Causative mechanisms for the occurrence of a triple layered mesospheric inversion event over low latitudes

Ramesh, K.; Sridharan, S.; Rao, S. Vijaya Bhaskara

doi:10.1002/2013ja019750

Cited by 6 publications

(9 citation statements)

References 59 publications

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“…Further, high solar activity enhances the photolysis of O 2 (O 2 + hν → O + O) in the lower thermosphere and increases [O] in the mesopause region through downward diffusion or mean advection. This enhanced O produces more heating rates through the exothermic reaction, R 5 above ~90–95 km [ Mlynczak and Solomon , ; Ramesh et al ., ]. Thus, the mesopause temperatures are comparatively larger (smaller) during solar active (quite) conditions.…”

Section: Discussionmentioning

confidence: 99%

“…SABER level 2A files of version 2.0 (V2.0) have the vertical profiles of temperature, number density, volume mixing ratios of ozone (O 3 ), atomic oxygen (O), atomic hydrogen (H), and the volume emission rates of O 2 and OH profiles. Likewise, SABER level 2B files of V2.0 have IR radiative cooling rates of CO 2 , O 3 , and H 2 O; solar heating rates of O 2 and O 3 of different absorption bands; and chemical heating rates due to dominant seven exothermic reactions between (H + O 2 ), (H + O 3 ), (O + O 3 ), (O + OH), (O + HO 2 ), (O + O), and (O + O 2 ) [ Mlynczak and Solomon , , ; Ramesh et al ., , ]. All these data sets are downloaded from ftp://saber.gats-inc.com/ in the latitude band, 10°N–15°N for 2002–2012.…”

Section: Databasementioning

confidence: 99%

“…Since the temperature is the key parameter for identifying the mesopause altitude (the altitude of secondary minimum in temperature profile), the TIMED-SABER zonal mean temperatures in the latitude region of 10°N-15°N for the period of 2002-2012 are used in the present study. In addition, the zonal mean of O 3 volume mixing ratios (vmr), chemical heating rates for seven dominant exothermic reactions (Table 1) [Mlynczak andSolomon, 1991, 1993;Ramesh et al, 2013Ramesh et al, , 2014. All these data sets are downloaded from ftp:// saber.gats-inc.com/ in the latitude band, 10°N-15°N for 2002-2012.…”

Section: Databasementioning

confidence: 99%

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Influence of solar cycle and chemistry on tropical (10°N–15°N) mesopause variabilities

2015

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Monthly averaged zonal mean temperature and ozone volume mixing ratios obtained from “Sounding of the Atmosphere using Broadband Emission Radiometry” instrument on board “Thermosphere Ionosphere Mesosphere Energetics and Dynamics” satellite for the years 2002–2012 are used to study the seasonal and solar cycle variabilities of tropical (10°N–15°N) mesopause structure. The mesopause temperature and ozone mixing ratios are positively correlated with solar cycle due to changes in CO2 and O, respectively. Although the seasonal variation in mesopause temperatures is quite small, the mesopause altitudes are comparatively higher (~99–100 km) in April and lower (~95 km) in September. The factors controlling the tropical mesopause structure are investigated by taking the mesopause variability for the year 2011 as a case study as it resembles the long‐term mean seasonal variation. It is found that the radiative cooling due to 15 µm CO2 infrared emissions is the only cooling mechanism in the mesopause region. The net heating rates obtained from (i) solar heating by O2 and O3, (ii) chemical heating due to seven major exothermic reactions, (iii) O3 long‐wave radiative heating, and (iv) CO2 cooling are smaller (~20 K/d) in April and larger (~85 K/d) in September at lower thermosphere (~99–101 km). The downward heat conduction from the lower thermosphere forces the mesopause to lower heights in September, although no downward heat conduction is observed in April.

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Section: Discussionmentioning

confidence: 99%

Section: Databasementioning

confidence: 99%

Section: Databasementioning

confidence: 99%

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Influence of solar cycle and chemistry on tropical (10°N–15°N) mesopause variabilities

2015

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“…The mesospheric temperature inversions can normally classified into lower and upper MILs. The lower MILs (~65–80 km) are believed to be due to planetary wave (PW) breaking [ Salby et al ., ; Ramesh et al ., ], and the upper MILs (above ~80–90 km) are dominantly due to gravity wave tidal interaction and/or chemical heating [ Meriwether and Gerrard , ; Sridharan et al ., ; Ramesh et al ., , ]. Sassi et al .…”

Section: Introductionmentioning

confidence: 99%

“…Similarly, Ramesh et al . [] found that the exothermic reaction, O + O + M → O 2 + M, played a dominant role for the large MIL occurred above ~90 km during September 2011 over Gadanki. Thus, in case of chemical heating, the dominant reaction responsible for the formation of middle (~80–85 km) and upper (~90 km) MILs is not the same, but it depends on the height of occurrence where the respective species concentration and background temperature differ.…”

Section: Introductionmentioning

confidence: 99%

A chemical perspective of day and night tropical (10°N–15°N) mesospheric inversion layers

et al. 2017

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The various occurrence characteristics of day and night tropical (10°N–15°N, 60°E–90°E) mesospheric inversion layers (MILs) are studied by using TIMED Sounding of the Atmosphere using Broadband Emission Radiometry satellite data products of kinetic temperature; volume mixing ratios of O, H, and O3; volume emission rates of O2 (1Δ) and OH (1.6 µm channel), and chemical heating rates due to seven dominant exothermic reactions among H, O, O2, O3, OH, HO2, and CO2 cooling rates for the year 2011. Although both dynamics and chemistry play important roles, the present study mainly focuses on the chemical processes involved in the formation of day and night MILs. It is found that the upper level height of daytime (nighttime) MIL descends (ascends) from ~88 km (~80 km) in winter to ~72 km (~90 km) in summer. The day and night inversion amplitudes are correlated with total chemical heating rates and CO2 cooling rates, and they show semi annual variation with larger (smaller) values during equinoxes (solstices). The daytime (nighttime) inversion layers are predominantly due to the exothermic reaction, R5: O + O + M → O2 + M and R6: O + O2 + M → O3 + M (R3: H + O3 → OH + O2). In addition, the CO2 causes large cooling at the top and small heating at the bottom levels of both day and night MILs. In the absence of dynamical effects, the chemical heating and CO2 cooling jointly contribute for the occurrence of day and night MILs.

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Gravity Wave Breaking Associated with Mesospheric Inversion Layers as Measured by the Ship-Borne BEM Monge Lidar and ICON-MIGHTI

et al. 2021

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During a recent 2020 campaign, the Rayleigh lidar aboard the Bâtiment d’Essais et de Mesures (BEM) Monge conducted high-resolution temperature measurements of the upper Mesosphere and Lower Thermosphere (MLT). These measurements were used to conduct the first validation of ICON-MIGHTI temperatures by Rayleigh lidar. A double Mesospheric Inversion Layer (MIL) as well as shorter-period gravity waves was observed. Zonal and meridional wind speeds were obtained from locally launched radiosondes and the newly launched ICON satellite as well as from the European Centre for Medium-Range Weather Forecasts (ECMWF-ERA5) reanalysis. These three datasets allowed us to see the evolution of the winds in response to the forcing from the MIL and gravity waves. The wavelet analysis of a case study suggests that the wave energy was dissipated in small, intense, transient instabilities about a given wavenumber in addition to via a broad spectrum of breaking waves. This article will also detail the recent hardware advances of the Monge lidar that have allowed for the measurement of MILs and gravity waves at a resolution of 5 min with an effective vertical resolution of 926 m.

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Causative mechanisms for the occurrence of a triple layered mesospheric inversion event over low latitudes

Cited by 6 publications

References 59 publications

Influence of solar cycle and chemistry on tropical (10°N–15°N) mesopause variabilities

Influence of solar cycle and chemistry on tropical (10°N–15°N) mesopause variabilities

A chemical perspective of day and night tropical (10°N–15°N) mesospheric inversion layers

Gravity Wave Breaking Associated with Mesospheric Inversion Layers as Measured by the Ship-Borne BEM Monge Lidar and ICON-MIGHTI

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