This paper describes the density correction of the NRLMSISE-00 using more than 15 years (2002–2016) of TIMED/SABER satellite atmospheric density data from the middle atmosphere (20–100 km). A bias ...correction factor dataset is established based on the density differences between the TIMED/SABER data and NRLMSISE-00. Seven height nodes are set in the range between 20 and 100 km. The different scale oscillations of the correction factor are separated at each height node, and the spherical harmonic function is used to fit the coefficients of the different timescale oscillations to obtain a spatiotemporal function at each height node. Cubic spline interpolation is used to obtain the correction factor at other non-node heights. The spatiotemporal correction function depends on six key parameters, including height, latitude, longitude, local time, day, and year. The evaluation results show that the spatiotemporal correction function proposed in this paper achieves a good correction effect on the atmospheric density of NRLMSISE-00. The correction effect becomes more pronounced as the height increases. After correction, the relative error of the model decreased by 40%–50% in July, especially at ±40° N in the 80–100 km region. The correction effect of the spatiotemporal correction function under different geomagnetic activity may have some potential relationships with geomagnetic activities. During geomagnetic storms, the relative errors in atmospheric density at 100, 70, and 32 km decrease from 41.21%, 22.09%, and 3.03% to −9.65%, 2.60%, and 1.44%, respectively, after correction. The relative errors in atmospheric density at 100, 70, and 32 km decrease from 68.95%, 21.02%, and 3.56% to 3.49%, 2.20%, and 1.77%, respectively, during the geomagnetic quiet period. The correction effect during the geomagnetic quiet period is better than that during geomagnetic storms at a height of 100 km. The subsequent effects of geomagnetic activity will be considered, and the atmospheric density during magnetic storms and quiet periods will be corrected separately near 100 km. The ability of the model to characterize the mid-atmosphere (20–100 km) is significantly improved compared with the pre-correction performance. As a result, the corrected NRLMSISE-00 can provide more reliable atmospheric density data for scientific researches and engineering fields, such as data analysis, instrument design, and aerospace vehicles.
This study reconstructed the 0.01–399.5 nm ultraviolet (UV) radiation band with a time resolution of 5 min under solar minimum conditions (18 October 2006) to investigate the effects of the solar ...flare event on the middle atmosphere. Five-minute resolution 0.01–399.5 nm UV radiation was used instead of daytime scale data to observe the response of the middle atmosphere to the instantaneous solar UV radiation enhancement. The results indicate that small temperature increases of 0.05 K in low latitudes were observed in the lower thermosphere and the stratosphere. The UV radiation enhancement led to an ozone increase of 0.6% in the stratosphere, which caused small temperature increases; and there is an ozone increase of up to 4% at 80 km, while a change of −2% occurred at 60–70 km and a change of −6% occurred in the low thermosphere. There was a 0.05% increase in atmospheric density above 60 km, and there was an increase of up to 0.15% at 80–90 km. The responses of the atmospheric temperature and density in the middle atmosphere to instantaneous UV radiation enhancements can therefore be captured via the UV radiation reconstruction. The simulation results were weaker than the previous study.
In this paper, we investigate the activity of atmospheric turbulence in the MLT region and the relationship between the activity of atmospheric turbulence and atmospheric wave activity. We use data ...from the Langfang MF radar (39.4∘N, 116.7∘E) from July 2019 to June 2020 and NRLMSIS 2.0 to calculate the parameters of atmospheric wave activity and atmospheric turbulence energy dissipation rate (ε). Atmospheric ε is modulated by different periods at different altitudes, and while there are 12 h and 24 h periods at all altitudes, the main period is different at different altitudes. A comparison of the ε with atmospheric tide activity shows that tides have an effect on ε, and the influence of tides on ε may be different at different altitudes. The pattern of variation in ε is similar to that of the atmospheric activity of the gravity wave, with both ε and the atmospheric activity of the gravity wave showing significant semi-annual variation.
The radio-occultation technique can provide vertical profiles of planetary ionospheric and atmospheric parameters, which merit the planetary-climate and space-weather scientific research so far. The ...Tianwen-1 one-way single-frequency radio-occultation technique was developed to retrieve Mars ionospheric and atmospheric parameters. The first radio-occultation event observation experiment was conducted on 5 August 2021. The retrieved excess Doppler frequency, bending angle, refractivity, electron density, neutral mass density, pressure and temperature profiles are presented. The Mars ionosphere M1 (M2) layer peak height is at 140 km (105 km) with a peak density of about 3.7 × 1010 el/m3 (5.3 × 1010 el/m3) in the retrieved electron-density profile. A planetary boundary layer (−2.35 km~5 km), a troposphere (temperature decreases with height) and a stratosphere (24 km–40 km) clearly appear in the retrieved temperature profile below 50 km. Results show that Tianwen-1 radio occultation data are scientifically reliable and useful for further Mars climate and space-weather studies.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Version 1.07 temperature measurements from SABER instrument on board of TIMED satellite during 2006–2007 are used to study the temperature stationary planetary waves (SPWs) from 20 to 120 km. To ...cover the high latitudes in both hemispheres (80°S–80°N) and most local times, 120‐day data are combined together into one data set. The most pronounced SPW features are the large amplitudes in the upper mesosphere and lower thermosphere (UMLT), while the SPWs below 90–95 km share common features with previous observations. In both hemispheric UMLT, SPWs amplitudes are large at middle and high latitudes throughout the year while their amplitudes in tropics are small. Wave 1 activity is generally stronger than the corresponding wave 2 activity with maximum amplitudes larger than 15 K, occurring at about 60°–70° north or south at the altitudes between 112 km and 119 km. Wave 1 amplitudes are larger in the Southern Hemisphere (SH) than in the Northern Hemisphere (NH). Their phases are normally tilt westward with increasing height below ∼110 km. Above this altitude, the wave 1 and wave 2 phases remain nearly unchanged with height, indicating the in situ generations and no propagations. Comparisons between the observed SPW structures and those from the NRLMSISE‐00 model have been done. Result shows their consistent features below ∼80 km and that NRLMSISE‐00 model gives no SPW information from 95 to 125 km but does have longitudinal variations above ∼125 km that are similar to the observed SPW features above ∼110 km.
Based on the data at~40°N at different longitudes during different stratospheric sudden warming（SSW）events,the responses of zonal winds in the stratosphere,mesosphere and lower thermosphere to SSWs ...are studied in this paper.The variations of zonal wind over Langfang,China（39.4°N,116.7°E）by MF radar and the modern era retrospective-analysis for research and applications（MERRA）wind data during 2010 and 2013 SSW and over Fort Collins,USA（41°N,105°W）by lidar and MERRA wind data during 2009 SSW are compared.Results show that the zonal wind at~40°N indeed respond to the SSWs while different specifics are found in different SSW events or at different locations.The zonal wind has significant anomalies during the SSWs.Over Langfang,before the onset of 2010 and 2013 SSW,the zonal wind reverses from eastward to westward below about 60–70 km and accelerates above this region,while westward wind prevails from 30 to 100 km after the onset of2010 SSW,and westward wind prevails in 30–60 and 85–100 km and eastward wind prevails in 60–85 km after the onset of2013 SSW.Over Fort Collins during 2009 SSW,eastward wind reverses to westward in 20–30 km before the onset while westward wind prevails in 20–30 and 60–97 km and eastward wind prevails in 30–60 and in 97–100 km after the onset.Moreover,simulations by the specified dynamics version of the whole atmosphere community climate model（SD-WACCM）are taken to explain different responding specifics of zonal wind to SSW events.It is found that the modulation of planetary wave（PW）plays the main role.Different phases of PWs would lead to the different zonal wind along with longitudes and the different amplitudes and phases in different SSW events can lead to the different zonal wind responses.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Data obtained from the newly installed MF radar at Langfang (39.4°N, 116.7°E), China, during the summer months of 2009 are used to study the short-term variability and summer averages of the mean ...wind and tidal oscillations in the mesosphere and lower thermosphere (MLT). Both the zonal and meridional daily winds between 80km and 98km show considerable day-to-day variability; their Lomb–Scargle spectra reveal active quasi-2-day and quasi-16-day planetary waves. The tidal large day-to-day variations have time scales of days or longer, which could be attributed to the contribution of planetary waves. The summer-averaged zonal wind is westward below 82km and eastward above 88km with the transition altitude at ∼85km. The meridional wind is dominated by the southward wind. The summer-averaged zonal and meridional semidiurnal tides exhibit amplitudes of 10–15m/s; they are larger than the diurnal tides, whose amplitudes are 5–10m/s. The phase tilt of the semidiurnal tide is downward, indicating this component is excited below the MLT. For the diurnal tide, the phase propagation is downward above 86km but it is upward below 86km, which indicates that the tide is evanescent or a mixture of evanescent and propagating modes. These wind and tide observations are compared with data from other mid-latitude stations at ∼40°N and with the HWM and GSWM models. Comparisons show that HWM-93 is better than HWM-07 in delineating the 2009 summer-averaged zonal wind over Langfang while both have systematic discrepancy in delineating the meridional mean winds. The prediction of the 2009 summer-averaged diurnal tide over Langfang by GSWM-09 is better than that from GSWM-02 but not the semidiurnal tide.
► Data obtained from the newly installed MF radar over Langfang are used. ► Short-term variation and summer-averages of wind and tides are firstly studied. ► Observations are compared with other stations near 40°N and HWM and GSWM models.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPUK
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