Climatology of semidiurnal lunar and solar tides at middle and high latitudes: Interhemispheric comparison

Abstract

The semidiurnal lunar and solar tides obtained from meteor radar measurements spanning from 2009 to 2013 observed at Davis (69°S) and Rio Grande (54°S) are presented and compared to the Northern Hemisphere ones at Andenes (69°N) and Juliusruh (54°N). Mean tidal differences for both intrahemispheric and interhemispheric scenarios are analyzed. Tidal behavior is also compared against numerical simulations during 2009 and 2013 sudden stratospheric warming (SSW) time periods. Possible influences in the Southern Hemisphere from the local stratosphere are also investigated using Modern Era Retrospective analysis for Research and Applications, version 2 (MERRA 2) data sets. The main features of the mean zonal wind are similar in both hemispheres, i.e., stronger amplitudes over midlatitude locations, eastward winds during winter and westward below 90 km with eastward higher up during corresponding summer times. On the other hand, the semidiurnal solar tides observed in the Southern Hemisphere show clear differences when compared to the Northern Hemisphere and between middle‐ and high‐latitude locations at the same hemisphere. These differences are even larger for the semidiurnal lunar tide, which shows stronger amplitudes from October to March and March to October, over Davis and Rio Grande, respectively. Our results indicate that the lunar tides over the Southern Hemisphere midlatitudes are more prone to react to the Northern Hemisphere stratospheric polar vortex influences, in agreement with numerical simulations, particularly for the time of the 2013 SSW.

Relations Between Semidiurnal Tidal Variants Through Diagnosing the Zonal Wavenumber Using a Phase Differencing Technique Based on Two Ground‐Based Detectors

“…These arrows, in total 60, are dominantly pointing toward m = 2, suggested by their average displayed as the black arrow. displays a significant seasonal variation and maximizes in the winter, December, January, and February, which is consistent with the climatology (e.g., Conte et al, ), and further demonstrates the robustness of our technique.…”

Mesospheric semidiurnal tides and near-12 h waves through jointly analyzing observations of five specular meteor radars from three longitudinal sectors at boreal midlatitudes

“…The scatters are further averaged seasonally displayed as the solid red, green, and blue lines, summarizing the main seasonal variations of SW1, SW2, and SW3. SW2 is characterized by two comparable peaks in September and in December and steep decreases in September-October and March-April (DoY 250-300 and 0-80), which is consistent with the seasonal variation of the 12.0 h harmonic amplitude (S2) observed from single-radar analyses (as used in, e.g., Conte et al, 2018), although the SW1 and SW3 are not negligible in comparison with SW2. SW1 is characterized by a single peak appearing in winter and a minimum in summer, which are largely consistent with thermospheric seasonal variation of SW1 at 50 • N according to CHAMP observations (Fig.…”

Middle‐ and High‐Latitude Mesosphere and Lower Thermosphere Mean Winds and Tides in Response to Strong Polar‐Night Jet Oscillations

“…The specular meteor radars (SMRs) located at the sites of Andenes (69.3 • N, 16 • E) and Juliusruh (54.6 • N, 13.3 • E) have been extensively used to study neutral winds and atmospheric waves in the MLT region (e.g., Chau et al, 2015;Hoffmann et al, 2007Hoffmann et al, , 2010Conte et al, 2017Conte et al, , 2018Wilhelm et al, 2017). Combined, they provide continuous measurements for a set that is currently comprised of more than 15 years worth of data.…”