.jmarsys.2008.11.026 ◽

2009 ◽

Vol 78 (1) ◽

pp. 28-41 ◽

Cited By ~ 413

Author(s):

James W. Hurrell ◽

Clara Deser

Keyword(s):

Climate Variability ◽

North Atlantic ◽

The North ◽

North Atlantic Climate ◽

The North Atlantic ◽

Evaluation of Leading Modes of Climate Variability in the CMIP Archives

Journal of Climate ◽

10.1175/jcli-d-19-1024.1 ◽

2020 ◽

Vol 33 (13) ◽

pp. 5527-5545 ◽

Cited By ~ 2

Author(s):

John T. Fasullo ◽

A. S. Phillips ◽

C. Deser

Keyword(s):

Climate Variability ◽

Southern Oscillation ◽

Internal Variability ◽

Intrinsic Variability ◽

Annular Modes ◽

Internal Climate Variability ◽

The North ◽

The Pacific ◽

The North Atlantic Oscillation ◽

Modes Of Climate Variability

AbstractThe adequate simulation of internal climate variability is key for our understanding of climate as it underpins efforts to attribute historical events, predict on seasonal and decadal time scales, and isolate the effects of climate change. Here the skill of models in reproducing observed modes of climate variability is assessed, both across and within the CMIP3, CMIP5, and CMIP6 archives, in order to document model capabilities, progress across ensembles, and persisting biases. A focus is given to the well-observed tropical and extratropical modes that exhibit small intrinsic variability relative to model structural uncertainty. These include El Niño–Southern Oscillation (ENSO), the Pacific decadal oscillation (PDO), the North Atlantic Oscillation (NAO), and the northern and southern annular modes (NAM and SAM). Significant improvements are identified in models’ representation of many modes. Canonical biases, which involve both amplitudes and patterns, are generally reduced across model generations. For example, biases in ENSO-related equatorial Pacific sea surface temperature, which extend too far westward, and associated atmospheric teleconnections, which are too weak, are reduced. Stronger tropical expression of the PDO in successive CMIP generations has characterized their improvement, with some CMIP6 models generating patterns that lie within the range of observed estimates. For the NAO, NAM, and SAM, pattern correlations with observations are generally higher than for other modes and slight improvements are identified across successive model generations. For ENSO and PDO spectra and extratropical modes, changes are small compared to internal variability, precluding definitive statements regarding improvement.

Robust winter warming over Eurasia under stratospheric sulfate geoengineering – the role of stratospheric dynamics

10.5194/acp-2020-965 ◽

2020 ◽

Author(s):

Antara Banerjee ◽

Amy H. Butler ◽

Lorenzo M. Polvani ◽

Alan Robock ◽

Isla R. Simpson ◽

...

Keyword(s):

North Atlantic ◽

Volcanic Eruptions ◽

Forced Response ◽

Positive Phase ◽

Dynamical Response ◽

The North ◽

The North Atlantic ◽

Abstract. It has been suggested that increased stratospheric sulfate aerosol loadings following large, low latitude volcanic eruptions can lead to wintertime warming over Eurasia through dynamical stratosphere-troposphere coupling. We here investigate the proposed connection in the context of hypothetical future stratospheric sulfate geoengineering in the Geoengineering Large Ensemble simulations. In those geoengineering simulations, we find that stratospheric circulation anomalies that resemble the positive phase of the Northern Annular Mode in winter is a distinguishing climate response which is absent when increasing greenhouse gases alone are prescribed. This stratospheric dynamical response projects onto the positive phase of the North Atlantic Oscillation, leading to associated side-effects of this climate intervention strategy, such as continental Eurasian warming and precipitation changes. Seasonality is a key signature of the dynamically-driven surface response. We find an opposite response of the North Atlantic Oscillation in summer, when no dynamical role of the stratosphere is expected. The robustness of the wintertime forced response stands in contrast to previously proposed volcanic responses.

Volcanic imprint in the North Atlantic climate variability as recorded by stable water isotopes of Greenland ice cores

10.21203/rs.3.rs-61016/v1 ◽

2020 ◽

Author(s):

Hera Guðlaugsdóttir ◽

Jesper Sjolte ◽

Árný Erla Sveinbjörnsdóttir ◽

Hans Christian Steen-Larsen

Keyword(s):

Climate Variability ◽

Atmospheric Circulation ◽

North Atlantic ◽

High Latitude ◽

Ice Cores ◽

Volcanic Eruptions ◽

The North ◽

The North Atlantic ◽

Abstract Volcanic eruptions are important drivers of climate variability on both seasonal and multi-decadal time scales as a result of atmosphere-ocean coupling. While the direct response after equatorial eruptions emerges as the positive phase of the North Atlantic Oscillation in the first two years after an eruption, less is known about high latitude northern hemisphere eruptions. In this study we assess the difference between equatorial and high latitude volcanic eruptions through the reconstructed atmospheric circulation and stable water isotope records of Greenland ice cores for the last millennia (1241-1979 CE), where the coupling mechanism behind the long-term response is addressed. The atmospheric circulation is studied through the four main modes of climate variability in the North Atlantic, the Atlantic Ridge, Scandinavian Blocking and the positive and negative phase of the North Atlantic Oscillation. We report a difference in the atmospheric circulation response after high latitude eruptions compared to the response after equatorial eruptions, where the positive phase of the North Atlantic Oscillation and the Atlantic Ridge seem to be more associated with equatorial eruptions while the negative phase of the North Atlantic Oscillation seems to follow high latitude eruptions. This response is present during the first five years and then again in years 8-12 after both equatorial and high latitude eruptions. Such a prolonged response is evidence of an ocean-atmosphere coupling that is initiated through different mechanisms, where we suspect sea ice to play a key role.