Solar 27-day signatures in standard phase height measurements above central Europe

Savigny, Christian von; Peters, D.; Entzian, G.

doi:10.5194/acp-19-2079-2019

Cited by 16 publications

(18 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The 27-day oscillation is most pronounced in the Lyman-α line (UV band) although it is present in the total solar irradiance. The evident signature of the 27-day oscillation was also reported in the long-period planetary wave activities in the stratosphere (Ebel et al 1981;von Savigny et al 2019).…”

Section: Introductionsupporting

confidence: 56%

Signature of the 27-day oscillation in the MLT tides and its relation with solar radiation at low latitudes

Guharay

Batista

Buriti

et al. 2020

Earth Planets Space

View full text Add to dashboard Cite

The modulation of the dominant atmospheric tides (i.e. diurnal, semidiurnal and terdiurnal) in the mesosphere and lower thermosphere (MLT) is investigated using long-term meteor wind database from three Southern hemispheric low-latitude locations, São João do Cariri (7.4° S, 36.5° W), Cachoeira Paulista (22.7° S, 45° W) and Santa Maria (29.7° S, 53.7° W). The spectral analysis reveals an evident and intermittent signature of a 27-day oscillation in the tidal amplitudes. Relationship between the 27-day tidal modulation in the MLT and solar rotation is looked into utilizing solar UV flux (Lyman-α) that indicates a conspicuous linkage of the tides with the solar short-term variability. The strong correlation between the solar variability and tidal modulation in the concerned period with positive lags at certain intervals may indicate predominate solar influence on the MLT tides. Potential involvement of the lower, middle and upper atmospheric dynamics and chemistry to support the observed oscillation feature is deemed plausible.

show abstract

Section: Introductionsupporting

confidence: 56%

Signature of the 27-day oscillation in the MLT tides and its relation with solar radiation at low latitudes

Guharay

Batista

Buriti

et al. 2020

Earth Planets Space

View full text Add to dashboard Cite

show abstract

“…The composite Mg II index provided by the university of Bremen (see Section 2.2) is used as the solar proxy for the SEA. The SEA has been described in detail in many other publications (e.g., Rong et al., 2020; von Savigny et al., 2019) and only a very brief summary is given here. In a first step anomaly time series of Mg II, foF2 and hmF2 are determined by subtracting a 35‐day running mean from the original time series (see Figure 14).…”

Section: Discussionmentioning

confidence: 99%

“…Solar 27‐day signatures have also been reported in several parameters or constituents in the middle atmosphere (i.e., stratosphere and mesosphere) including temperature (e.g., Dyrland & Sigernes, 2007; Hood, 1986; Rong et al., 2020; Thomas et al., 2015; von Savigny et al., 2012), ozone (e.g., Fioletov, 2009; Hood, 1986), odd hydrogen (Wang et al., 2015), mesospheric water vapor (Thomas et al., 2015), atomic oxygen in the MLT region (Lednyts'kyy et al., 2017), radio reflection heights (von Savigny et al., 2019), and even in noctilucent clouds (Robert et al., 2010)—also known as polar mesospheric clouds. In many cases, the identification of solar 27‐day signatures in middle atmospheric parameters is relatively straightforward and typically based on correlation analyses or SEA.…”

Section: Discussionmentioning

confidence: 99%

The Height‐Dependent Delayed Ionospheric Response to Solar EUV

et al. 2022

View full text Add to dashboard Cite

Based on the analysis of electron density Ne profiles (Grahamstown ionosonde), a case study of the height‐dependent ionospheric response to two 27‐day solar rotation periods in 2019 is performed. A well‐defined sinusoidal response is observed for the period from 27 April 2019 to 24 May 2019 and reproduced with a Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model simulation. The occurring differences between model and observations as well as the driving physical and chemical processes are discussed based on the height‐dependent variations of Ne and major species. Further simulations with an artificial noise free sinusoidal solar flux input show that the Ne delay is defined by contributions due to accumulation of O+ at the Ne peak (positive delay) and continuous loss of O2+ ${\mathrm{O}}_{2}^{+}$ in the lower ionosphere (negative delay). The neutral parts' 27‐day signatures show stronger phase shifts. The time‐dependent and height‐dependent impact of the processes responsible for the delayed ionospheric response can therefore be described by a joint analysis of the neutral and ionized parts. The return to the initial ionospheric state (and thus the loss of the accumulated O+) is driven by an increase of downward transport in the second half of the 27‐day solar rotation period. For this reason, the neutral vertical winds (upwards and downwards) and their different height‐dependent 27‐day signatures are discussed. Finally, the importance of a wavelength‐dependent analysis, statistical methods (superposed epoch analysis), and coupling with the middle atmosphere is discussed to outline steps for future analysis.

show abstract

“…The 27 d solar cycle is caused by the differential rotation of the sun, which leads to apparent variations in solar flux with a period of about 27 d (e.g., Sakurai, 1980, and references therein). Previous studies have identified 27 d solar signatures in many different atmospheric parameters, e.g., noctilucent clouds (e.g., Robert et al, 2010), mesospheric water vapor (e.g., Thomas et al, 2015), tropical upper stratospheric ozone (e.g., Hood, 1986;Fioletov, 2009), the middle atmospheric odd hydrogen species (e.g., Wang et al, 2015), upper mesospheric atomic oxygen (Lednyts'kyy et al, 2017) and especially in temperature (e.g., Ebel et al, 1986;Hood, 1986;Keating et al, 1987;Hood et al, 1991;Hall et al, 2006;Dyrland and Sigernes, 2007;Robert et al, 2010;von Savigny et al, 2012;Thomas et al, 2015;Hood, 2016;Beig, 2002;Beig et al, 2008) in the middle atmosphere. The term "middle atmosphere" refers to the height region of approximately 15-90 km and comprises the stratosphere and mesosphere.…”

Section: Introductionmentioning

confidence: 99%

Response of middle atmospheric temperature to the 27 d solar cycle: an analysis of 13 years of microwave limb sounder data

Rong¹,

Savigny²,

Zhang³

et al. 2020

Atmos. Chem. Phys.

Self Cite

View full text Add to dashboard Cite

Abstract. This work focuses on studying the presence and characteristics of 27 d solar signatures in middle atmospheric temperature observed by the microwave limb sounder (MLS) on NASA's Aura spacecraft. The 27 d signatures in temperature are extracted using the superposed epoch analysis (SEA) technique. We use time-lagged linear regression (sensitivity analysis) and a Monte Carlo test method (significance test) to explore the dependence of the results on latitude and altitude, solar activity, and season, as well as on different parameters (e.g., smoothing filter, window width and epoch centers). Using different parameters does impact the results to a certain degree, but it does not affect the overall results. Analyzing the 13-year data set shows that highly significant 27 d solar signatures in middle atmospheric temperature are present at many altitudes and latitudes. A tendency to higher temperature sensitivity to solar forcing in the winter hemisphere compared to the summer hemisphere is found. In addition, the sensitivity of temperature to 27 d solar forcing tends to be larger at high latitudes than at low latitudes. For 11-year solar minimum conditions no statistically significant identification of a 27 d solar signature is possible at most altitudes and latitudes. Several results we obtained suggest that processes other than solar variability drive atmospheric temperature variability at periods around 27 d. Comparisons of the obtained sensitivity values with earlier experimental and model studies show good overall agreement.

show abstract

Solar 27-day signatures in standard phase height measurements above central Europe

Cited by 16 publications

References 40 publications

Signature of the 27-day oscillation in the MLT tides and its relation with solar radiation at low latitudes

Signature of the 27-day oscillation in the MLT tides and its relation with solar radiation at low latitudes

The Height‐Dependent Delayed Ionospheric Response to Solar EUV

Response of middle atmospheric temperature to the 27 d solar cycle: an analysis of 13 years of microwave limb sounder data

Contact Info

Product

Resources

About