Simultaneous and common‐volume lidar observations of K/Na layers and temperature at Arecibo Observatory (18°N, 67°W)

Yue, Xianchang; Zhou, Qihou; Yi, Fan; Friedman, J. S.; Raizada, S.; Tepley, C. A.

doi:10.1002/2015jd024494

Cited by 7 publications

(8 citation statements)

References 57 publications

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“…This explanation simply means that the ions are concentrated by a neutral horizontal wind shear mechanism (Axford, ; Mathews, ; Whitehead, ) to produce a high‐density ion layer (i.e., E s layer) in which sodium ions are rapidly neutralized to form a sodium atom layer. In addition, there are other theories, such as direct meteor deposition (Clemesha et al, ; Clemesha et al, ), increasing temperature in the atmosphere (Delgado et al, ; Qian et al, ; Yue et al, ; Zhou et al, ; Zhou & Mathews, ), and the redistribution of the background layer (Clemesha et al, ).…”

Section: Introductionmentioning

confidence: 99%

Large‐Scale Horizontally Enhanced Sodium Layers Coobserved in the Midlatitude Region of China

Xue

Dou

et al. 2019

JGR Space Physics

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We report 19 coobserved enhanced sodium layers, including sporadic sodium layers (SSLs) and thermospheric enhanced sodium layers (TeSLs), over Hefei (31.8°N, 117.3°E) and Wuhan (30.5°N, 114.4°E) from 2011 to 2018. The total coobservation time at Hefei and Wuhan was 387.24 hr, and the average occurrence rates were 0.038 hr−1 and 0.028 hr−1 for the SSLs and TeSLs, respectively. The SSL and TeSL occurrence rates in summer were 0.078 and 0.039 hr−1, respectively, which were considerably higher than those in other seasons. Among all 19 cases, 16 cases, including 9 SSL cases and 7 TeSL cases, occurred almost simultaneously over Hefei and Wuhan without a time delay. Seven TeSLs and four out of the nine SSLs were accompanied by ionospheric sporadic E (Es), suggesting that an “Es‐SSL (TeSL)” chain formed via the wave‐induced wind shear mechanism. Three SSLs were modulated by waves and the two other cases were related with gravity wave overturning. In general, the correlation coefficients between Hefei and Wuhan for long‐duration cases (more than 2 hr) were high due to some large‐scale mechanism, and the short‐duration cases (less than 2 hr) had poor correlation due to different local characteristics. In addition, three cases were observed with an apparent time delay over Hefei and Wuhan, which might indicate the possible existence of long‐distance transport processes.

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Section: Introductionmentioning

confidence: 99%

Large‐Scale Horizontally Enhanced Sodium Layers Coobserved in the Midlatitude Region of China

Xue

Dou

et al. 2019

JGR Space Physics

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“…5c, 7c and 9c and 5d, 7d and 9d, respectively. In the raw data, temperature error due to photon noise is usually less than 5 K in the 87-97 km altitude range because the K density in this range is usually much larger (e.g., Yue et al, 2017). To show the seasonal variation of each parameter more clearly, the data between 87 and 97 km are averaged by altitude and then fitted to the same seasonal model consisting of the annual mean, AO, and SAO.…”

Section: Resultsmentioning

confidence: 99%

“…10 and 11). The altitude of ∼ 97 km is in the vicinity of their wave turbopause altitude range, is close to the mesopause over this site (Friedman and Chu, 2007;Xu et al, 2007a;Yue et al, 2017), and is the level at which the seasonal variation of zonal winds changing from a clear SAO pattern to a AO dominant pattern is evident (e.g., Li et al, 2012). This result suggests a possible mechanism for the GW energy dissipation; i.e., the GW dissipates or deposes energy or momentum below about the mesopause (or the wave turbopause defined by Offermann et al, 2006).…”

Section: Reduction Of Gwpementioning

confidence: 92%

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Long-term lidar observations of the gravity wave activity near the mesopause at Arecibo

et al. 2019

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Abstract. Using 11-year-long K Doppler lidar observations of temperature profiles in the mesosphere and lower thermosphere (MLT) between 85 and 100 km, conducted at the Arecibo Observatory, Puerto Rico (18.35∘ N, 66.75∘ W), seasonal variations of mean temperature, the squared Brunt–Väisälä frequency, N2, and the gravity wave potential energy (GWPE) are estimated in a composite year. The following unique features are obtained. (1) The mean temperature structure shows similar characteristics to an earlier report based on a smaller dataset. (2) Temperature inversion layers (TILs) occur at 94–96 km in spring, at ∼92 km in summer, and at ∼91 km in early autumn. (3) The first complete range-resolved climatology of GWPE derived from temperature data in the tropical MLT exhibits an altitude-dependent combination of annual oscillation (AO) and semiannual oscillation (SAO). The maximum occurs in spring and the minimum in summer, and a second maximum is in autumn and a second minimum in winter. (4) The GWPE per unit volume reduces below ∼97 km altitude in all seasons. The reduction of GWPE is significant at and below the TILs but becomes faint above; this provides strong support for the mechanism that the formation of upper mesospheric TILs is mainly due to the reduction of GWPE. The climatology of GWPE shows an indeed pronounced altitudinal and temporal correlation with the wind field in the tropical mesopause region published in the literature. This suggests the GW activity in the tropical mesopause region should be manifested mainly by the filtering effect of the critical level of the local background wind and the energy conversion due to local dynamical instability.

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“…Recently, different temperature dependences of key chemical reactions between Na and K chemical models have been used to explain the differences between the Na and K layers at the same site [ Plane et al . []; Yue et al ., ]. Finally, we note that although the seasonal variation of tides can affect metal layers as well, it has not been studied much and may prove to be able to explain some of the seasonal differences.…”

Section: Discussionmentioning

confidence: 99%

Structure and seasonal variations of the nocturnal mesospheric K layer at Arecibo

Yue

Friedman

et al. 2017

JGR Atmospheres

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We present the seasonal variations of the nocturnal mesospheric potassium (K) layer at Arecibo, Puerto Rico (18.35°N, 66.75°W) from 160 nights of K Doppler lidar observations between December 2003 and January 2010, during which the solar activity is mostly low. The background temperature is also measured simultaneously by the lidar and shows a strong semiannual oscillation with maxima occurring during equinoxes at all altitudes. The annual mean K density profile is approximately Gaussian with a peak altitude of 91.7 km. The K column abundance and the centroid height have strong semiannual variations, with maxima at the solstices. Both parameters are negatively correlated to the mean background temperature with a correlation coefficient < −0.5. The root‐mean‐square (RMS) width has a distinct annual oscillation with the largest width occurring in May. The seasonal variation of the centroid height is similar to that of the Fe layer at the same site. The seasonal temperature variation indicates significant enhanced wave‐induced downward transport for both species during spring and autumn. This explains the metal layer centroid height and column abundance variations at Arecibo and provides a general mechanism to account for the seasonal variations in the centroid height of all metal species measured at low‐latitude and midlatitude sites.

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Simultaneous and common‐volume lidar observations of K/Na layers and temperature at Arecibo Observatory (18°N, 67°W)

Cited by 7 publications

References 57 publications

Large‐Scale Horizontally Enhanced Sodium Layers Coobserved in the Midlatitude Region of China

Large‐Scale Horizontally Enhanced Sodium Layers Coobserved in the Midlatitude Region of China

Long-term lidar observations of the gravity wave activity near the mesopause at Arecibo

Structure and seasonal variations of the nocturnal mesospheric K layer at Arecibo

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