Solar cycle response and long‐term trends in the mesospheric metal layers

Dawkins, E. C. M.; Plane, J. M. C.; Chipperfield, Martyn P.; Feng, Wuhu; Marsh, Daniel R.; Höffner, J.; Janches, Diego

doi:10.1002/2016ja022522

Cited by 19 publications

(36 citation statements)

References 49 publications

(82 reference statements)

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“…Interestingly, an investigation of Dawkins et al () of the global long‐term variations of the K column density N K with free running WACCM for the period from 1955 to 2005 resulted in a solar cycle effect of −14.4 ± 1.3% per 100 sfu and a long‐term trend of +3.1 ± 0.5% per decade for the latitude interval between the equator and 30°S. Moreover, the same study shows a much less negative solar forcing for the Na column density, which agrees with the differences between the Na and K nightglow intensities discussed in section .…”

Section: K Nightglow Simulation With the Waccm‐k Modelsupporting

confidence: 57%

“…Interestingly, an investigation of Dawkins et al (2016) of the global long-term variations of the K column density N K with free running WACCM for the period from 1955 to 2005 resulted in a solar cycle effect of −14.4 ± 1.3% per 100 sfu and a long-term trend of +3.1 ± 0.5% per decade for the latitude interval between the equator and 30 • S. Moreover, the same study shows a much less negative solar forcing for the Na column density, which agrees with the differences between the Na and K nightglow intensities discussed in section 3.2. Hence, the presence of a negative solar cycle effect for K nightglow appears to be related to variations in the metal atom abundance, which is dominated by changes in the equilibrium between the metal atom and its reservoir species, that is, molecules and ions.…”

Section: Long-term Variationsmentioning

confidence: 99%

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Observations and Modeling of Potassium Emission in the Terrestrial Nightglow

et al. 2019

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The ablation of cosmic dust entering the atmosphere causes the formation of an atomic potassium (K) layer in the mesopause region. It can be studied via resonance fluorescence from the K(D1) line at 769.9 nm, stimulated by sunlight or a laser. In addition, the faint emission from a chemiluminescent cycle involving ozone and oxygen atoms has been observed with a nocturnal mean intensity of about 1 Rayleigh. In this study, the K nightglow is investigated in much greater detail, using 2,299 high‐resolution spectra taken with the astronomical echelle spectrograph Ultraviolet and Visual Echelle Spectrograph at Cerro Paranal in Chile (24.6°S) between 2000 and 2014. The seasonal variation is dominated by a maximum in June. During the night, the highest intensities are found close to sunrise. Moreover, there is a clear negative correlation with solar activity. These variations are very different from those of the well‐studied sodium (Na) nightglow. The K nightglow at Cerro Paranal was also simulated with the Whole Atmosphere Community Climate Model including K chemistry. The observed and modeled climatologies do not match well, largely because of unreliable Whole Atmosphere Community Climate Model ozone densities. Satellite‐based profile retrievals for ozone and temperature from Sounding of the Atmosphere using Broadband Emission Radiometry and K from Optical Spectrograph and Infrared Imaging System were then used to simulate the K nightglow and to derive the quantum yield of the K(D) emission with respect to the reaction of K with ozone. Considering that the obscured K(D2) line is expected on theoretical grounds to be 1.67 times brighter than K(D1), we find about 30% for this quantum yield, which is much higher than for Na(D) emission.

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Section: K Nightglow Simulation With the Waccm‐k Modelsupporting

confidence: 57%

Section: Long-term Variationsmentioning

confidence: 99%

Observations and Modeling of Potassium Emission in the Terrestrial Nightglow

et al. 2019

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“…(2) Above 100 km, the significant anticorrelation of the metal layers with SSI is explained by the role of ion‐molecule chemistry (Plane et al, ). (3) At the metal layer peaks, only K shows a small anticorrelation within error, which is consistent with the response of the K layer to the 11‐year solar cycle (Dawkins et al, ). The only available observational data of the Na layer made by the spaceborne OSIRIS instrument also shows a weak anticorrelation to the 27‐day solar rotational cycle during 2004–2013, which is consistent with the WACCM analysis.…”

Section: Discussionsupporting

confidence: 83%

The 27‐Day Solar Rotational Cycle Response in the Mesospheric Metal Layers at Low Latitudes

Feng

Xue

et al. 2019

Geophysical Research Letters

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To investigate the response of the meteoric metal layers in the mesosphere and lower thermosphere regions to the 27‐day solar rotational cycle, a long‐term simulation of the Whole Atmosphere Community Climate Model with the chemistry of three metals (Na, K, and Fe) was analyzed. The correlation between variability in the metal layers and solar 27‐day forcing during different phases of the solar 11‐year cycle reveals that the response in the metal layers is much stronger during solar maximum. The altitude‐dependent correlation and sensitivity of the metal layers to the solar spectral irradiance demonstrates that there is a significant increase in sensitivity to solar rotational cycle with increasing altitude. Above 100 km, the sensitivity of the metals to changes of 10% in the solar spectral irradiance at Lyman‐alpha is estimated to be −5%. A similar response is seen in Na layer measurements made by the Optical Spectrograph and InfraRed Imaging System instrument on the Odin satellite.

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“…Recently, Dawkins et al . [] explore the long‐term trends in the K layer due to climate change and solar variability. The K layer is predicted to be much more sensitive to both.…”

Section: Discussionmentioning

confidence: 99%

“…The semiannual oscillation of the K centroid height reported here is in contrast to the lack of strong oscillations reported by Friedman et al [2002] and Zhou et al [2005] for solar maximum conditions. Recently, Dawkins et al [2016] explore the long-term trends in the K layer due to climate change and solar variability. The K layer is predicted to be much more sensitive to both.…”

Section: Discussionmentioning

confidence: 99%

Structure and seasonal variations of the nocturnal mesospheric K layer at Arecibo

Yue

Friedman

et al. 2017

JGR Atmospheres

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We present the seasonal variations of the nocturnal mesospheric potassium (K) layer at Arecibo, Puerto Rico (18.35°N, 66.75°W) from 160 nights of K Doppler lidar observations between December 2003 and January 2010, during which the solar activity is mostly low. The background temperature is also measured simultaneously by the lidar and shows a strong semiannual oscillation with maxima occurring during equinoxes at all altitudes. The annual mean K density profile is approximately Gaussian with a peak altitude of 91.7 km. The K column abundance and the centroid height have strong semiannual variations, with maxima at the solstices. Both parameters are negatively correlated to the mean background temperature with a correlation coefficient < −0.5. The root‐mean‐square (RMS) width has a distinct annual oscillation with the largest width occurring in May. The seasonal variation of the centroid height is similar to that of the Fe layer at the same site. The seasonal temperature variation indicates significant enhanced wave‐induced downward transport for both species during spring and autumn. This explains the metal layer centroid height and column abundance variations at Arecibo and provides a general mechanism to account for the seasonal variations in the centroid height of all metal species measured at low‐latitude and midlatitude sites.

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Solar cycle response and long‐term trends in the mesospheric metal layers

Cited by 19 publications

References 49 publications

Observations and Modeling of Potassium Emission in the Terrestrial Nightglow

Observations and Modeling of Potassium Emission in the Terrestrial Nightglow

The 27‐Day Solar Rotational Cycle Response in the Mesospheric Metal Layers at Low Latitudes

Structure and seasonal variations of the nocturnal mesospheric K layer at Arecibo

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