Объединенная Китайско-Бразильская лаборатория исследования космической погоды, Китайская академия наук
Пекин, Китайская Народная Республика
Пекин, Китайская Народная Республика
Пекин, Китайская Народная Республика
Ухань, Китайская Народная Республика
Ухань, Китайская Народная Республика
Разработка двухлучевого лазерного лидара для измерения калиевого (K) слоя над Пекином (40.5° N, 116.2° E) была успешно осуществлена в 2010 г. Приведены параметры спорадических Ks-слоев и их распределения. Получено сезонное распределение частоты появления слоя Ks с двумя максимумами в июле и январе. Сезонное распределение частоты появления слоя Es над Пекином отличается от Ks. Тем не менее, хорошая корреляция Es и Ks в отдельных исследованиях подтверждает механизм нейтрализации ионов металла в опускающемся Е-слое.
лидар, спорадические калиевые слои, спорадические Е-слои
1. INTRODUCTION
Meteoric metal (Na, K, Ca, Mg, etc.) layers between 80 and 110 km originate from meteor ablation [Plane, 1991; Kane et al., 2001]. Lidar observations and studies of metal layers have been carried out for about 40 years, promoting better understanding of chemical and dynamic processes in the mesopause region. Sporadic or narrow metal layers (Ns) were often observed in lidar data.
There are fewer lidar observations of the K layer than the sodium (Na) one. This is because the density of the K layer is approximately two orders of magnitude lower than that of the Na layer [Megie et al., 1978]. While several lidar observations of K layers over dif-ferent regions were made [Eska, Hoffner, 1988; Eska et al., 1998; von Zahn et al., 1999; Friedman et al., 2002], reports on Ks layers were limited in number: two dif-ferent sporadic layer events were analyzed by Delgado et al. [2012], and the Ks layers were observed in both neutral K and Ca+ layers with a lidar. A temperature-dependent chemical model was also developed to simulate the observations: one event that occurred be-tween June 12 and 13, 2002 was successfully reproduced. Raizada et al. [2004] found that sudden increases in both K and Ca densities were often observed during early morning hours or at night when meteor showers occurred.
Among many mechanisms for interpreting the Ns formation, the most promising is the neutralization of ions, as evidenced by the high temporal and spatial correlation between enhanced metal atoms and Es layers [Gardner et al., 1993; Friedman et al., 2000; Williams et al., 2007; Delgado et al., 2012; Dou et al., 2012]. However, no reports examined the relationship between the Ks and Es layers.
In this paper, using lidar and digital ionosonde observations from the newly launched Meridian Project, the aim of which is to help researchers better understand and predict space weather conditions over China, we statistically analyzed the Ks and Es layer events at Beijing. The observational data were obtained by the Na-K lidar at Beijing from November 2010 to October 2011 and from May 2013 to April 2014.
1. Cheng X., Yang G., Yang Y., Li F., Wang J., Liu Y., Li Y., Lin X., Gong S. Na layer and K layer simultaneous observation by lidar. Chinese J. Lasers. 2011, vol. 38, no. 2, pp. 233-237. (In Chinese).
2. Delgado R., Friedman J.S., Fentzke J.T., Raizada S., Tepley C.A., Zhou Q. Sporadic metal atom and ion layers and their connection to chemistry and thermal structure in the mesopause region at Arecibo. J. Atmos. Solar-Terr. Phys. 2012, vol. 74, pp. 11-23. DOI:https://doi.org/10.1016/j.jastp.2011.09.004.
3. Dou X.K., Xue X.H., Li T., Chen T.D., Chen C., Qiu S.C. Possible relations between meteors, enhanced electron density layers, and sporadic sodium layers. J. Geophys. Res.: Space Phys. 2010, vol. 115., CiteID A06311. DOI:https://doi.org/10.1029/2009ja014575.
4. Eska V., Hoffner J. Observed linear and nonlinear K layer response. Geophys. Res. Lett. 1998, vol. 25, no. 15, pp. 2933- 2936. DOI:https://doi.org/10.1029/98gl02110.
5. Eska V., Hoffner J., von Zahn U. Upper atmosphere potassium layer and its seasonal variations at 54 degrees N. J. Geophys. Res.: Space Phys. 1998, vol. 103, no. A12, pp. 29207-29214. DOI:https://doi.org/10.1029/98ja02481.
6. Eska V., von Zahn U., Plane J.M.C. The terrestrial potassium layer (75-110 km) between 71 degrees S and 54 degrees N: Observations and modeling, J. Geophys. Res.: Space Phys. 1999, vol. 104, no. A8, pp. 17173-17186. DOI:https://doi.org/10.1029/1999ja900117.
7. Friedman J.S., Collins S.C., Delgado R., Castleberg P. A. Mesospheric potassium layer over the Arecibo Observatory, 18.3 degrees N 66.75 degrees W. Geophys. Res. Lett. 2002, vol. 29, no. 5, pp. 15-1, CiteID 1071. DOI: 10.1029/ 2001gl013542.
8. Friedman J.S., Gonzalez S.A., Tepley C.A., Zhou Q., Sulzer M.P., Collins S.C., Grime B.W. Simultaneous atomic and ion layer enhancements observed in the mesopause region over Arecibo during the Coqui II sounding rocket campaign. Geophys. Res. Lett. 2000, vol. 27, no. 4, pp. 449-452. DOI:https://doi.org/10.1029/1999gl900605.
9. Gardner C.S., Kane T.J., Senft D.C., Qian J., Papen G.C. Simultaneous observations of sporadic-E, Na, Fe, and Ca+ layers at Urbana, Illinois - 3 case-studies. J. Geophys. Res.: Atmos. 1993, vol. 98, no. D9, pp. 16865-16873. DOI:https://doi.org/10.1029/93jd01477.
10. Gong S.S., Yang G.T., Wang J.M., Liu B.M., Cheng X.W., Xu J.Y., Wan W.X. Occurrence and characteristics of sporadic sodium layer observed by lidar at a mid-latitude location. J. Atmos. Solar-Terr. Phys. 2002, vol. 64, no. 18, pp. 1957-1966. DOI: http://dx.doi.org/10.1016/S1364-6826(02)00216-X.
11. Kane T., Grime B., Franke S., Kudeki E., Urbina J., Kelley M., Collins S. Joint observations of sodium enhancements and field-aligned ionospheric irregularities Geophys. Res. Lett. 2001, vol. 28, no. 7, pp. 1375-1378. DOI: 10.1029/ 2000gl012176.
12. Ma Z., Wang X., Chen L., Wu J. First report of sporadic Na layers at Qingdao (36 degrees N, 120 degrees E), China. Ann. Geophys. 2014, vol. 32, no. 7, pp. 739-748. DOI:https://doi.org/10.5194/angeo-32-739-2014.
13. Megie G., Bos F., Blamont J.E., Chanin M.L. Simultaneous nighttime lidar measurements of atmospheric sodium and potassium. Planetary and Space Sci. 1978, vol. 26, no. 1, pp. 27-35. DOI:https://doi.org/10.1016/0032-0633(78)90034-x.
14. Plane J.M.C. The chemistry of meteoric metals in the Earth’s upper-atmosphere. Int. Rev. Phys. Chem. 1991, vol. 10, no. 1, pp. 55-106. DOI:https://doi.org/10.1080/01442359109353254.
15. Plane J.M.C., Feng W., Dawkins E., Chipperfield M.P., Höffner J., Janches D., Marsh D.R. Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere. Geophys. Res. Lett. 2014, vol. 41, no. 13, pp. 4753-4760. DOI:https://doi.org/10.1002/2014GL060334.
16. Raizada S., Tepley C.A., Janches D., Friedman J.S., Zhou Q., Mathews J.D. Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity. J. Atmos. Solar-Terr. Phys. 2004, vol. 66, no. 6-9, pp. 595-606. DOI: http://dx.doi.org/10.1016/ j.jastp.2004.01.030.
17. von Zahn U., Gerding M., Hoffner J., McNeil W.J., Murad E. Iron, calcium, and potassium atom densities in the trails of Leonids and other meteors: Strong evidence for differential ablation. Meteoritics & Planetary Sci. 1999, vol. 34, no. 6, pp. 1017-1027.
18. Wang C. New chains of space weather monitoring stations in China. Space Weather. 2010, vol. 8, no. 8, S08001. DOI:https://doi.org/10.1029/2010SW000603.
19. Williams B.P., Berkey F.T., Sherman J., She C.Y. Coincident extremely large sporadic sodium and sporadic E layers observed in the lower thermosphere over Colorado and Utah. Ann. Geophys. 2007, vol. 25, no. 1, pp. 3-8.
