Simultaneous observations of the quasi 2-day wave climatology over the low and equatorial latitudes in the mesosphere lower thermosphere

Kumar, Karanam Kishore; Subrahmanyam, K. V.; Mathew, Sneha Susan; Koushik, N.; Ramkumar, Geetha

doi:10.1007/s00382-017-3916-2

Cited by 12 publications

(7 citation statements)

References 34 publications

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“…The mean winds over the three radar sites show very good agreement. These height-month sections of winds over Thumba and Kototabang are comparable to the climatology of the winds reported by Kumar et al (2017). It can be noted that the westward winds during the spring season are relatively stronger as compared to those of the fall season.…”

Section: 1029/2019ja026510supporting

confidence: 83%

“…However, all the three locations exhibit pronounced annual oscillations in the meridional winds as shown in Figure 8. These height-month sections of winds over Thumba and Kototabang are comparable to the climatology of the winds reported by Kumar et al (2017). It is known that the semiannual oscillation in the zonal winds over the equatorial and lowlatitude MLT region is driven by the wave-mean flow interactions (planetary as well as gravity wave interactions with background flow), which in turn are modulated by the stratospheric winds (Antonita et al, 2008).…”

Section: Casesupporting

confidence: 81%

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Meteor Radar Estimations of Gravity Wave Momentum Fluxes: Evaluation Using Simulations and Observations Over Three Tropical Locations

Pramitha¹,

Kumar

Ratnam

et al. 2019

JGR Space Physics

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Meteor radars are widely used to study gravity wave (GW) variances and their momentum fluxes at the altitudes where meteor counts are sufficient to yield good statistical fits to the data. These radars provide hourly zonal and meridional wind observations round the clock in 80‐ to 100‐km height domain. However, the capability of meteor radars in estimating GW momentum fluxes should be evaluated before they can be used for any research applications. In this regard, the present study evaluates the meteor radar observations of GW momentum fluxes obtained from Thumba (8.5°N, 77°E; 2006–2015), Kototabang (0.2°S, 100.3°E; 2002–2017), and Tirupati (13.63°N, 79.4°E; 2013–2018) using three‐dimensional wind field simulations, which include specified tidal, planetary and GW fields. A modified composite day analysis is adopted to estimate the GW momentum fluxes, which also accounts for the tidal and planetary wave contributions. The results showed that the retrieved and specified GW momentum fluxes agree very well over Tirupati followed by Thumba and Kototabang. It is noted that the agreement between the retrieved and simulated fields depend on the number of meteor detections used in the analysis. After evaluating the meteor radar retrieved GW momentum fluxes by employing simulations, their interannual variability and climatologies over the three observational locations are constructed. The significance of the present study lies in evaluating the capability of three meteor radars located in equatorial and low‐latitudes in estimating GW momentum fluxes by employing three‐dimensional wind field simulations with specified mean winds, tidal, planetary, and GW fields.

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Section: 1029/2019ja026510supporting

confidence: 83%

Section: Casesupporting

confidence: 81%

Meteor Radar Estimations of Gravity Wave Momentum Fluxes: Evaluation Using Simulations and Observations Over Three Tropical Locations

Pramitha¹,

Kumar

Ratnam

et al. 2019

JGR Space Physics

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“…The Q2DW at middle latitudes has been reported to reach maximum amplitudes during the summer (e.g., Kumar et al., 2018). In our results, the Q2DW is active mostly in summer, in agreement with previous studies.…”

Section: Resultsmentioning

confidence: 99%

First Studies of Mesosphere and Lower Thermosphere Dynamics Using a Multistatic Specular Meteor Radar Network Over Southern Patagonia

Conte

Chau

Urco

et al. 2021

Earth and Space Science

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“…Meanwhile, the barotropic/baroclinic instabilities also contribute to the amplifications of planetary waves through wave‐mean flow interaction (Wang et al, ). Finally, maximum wave amplitudes of 50–100 m/s and 10–20 K are identified in the mesosphere and lower thermosphere region for wind and temperature components, respectively (Kumar et al, ; Rao et al, ), which are then weakened quickly in the lower thermosphere due the strong molecular dissipation (Yue et al, ). The strong momentum flux deposited to the background state causes additional variations in the residual circulation, which results in the couplings between different atmospheric layers and the change of atmospheric compositions (Gan et al, ; Gu, Lei, et al, ; Gu, Liu, et al, ; Yue & Wang, ).…”

Section: Introductionmentioning

confidence: 99%

Climatology and Anomaly of the Quasi‐Two‐Day Wave Behaviors During 2003–2018 Austral Summer Periods

Dou

Yang

et al. 2019

JGR Space Physics

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The Sounding of the Atmosphere using Broadband Emission Radiometry satellite instrument has been measuring the mesospheric global temperature since February 2002, providing the longest continuous data set to statistically study the climatology and anomaly of the quasi‐two‐day waves (QTDWs), including the westward zonal wave number 2 (W2), 3 (W3), and 4 (W4) modes. It is found that the W2 QTDW generally peaks earliest, followed by the W3 mode with the W4 QTDW being amplified lastly. This temporal pattern is always disordered during the sudden stratospheric warming (SSW) periods. The temperature oscillations of the QTDW usually peak at nearly the same period at different altitudes and different latitudes for a certain case but would be different from year to year. The statistical results show that the periods of the W2 QTDWs are more frequently observed to be at 45–48 hr and the periods of the W3 mode are mostly confined between 45 and 52 hr. Nevertheless, the oscillations of the W4 QTDW peak more dispersedly between 41 and 56 hr. The W3 QTDW is usually the strongest among the three modes, whereas it is sometimes equal to or even weaker than W2 and W4 QTDWs, especially during SSW periods. Besides, we found that the vertical distribution of the W3 QTDW splits into a bimodal structure during the SSW periods of 2006 and 2011. And the solar cycle trend of the QTDWs is frequently disturbed by a 2‐ to 5‐year variability, which seems to be a common feature for all the QTDW modes.

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Simultaneous observations of the quasi 2-day wave climatology over the low and equatorial latitudes in the mesosphere lower thermosphere

Cited by 12 publications

References 34 publications

Meteor Radar Estimations of Gravity Wave Momentum Fluxes: Evaluation Using Simulations and Observations Over Three Tropical Locations

Meteor Radar Estimations of Gravity Wave Momentum Fluxes: Evaluation Using Simulations and Observations Over Three Tropical Locations

First Studies of Mesosphere and Lower Thermosphere Dynamics Using a Multistatic Specular Meteor Radar Network Over Southern Patagonia

Climatology and Anomaly of the Quasi‐Two‐Day Wave Behaviors During 2003–2018 Austral Summer Periods

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