scholarly journals Tidal variability in the ionospheric dynamo region

2008 ◽  
Vol 113 (A2) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. M. Forbes ◽  
X. Zhang ◽  
S. Palo ◽  
J. Russell ◽  
C. J. Mertens ◽  
...  
Keyword(s):  
Ionospheric Dynamo ◽  
Tidal Variability

scholarly journals Impact of semidiurnal tidal variability during SSWs on the mean state of the ionosphere and thermosphere

2016 ◽  
Vol 121 (8) ◽  
pp. 8077-8088 ◽  
Author(s):  
N. M. Pedatella ◽  
A. D. Richmond ◽  
A. Maute ◽  
H.‐L. Liu
Keyword(s):  
The Mean ◽  
Tidal Variability ◽  
Mean State

The conductive dusty ionosphere of Saturn

2021 ◽  
Author(s):  
Oleg Shebanits ◽  
Lina Hadid ◽  
Hao Cao ◽  
Michiko Morooka ◽  
Michele Dougherty ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Dusty Plasma ◽  
Local Time ◽  
Equatorial Region ◽  
In Situ Measurements ◽  
Ionospheric Dynamo ◽  
Magnetometer Data ◽  
Remote Measurements

<p>Cassini’s Grand Finale orbits brought us historical first in-situ measurements of Saturn’s ionosphere, showing that it contains dusty plasma in the equatorial region. We present the Pedersen and Hall conductivities of the top ionosphere (10:50 – 12:17 Saturn Local Time, 10N – 20S planetocentric latitude), derived from particle and magnetometer data. We constrain the Pedersen conductivities to be at least 10<sup>-5</sup> – 10<sup>-4</sup> S/m at ionospheric peak, a factor 10-100 higher than estimated previously by remote measurements, while the Hall conductivities are very close to 0 or in fact negative. We show that this is an effect of dusty plasma. Another effect is that ionospheric dynamo region thickness is increased to 300-800 km. Furthermore, our results suggest a temporal variation (decrease) of the plasma densities, mean ion masses and consequently the conductivities over the period of one month.</p>

Mesopause-region tidal variability observed by meteor radar

1997 ◽  
Vol 20 (6) ◽  
pp. 1237-1240 ◽  
Author(s):  
A.G. Beard ◽  
N.J. Mitchell ◽  
P.J.S. Williams ◽  
W. Jones ◽  
H.G. Muller
Keyword(s):  
Meteor Radar ◽  
Mesopause Region ◽  
Tidal Variability

scholarly journals Tidal variability in the Hong Kong region

2018 ◽  
Author(s):  
Adam T. Devlin ◽  
Jiayi Pan ◽  
Hui Lin
Keyword(s):  
Hong Kong ◽  
Coastal Development ◽  
Strong Correlations ◽  
Full Spectrum ◽  
Sea Levels ◽  
Close Analysis ◽  
Tidal Variability ◽  
The Taiwan Strait ◽  
Flooding Events ◽  
Tidal Response

Abstract. Mean sea-level (MSL) is rising worldwide, and correlated changes in ocean tides are also occurring; their combination may influence future total sea-levels (TSL), possibly increasing coastal inundation and nuisance flooding events in sensitive regions. Analyses of a set of tide gauges in Hong Kong and in the South China Sea (SCS) reveal complex tidal behavior. Most prominent in the results are strong correlations of MSL variability to tidal variability which may further increase local flood levels under future MSL rise. We also highlight inter-tidal correlations of diurnal (D1) tides to semidiurnal (D2) tides, positively reinforced through the northern SCS, and the correlations of overtide (OT) fluctuations to D1 and D2, negatively reinforced (i.e., anti-correlated) across the same region, thought to be related to the baroclinic energetics in the Luzon Strait and the Taiwan Strait. The baroclinic signals may be enhanced at the northern shelf of the SCS and can generate PSI interactions that may amplify minor tides such as M3. Additionally, there are anomalous tidal events observed in some enclosed harbor regions of Hong Kong, corresponding to times of rapidly changing MSL as well as rapid coastal development projects. Results support the hypothesis that the observed variability is due to multiple spatial processes, best described as an amplification of the local (Hong Kong) tidal response to the prevailing regional (SCS) tidal patterns, enhanced by local harbor changes. A close analysis of the full-spectrum tidal response suggests that a change in the resonant and frictional response may have occurred.

scholarly journals Aliased Tidal Variability in Mesoscale Sea Level Anomaly Maps

2018 ◽  
Vol 35 (12) ◽  
pp. 2421-2435 ◽  
Author(s):  
Edward D. Zaron ◽  
Richard D. Ray
Keyword(s):  
Sea Level ◽  
High Frequency ◽  
Objective Assessment ◽  
Coastal Ocean ◽  
Open Ocean ◽  
Objective Analysis ◽  
Small Scale ◽  
Phase Variable ◽  
Sea Level Anomaly ◽  
Tidal Variability

AbstractSea level anomaly (SLA) maps are routinely produced by objective analysis of data from the constellation of satellite altimeter missions in operation since 1992. Beginning in 2014, changes in the Data Unification and Altimeter Combination System (DUACS) used to create the SLA maps resulted in improved spatial resolution of mesoscale variability, but it also increased the levels of aliased tidal variability compared to the methodology employed prior to 2014. The present work investigates the magnitude and spatial distribution of these tidal signals, which are typically smaller than 1 cm in the open ocean but can reach tens of centimeters in the coastal ocean. In the open ocean, the signals are caused by a combination of phase-locked and phase-variable baroclinic tides. In the coastal ocean, the signals are a combination of aliased high-frequency nontidal variability and aliased variability caused by erroneous tidal corrections applied to the along-track altimetry prior to objective analysis. Several low-pass and bandpass filters are implemented to reduce the tidal signals in the mapped SLA, and independent tide gauge data are used to provide an objective assessment of the performance of the filters. The filter that attenuates both the small-scale (less than 200 km) and the high-frequency (period shorter than 108 days) components of SLA removes aliased baroclinic tidal variability and improves the accuracy of tidal analysis in the open ocean while also performing acceptably in the coastal ocean.

Sign in / Sign up

Export Citation Format

Share Document