Atmospheric Tides Research Articles

Preliminary Results of the Three-Dimensional Plasma Drift Velocity at East Asian Low-Latitudes Observed by the Sanya Incoherent Scattering Radar (SYISR)

As the first advanced modular phase array incoherent scatter radar (ISR) established in the Eastern Hemisphere at low latitudes, Sanya ISR (SYISR) can measure the line-of-sight (LOS) velocity of ion drift in multiple directions, potentially yielding the spatial distribution of ionospheric plasma drift. Three beam-scanning modes are designed for plasma drift detection: meridian, zonal and cross-shaped (both meridian and zonal) plane, which will provide the distribution of plasma drift in latitude/longitude as well as altitude. The altitude profile of plasma drift and the first presented distribution of low latitude plasma drift in the meridian plane for March to May 2021 are inversed through LOS velocity using cross-shaped and meridian beam-scanning modes, respectively. A statistical correlation coefficient between the vpn and crest-to-trough ratio (CTR) of equatorial ionization anomaly (EIA) TEC and a case study of magnetic storm response in plasma drift show that the inversed plasma drift can be a good indicator in response to the changes in atmospheric tide and solar wind at different time scales and explain the corresponding ionospheric electron density variations at low and equatorial latitudes. This study proves that the SYISR-measured plasma drift is reliable and will play an important role in the atmosphere-ionosphere-magnetospheric coupling study in the East Asian region.

Detection of Migrating and Non-Migrating Atmospheric Tides Derived from ERA5 Temperature Meteorological Analyses

To better extract the tides represented in the European meteorological analysis ERA5, an analysis of the histograms of the diurnal and semi-diurnal modes as a function of longitudes was performed. This analysis revealed that modes with different characteristics appeared regionally along a single longitude. Retrieved migrating tides were compared with a tidal model showing global agreement below 60 km and twice the amplitude in meteorological analyses at mid-latitude. Non-migrating tidal modes have been identified along the tropical band. They logically appear above the convective zones, probably due to water vapor excess. Their characteristics are different from migrating components. This preliminary study has shown that it is necessary to develop additional observations allowing for more frequent sampling to retrieve migrating and non-migrating tides that can only be achieved with satellite constellations from space.

Simulation of horizontal sporadic E layer movement driven by atmospheric tides

The present study aims to reveal horizontal sporadic E (Es) movements driven by atmospheric diurnal/semi-diurnal tides using a three-dimensional (3D) ionospheric model. Horizontal Es movements have been investigated since the mid-twentieth century, using a variety of 1D/2D observational techniques. However, there are no comprehensive studies that explain the different results asserted by the observations. Herein, we performed 3D Es simulations at mid- and low-latitudes. This is the first study to investigate horizontal Es movements from a 3D perspective. We found that the Es layers are constrained at the zonal-wind shear nodes above sim110 km, but transported by horizontal winds below sim110 km. The Es layers that descend with the downward tidal phases move southward. The descending Es layers move westward as they lag behind the zonal-wind shear nodes. The Es layers that stagnate at sim100 km are transported by the semi-diurnal tides. In general, the descending and stagnating Es layers do not move eastward. This is because the Es layers diffuse vertically in the eastward/northward wind region or in the early stage of formation in the eastward/southward wind region. The horizontal Es movement tendency in the simulations agreed with and provided a general explanation for previous observations.Graphic

Diurnal Variations in Vegetation Activity affecting Shallow Groundwater Flow identified by Microthermal Measurements

Observations of summer microthermal temperature variations suggest, next to hydrological factors, a significant influence of plant activity on groundwater flow in fractured claystone materials. Variations in groundwater microtemperature were compared to variations in meteorological parameters and electrical potential of plants. With an increase in surface temperature, relative air humidity decreases and an increase in tree electrical potential, measured as the difference between the northern and the southern stem exposure (N–S), can be observed. This increase in electrical potential is concomitant with a change in groundwater temperature of approximately 2 mK. This relationship does not always occur. At high temperatures (+30°C) the decrease amounts to just 1 mK. This fact is related to the change in transpiration of plants, decreased or even suspended at high surface temperatures. A frequency analysis of all data showed a daily frequency of high magnitude in all parameters. Possibly changes in the macro weather situation events were observed in the results of atmospheric pressure, southern electric potential and groundwater temperature. The lag time between changes in electric potential and subsurface microtemperature changes amounts to 17 hours, possibly a result of the electrical potential difference between the northern and the southern exposure of the stem (N–S), and 5 hours, the result of the change in electrical potential difference between the southern and the northern stem exposure side (S–N). A comparison between potential changes and the computed change in gravity resulting from earth tidal effects showed that the correlation between the subsurface temperature variation with up to 2 mK and the change in surface temperature variation does not match directly. Other study shows that the impact of earth tides on subsurface microtemperature variation amounts to ca. 1mK. The effect of groundwater abstraction by mature vegetation is determined at the same range. Atmospheric tides can be correlated with the changes in north and south electric potentials.

Modeling the Climatology of Low‐ and Mid‐Latitude F‐Region Ionospheric Currents Using the Swarm Constellation

AbstractWe present a new empirical model of quiet‐time F‐region ionospheric currents and associated magnetic fields. This model is designed to accurately represent these currents and fields at low and mid latitudes. For each individual Swarm satellite, the preprocessed data is represented as a non‐potential toroidal magnetic field using the Mie representation in a thin‐shell and spherical harmonic expansions. This approach allows to fully separate spatial and climatological variations as well as to assess the robustness of the model with respect to both measurement errors and data sampling with local time. The obtained model describes the toroidal magnetic fields and the associated radial poloidal electric currents at two distinct altitudes in the ionosphere F region. Clear signatures of low‐ and mid‐latitude interhemispheric field‐aligned currents (IHFACs) are identified. The model reproduces well‐known characteristics of the climatology of IHFACs and provides new insights, for example, on the average daily variations of IHFACs during winter in the Northern Hemisphere. It also well recovers the variations of IHFACs with longitude. The potential driving mechanisms of these variations, such as longitudinal variations of the main field and modulation by upward propagating atmospheric tides, are discussed. The new model can be used to analyze the relationship between atmospheric tides and IHFACs. It can also be used to investigate the connection between the magnetic fields and electric currents from the ionospheric E and F regions in order to improve the separation of these fields as well as our understanding of the overall ionospheric electric current system.

Venus-Earth seismicity related to the orbital movement

The potential seismicity of Venus has been discussed over recent decades. Even though Venusian seismic recordings are not available, measurements of sulfur dioxide (SO2) were made using sensors and were related to volcanic activity. Seismicity related to terrestrial volcanoes has been correlated with tidal effects and Venusian volcanoes to gravitational and thermal tides by solar heating. To analyze the relationship between deep seismicity, volcanic activity, and gravitational movements an analysis of time series and spectral approaches was performed. The results showed that the frequencies of SO2 emissions on Venus and Earth have concentrated in the period of ∼7.5 months and its divisions, ∼2 and ∼4 months. Venus completes its orbit every ∼7.5 months and passes between the Earth and the Sun near the quadrants. In addition, when the Earth presents higher volcanic activity, deep seismicity and Venusian SO2 decrease, and vice versa. Thus, volcanic activity on Venus could be better related to the triggers of deep earthquakes than terrestrial volcanic activity. Machine learning results presented the highest correlation with Venusian eccentricity (EC) and the argument of Periapsis (W) orbital parameters. Venusian SO2 values and deep earthquakes showed concentrations in 2009 and 2010, years where occurred repeated conjunctions, related to EC, and maximum values of orbit inclination (W). The fact that the values of SO2 emissions on Venus are more connected to the EC parameter and SO2 emissions on Earth to the W parameter may be related to perturbations that make each body move in its orbit around the Sun.

O2 (а1Δg) Airglow at 1.27 μM and upper Mesosphere Dynamics on the Night Side of Venus

This research studies the O2 (a1 Δg) nightglow distribution in 1.27 μm to understand the dynamics of the atmosphere of Venus. Several factors were considered in the retrieval process, such as thermal emission of the lower atmosphere, reflection by the clouds. Results show deviation from SS-AS circulation mode: the area where horizontal flows from the dayside converge and where oxygen recombines and emits shifts from the midnight to 22–23 hours local time. This shift is caused by solar-induced thermal tide on Venus nightside. Some conclusions about the upper mesosphere dynamics are also presented.

Analysis of Sea Surface Dynamics during the Coastal Floods in Manado

Coastal flooding is one of the serious problems facing most coastal areas in the world. On January 17 and December 7, 2021, coastal flooding hit the coastal area of Manado, North Sulawesi, Indonesia. The disaster disrupted economic activities on the coast of Manado Bay. This study analyzed the dynamics of the atmosphere and the sea during coastal flood events using water level data from the Geospatial Information Agency, which was then filtered to separate residual and atmospheric tide, and oceanographic reanalysis data of Wavewatch-III from BMKG Ocean Forecast System (OFS). The results show that events on January 17 and December 7, 2021, coincided with the occurrence of the maximum tide. The residual water level shows a significant value of around 0.2 – 0.3 m, indicating the influence of atmospheric phenomena on sea level rise. According to oceanographical data, the local wind is the main factor of flood occurrence, which is shown by wind speed data which increased wave height significantly to 1,5 m on January 17, 2021, and to 2,0 m on December 7, 2021, around Manado Bay coast. Another factor that might contribute to the event is Manado's land morphology. Further study must be conducted to discover the influence of land morphology on coastal floods.
 Keywords: Coastal flood; Water level; Tide
 
 
 Copyright (c) 2023 Geosfera Indonesia and Department of Geography Education, University of Jember
 This work is licensed under a Creative Commons Attribution-Share A like 4.0 International License

Interaction of Air Pressure and Groundwater as Main Cause of Sub‐Daily Relative Seismic Velocity Changes

AbstractOur study investigates variations of seismic velocity that occur over short time scales of hours. We use coda wave interferometry to inspect 5 months of continuous data from a seismological array in southern Germany. This results in relative seismic velocities (dv/v) that show temporal variations on the order of 10−4. Spectra of the velocity time series contain strong daily and sub‐daily behavior indicating that the daily and sub‐daily changes in the seismic velocity are primarily caused by atmospheric tides. We also note the influence of temperature changes on daily variations, but as a second‐order effect. The explanatory model focuses on depth variations of the groundwater table, linking atmospheric pressure (loading and de‐loading the Earth's surface) to variations in seismic velocity. Our results highlight an important environmental influence on seismic velocity that needs to be considered before seismic velocity variations can be used for inspecting fluid and stress variations in situ.

Effects of Forcing Uncertainties on the Thermospheric and Ionospheric States During Geomagnetic Storm and Quiet Periods

AbstractUpper‐atmospheric weather prediction is subject to various types of forcing uncertainties. Understanding the sensitivity of the thermosphere and ionosphere to forcing uncertainties under different geomagnetic conditions is critical for space weather predictions. Ensemble simulations of a whole atmospheric model, the National Center for Atmospheric Research Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (WACCM‐X), with various kinds of forcing perturbation is used to evaluate the upper atmosphere's response to the uncertainties of different forcings. Two kinds of forcing uncertainties are addressed: the lower atmospheric wave and tide forcing uncertainties and high‐latitude electric potential uncertainty. These uncertainties are estimated in different ways and applied to generate forcing perturbations in the WACCM‐X. WACCM‐X can simulate the upper atmosphere's response to the uncertainties of the lower atmospheric wave and tide forcings related to different lower atmospheric conditions. High‐latitude electric potential uncertainty is estimated based on the SuperMag and SuperDARN data through the Assimilative Mapping of Geospace Observations, which is applied to generate the forcing perturbation of high‐latitude electric potential in the WACCM‐X. The results show that the impact of high‐latitude electric potential uncertainty is significant globally during the 2013 St. Patrick's Day storm. The lower atmospheric wave and tide forcing uncertainties result in a global impact on the upper atmosphere in the model. The sensitivity of the upper atmosphere to both uncertainties is approximately the combination of the two individually, though the combined effects are not a linear sum, indicating non‐linearities in the ionosphere and thermosphere response to forcing uncertainties.

Cold Collar Reproduced by a Venus GCM With the Akatsuki Horizontal Wind Assimilation

AbstractThe thermal structure of the upper atmosphere in the Venus polar region is reproduced by the assimilation of horizontal winds in low‐ and mid‐latitudes derived from the Akatsuki ultra‐violet images. The obtained structure is well consistent with infrared and radio occultation measurements. In particular, the unique thermal features in the Venus polar vortex such as the cold collar and the warm polar region in our model are realistic: the level where the cold collar is located and the temperature difference between the cold collar and the warm polar region are consistent with data. The reasons why the thermal structure of the upper atmosphere in the Venus polar region is realistic are that the zonal wind distribution around the cloud top level and the structure of the residual mean meridional circulation induced by the thermal tides are improved with respect to the model without data assimilation. Our results also suggest that the thermal structure in the Venus upper polar region is closely related to the atmospheric dynamics.

Terdiurnal Radiational Tides

Abstract Terdiurnal atmospheric tides induce an S3 radiational ocean tide, similar to radiational tides S1 and S2 in the diurnal and semidiurnal bands. Although of small amplitude, the terdiurnal tide has some intriguing properties. The tide has an unusually pronounced seasonal variation, manifested by annual sidelines here denoted R3 and T3, which causes the tide to nearly vanish during times near an equinox. Forcing is generally largest in the winter hemisphere. Complicating matters, the two sideline frequencies coincide with those of nonlinear compound tides SK3 and SP3. Whether radiational tides or nonlinear tides (or both) are appearing at any given tide gauge can usually be determined by the relative amplitudes and phase differences of the two sidelines. The amplitudes of R3 and T3 are generally comparable; the amplitudes of SK3 and SP3 are not. Proper identification can lead to a small improvement in tidal prediction, but more importantly can lead to improved physical interpretation. An example from recent measurements under the Ross Ice Shelf bears on the role of nonlinearity in interactions between the ocean tide and the floating ice shelf.

Long‐Term Variation of the Quasi‐Five‐Day Wave in the Top Layer of Venus Clouds

AbstractPlanetary waves play an essential role in the momentum budget of Venus's atmosphere superrotation. Using the Longwave Infrared Camera (LIR) observations of the Akatsuki and their cloud‐tracking wind fields, we study the characteristics of planetary waves and their long‐term variations. The dominant planetary wave is a wavenumber 1 wave with a period of 5–6 days (Quasi‐Five‐Day wave or QFDW) and is symmetrically distributed in the midlatitudes of both hemispheres. The wave phase speed is close to the background zonal wind, indicating the possible existence of a critical level near the LIR emission altitude of 65 km. The QFDW tends to appear at ∼8:00 a.m. local time, suggesting a modulation by the thermal tide. The QFDW amplitude is correlated with the vertical shear of the background zonal wind modulated by the thermal tide. This indicates some nonlinear interaction between the thermal tide and the QFDW.

MAVEN Accelerometer Observations of Thermospheric Densities During Aerobraking and Deep Dip 2: Wave Features and Connections to Upward Propagating Thermal Tides

AbstractIn early 2019, the Mars Atmosphere and Volatile Evolution (MAVEN) mission underwent an ∼2‐month aerobraking campaign during which time the spacecraft periapsis altitude was lowered from its nominal altitude range of 140–160 km to as low as ∼123 km. Excluding spacecraft walk‐in/out maneuvers, accelerometer measurements were made along 272 orbits with coverage spanning Ls 340–3°, latitudes ∼5°–54°S, longitudes 0–360°, and local solar time ∼22–17 hr. In this study, we perform a diagnostic analysis of the full aerobraking data set by fitting 4‐harmonic waves to mass densities. We then study the variations of these waves as a function of latitude with an emphasis on those observed previously in Mars' thermosphere by MAVEN and other missions. Additionally, we utilize data collected during the same time period from the Mars Reconnaissance Orbiter's Mars Climate Sounder to study the vertical propagation of waves originating from the middle atmosphere. Key results indicate that normalized wave amplitudes decrease with latitude, and this is consistent with the latitudinal structure of a diurnal Kelvin mode. We also observe that waves imprinted from the middle atmosphere show normalized amplitude growth with increasing altitude. A complete summary of data sets, analysis methodology, and scientific results is given. The purpose of this study is to add to the body of knowledge surrounding Martian atmospheric wave features and to provide further constraints for future numerical modeling and subsequent tidal mode identification.

Delineating the effect of upward propagating migrating solar tides with the TIEGCM-ICON

Introduction: The vertical coupling of the lower and upper atmosphere via atmospheric solar tides is very variable and affects the thermosphere and ionosphere system. In this study, we use Ionospheric Connection (ICON) explorer data from 220–270 Day Of Year (DOY), 2020 when large changes in the migrating semidiurnal tide (SW2) and the zonal and diurnal mean (ZM) zonal wind occur within 8 days.Method: We use the ICON Level4 product, the thermosphere-ionosphere-electrodynamics general circulation model (TIEGCM) driven by tides fitted to ICON observations via the Hough Mode Extension (HME) method. The effect of the upward propagating tides is isolated by examining the difference between two TIEGCM simulations with and without tidal HME forcing at the model lower boundary.Results: The simulations reveals that the solar SW2 changes its latitudinal structure at 250 after DOY 232 from two peaks at mid latitudes to one broad low latitude peak, while at 110 km the two-peak structure persists. The ZM zonal wind at 250 km undergoes a similar dramatic change. These SW2 changes are associated with the prevalence of antisymmetric HMEs after DOY 232. The migrating diurnal, terdiurnal and quaddiurnal tides at 250 km undergo similar variations as SW2. TW3 is strong in the thermosphere and most likely caused by non-linear tidal interaction between DW1 and SW2 above 130 km. Surprisingly, the solar in situ forcing of TW3 and SW2 in the upper thermosphere is not nearly as important as their upward propagating tidal component. Associated with the strong dynamical changes, the zonal and diurnal mean NmF2 decreases by approximately 15%–20%, which has a major contribution from the O/N2 decrease by roughly 10%. These changes are stronger than general seasonal behavior.Discussion: While studies have reported on the dynamical changes via SW2 in the mesosphere-lower thermosphere (MLT) region during the equinox transition period, this study is, to our knowledge, the first to examine the effects of rapid changes in SW2 on the upper thermosphere and ionosphere. The study highlights the potential of using ICON-TIEGCM for scientific studies.

Near Surface Atmospheric Temperatures at Jezero From Mars 2020 MEDA Measurements

AbstractThe Mars Environmental Dynamics Analyzer instrument on Mars 2020 has five Atmospheric Temperature Sensors at two altitudes (0.84 and 1.45 m) plus a Thermal InfraRed Sensor that measures temperatures on the surface and at ∼40 m. We analyze the measurements from these sensors to describe the evolution of temperatures in Jezero up to mission sol 400 (solar longitude LS = 13°–203°). The diurnal thermal cycle is characterized by a daytime convective period and a nocturnal stable atmosphere with a variable thermal inversion. We find a linear relationship between the daytime temperature fluctuations and the vertical thermal gradient with temperature fluctuations that peak at noon with typical values of 2.5 K at 1.45 m. In the late afternoon (∼17:00 Local True Solar Time), the atmosphere becomes vertically isothermal with vanishing fluctuations. We observe very small seasonal changes in air temperatures during the period analyzed. This is related to small changes in solar irradiation and dust opacity. However, we find significant changes in surface temperatures that are related to the variety of thermal inertias of the terrains explored along the traverse of Perseverance. These changes strongly influence the vertical thermal gradient, breaking the nighttime thermal inversion over terrains of high thermal inertia. We explore possible detections of atmospheric tides on near‐surface temperatures and we examine variations in temperatures over timescales of a few sols that could be indicative of atmospheric waves affecting near‐surface temperatures. We also discuss temperatures during a regional dust storm at LS = 153°–156° that simultaneously warmed the near surface atmosphere while cooling the surface.

GOLD Synoptic Observations of Thermospheric Annual and Semiannual Variations in Composition During Solar Minimum Years

AbstractThis study investigates thermospheric seasonal variations composed of annual and semiannual oscillations (AO and SAO) in the column density ratio of atomic oxygen to molecular nitrogen observed by Global‐scale Observations of Limb and Disk. On the basis of multiple analysis approaches, it is revealed that the AO is the predominant component at middle latitudes, while the SAO tends to be increasingly important toward the lower latitudes. The SAO is also evident in the southern mid‐latitudes. Quantitative analyses demonstrate that AO (SAO) peaks around winter solstices (equinoxes). Additionally, the seasonal variation at low‐latitudes exhibits greater amplitudes in the early morning and around noon, whereas it gradually weakens from early morning toward late afternoon at mid‐latitudes. A hypothesis is that seasonal variations are likely modulated by atmospheric tides, including those generated in the thermosphere and those propagating upward from the lower atmosphere.

Dynamical Core Damping of Thermal Tides in the Martian Atmosphere

Abstract Atmospheric oscillations with daily periodicity are observed in in situ near-surface pressure, temperature, and winds observations and also in remotely sensed temperature and pressure observations of the Martian atmosphere. Such oscillations are interpreted as thermal tides driven by the diurnal cycle of solar radiation and occur at various frequencies, with the most prominent being the diurnal, semidiurnal, terdiurnal, and quadiurnal tides. Mars global circulation models reproduce these tides with varying levels of success. Until recently, both the MarsWRF and newly developed MarsMPAS models were able to produce realistic diurnal and semidiurnal tide amplitudes but predicted higher-order mode amplitudes that were significantly weaker than observed. We use linear wave analysis to show that the divergence damping applied within both MarsWRF and MarsMPAS is responsible for suppressing the amplitude of thermal tides with frequency greater than 2 per sol, despite being designed to suppress only acoustic wave modes. Decreasing the strength of the divergence damping in MarsWRF and MarsMPAS allows for excellent prediction of the higher-order tidal modes. This finding demonstrates that care must be taken when applying numerical dampers and filters that may eliminate some desired dynamical features in planetary atmospheres.

Martian Atmospheric Temperature and Density Profiles During the First Year of NOMAD/TGO Solar Occultation Measurements

AbstractWe present vertical profiles of temperature and density from solar occultation (SO) observations by the “Nadir and Occultation for Mars Discovery” (NOMAD) spectrometer on board the Trace Gas Orbiter during its first operational year, which covered the second half of Mars Year 34. We used calibrated transmittance spectra in 380 scans, and apply an in‐house pre‐processing to clean data systematics. Temperature and CO2 profiles up to about 90 km, with consistent hydrostatic adjustment, are obtained, after adapting an Earth‐tested retrieval scheme to Mars conditions. Both pre‐processing and retrieval are discussed to illustrate their performance and robustness. Our results reveal the large impact of the MY34 Global Dust Storm (GDS), which warmed the atmosphere at all altitudes. The large GDS aerosols opacity limited the sounding of tropospheric layers. The retrieved temperatures agree well with global climate models (GCM) at tropospheric altitudes, but NOMAD mesospheric temperatures are wavier and globally colder by 10 K in the perihelion season, particularly during the GDS and its decay phase. We observe a warm layer around 80 km during the Southern Spring, especially in the Northern Hemisphere morning terminator, associated to large thermal tides, significantly stronger than in the GCM. Cold mesospheric pockets, close to CO2 condensation temperatures, are more frequently observed than in the GCM. NOMAD CO2 densities show oscillations upon a seasonal trend that track well the latitudinal variations expected. Results uncertainties and suggestions to improve future data re‐analysis are briefly discussed.

Three-dimensional modeling of Venus photochemistry and clouds

We present here three-dimensional simulations of the Venus photochemistry and clouds from the ground to the bottom of the thermosphere. For that purpose, we have implemented a state-of-the-art photochemical and equilibrium cloud model in the Venus Planetary Climate Model (Venus PCM). The interactive coupling between dynamics, radiation, chemistry and clouds allows a comprehensive description of the CO2, CO, sulfur, chlorine, oxygen, and hydrogen species, with tracking of the condensed phase. Regarding the clouds, the Venus PCM calculates the composition, number density, and sedimentation rates of the binary H2SO4-H2O liquid aerosols, based on observed altitude-dependent size distributions. The article describes in detail the new components implemented in the Venus PCM. It then presents an overview of the results concerning clouds and atmospheric chemistry, which are compared with a wide range of observations. The modeled cloud characteristics and vertical profiles of minor species are found to be in broad agreement with most of the measurements available between 30 and 100 km. In particular, the Venus PCM reproduces the steep decrease of H2O and SO2 mixing ratio inside the cloud layer, as well as the observed vertical distribution of species well identified above the clouds, such as CO and O3. The model also agrees with the ground-based measurements of HCl, but not with the conflicting HCl vertical profiles derived from Venus Express. On the quasi-horizontal plane, latitudinal contrasts in the modeled trace species mostly result from the Hadley-type mean meridional circulation. Large-scale longitudinal variations are essentially created by the diurnal thermal tide above the clouds, and by photolysis above 80 km.