Solar and lunar tides in noctilucent clouds as determined by ground-based lidar

Fiedler, Jens; Baumgarten, Gerd

doi:10.5194/acp-2018-582

Cited by 3 publications

(5 citation statements)

References 11 publications

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“…In order to investigate the tidal behavior in MTD, an hourly composite of the June-July, 2003-2017 diffusion coefficient data for the high-latitude station, Andenes is shown in Figure 4. Here it can be seen that the dominant variation is the diurnal tide, which is, in general, the strongest tide observed in the lidar dataset (e.g., Fiedler and Baumgarten, 2018), but presence of semidiurnal (two max./min.) can also be noted.…”

Section: Discussionmentioning

confidence: 73%

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Laskar¹

2019

Preprint

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The Andenes specular meteor radar shows meteor-trail diffusion rates increasing on average by ∼ 20% at times and locations where a lidar observes noctilucent clouds (NLCs). This high-latitude effect has been attributed to the presence of charged NLC but this study shows that such behaviors result predominantly from thermal tides. To make this claim, the current study evaluates data from three stations, at high-, mid-, and low-latitudes, for the years 2012 to 2016, comparing diffusion to show that thermal tides correlate strongly with the presence of NLCs. This data also shows that the connection between meteortrail diffusion and thermal tide occurs at all altitudes in the mesosphere, while the NLC influence exists only at high-latitudes and at around peak of NLC layer. This paper discusses a number of possible explanations for changes in the regions with NLCs and leans towards the hypothesis that relative abundance of background electron density plays the leading role. A more accurate model of the meteor trail diffusion around NLC particles would help researchers determine mesospheric temperature and neutral density profiles from meteor radars. Copyright statement. 1 Introduction The motion and diffusion of meteor trails depends sensitively upon the properties of the neutral atmosphere where they ablate. Measuring meteor properties with radars enables researchers and weather modelers to estimate the state of the lower thermosphere and upper mesosphere. Meteor radars most often observe underdense meteors in which the radar frequency exceeds the plasma frequency set by the peak meteor plasma density. Typically they have lifetimes that varies from 0.01-0.3 s at altitudes below 110 km. Studies of the meteor trail decay-time and effort to derive ambient temperatures from them have a long history (e.g., Greenhow and Neufeld, 1955; Murray, 1959), but even today there exist several subtle difficulties. Theoretically the meteor trail diffusion (hereafter we refer it as MTD or D a should increase exponentially with altitude.

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Section: Discussionmentioning

confidence: 73%

“…(2011) and Fiedler and Baumgarten (2018). From Figure 3 it can be seen that the altitude of maximum separation between NLC and non-NLC diffusion profiles does not coincide with the altitude of maximum NLC occurrence, particularly in the years 2012 and 2013 where minor separation can be seen even at altitudes above NLC layer.…”

Section: Discussionmentioning

confidence: 94%

Response to RC1

Laskar¹

2019

Preprint

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“…NLCs are susceptible to perturbations from loweratmospheric activities such as gravity waves (Gao et al, 2018) and planetary waves (France et al, 2018). NLCs are strongly influenced by both solar and lunar tides, with diurnal and semidiurnal variations observed in the NLC properties (Fiedler and Baumgarten, 2018;Stevens et al, 2017;. NLCs can also be affected by solar ac-tivities on various timescales, including solar proton events (Bardeen et al, 2016;Winkler et al, 2012), the 27 d solar rotation (Robert et al, 2010;Thomas et al, 2015;Thurairajah et al, 2017) and the 11-year solar cycle (Dalin et al, 2018;DeLand and Thomas, 2019;Hervig et al, 2019).…”

Section: Nlcsmentioning

confidence: 99%

“…NLCs are dominantly influenced by the solar tides with the diurnal variation, and the NLC occurrences are usually more frequent at the local time of morning (Fiedler and Baumgarten, 2018;Stevens et al, 2017). In addition, the NLCs can also be affected by the lunar tides, and the longitudinal variations in NLCs attributed to the non-migrating lunar tides have been found (Liu et al, 2016;.…”

Section: Correlation Analysis Of Day-to-day Responses Ofmentioning

confidence: 99%

Responses of CIPS/AIM noctilucent clouds to the interplanetary magnetic field

2022

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Abstract. This study investigates the link between the interplanetary magnetic field (IMF) By component and the noctilucent clouds (NLCs) measured by the Cloud Imaging and Particle Size (CIPS) experiment onboard the Aeronomy of Ice in the Mesosphere (AIM) satellite. The mean ice particle radius in NLCs is found to be positively correlated with IMF By in the Southern Hemisphere (SH) and negatively correlated with IMF By in the Northern Hemisphere (NH), respectively, on a day-to-day timescale in most of the 20 summer seasons during the 2007–2017 period with a near 0 d lag time, and the response in the SH is stronger than that in the NH. Moreover, the albedo, ice water content and frequency of occurrence of NLCs present positive correlation with IMF By in the SH but no significant correlation in the NH. The superposed epoch analysis (SEA) further indicates the rm on average changes by about 0.73 nm after IMF By reversals, which is significant at the 90 % confidence level in Monte Carlo sensitivity tests. Our results suggest an IMF By-driven pathway: the influence of the solar wind on the polar ionospheric electric potential affects the nucleation processes in NLCs and consequently the ice particle radius and NLC brightness.

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“…In the ionosphere, the LSD has been extensively studied using data of the equatorial electrojet (Siddiqui et al., 2015, 2018; Stening, 2011; Yamazaki et al., 2017), the total electron content (Lin et al., 2019; Liu et al., 2019; Pedatella & Forbes, 2010; Sridharan, 2017), the noctilucent clouds (Dalin et al., 2017; Hoffmann et al., 2018; Fiedler & Baumgarten, 2018; von Savigny et al., 2017), and the temperature and electron density measured from satellites (Forbes & Zhang, 2012, 2019; Forbes et al., 2013; Paulino et al., 2013; Pedatella, 2014; Zhang & Forbes, 2014). In the MLT region, the neutral winds observed by meteor radars and medium‐frequency radars provide an advantage to reveal the long‐term variations of the LSD.…”

Section: Introductionmentioning

confidence: 99%

Long‐Term Variation of Lunar Semidiurnal Tides in the MLT Region Revealed by a Meteor Radar Chain

Luo

Gong

et al. 2022

JGR Space Physics

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Atmospheric tides are one of the most important dynamic processes in coupling the lower atmosphere and the upper atmosphere. They are usually observed by radars and satellites in the mesosphere and lower thermosphere (MLT) region. The solar thermal and lunar gravitational tides are the predominant periodic oscillations in the atmosphere. The solar tides, modulated by the variations of water vapor, ozone, and molecular oxygen in the atmosphere, are mainly generated by solar heating (Forbes, 1995). In contrast, the lunar tides are primarily generated by the gravitational forcing of the Moon on the lower atmosphere (Chapman & Lindzen, 1970). Since the forcing is virtually constant, the variations of lunar tides in the MLT region are related to the changes in the background atmosphere (Forbes & Zhang, 2012;Sandford et al., 2007;Yamazaki et al., 2012). Hence, the determination of the lunar tides in the MLT region is an excellent tool to understand the coupling of the atmosphere (Forbes et al., 2013;Stening et al., 1997).Using numerical simulations, Chapman and Lindzen (1970) predicted that the lunar tides potentially consist of three main modes: Long-term semimonthly lunar tide, lunar diurnal tide, and lunar semidiurnal (LSD) tide. The observed LSD with a period of 12.42 hr consists of a migrating tide with zonal wavenumber 2 (M 2 ) and a nonmigrating component, which has the largest amplitude among the three modes (Pedatella et al., 2012;Vial & Forbes, 1994). Observations of the LSD in the atmosphere are difficult because the frequency of LSD is very close to the frequency of solar semidiurnal tide. Thus, a high spectral resolution in the data sets is required to distinguish the solar and lunar components.

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Solar and lunar tides in noctilucent clouds as determined by ground-based lidar

Cited by 3 publications

References 11 publications

Response to RC1

Response to RC1

Responses of CIPS/AIM noctilucent clouds to the interplanetary magnetic field

Long‐Term Variation of Lunar Semidiurnal Tides in the MLT Region Revealed by a Meteor Radar Chain

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