Planetary and gravity wave activity in the equatorial lower stratosphere as seen by ultra-long duration balloons

Hertzog, Albert; Vial, F.; Mechoso, Carlos R.; Basdevant, C.; Cocquerez, Philippe; Dubourg, Vincent; Nouel, F.

doi:10.1016/s0273-1177(02)00555-0

Cited by 6 publications

(7 citation statements)

References 6 publications

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“…Wilson et al, 1991b;Eckermann et al, 1995;Fritts and Hoppe, 1995;Hertzog et al, 2002). However, there have been only few measurements which resolve gravity waves with small vertical and horizontal scales and short periods.…”

Section: Introductionmentioning

confidence: 99%

Seasonal changes in gravity wave activity measured by lidars at mid-latitudes

2008

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Apart from some gaps due to the adverse weather conditions the measurements are well distributed throughout the year. Comprehensive information about the activity of mediumand low-frequency gravity waves was extracted from this data set. The dominating vertical wavelengths found are between 10 and 20 km and do not show any seasonal variation. In contrast the temperature fluctuations due to gravity waves experience a clear annual cycle with a maximum in winter. The most significant differences exist around 60 km where the fluctuations in winter are more than two times larger than they are in summer. Only small seasonal differences are observed above 90 km and below 35 km. Generally, the fluctuations grow from about 0.5 K up to 8 K between 20 and 100 km. Damping of waves is observed at nearly all altitudes and in all seasons. The planetary wave activity shows a similar structure in altitude and season as the gravity wave activity which indicates that similar mechanisms influencing different scales. Combining the monthly mean temperatures and the fluctuations we show that the transition between winter and summer season and vice versa seems to start in the mesopause region and to penetrate downward.

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Section: Introductionmentioning

confidence: 99%

Seasonal changes in gravity wave activity measured by lidars at mid-latitudes

2008

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“…The quasi-Langrangian movement of balloon observation seems to be more advantageous for studying wave-induced disturbances. Long-duration super pressure balloons can implement the stratosphere flight for a long time (last for weeks), which can characterize the main features of the large-and meso-scale dynamics of this atmospheric region [27,28]. There is no observation in the vertical direction matching the flat-floating stage for both long-duration super pressure balloons and aircraft; however, in our study, through RTAFSS, it can meet controllable high frequency observation, including the three stages, "rising, flat-floating and falling", and characterize the main features of the meso-scale, micro-scale and weather-scale dynamics of this atmospheric region.…”

Section: Overview and Discussionmentioning

confidence: 99%

Spectrum Analysis of Gravity Waves Based on Sensors Mounted on a New Round-Trip Airborne Flat-Floating Sounding System

Sheng

Zhang

et al. 2020

Sensors

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In this study, sensors mounted on a new type of round-trip airborne flat-floating sounding system (RTAFSS) were used to obtain the observation data of the three stages of "rising, flat-floating and falling". This new sounding method has a good application prospect. We performed spectrum analysis on the normalized temperature fluctuation, and the vertical wavenumber spectrum from the rising and falling stages and the horizontal wavenumber spectrum from the flat-floating stage were obtained. This is the first time the complete gravity wave spectrum characteristics were obtained from three consecutive stages: rising, flat-floating and falling. The results show that the gravity wave spectrum of the three stages can be well obtained by RTAFSS. For the horizontal wavenumber spectrum, the spectral slope is basically around −2, and the difference in the spectral structure of the horizontal wave number spectrum may be due to the intermittent turbulent activity and the variable intensity of the gravitational wave during its propagation. This study aims to make experimental exploration of the spectrum characteristics of gravity waves by this new type of observation data. It is expected to reveal the spectrum characteristics of horizontal wavenumber in the stratosphere region of China, providing a theoretical basis for spectrum analysis in a wider space-time range after further network observation of RTAFSS.

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“…A more fundamental question addresses the role of nonlinear interactions of gravity waves compared to a quasi-linear superposition. This leads to rather different concepts regarding gravity wave parametrization (Lindzen, 1981;Gavrilov, 1990;Fritts and Lu, 1993;Medvedev and Klaassen, 1995;Hines, 1997;Becker and Schmitz, 2002). It could well be that the applicability of one concept or the other depends on the temporal and spatial scales under consideration.…”

Section: Gravity Wavesmentioning

confidence: 99%

“…be made by VAHCOLI. To address the question, if energy is cascading from large to small scales ("forward") or the other way around ("inverse") it is helpful to consider not only the horizontal kinetic energy spectra (typically from aircraft observations) but also the vertical spectra of horizontal kinetic and potential energy typically derived from balloonborne observations (Li and Lindborg, 2018;Alisse and Sidi, 2000;Hertzog et al, 2002). Note that a fundamental scale invariance of the Boussinesq equations in the limit of strong stratification implies an equi-partitioning of potential and kinetic energy (Billant and Chomaz, 2001).…”

Section: Stratified Turbulence (St)mentioning

confidence: 99%

VAHCOLI, a new concept for lidars: technical setup, science applications, and first measurements

Lübken¹,

Höffner²

2021

Atmos. Meas. Tech.

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Abstract. A new concept for a cluster of compact lidar systems named VAHCOLI (Vertical And Horizontal COverage by LIdars) is presented, which allows for the measurement of temperatures, winds, and aerosols in the middle atmosphere (∼ 10–110 km) with high temporal and vertical resolution of minutes and some tens of meters, respectively, simultaneously covering horizontal scales from a few hundred meters to several hundred kilometers (“four-dimensional coverage”). The individual lidars (“units”) being used in VAHCOLI are based on a diode-pumped alexandrite laser, which is currently designed to detect potassium (λ=770 nm), and on sophisticated laser spectroscopy measuring all relevant frequencies (seeder laser, power laser, backscattered light) with high temporal resolution (2 ms) and high spectral resolution applying Doppler-free spectroscopy. The frequency of the lasers and the narrowband filter in the receiving system are stabilized to typically 10–100 kHz, which is a factor of roughly 10−5 smaller than the Doppler-broadened Rayleigh signal. Narrowband filtering allows for the measurement of Rayleigh and/or resonance scattering separately from the aerosol (Mie) signal during both night and day. Lidars used for VAHCOLI are compact (volume: ∼ 1 m3) and multi-purpose systems which employ contemporary electronic, optical, and mechanical components. The units are designed to autonomously operate under harsh field conditions in remote locations. An error analysis with parameters of the anticipated system demonstrates that temperatures and line-of-sight winds can be measured from the lower stratosphere to the upper mesosphere with an accuracy of ±(0.1–5) K and ±(0.1–10) m s−1, respectively, increasing with altitude. We demonstrate that some crucial dynamical processes in the middle atmosphere, such as gravity waves and stratified turbulence, can be covered by VAHCOLI with sufficient temporal, vertical, and horizontal sampling and resolution. The four-dimensional capabilities of VAHCOLI allow for the performance of time-dependent analysis of the flow field, for example by employing Helmholtz decomposition, and for carrying out statistical tests regarding, for example, intermittency and helicity. The first test measurements under field conditions with a prototype lidar were performed in January 2020. The lidar operated successfully during a 6-week period (night and day) without any adjustment. The observations covered a height range of ∼ 5–100 km and demonstrated the capability and applicability of this unit for the VAHCOLI concept.

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Planetary and gravity wave activity in the equatorial lower stratosphere as seen by ultra-long duration balloons

Cited by 6 publications

References 6 publications

Seasonal changes in gravity wave activity measured by lidars at mid-latitudes

Seasonal changes in gravity wave activity measured by lidars at mid-latitudes

Spectrum Analysis of Gravity Waves Based on Sensors Mounted on a New Round-Trip Airborne Flat-Floating Sounding System

VAHCOLI, a new concept for lidars: technical setup, science applications, and first measurements

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