The Diurnal and the Semidiurnal Atmospheric Solar Tide

Tellus ◽  
1958 ◽  
Vol 10 (4) ◽  
pp. 415-429
Author(s):  
P. Thrane
Keyword(s):  
Solar Tide

scholarly journals Identification of the mechanisms responsible for anomalies in the tropical lower thermosphere/ionosphere caused by the January 2009 sudden stratospheric warming

2019 ◽  
Vol 9 ◽  
pp. A39 ◽  
Author(s):  
Maxim V. Klimenko ◽  
Vladimir V. Klimenko ◽  
Fedor S. Bessarab ◽  
Timofei V. Sukhodolov ◽  
Pavel A. Vasilev ◽  
...  
Keyword(s):  
Electric Field ◽  
Phase Change ◽  
Lower Thermosphere ◽  
Upper Atmosphere ◽  
Electron Content ◽  
Stratospheric Warming ◽  
Sudden Stratospheric Warming ◽  
Low Latitude ◽  
Plasma Drift ◽  
Solar Tide

We apply the Entire Atmosphere GLobal (EAGLE) model to investigate the upper atmosphere response to the January 2009 sudden stratospheric warming (SSW) event. The model successfully reproduces neutral temperature and total electron content (TEC) observations. Using both model and observational data, we identify a cooling in the tropical lower thermosphere caused by the SSW. This cooling affects the zonal electric field close to the equator, leading to an enhanced vertical plasma drift. We demonstrate that along with a SSW-related wind disturbance, which is the main source to form a dynamo electric field in the ionosphere, perturbations of the ionospheric conductivity also make a significant contribution to the formation of the electric field response to SSW. The post-sunset TEC enhancement and pre-sunrise electron content reduction are revealed as a response to the 2009 SSW. We show that at post-sunset hours the SSW affects low-latitude TEC via a disturbance of the meridional electric field. We also show that the phase change of the semidiurnal migrating solar tide (SW2) in the neutral wind caused by the 2009 SSW at the altitude of the dynamo electric field generation has a crucial importance for the SW2 phase change in the zonal electric field. Such changes lead to the appearance of anomalous diurnal variability of the equatorial electromagnetic plasma drift and subsequent low-latitudinal TEC disturbances in agreement with available observations. Plain Language Summary – Entire Atmosphere GLobal model (EAGLE) interactively calculates the troposphere, stratosphere, mesosphere, thermosphere, and plasmasphere–ionosphere system states and their response to various natural and anthropogenic forcing. In this paper, we study the upper atmosphere response to the major sudden stratospheric warming that occurred in January 2009. Our results agree well with the observed evolution of the neutral temperature in the upper atmosphere and with low-latitude ionospheric disturbances over America. For the first time, we identify an SSW-related cooling in the tropical lower thermosphere that, in turn, could provide additional information for understanding the mechanisms for the generation of electric field disturbances observed at low latitudes. We show that the SSW-related vertical electromagnetic drift due to electric field disturbances is a key mechanism for interpretation of an observed anomalous diurnal development of the equatorial ionization anomaly during the 2009 SSW event. We demonstrate that the link between thermospheric winds and the ionospheric dynamo electric field during the SSW is attained through the modulation of the semidiurnal migrating solar tide.

scholarly journals On the variability of the semidiurnal solar and lunar tides of the equatorial electrojet during sudden stratospheric warmings

2018 ◽  
Author(s):  
Tarique A. Siddiqui ◽  
Astrid Maute ◽  
Nick Pedatella ◽  
Yosuke Yamazaki ◽  
Hermann Lühr ◽  
...  
Keyword(s):  
Zonal Wind ◽  
Equatorial Electrojet ◽  
Stratospheric Warming ◽  
Tidal Amplitude ◽  
Lunar Tide ◽  
Sudden Stratospheric Warming ◽  
Lunar Tides ◽  
Neutral Temperature ◽  
Tidal Changes ◽  
Solar Tide

Abstract. The variabilities of the semidiurnal solar and lunar tide of the equatorial electrojet (EEJ) are investigated during the 2003, 2006, 2009 and 2013 major sudden stratospheric warming (SSW) events in this study. For this purpose, the ground-magnetometer recordings at the equatorial observatories in Huancayo and Fuquene are utilized. Results show a major enhancement in the amplitude of the EEJ semidiurnal lunar tide in each of the four warming events. The EEJ semidiurnal solar tidal amplitude shows an amplification prior to the onset of warmings, a reduction during the deceleration of the zonal mean zonal wind at 60° N and 10 hPa and a second enhancement a few days after the peak reversal of the zonal mean zonal wind during all the four SSWs. Results also reveal that the amplitude of the EEJ semidiurnal lunar tide becomes comparable or even greater than the amplitude of the EEJ semidiurnal solar tide during all these warming events. The present study also compares the EEJ semidiurnal solar and lunar tidal changes with numerical simulations of the variability of the migrating semidiurnal solar (SW2) and lunar (M2) tide in neutral temperature at ~ 120 km altitude. A better agreement between the enhancements of the EEJ semidiurnal lunar tide and the M2 tide in neutral temperature is observed in comparison with the enhancements of the EEJ semidiurnal solar tide and the SW2 tide in neutral temperature.

3. The Moon’s influence on us

2015 ◽  
pp. 46-59
Author(s):  
David A. Rothery
Keyword(s):  
Human Behaviour ◽  
Day Length ◽  
The Moon ◽  
Ocean Water ◽  
Ocean Tides ◽  
Human Culture ◽  
The Future ◽  
Solar Tide ◽  
Gravitational Pull ◽  
Length Changes

The Moon’s presence in the sky has long pervaded human culture in many ways. ‘The Moon’s influence on us’ considers the influence on timekeeping and how the orbits of the Moon and Earth are the origin of our calendar. Ocean tides are caused by the gravitational pull of the Moon and Sun on ocean water with the Moon’s influence being twice as strong as the solar tide. The elliptical nature of the Moon’s orbit affects lunar and solar eclipses; these are explained along with orbital recession and day-length changes. The Moon’s influence on human behaviour and wildlife is also considered, along with the potential of a more sustained lunar presence in the future.

Lunar–solar tide effects in the Earth’s crust and atmosphere

2017 ◽  
Vol 53 (4) ◽  
pp. 565-580 ◽  
Author(s):  
V. V. Adushkin ◽  
S. A. Riabova ◽  
A. A. Spivak
Keyword(s):  
Earth’S Crust ◽  
Solar Tide ◽  
Earth's Crust

scholarly journals Atmospheric tides in the ionosphere IV. Studies of the solar tide, and the location of the regions producing the diurnal magnetic variations

1948 ◽  
Vol 194 (1039) ◽  
pp. 445-463 ◽  
Keyword(s):  
Solar Flares ◽  
Global Distribution ◽  
Atmospheric Tides ◽  
Tidal Effects ◽  
Magnetic Variation ◽  
Independent Test ◽  
Solar Tide

Solar tidal effects are sought in ionospheric data from representative latitudes. They are found in the E, F 1 and F 2 regions. For the F 2 region the seasonal semi-diurnal harmonics arising from P 2/3 are comparable with those from P 2/2 . The amplitudes and phases of these harmonics are determined, and they are used to interpret the global distribution of F 2 ionization. Evidence is found that the lunar magnetic variation is produced mainly by currents in the D region of the ionosphere, but is opposed by the corresponding currents in the E and F 1 regions. This finding is submitted to an independent test, using McNish’s evidence of the effects of solar flares on the magnetic variation.

scholarly journals Radon signals at the Roded site, Southern Israel

Solid Earth ◽  
2010 ◽  
Vol 1 (1) ◽  
pp. 99-109 ◽  
Author(s):  
G. Steinitz ◽  
O. Piatibratova
Keyword(s):  
Spectral Analysis ◽  
Time Window ◽  
Temporal Variations ◽  
Precambrian Basement ◽  
Upper Crust ◽  
Variation Patterns ◽  
Annual Periodicity ◽  
Solar Tide ◽  
Tidal Constituents ◽  
Gravity Tide

Abstract. Temporal variations of radon in the geological environment (upper crust) are frequent and recognized as unique in terms of the signals encountered and for the lack of substantial and generally applicable explanations. The phenomena observed at the Roded site, located in arid southern Israel, illustrate this situation. The monitoring of radon in the last 10 years or more has been carried out in massive meta-diorite of the Precambrian basement block of Roded. The measurement is conducted using an alpha detector at a resolution of 15-min, placed in a borehole at a depth of 9 m, within a PVC casing to that depth. Systematic temporal variation patterns, manifested as large relative signals are composed of sub-diurnal (SDR) radon, multi-day (MD) and annual (AR) signals. The overall variation is dominated by the intense SDR signals which occur in some days, and may vary from background levels (5 counts or less) to peak values (attaining >1000 counts) and back to background at an interval of 6 to 12 h. Intervals of up to several tens of days without significant SDR signals interchange with times of intense daily occurrences of such signals. Their occurrence indicates very fast variations of radiation from radon at the point of measurement. The peak times, within the diurnal 24-h cycle of SDR signals occur preferentially at an interval of 14–16 h (UT+2). Spectral analysis indicates: (a) A diurnal periodicity composed of a primary 24-h and a secondary 12-h periodicity, which are attributed to the solar tide constituents S1 and S2. Tidal constituents indicative for gravity tide (O1, M2) are lacking; (b) An annual periodicity. A compound relation among the diurnal and annual periodicity is indicated by: (a) Continuous Wavelet Transform (CWT) analysis shows an overall annual structure with a modulation of the S1 and S2 periodicities; (b) Moving-time-window Fourier spectral analysis showing that the amplitudes of S1 and S2 vary in an annual pattern, with relatively high values in summer. The phase of S1, S2 and S3 shows a systematic multi-year variation. It is suggested that the significant signatures of the periodic phenomena and their modulations reflect a direct link with the solar radiation tide.

scholarly journals Impact of Gravity wave drag on the thermospheric circulation: Implementation of a nonlinear gravity wave parameterization in a whole atmosphere model

2019 ◽  
Author(s):  
Yasunobu Miyoshi ◽  
Erdal Yiğit
Keyword(s):  
Gravity Wave ◽  
General Circulation ◽  
Lower Thermosphere ◽  
Circulation Model ◽  
Wave Drag ◽  
Zonal Wavenumber ◽  
Semidiurnal Variation ◽  
Solar Tide ◽  
Atmosphere General Circulation Model ◽  
Thermospheric Dynamics

Abstract. To investigate the effects of the gravity wave (GW) drag on the general circulation in the thermosphere, a nonlinear GW parameterization that estimates the GW drag in the whole atmosphere system is implemented in a whole atmosphere general circulation model (GCM). Comparing the simulation results obtained with the whole atmosphere scheme with the ones obtained with a conventional linear scheme, we study the GW effects on the thermospheric dynamics for solstice conditions. The GW drag significantly decelerates the mean zonal wind in the thermosphere. The GWs attenuate the migrating semidiurnal solar tide (SW2) amplitude in the lower thermosphere, and modifies the latitudinal structure of the SW2 above 150 km height. The SW2 simulated by the GCM based on the nonlinear whole atmosphere scheme agrees well with the observed SW2. The GW drag in the lower thermosphere has zonal wavenumber 2 and semidiurnal variation, while the GW drag above 150 km height is enhanced in high latitude. The GW drag in the thermosphere is a significant dynamical and plays an important role in the momentum budget of the thermosphere. Therefore, a GW parameterization accounting for thermospheric processes is essential for coarse-grid whole atmosphere GCMs in order to more realistically simulate the atmosphere-ionosphere system.

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