A Fabry-Perot interferometer,funded by the Meridian Project in China,was deployed at the Xinglong station(40.2°N,117.4°E) of the National Astronomical Observatories in Hebei Province,China.The instrument has...A Fabry-Perot interferometer,funded by the Meridian Project in China,was deployed at the Xinglong station(40.2°N,117.4°E) of the National Astronomical Observatories in Hebei Province,China.The instrument has been operating since April 2010,measuring mesospheric and thermospheric winds.The first observational data of winds at three heights in the mesosphere and thermosphere were analyzed,demonstrating the capacity of this instrument to aid basic scientific research.The wavelengths of three airglow emissions were OH892.0,OI 557.7,and OI 630.0 nm,which corresponded to heights of 87,98,and 250 km,respectively.Three 38-day data sets of horizontal winds,from April 5,2010 to May 12,2010,show clear day-to-day variations at the same height.The minimum and maximum meridional winds at heights of 87,98,and 250 km were-16.5 to 8.7 m/s,-24.4 to 15.9 m/s,and-43.6 to 1.5 m/s.Measurements of zonal winds were-5.4 to 7.6 m/s,2.3 to 23.0 m/s,and-22.6 to 49.3 m/s.The average data from the observations was consistent with the data from HWM93.The wind data at heights of 87 and 98 km suggest a semi-diurnal oscillation,clearly consistent with HWM93 results.Conversely there was a clear discrepancy between the observations and the model at 250 km.In general,this Fabry-Perot interferometer is a useful ground-based instrument for measuring mesospheric and thermospheric winds at middle latitudes.展开更多
The Wuhan meteor radar is the first all-sky meteor radar in China. The circulation near the mesopause from February to September 2002 is studied based on the data obtained by the Wuhan meteor radar. The zonal wind is ...The Wuhan meteor radar is the first all-sky meteor radar in China. The circulation near the mesopause from February to September 2002 is studied based on the data obtained by the Wuhan meteor radar. The zonal wind is usually eastward in winter from 80 to 100 km. The mean zonal wind become westward from March to early of May, when the winter circulation reverses to the summer circulation. But at the meteor heights, the zonal circulation usually becomes eastward after the middle of May. The meridional circulation is always equatorward. The peaks of the meridional wind move downward with the height, and the peak value reaches its maximum of 21 ms-1 in July. Having made a comparison between monthly mean wind and HWM93 model wind, the value of southward wind, the maximal value of eastward wind as well as the reversal height of zonal wind are found to be quite different from each other.展开更多
The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°...The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°N,116.6°E),Langfang,Hebei in China.Quasi-monochromatic gravity waves (QMGWs) are found clearly in the observation data.Case studies show that their horizontal wavelengths,horizontal phase velocities,azimuth angles of horizontal propagation directions and periods of three QMGW examples are about 12.3 km,41 m/s,327°,5 min;25 km,35 m/s,68°,12 min;and 10 km,48 m/s,341°,3.5 min respectively.展开更多
A SpectroMeter of Atmospheric RadiaTion （SMART） was developed and installed at the Xinglong station of the National Astronomical Observatories in Hebei province, China, which was supported by the Meridian Project [1...A SpectroMeter of Atmospheric RadiaTion （SMART） was developed and installed at the Xinglong station of the National Astronomical Observatories in Hebei province, China, which was supported by the Meridian Project [1]. The experimental tests of spectrometric observation of the hydroxyl emission and rotational temperature in China were conducted for the first time on the night of February 23, 2011 and the night of April 27, 2011, respectively. OH 6-2 band and OH 8-3 band spectra were measured and the rotational temperature was retrieved. Hourly average temperatures （186.82±6.40） K of OH 8-3 band and （178.07±6.73） K of OH 6-2 band were derived from the spectra observed on the night of February 23,2011. Intensities and ro- tational temperature against local time were determined by the spectra measured in the whole night of April 27, 2011. The rotational temperature was consistent with the spatial average temperature of NRLMSISE00 empirical model at height 83-91 km and the average temperature of TIMED/SABER from April to May of seven years at height 83-91 kin, with some discrepancies. The results showed that the new instrument and the retrieval method of the rotational temperature can give reasonable results of the airglow emission of OH and the temperature of mesopause.展开更多
A time-dependent two-dimensional photochemical-dynamical coupling gravity wave model of sodium layer is developed, which combines the sodium photochemical theory, a time-dependent two-dimensional atmospheric photochem...A time-dependent two-dimensional photochemical-dynamical coupling gravity wave model of sodium layer is developed, which combines the sodium photochemical theory, a time-dependent two-dimensional atmospheric photochemical model, a two-dimensional gravity wave model, and the International Reference Ionosphere model (IRI-95)with the diabatic process induced by photochemical reactions and the transport of chemical species by gravity waves included. The pseudospectral method is used in the horizontal direction, the finite difference approximations are used in vertical direction z and time t. And FICE method is used to solve the model. The simulation results indicate that intense perturbations of the sodium layer can be induced by the propagation of gravity waves. The results are consistent with the observations.展开更多
The atmospheric temperatures and densities in the mesosphere and lower thermosphere(MLT)region are essential for studying the dynamics and climate of the middle and upper atmosphere.In this study,we present more than ...The atmospheric temperatures and densities in the mesosphere and lower thermosphere(MLT)region are essential for studying the dynamics and climate of the middle and upper atmosphere.In this study,we present more than 9 years of mesopause temperatures and relative densities estimated by using ambipolar diffusion coefficient measurements observed by the Mengcheng meteor radar(33.4°N,116.5°E).The intercomparison between the meteor radar and Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere by Broadband Emission Radiometry(TIMED/SABER)and Earth Observing System(EOS)Aura/Microwave Limb Sounder(MLS)observations indicates that the meteor radar temperatures and densities agree well with the simultaneous satellite measurements.Annual variations dominate the mesopause temperatures,with the maximum during winter and the minimum during summer.The mesopause relative densities also show annual variations,with strong maxima near the spring equinox and weak maxima before the winter solstice,and with a minimum during summer.In addition,the mesopause density exhibits a structure similar to that of the zonal wind:as the zonal wind flows eastward(westward),the mesopause density decreases(increases).At the same time,the meridional wind shows a structure similar to that of the mesopause temperature:as the meridional wind shows northward(southward)enhancements,the mesopause temperature increases(decreases).Simultaneous horizontal wind,temperature,and density observations provide multiple mesospheric parameters for investigating mesospheric dynamics and thermodynamic processes and have the potential to improve widely used empirical atmospheric models.展开更多
The data observed by a spectral airglow temperature imager （SATI） at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. Fr...The data observed by a spectral airglow temperature imager （SATI） at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. From variations of temperature at 87 and 94 km obtained from OH （6-2） and 02 （0-1） airglow spectra, temperature at night is shown lowest in the summer and highest in the winter. In summer, average temperature at 87 km is 173.9 K, lower than average temperature 180.1 K at 94 km. But in winter, average temperature at 87 Ion is 201.2 K, higher than average temperature 194.8 K at 94 kin. The altitude of mesopause in Beijing is below 87 km in summer and above 94 km in winter. There are about 120-150 days when the mesopause locates below 87 km, which is in agreement with the results of SABER/TIMED. Variations of temperatures at 87 and 94 km are analyzed by harmonic method. Our results show that amplitudes of annual oscillation of temperature at 87 and 94 km are 17.5 and 7.8 K respectively. Amplitudes of semi-annual oscillation at 87 and 94 km are 1.6 and 5.3 K, which are smaller than those of annual oscillation. Although there are differences among different observations because of different locations and different instruments, our results are in general agreement with observation at similar latitude as Beijing.展开更多
The global atmospheric static stability(N2)in the middle atmosphere and its relation to gravity waves(GWs)were investigated by using the temperature profiles measured by the Sounding of the Atmosphere using Broadband ...The global atmospheric static stability(N2)in the middle atmosphere and its relation to gravity waves(GWs)were investigated by using the temperature profiles measured by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instrument from 2002 to 2018.At low latitudes,a layer with enhanced N2 occurs at an altitude of^20 km and exhibits annual oscillations caused by tropopause inversion layers.Above an altitude of^70 km,enhanced N2 exhibits semiannual oscillations at low latitudes caused by the mesosphere inversion layers and annual oscillations at high latitudes resulting from the downward shift of the summer mesopause.The correlation coefficients between N2 and GW amplitudes can be larger than 0.8 at latitudes poleward of^40°N/S.This observation provides factual evidence that a large N2 supports large-amplitude GWs and indicates that N2 plays a dominant role in maintaining GWs at least at high latitudes of the middle atmosphere.This evidence also partially explains the previous results regarding the phase changes of annual oscillations of GWs at high latitudes.展开更多
Data obtained from the mobile SOUSY VHF radar at And?ya/Norway in summer 1987 have been used to study the nonlinear interactions between planetary waves, tides and gravity waves in the polar mesosphere, and the instab...Data obtained from the mobile SOUSY VHF radar at And?ya/Norway in summer 1987 have been used to study the nonlinear interactions between planetary waves, tides and gravity waves in the polar mesosphere, and the instability of background atmosphere above the mesopause. It is observed that 35-h planetary wave, diurnal, semidiurnal and terdiurnal tides are the prominent perturbations in the Lomb-Scargle spectra of the zonal wind component. By inspecting the frequency combinations, several triads are identified. By bispectral analysis it is shown that most bispectral peaks stand for quadratic coupling between tidal harmonics or between tide and planetary or gravity wave, and the height dependence of bispectral peaks reflects the variation of wave-wave interactions. Above the mesopause, the occurrence heights of the maximum L-S power spectral peaks corresponding to the prominent wave components ten to increase with their frequencies. This may result from the process in which two low frequency waves interact to generate a high frequency wave. Intensities of the planetary wave and tides increase gradually, arrive at their maxima, and then decay quickly in turn with increasing height. This kind of scene correlates with a “chain” of wave-wave resonant interactions that shifts with height from lower frequency segment to higher frequency segment. By instability analysis, it is observed that above the mesopause, theRichardson number becomes smaller and smaller with height, implying that the turbulent motion grows stronger and stronger and accordingly the background atmosphere more and more instable. It is suggested that the wave-wave sum resonant interaction and the wave dissipation due to instability are two dominant dynamical processes that occur in the mesopause region. The former invokes the energy transfer from lower frequency waves to higher frequency waves. The latter results in the heating of the atmosphere and accelerating of the background flow.展开更多
A nonlinear, compressible, non-isothermal gravity wave model that involves photochemistry is used to study the effects of gravity wave on atmospheric chemical species distributions in this paper. The changes in the di...A nonlinear, compressible, non-isothermal gravity wave model that involves photochemistry is used to study the effects of gravity wave on atmospheric chemical species distributions in this paper. The changes in the distributions of oxygen compound and hydrogen compound density induced by gravity wave propagation are simulated. The results indicate that when a gravity wave propagates through a mesopause region, even if it does not break, it can influence the background distributions of chemical species. The effect of gravity wave on chemical species at night is larger than in daytime.展开更多
基金supported by the National Natural Science Foundation of China (40890165,40921063 and 40911120063)the National Large-Scale Scientific Project "Meridian Project"the Specialized Research Fund for State Key Laboratories
文摘A Fabry-Perot interferometer,funded by the Meridian Project in China,was deployed at the Xinglong station(40.2°N,117.4°E) of the National Astronomical Observatories in Hebei Province,China.The instrument has been operating since April 2010,measuring mesospheric and thermospheric winds.The first observational data of winds at three heights in the mesosphere and thermosphere were analyzed,demonstrating the capacity of this instrument to aid basic scientific research.The wavelengths of three airglow emissions were OH892.0,OI 557.7,and OI 630.0 nm,which corresponded to heights of 87,98,and 250 km,respectively.Three 38-day data sets of horizontal winds,from April 5,2010 to May 12,2010,show clear day-to-day variations at the same height.The minimum and maximum meridional winds at heights of 87,98,and 250 km were-16.5 to 8.7 m/s,-24.4 to 15.9 m/s,and-43.6 to 1.5 m/s.Measurements of zonal winds were-5.4 to 7.6 m/s,2.3 to 23.0 m/s,and-22.6 to 49.3 m/s.The average data from the observations was consistent with the data from HWM93.The wind data at heights of 87 and 98 km suggest a semi-diurnal oscillation,clearly consistent with HWM93 results.Conversely there was a clear discrepancy between the observations and the model at 250 km.In general,this Fabry-Perot interferometer is a useful ground-based instrument for measuring mesospheric and thermospheric winds at middle latitudes.
基金supported by the National Natura1 Science Foundations of China(Grant Nos.40174048 and 40134020)
文摘The Wuhan meteor radar is the first all-sky meteor radar in China. The circulation near the mesopause from February to September 2002 is studied based on the data obtained by the Wuhan meteor radar. The zonal wind is usually eastward in winter from 80 to 100 km. The mean zonal wind become westward from March to early of May, when the winter circulation reverses to the summer circulation. But at the meteor heights, the zonal circulation usually becomes eastward after the middle of May. The meridional circulation is always equatorward. The peaks of the meridional wind move downward with the height, and the peak value reaches its maximum of 21 ms-1 in July. Having made a comparison between monthly mean wind and HWM93 model wind, the value of southward wind, the maximal value of eastward wind as well as the reversal height of zonal wind are found to be quite different from each other.
基金supported by the National Natural Science Foundation of China (Grant No.40774087)
文摘The first imaging observation experiment of the atmospheric gravity waves in the mesopause region with the all-sky OH Meinel band airglow CCD imager is made during 02:00 to 06:00 on January 5,2009,at Hancun (39.4°N,116.6°E),Langfang,Hebei in China.Quasi-monochromatic gravity waves (QMGWs) are found clearly in the observation data.Case studies show that their horizontal wavelengths,horizontal phase velocities,azimuth angles of horizontal propagation directions and periods of three QMGW examples are about 12.3 km,41 m/s,327°,5 min;25 km,35 m/s,68°,12 min;and 10 km,48 m/s,341°,3.5 min respectively.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41074109, 40890165, 40921063, 41004063)the National Important Basic Research Project of China (Grant No. 2011-CB811405)the Specialized Research Fund for State Key Laboratories
文摘A SpectroMeter of Atmospheric RadiaTion （SMART） was developed and installed at the Xinglong station of the National Astronomical Observatories in Hebei province, China, which was supported by the Meridian Project [1]. The experimental tests of spectrometric observation of the hydroxyl emission and rotational temperature in China were conducted for the first time on the night of February 23, 2011 and the night of April 27, 2011, respectively. OH 6-2 band and OH 8-3 band spectra were measured and the rotational temperature was retrieved. Hourly average temperatures （186.82±6.40） K of OH 8-3 band and （178.07±6.73） K of OH 6-2 band were derived from the spectra observed on the night of February 23,2011. Intensities and ro- tational temperature against local time were determined by the spectra measured in the whole night of April 27, 2011. The rotational temperature was consistent with the spatial average temperature of NRLMSISE00 empirical model at height 83-91 km and the average temperature of TIMED/SABER from April to May of seven years at height 83-91 kin, with some discrepancies. The results showed that the new instrument and the retrieval method of the rotational temperature can give reasonable results of the airglow emission of OH and the temperature of mesopause.
基金National Natural Science Foundation of China (40225011) the National Research Project (G2000078407) project of CAS (KZCX3-SW-217).
文摘A time-dependent two-dimensional photochemical-dynamical coupling gravity wave model of sodium layer is developed, which combines the sodium photochemical theory, a time-dependent two-dimensional atmospheric photochemical model, a two-dimensional gravity wave model, and the International Reference Ionosphere model (IRI-95)with the diabatic process induced by photochemical reactions and the transport of chemical species by gravity waves included. The pseudospectral method is used in the horizontal direction, the finite difference approximations are used in vertical direction z and time t. And FICE method is used to solve the model. The simulation results indicate that intense perturbations of the sodium layer can be induced by the propagation of gravity waves. The results are consistent with the observations.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42125402 and 42174183)the National Key Technologies R&D Program of China (Grant No. 2022YFF0503703)+5 种基金the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB41000000)the foundation of the National Key Laboratory of Electromagnetic Environmentthe Fundamental Research Funds for the Central Universitiesthe Chinese Meridian Projectfunded by the Anhui Provincial Natural Science Foundation (Grant No. 2008085MD113)the Joint Open Fund of Mengcheng National Geophysical Observatory (No. MENGO-202209)
文摘The atmospheric temperatures and densities in the mesosphere and lower thermosphere(MLT)region are essential for studying the dynamics and climate of the middle and upper atmosphere.In this study,we present more than 9 years of mesopause temperatures and relative densities estimated by using ambipolar diffusion coefficient measurements observed by the Mengcheng meteor radar(33.4°N,116.5°E).The intercomparison between the meteor radar and Thermosphere Ionosphere Mesosphere Energetics and Dynamics/Sounding of the Atmosphere by Broadband Emission Radiometry(TIMED/SABER)and Earth Observing System(EOS)Aura/Microwave Limb Sounder(MLS)observations indicates that the meteor radar temperatures and densities agree well with the simultaneous satellite measurements.Annual variations dominate the mesopause temperatures,with the maximum during winter and the minimum during summer.The mesopause relative densities also show annual variations,with strong maxima near the spring equinox and weak maxima before the winter solstice,and with a minimum during summer.In addition,the mesopause density exhibits a structure similar to that of the zonal wind:as the zonal wind flows eastward(westward),the mesopause density decreases(increases).At the same time,the meridional wind shows a structure similar to that of the mesopause temperature:as the meridional wind shows northward(southward)enhancements,the mesopause temperature increases(decreases).Simultaneous horizontal wind,temperature,and density observations provide multiple mesospheric parameters for investigating mesospheric dynamics and thermodynamic processes and have the potential to improve widely used empirical atmospheric models.
文摘在卫星上对中间层顶区域的气辉辐射成像观测,对于全球大气波动的监测和研究具有重要的意义.利用TDICCD对O_2A(0-0)气辉进行成像观测,计算了曝光积分时间、信噪比和能达到的最高空间分辨率,分析了地球自转对空间分辨率的影响,在此基础上提出一种星载全球大气波动成像仪方案,该方案可以观测垂直波长大于10 km的大气波动,最高水平分辨率可以达到0.33 km.
基金supported by the National Natural Science Foundation of China (Grant No. 40974086)the National Important Basic Research Project (Grant No. 2011CB811405)
文摘The data observed by a spectral airglow temperature imager （SATI） at Beijing National Observatory of Space Environment from July 23, 2008 to July 3l, 2009 are used to study night mesopause temperature in Beijing. From variations of temperature at 87 and 94 km obtained from OH （6-2） and 02 （0-1） airglow spectra, temperature at night is shown lowest in the summer and highest in the winter. In summer, average temperature at 87 km is 173.9 K, lower than average temperature 180.1 K at 94 km. But in winter, average temperature at 87 Ion is 201.2 K, higher than average temperature 194.8 K at 94 kin. The altitude of mesopause in Beijing is below 87 km in summer and above 94 km in winter. There are about 120-150 days when the mesopause locates below 87 km, which is in agreement with the results of SABER/TIMED. Variations of temperatures at 87 and 94 km are analyzed by harmonic method. Our results show that amplitudes of annual oscillation of temperature at 87 and 94 km are 17.5 and 7.8 K respectively. Amplitudes of semi-annual oscillation at 87 and 94 km are 1.6 and 5.3 K, which are smaller than those of annual oscillation. Although there are differences among different observations because of different locations and different instruments, our results are in general agreement with observation at similar latitude as Beijing.
基金supported by the USTC Research Funds of the Double First-Class Initiative(YD3420002004)the National Natural Science Foundation of China(42125402,41974174,42188101,41831071,42174183,and 41904135)+4 种基金the B-type Strategic Priority Program of CAS(XDB41000000)the Project of Stable Support for Youth Team in Basic Research Field,CAS(YSBR-018)the Fundamental Research Funds for the Central Universitiesthe Anhui Provincial Natural Science Foundation(2008085MD113)the Joint Open Fund of Mengcheng National Geophysical Observatory(MENGO202209).
基金This work was supported by the National Natural Science Foundation of China(grants 41831073 and 41874182).
文摘The global atmospheric static stability(N2)in the middle atmosphere and its relation to gravity waves(GWs)were investigated by using the temperature profiles measured by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instrument from 2002 to 2018.At low latitudes,a layer with enhanced N2 occurs at an altitude of^20 km and exhibits annual oscillations caused by tropopause inversion layers.Above an altitude of^70 km,enhanced N2 exhibits semiannual oscillations at low latitudes caused by the mesosphere inversion layers and annual oscillations at high latitudes resulting from the downward shift of the summer mesopause.The correlation coefficients between N2 and GW amplitudes can be larger than 0.8 at latitudes poleward of^40°N/S.This observation provides factual evidence that a large N2 supports large-amplitude GWs and indicates that N2 plays a dominant role in maintaining GWs at least at high latitudes of the middle atmosphere.This evidence also partially explains the previous results regarding the phase changes of annual oscillations of GWs at high latitudes.
基金the National Natural Science Foundation of China under grant 49625407 and grant 49990450
文摘Data obtained from the mobile SOUSY VHF radar at And?ya/Norway in summer 1987 have been used to study the nonlinear interactions between planetary waves, tides and gravity waves in the polar mesosphere, and the instability of background atmosphere above the mesopause. It is observed that 35-h planetary wave, diurnal, semidiurnal and terdiurnal tides are the prominent perturbations in the Lomb-Scargle spectra of the zonal wind component. By inspecting the frequency combinations, several triads are identified. By bispectral analysis it is shown that most bispectral peaks stand for quadratic coupling between tidal harmonics or between tide and planetary or gravity wave, and the height dependence of bispectral peaks reflects the variation of wave-wave interactions. Above the mesopause, the occurrence heights of the maximum L-S power spectral peaks corresponding to the prominent wave components ten to increase with their frequencies. This may result from the process in which two low frequency waves interact to generate a high frequency wave. Intensities of the planetary wave and tides increase gradually, arrive at their maxima, and then decay quickly in turn with increasing height. This kind of scene correlates with a “chain” of wave-wave resonant interactions that shifts with height from lower frequency segment to higher frequency segment. By instability analysis, it is observed that above the mesopause, theRichardson number becomes smaller and smaller with height, implying that the turbulent motion grows stronger and stronger and accordingly the background atmosphere more and more instable. It is suggested that the wave-wave sum resonant interaction and the wave dissipation due to instability are two dominant dynamical processes that occur in the mesopause region. The former invokes the energy transfer from lower frequency waves to higher frequency waves. The latter results in the heating of the atmosphere and accelerating of the background flow.
基金National Research Project (G2000078407) the National Natural Science Foundation of China (Grant Nos. 49974038, 49990454).
文摘A nonlinear, compressible, non-isothermal gravity wave model that involves photochemistry is used to study the effects of gravity wave on atmospheric chemical species distributions in this paper. The changes in the distributions of oxygen compound and hydrogen compound density induced by gravity wave propagation are simulated. The results indicate that when a gravity wave propagates through a mesopause region, even if it does not break, it can influence the background distributions of chemical species. The effect of gravity wave on chemical species at night is larger than in daytime.
