Response of Planetary Waves and Tides to the 2019 Southern Hemisphere Ssw and q2dw Enhancement in Jan-Feb 2020 Observed by Condor Meteor Radar in Chile and Adelaide Meteor Radar in Australia

A new multi-static meteor radar (CONDOR) has recently been installed in northern Chile. This CONDOR meteor radar (30.3°S, 70.7°W) and the Adelaide meteor radar (35°S, 138°E) have provided longitudinally spaced observations of the mean winds, tides and planetary waves of the PW-tides interaction cases we present here. We have observed a Quasi-6-Day Wave (Q6DW) enhancement in MLT winds at the middle latitudes (30.3°S, 35°S) during the unusual minor South Hemisphere SSW 2019 by the ground-based meteor radars. Tidal analysis also indicates modulation of the Q6DW w/ amplitude ~15 [m/s] and diurnal tides w/ amplitude ~60 [m/s]. Another case we present here is a dominant Quasi-2-Day Wave (Q2DW) with up to 50 [km/s] amplitude occurring in SH summer 2020 and its interaction with the diurnal and semidiurnal tides. The period of this Q2DW activity changes from ~50hr to ~48hr since Jan 19, which suggests the phase locking mechanism [McCormack et al., 2010]. The 24hr-feature and 12hr-feature show off-phase variations during the Q2DW enhancement time with amplitude of ~40 [m/s]

Infrastructure needs on latitudinal and longitudinal chains of co-located ground-based observations

The generation, propagation, and dissipation of atmospheric planetary waves (PW), tides, and gravity waves (GW) constitute the primary mechanism that transfers energy and momentum from the atmosphere to space. While single-location ground-based observations have been making successful measurements of such waves over the past decades, NSF funded ground-based observations are not yet systematically distributed at the same latitude or the same longitude, despite the importance of latitudinal and longitudinal dependence of dynamical processes like large scale wave propagation, interaction, and dissipation. This white paper discusses the significance and potential of coordinating a chain of ground-based instruments with the current large facilities to extend the latitudinal and longitudinal observational coverage in the American sector (both South and North America). We further discuss the benefits of co-locating heterogeneous instruments with different techniques and different temporal/spatial resolution/coverage, for instance, radio instruments (e.g., ISR, HF radar, meteor radar), optical instruments (e.g., FPI, lidar, airglow imager), magnetometers, ionosondes, sounding rockets and so on

Gravity Waves Generated by the Hunga Tonga-Hunga Ha‘Apai Volcanic Eruption and Their Global Propagation in The Mesosphere/Lower Thermosphere Observed by Meteor Radars And Modeled With the High-Altitude General Mechanistic Circulation Model

The Hunga Tonga-Hunga Ha‘apai volcano erupted on 15th January 2022, launching Lamb waves and gravity waves into the atmosphere. In this study, we present results using 13 globally distributed meteor radars and identify the volcanic- caused gravity waves in the mesospheric/lower thermospheric winds. Leveraging the High-Altitude Mechanistic General Circulation Model (HIAMCM), we compare the global propagation of these gravity waves. We observed an eastward propagating gravity wave packet with an observed phase speed of 240±5.7 m/s and a westward propagating gravity wave with an observed phase speed of 166.5 ±6.4 m/s. We identified these waves in the HIAMCM and obtained very good agreement of the observed phase speeds of 239.5±4.3 m/s and 162.2±6.1 m/s for the eastward and the westward waves, respectively. Considering that HIAMCM perturbations in the mesosphere/lower thermosphere were the result of the secondary waves generated by the dissipation of the primary gravity waves from the volcanic eruption affirms the importance of higher-order wave generation. Furthermore, based on meteor radar observations of the gravity wave propagation around the globe, we estimate the eruption time to be within 6 minutes of the nominal value of 15th January 2022 04:15 UTC and localized the volcanic eruption to be within 78 km relative to the World Geodetic System 84 coordinates of the volcano confirming our estimates to be realistic

Comparison of MLT Momentum Fluxes Over the Andes at Four Different Latitudinal Sectors Using Multistatic Radar Configurations

The middle atmosphere over South America, particularly above the Andes mountain range, is known as one of the most dynamically active regions in the world. Previous studies have investigated wave dynamics at mesosphere and lower thermosphere (MLT) altitudes within this region, but only a handful of them have made use of continuous measurements provided by specular meteor radars (SMRs). Furthermore, it was only until recently that MLT horizontal wind gradients were estimated for the first time using Spread Spectrum Interferometric Multistatic meteor radar Observing Network (SIMONe) Argentina, a multistatic SMR network located in southern Patagonia. By observing larger amounts of meteors from different viewing angles, multistatic SMRs allow, among others, for more reliable momentum flux estimates. In this work, we explore and compare the summer and winter MLT momentum flux dynamics at low and middle latitude sectors over the Andes mountain range. We also investigate the intermittency of the total momentum flux over these sectors. For this purpose, we analyze measurements provided by four multistatic SMR networks: SIMONe Peru (12°S), CONDOR (30°S), SIMONe Argentina (49°S) and MMARIA-SAAMER (54°S). We find that the momentum flux dynamics can change considerably over distances of only a few hundred km (e.g., southern Argentina). On the other hand, the contributions of large momentum fluxes to the total flux can be similar between regions separated by thousands of km (e.g., between Peru and southern Argentina)

Atmospheric Tomography Using the Nordic Meteor Radar Cluster And Chilean Observation Network de Meteor Radars: Network Details and 3D-Var Retrieval

Ground-based remote sensing of atmospheric parameters is often limited to single station observations by vertical profiles at a certain geographic location. This is a limiting factor for investigating gravity wave dynamics as the spatial information is often missing, e.g., horizontal wavelength, propagation direction or intrinsic frequency. In this study, we present a new retrieval algorithm for multistatic meteor radar networks to obtain tomographic 3-D wind fields within a pre-defined domain area. The algorithm is part of the Agile Software for Gravity wAve Regional Dynamics (ASGARD) and called 3D-Var, and based on the optimal estimation technique and Bayesian statistics. The performance of the 3D-Var retrieval is demonstrated using two meteor radar networks: the Nordic Meteor Radar Cluster and the Chilean Observation Network De Meteor Radars (CONDOR). The optimal estimation implementation provide statistically sound solutions and diagnostics from the averaging kernels and measurement response. We present initial scientific results such as body forces of breaking gravity waves leading to two counter-rotating vortices and horizontal wavelength spectra indicating a transition between the rotational k-3 and divergent k-5/3 mode at scales of 80–120 km. In addition, we performed a keogram analysis over extended periods to reflect the latitudinal and temporal impact of a minor sudden stratospheric warming in December 2019. Finally, we demonstrate the applicability of the 3D-Var algorithm to perform large-scale retrievals to derive meteorological wind maps covering a latitude region from Svalbard, north of the European Arctic mainland, to central Norway

Gravity waves generated by the Hunga Tonga–Hunga Ha′apai volcanic eruption and their global propagation in the mesosphere/lower thermosphere observed by meteor radars and modeled with the High-Altitude general Mechanistic Circulation Model

The Hunga Tonga–Hunga Ha′apai volcano erupted on 15 January 2022, launching Lamb waves and gravity waves into the atmosphere. In this study, we present results using 13 globally distributed meteor radars and identify the volcanogenic gravity waves in the mesospheric/lower thermospheric winds. Leveraging the High-Altitude Mechanistic general Circulation Model (HIAMCM), we compare the global propagation of these gravity waves. We observed an eastward-propagating gravity wave packet with an observed phase speed of 240 ± 5.7 m s−1 and a westward-propagating gravity wave with an observed phase speed of 166.5 ± 6.4 m s−1. We identified these waves in HIAMCM and obtained very good agreement of the observed phase speeds of 239.5 ± 4.3 and 162.2 ± 6.1 m s−1 for the eastward the westward waves, respectively. Considering that HIAMCM perturbations in the mesosphere/lower thermosphere were the result of the secondary waves generated by the dissipation of the primary gravity waves from the volcanic eruption, this affirms the importance of higher-order wave generation. Furthermore, based on meteor radar observations of the gravity wave propagation around the globe, we estimate the eruption time to be within 6 min of the nominal value of 15 January 2022 04:15 UTC, and we localized the volcanic eruption to be within 78 km relative to the World Geodetic System 84 coordinates of the volcano, confirming our estimates to be realistic

Evidence for SSW triggered Q6DW-Tide-Gravity Wave interactions observed by meteor radars at 30ºS

This data set contains the data used for the figures of the letter "Evidence for SSW triggered Q6DW-Tide-Gravity Wave interactions observed by meteor radars at 30ºS".</p

Code for "Mesospheric Temperature and Circulation Response to the Hunga Tonga-Hunga-Ha'apai Volcanic Eruption"

&lt;p&gt;This upload contains all the code used in the journal article "Mesospheric Temperature and Circulation Response to the Hunga Tonga-Hunga-Ha'apai Volcanic Eruption" (DOI: 10.1029/2023JD039636). The description of each file is as follows:&lt;/p&gt;&lt;p&gt;Functions:&lt;/p&gt;&lt;p&gt;&nbsp; load_functions.py:&lt;/p&gt;&lt;p&gt;&nbsp; &nbsp; Python code to load all functions, including basic functions in functions_basics.py; trend models and PMC models in functions_models.py; functions related to I/O in functions_io.py; related to statistics in functions_statistics.py; related to plotting in functions_plot.py, related to physics in functions_physics.py; and functions that grid the data into funtions_grid.py.&lt;/p&gt;&lt;p&gt;Other code:&lt;/p&gt;&lt;p&gt;&nbsp; figs_for_paper.ipynb:&lt;/p&gt;&lt;p&gt;&nbsp; &nbsp; the Jupyter Notebook that generates all figures and tabless for this paper.&lt;/p&gt;&lt;p&gt;&nbsp; residual_circulation.py:&lt;/p&gt;&lt;p&gt;&nbsp; &nbsp; python code that calculate the variables related to residual circulation&lt;/p&gt;&lt;p&gt;&nbsp; download.sh:&nbsp;&lt;/p&gt;&lt;p&gt;&nbsp; &nbsp; bash script that downloads SABER data&nbsp;&lt;/p&gt;&lt;p&gt;&nbsp; grid_saber.py:&lt;/p&gt;&lt;p&gt;&nbsp; &nbsp; python code that grids SABER data&lt;/p&gt;&lt;p&gt;&nbsp;&nbsp;&lt;/p&gt

Comparison of MLT Momentum Fluxes Over the Andes at Four Different Latitudinal Sectors Using Multistatic Radar Configurations

The middle atmosphere over South America, particularly above the Andes mountain range, is known as one of the most dynamically active regions in the world. Previous studies have investigated wave dynamics at mesosphere and lower thermosphere (MLT) altitudes within this region, but only a handful of them have made use of continuous measurements provided by specular meteor radars (SMRs). Furthermore, it was only until recently that MLT horizontal wind gradients were estimated for the first time using Spread Spectrum Interferometric Multistatic meteor radar Observing Network (SIMONe) Argentina, a multistatic SMR network located in southern Patagonia. By observing larger amounts of meteors from different viewing angles, multistatic SMRs allow, among others, for more reliable momentum flux estimates. In this work, we explore and compare the summer and winter MLT momentum flux dynamics at low and middle latitude sectors over the Andes mountain range. We also investigate the intermittency of the total momentum flux over these sectors. For this purpose, we analyze measurements provided by four multistatic SMR networks: SIMONe Peru (12°S), CONDOR (30°S), SIMONe Argentina (49°S) and MMARIA-SAAMER (54°S). We find that the momentum flux dynamics can change considerably over distances of only a few hundred km (e.g., southern Argentina). On the other hand, the contributions of large momentum fluxes to the total flux can be similar between regions separated by thousands of km (e.g., between Peru and southern Argentina)

Atmospheric Tomography Using the Nordic Meteor Radar Cluster And Chilean Observation Network de Meteor Radars: Network Details and 3D-Var Retrieval

Ground-based remote sensing of atmospheric parameters is often limited to single station observations by vertical profiles at a certain geographic location. This is a limiting factor for investigating gravity wave dynamics as the spatial information is often missing, e.g., horizontal wavelength, propagation direction or intrinsic frequency. In this study, we present a new retrieval algorithm for multistatic meteor radar networks to obtain tomographic 3-D wind fields within a pre-defined domain area. The algorithm is part of the Agile Software for Gravity wAve Regional Dynamics (ASGARD) and called 3D-Var, and based on the optimal estimation technique and Bayesian statistics. The performance of the 3D-Var retrieval is demonstrated using two meteor radar networks: the Nordic Meteor Radar Cluster and the Chilean Observation Network De Meteor Radars (CONDOR). The optimal estimation implementation provide statistically sound solutions and diagnostics from the averaging kernels and measurement response. We present initial scientific results such as body forces of breaking gravity waves leading to two counter-rotating vortices and horizontal wavelength spectra indicating a transition between the rotational k-3 and divergent k-5/3 mode at scales of 80–120 km. In addition, we performed a keogram analysis over extended periods to reflect the latitudinal and temporal impact of a minor sudden stratospheric warming in December 2019. Finally, we demonstrate the applicability of the 3D-Var algorithm to perform large-scale retrievals to derive meteorological wind maps covering a latitude region from Svalbard, north of the European Arctic mainland, to central Norway