Response of the middle atmosphere to the 11‐year solar cycle simulated with the Whole Atmosphere Community Climate Model

Tsutsui, Junichi; Nishizawa, Keiichi; Sassi, Fabrizio

doi:10.1029/2008jd010316

Cited by 12 publications

(14 citation statements)

References 44 publications

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“…However, the anomaly did not migrate poleward and downward, thus leading to a weak response in the polar vortex. This was also found by Tsutsui et al [2009]. During October and November, the structure of the PNJ in WACCM3.5 is more realistic than in WACCM3.1, particularly at the polar stratopause (not shown).…”

Section: The Solar Signal During Northern Hemisphere Wintersupporting

confidence: 59%

“…Another limitation of most previous modeling studies, when the analysis was extended to the extratropics and focused on the seasonal evolution of the solar signal in zonal wind and temperature, was the use of single simulations instead of an ensemble [e.g., Matthes et al , 2004; Tsutsui et al , 2009; Schmidt et al , 2010]. The significance of the simulated solar signals is then generally small because of the high levels of variability, especially at high latitudes.…”

Section: Introductionmentioning

confidence: 99%

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The 11 year solar cycle signal in transient simulations from the Whole Atmosphere Community Climate Model

et al. 2012

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[1] The atmospheric response to the 11 year solar cycle (SC) and its combination with the quasi-biennal oscillation (QBO) are analyzed in four simulations of the Whole Atmosphere Community Climate Model version 3.5 (WACCM3.5), which were performed with observed sea surface temperatures, volcanic eruptions, greenhouse gases, and a nudged QBO. The analysis focuses on the annual mean response of the model to the SC and on the evolution of the solar signal during the Northern Hemispheric winter. WACCM3.5 simulates a significantly warmer stratosphere under solar maximum conditions compared to solar minimum. The vertical structure of the signal in temperature and ozone at low latitudes agrees with observations better than previous versions of the model. The temperature and wind response in the extratropics is more uncertain because of its seasonal dependence and the large dynamical variability of the polar vortex. However, all four simulations reproduce the observed downward propagation of zonal wind anomalies from the upper stratosphere to the lower stratosphere during boreal winter resulting from solar-induced modulation of the polar night jet and the Brewer-Dobson circulation. Combined QBO-SC effects in the extratropics are consistent with observations, but they are not robust across the ensemble members. During boreal winter, solar signals are also found in tropospheric circulation and surface temperature. Overall, these results confirm the plausibility of proposed dynamical mechanisms driving the atmospheric response to the SC. The improvement of the model climatology and variability in the polar stratosphere is the basis for the success in simulating the evolution and magnitude of the solar signal.

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Section: The Solar Signal During Northern Hemisphere Wintersupporting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

The 11 year solar cycle signal in transient simulations from the Whole Atmosphere Community Climate Model

et al. 2012

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“…In WACCM, the annual mean modeled solar temperature and ozone response in the upper stratosphere agrees generally with other CCM studies [e.g., Marsh et al , ; Tsutsui et al , ; Schmidt et al , ] and observations (for a review, see Gray et al []). The response in the tropical middle and lower stratosphere differs from other CCM studies and agrees well with ERA‐40, radiosonde, and SAGE observations [ SPARC CCMVal , ], as well as an ensemble of transient WACCM experiments for the recent past [ Chiodo et al , ].…”

Section: Solar Signalsmentioning

confidence: 99%

“…The latter study uses a newer WACCM version (3.5) than this study, with improved NH winter climatology and variability, and shows a statistically significant threefold structure of the solar signal in the tropics which agrees very well with observations. Other recent CCM studies with constant SSTs comparable to our study either did not include a QBO in WACCM [ Marsh et al , ; Tsutsui et al , ] or had a self‐consistent QBO with an unrealistic phase which was in phase with the annual cycle [ Schmidt et al , ].…”

Section: Solar Signalsmentioning

confidence: 99%

The importance of time‐varying forcing for QBO modulation of the atmospheric 11 year solar cycle signal

et al. 2013

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[1] We present results from three multidecadal sensitivity experiments with time-varying solar cycle and quasi-biennial oscillation (QBO) forcings using National Center for Atmospheric Research's Whole Atmosphere Community Climate Model (WACCM3.1). The model experiments are unique compared to earlier studies as they use time-varying forcings for the solar cycle only and the QBO, both individually and combined. The results show that the annual mean solar response in the tropical upper stratosphere is independent of the presence of the QBO. The response in the middle to lower stratosphere differs depending on the presence of the QBO and the solar cycle but is statistically indistinguishable in the three experiments. The seasonal evolution of the solar and the combined solar-QBO signals reveals a reasonable agreement with observations only for the experiment in which both the solar cycle and the QBO forcing are present, suggesting that both forcings are important to generate the observed response. More stratospheric warmings occur during solar maximum and QBO west conditions. This appears to be the result of a QBO modulation of the background zonal mean wind climatology, which modifies the solar signal. Depending on the background wind, the small initial early winter solar signal in the subtropical upper stratosphere/lower mesosphere is enhanced during QBO east and diminished during QBO west conditions. This consequently influences the transfer of the solar-QBO signal during winter and results in the observed differences during late winter.

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“…It is very likely that the associated ozone trends are smaller, too. The overall response of mesospheric ozone to the H 2 O from HALOE should be reanalyzed and compared with the model simulations of the SC‐like responses of ozone [e.g., Schmidt et al , 2006; Marsh et al , 2007; Tsutsui et al , 2009]. Still, the direct effects of the solar cycle forcing for ozone are much smaller than for H 2 O in the upper mesosphere.…”

Section: Implications Of the Solar Cycle Responses In H2omentioning

confidence: 99%

Observed seasonal to decadal scale responses in mesospheric water vapor

Remsberg

2010

J. Geophys. Res.

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[1] The 14 year (1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) time series of mesospheric water vapor from the Halogen Occultation Experiment (HALOE) are analyzed using multiple linear regression (MLR) techniques for their seasonal and longer-period terms from 45°S to 45°N. The distribution of annual average water vapor shows a decrease from a maximum of 6.5 ppmv at 0.2 hPa to about 3.2 ppmv at 0.01 hPa, in accord with the effects of the photolysis of water vapor due to the Lyman-a flux. The distribution of the semiannual cycle amplitudes is nearly hemispherically symmetric at the low latitudes, while that of the annual cycles shows larger amplitudes in the Northern Hemisphere. The diagnosed 11 year, or solar cycle, max minus min, water vapor values are of the order of several percent at 0.2 hPa to about 23% at 0.01 hPa. The solar cycle terms have larger values in the Northern than in the Southern Hemisphere, particularly in the middle mesosphere, and the associated linear trend terms are anomalously large in the same region. Those anomalies are due, at least in part, to the fact that the amplitudes of the seasonal cycles were varying at northern midlatitudes during 1991-2005, while the corresponding seasonal terms of the MLR model do not allow for that possibility. Although the 11 year variation in water vapor is essentially hemispherically symmetric and antiphased with the solar cycle flux near 0.01 hPa, the concurrent temperature variations produce slightly colder conditions at the northern high latitudes at solar minimum. It is concluded that this temperature difference is most likely the reason for the greater occurrence of polar mesospheric clouds at the northern versus the southern high latitudes at solar minimum during the HALOE time period.

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Response of the middle atmosphere to the 11‐year solar cycle simulated with the Whole Atmosphere Community Climate Model

Cited by 12 publications

References 44 publications

The 11 year solar cycle signal in transient simulations from the Whole Atmosphere Community Climate Model

The 11 year solar cycle signal in transient simulations from the Whole Atmosphere Community Climate Model

The importance of time‐varying forcing for QBO modulation of the atmospheric 11 year solar cycle signal

Observed seasonal to decadal scale responses in mesospheric water vapor

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