Signatures of naturally induced variability in the atmosphere using multiple reanalysis datasets

Mitchell, Dann; Gray, Lesley J.; Fujiwara, Masatomo; Hibino, T.; Anstey, James; Ebisuzaki, Wesley; Harada, Yusuke; Long, Craig S.; Misios, Stergios; Stott, Peter; Tan, David

doi:10.1002/qj.2492

Cited by 77 publications

(180 citation statements)

References 93 publications

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“…However, there are some inhomogeneities in Modern Era Retrospective Analysis for Research and Applications upper stratospheric temperature (used for SAGE processing) due to drifting of the NOAA satellite platform carrying the stratospheric sounding unit (SSU) instruments [Wang et al, 2012], causing relatively small correlations even for SAGE v7.0 data. The effects of drifts in SSU temperatures on the SCS estimation are also discussed in Mitchell et al [2014].…”

Section: Resultsmentioning

confidence: 99%

On the ambiguous nature of the 11 year solar cycle signal in upper stratospheric ozone

Dhomse

Chipperfield

Damadeo

et al. 2016

Geophysical Research Letters

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Up to now our understanding of the 11 year ozone solar cycle signal (SCS) in the upper stratosphere has been largely based on the Stratospheric Aerosol and Gas Experiment (SAGE) II (v6.2) data record, which indicated a large positive signal which could not be reproduced by models, calling into question our understanding of the chemistry of the upper stratosphere. Here we present an analysis of new v7.0 SAGE II data which shows a smaller upper stratosphere ozone SCS, due to a more realistic ozone‐temperature anticorrelation. New simulations from a state‐of‐art 3‐D chemical transport model show a small SCS in the upper stratosphere, which is in agreement with SAGE v7.0 data and the shorter Halogen Occultation Experiment and Microwave Limb Sounder records. However, despite these improvements in the SAGE II data, there are still large uncertainties in current observational and meteorological reanalysis data sets, so accurate quantification of the influence of solar flux variability on the climate system remains an open scientific question.

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Section: Resultsmentioning

confidence: 99%

On the ambiguous nature of the 11 year solar cycle signal in upper stratospheric ozone

Dhomse

Chipperfield

Damadeo

et al. 2016

Geophysical Research Letters

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“…Our results are particularly relevant given the 10 uncertainties surrounding the observed atmospheric impacts of the 11-year solar cycle forcing (e.g. Mitchell et al, 2015a;2015b).…”

Section: Introductionmentioning

confidence: 94%

“…Gray et al, 2010). In the tropical upper stratosphere, a temperature change of ~0.7-1.1 K between solar maximum and minimum has been reported from rocketsonde and satellite data (Dunkerton et al, 1998;Ramaswamy et al, 2001;Keckhut et al, 2005;Randel et al, 2009;SPARC, 2010), with somewhat larger responses found in a number of reanalysis studies (Frame and Gray, 2010;Mitchell et al, 2015b). In addition to the temperature and ozone responses in the mid-/upper stratosphere, secondary tropical maxima have been identified in the 30 lower stratosphere; these are often explained to be of dynamical origin (see below).…”

Section: Introductionmentioning

confidence: 96%

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Simulating the atmospheric response to the 11-year solar cycle forcing with the UM-UKCA model: the role of detection method and natural variability

Bednarz¹,

Maycock²,

Telford³

et al. 2018

Preprint

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The 11-year solar cycle forcing is recognised as a potentially important atmospheric forcing; however, there remain uncertainties in characterising the effects of the solar variability on the atmosphere from observations and models. Here we 15 present the first detailed assessment of the atmospheric response to the 11-year solar cycle in the UM-UKCA chemistryclimate model using an ensemble of integrations over the recent past. Comparison of the model simulations is made with observations and reanalysis. Importantly, in contrast to the majority of previous studies of the solar cycle impacts, we pay particular attention to the role of detection method by comparing the results diagnosed using both a composite and a multiple linear regression method. We show that stratospheric solar responses diagnosed using both techniques largely agree with 20 each other within the associated uncertainties; however, the results show that apparently different signals can be identified by the methods in the troposphere and in the tropical lower stratosphere. Lastly, we focus on the role of internal atmospheric variability on the detection of the 11-year solar responses by comparing the results diagnosed from individual model ensemble members (as opposed to those diagnosed from the full ensemble). We show overall agreement between the ensemble members in the tropical and mid-latitude mid-stratosphere-to-lower-mesosphere, but larger apparent differences at 25 NH high latitudes during the dynamically active season. Our results highlight the need for long data sets for confident detection of solar cycle impacts in the atmosphere, as well as for more research on possible interdependence of the solar cycle forcing with other atmospheric forcings and processes (e.g. QBO, ENSO… etc.).Atmos. Chem. Phys. Discuss., https://doi

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“…However, there are still uncertainties in the observed atmospheric signals of solar variability (Mitchell et al, 2015a) and its transfer mechanism(s) to the surface. Proposed transfer mechanisms include changes in TSI and SSI, as well as in solar-driven energetic particles (e.g., .…”

Section: Introductionmentioning

confidence: 99%

Solar forcing for CMIP6 (v3.2)

et al. 2017

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Abstract. This paper describes the recommended solar forcing dataset for CMIP6 and highlights changes with respect to CMIP5. The solar forcing is provided for radiative properties, namely total solar irradiance (TSI), solar spectral irradiance (SSI), and the F10.7 index as well as particle forcing, including geomagnetic indices Ap and Kp, and ionization rates to account for effects of solar protons, electrons, and galactic cosmic rays. This is the first time that a recommendation for solar-driven particle forcing has been provided for a CMIP exercise. The solar forcing datasets are provided at daily and monthly resolution separately for the CMIP6 preindustrial control, historical (1850CMIP6 preindustrial control, historical ( -2014, and future (2015-2300) simulations. For the preindustrial control simulation, both constant and time-varying solar forcing components are provided, with the latter including variability on 11-year and shorter timescales but no long-term changes. For the future, we provide a realistic scenario of what solar behavior could be, as well as an additional extreme Maunderminimum-like sensitivity scenario. This paper describes the forcing datasets and also provides detailed recommendations as to their implementation in current climate models.For the historical simulations, the TSI and SSI time series are defined as the average of two solar irradiance models that are adapted to CMIP6 needs: an empirical onePublished by Copernicus Publications on behalf of the European Geosciences Union. A new and lower TSI value is recommended: the contemporary solar-cycle average is now 1361.0 W m −2 . The slight negative trend in TSI over the three most recent solar cycles in the CMIP6 dataset leads to only a small global radiative forcing of −0.04 W m −2 . In the 200-400 nm wavelength range, which is important for ozone photochemistry, the CMIP6 solar forcing dataset shows a larger solar-cycle variability contribution to TSI than in CMIP5 (50 % compared to 35 %).We compare the climatic effects of the CMIP6 solar forcing dataset to its CMIP5 predecessor by using timeslice experiments of two chemistry-climate models and a reference radiative transfer model. The differences in the long-term mean SSI in the CMIP6 dataset, compared to CMIP5, impact on climatological stratospheric conditions (lower shortwave heating rates of −0.35 K day −1 at the stratopause), cooler stratospheric temperatures (−1.5 K in the upper stratosphere), lower ozone abundances in the lower stratosphere (−3 %), and higher ozone abundances (+1.5 % in the upper stratosphere and lower mesosphere). Between the maximum and minimum phases of the 11-year solar cycle, there is an increase in shortwave heating rates (+0.2 K day −1 at the stratopause), temperatures (∼ 1 K at the stratopause), and ozone (+2.5 % in the upper stratosphere) in the tropical upper stratosphere using the CMIP6 forcing dataset. This solar-cycle response is slightly larger, but not statistically significantly different from that for the CMIP5 forcing dataset.CMIP6 models wi...

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Signatures of naturally induced variability in the atmosphere using multiple reanalysis datasets

Cited by 77 publications

References 93 publications

On the ambiguous nature of the 11 year solar cycle signal in upper stratospheric ozone

On the ambiguous nature of the 11 year solar cycle signal in upper stratospheric ozone

Simulating the atmospheric response to the 11-year solar cycle forcing with the UM-UKCA model: the role of detection method and natural variability

Solar forcing for CMIP6 (v3.2)

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