First global observations of the mesospheric potassium layer

Dawkins, E. C. M.; Plane, J. M. C.; Chipperfield, Martyn P.; Feng, Wuhu; Gumbel, J.; Hedin, Jonas; Höffner, J.; Friedman, J. S.

doi:10.1002/2014gl060801

Cited by 19 publications

(37 citation statements)

References 52 publications

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“…[] and Dawkins et al . [], respectively. These near‐global retrieved data sets extend from 2004 to mid‐2013 and span portions of solar cycles 23 and 24.…”

Section: The Solar Cycle Response Of the Na And K Layersmentioning

confidence: 99%

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

et al. 2016

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The meteoric metal layers (Na, Fe, and K)—which form as a result of the ablation of incoming meteors—act as unique tracers for chemical and dynamical processes that occur within the upper mesosphere/lower thermosphere region. In this work, we examine whether these metal layers are sensitive indicators of decadal long‐term changes within the upper atmosphere. Output from a whole‐atmosphere climate model is used to assess the response of the Na, K, and Fe layers across a 50 year period (1955–2005). At short timescales, the K layer has previously been shown to exhibit a very different seasonal behavior compared to the other metals. Here we show that this unusual behavior is also exhibited at longer timescales (both the ~11 year solar cycle and 50 year periods), where K displays a much more pronounced response to atmospheric temperature changes than either Na or Fe. The contrasting solar cycle behavior of the K and Na layers predicted by the model is confirmed using satellite and lidar observations for the period 2004–2013.

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“…[] and Dawkins et al . [], respectively. These near‐global retrieved data sets extend from 2004 to mid‐2013 and span portions of solar cycles 23 and 24.…”

Section: The Solar Cycle Response Of the Na And K Layersmentioning

confidence: 99%

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

et al. 2016

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“…These spaceborne spectrometers typically were on board satellites with Sun-synchronous and polar orbits and a maximum scanned latitude of up to 82 • that retrieved densities for Mg and/or Mg + (see, e.g., Joiner and Aikin, 1996;Correira et al, 2008;Scharringhausen et al, 2008;Langowski et al, 2015), K (see, e.g., Dawkins et al, 2014) and Na (see, e.g., Fussen et al, 2004;Casadio et al, 2007;Fan et al, 2007;Gumbel et al, 2007;Fussen et al, 2010;Hedin and Gumbel, 2011;Langowski et al, 2016). Along with the measurements, global atmospheric models for the metal layers in the MLT have been developed for Na (Marsh et al, 2013a), Fe (Feng et al, 2013), Mg (Langowski et al, 2015), K Dawkins et al, 2015), and Si atoms, molecules and ions.…”

Section: Introductionmentioning

confidence: 99%

Comparison of global datasets of sodium densities in the mesosphere and lower thermosphere from GOMOS, SCIAMACHY and OSIRIS measurements and WACCM model simulations from 2008 to 2012

Langowski¹,

Savigny²,

Burrows³

et al. 2017

Atmos. Meas. Tech.

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Abstract. During the last decade, several limb sounding satellites have measured the global sodium (Na) number densities in the mesosphere and lower thermosphere (MLT). Datasets are now available from Global Ozone Monitoring by Occultation of Stars (GOMOS), the SCanning Imaging Absorption spectroMeter for Atmospheric CHartography (SCIAMACHY) (both on Envisat) and the Optical Spectrograph and InfraRed Imager System (OSIRIS) (on Odin). Furthermore, global model simulations of the Na layer in the MLT simulated by the Whole Atmosphere Community Climate Model, including the Na species (WACCM-Na), are available. In this paper, we compare these global datasets.The observed and simulated monthly averages of Na vertical column densities agree reasonably well with each other. They show a clear seasonal cycle with a summer minimum most pronounced at the poles. They also show signs of a semi-annual oscillation in the equatorial region. The vertical column densities vary from 0.5 × 10 9 to 7 × 10 9 cm −2 near the poles and from 3 × 10 9 to 4 × 10 9 cm −2 at the Equator. The phase of the seasonal cycle and semi-annual oscillation shows small differences between the Na amounts retrieved from different instruments. The full width at half maximum of the profiles is 10 to 16 km for most latitudes, but significantly smaller in the polar summer. The centroid altitudes of the measured sodium profiles range from 89 to 95 km, whereas the model shows on average 2 to 4 km lower centroid altitudes. This may be explained by the mesopause being 3 km lower in the WACCM simulations than in measurements. Despite this global 2-4 km shift, the model captures well the latitudinal and temporal variations. The variation of the WACCM dataset during the year at different latitudes is similar to the one of the measurements. Furthermore, the differences between the measured profiles with different instruments and therefore different local times (LTs) are also present in the model-simulated profiles. This capturing of latitudinal and temporal variations is also found for the vertical column densities and profile widths.

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“…There are far fewer lidar observations of the K layer than of the Na layer; this is because the density of the K layer is about 2 orders of magnitude lower than that of the Na layer, which makes the K layer harder to be observed [ Megie et al ., ]. Several lidar observations of K layers at different locations were made [ Eska and Hoffner , ; Eska et al ., ; Friedman et al ., ; von Zahn et al ., ], and the first global observation of the mesospheric K layer based on satellite data has also recently been made [ Dawkins et al ., ]. However, reports of K s layers are rare.…”

Section: Introductionmentioning

confidence: 99%

First report of sporadic K layers and comparison with sporadic Na layers at Beijing, China (40.6°N, 116.2°E)

et al. 2015

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A double-laser beam lidar was successfully developed to simultaneously measure K and Na layers at Beijing (40.6°N, 116.2°E) in 2010. Statistical analysis of the parameters of sporadic K (K s ) and sporadic Na (Nas) layers was performed over 2 years of lidar data, and different characteristics of them were found. The average K s occurrence (2.9%) was lower than that of Nas (5.9%); the Nas occurrence had a maximum (19.3%) in May-June months and a minimum (1.6%) in January-February months, while the K s occurrence had a maximum (4.9%) in January-February months and a minimum (1.0%) in September-October months; most K s peaks tended to occur around 93 km, which was~2 km lower than that of Nas (~95 km); the K s peak density was often at least 1 order of magnitude lower than that of Nas; notably, two K s with high peak densities (>1000 cm À3 ) were observed, which were much higher than K density (15-300 cm À3 ) reported before. The ascending time of K s was often longer than its descending time, but an opposite trend occurred for Nas. During the 152 cases of joint observation for the K and Na layers, 21% (32/152) were cases in which K s and Nas events simultaneously occurred, while 79% (120/152) were cases in which only one layer (K or Na) exhibited a strong K s or Nas.

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First global observations of the mesospheric potassium layer

Cited by 19 publications

References 52 publications

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

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

Comparison of global datasets of sodium densities in the mesosphere and lower thermosphere from GOMOS, SCIAMACHY and OSIRIS measurements and WACCM model simulations from 2008 to 2012

First report of sporadic K layers and comparison with sporadic Na layers at Beijing, China (40.6°N, 116.2°E)

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