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http://dx.doi.org/10.5140/JASS.2021.38.2.135

The First Report on the Afternoon E-Region Plasma Density Irregularities in Middle Latitude  

Yang, Tae-Yong (Korea Astronomy and Space Science Institute)
Kwak, Young-Sil (Korea Astronomy and Space Science Institute)
Lee, Jaewook (Korea Astronomy and Space Science Institute)
Park, Jaeheung (Korea Astronomy and Space Science Institute)
Choi, Seonghwan (Korea Astronomy and Space Science Institute)
Publication Information
Journal of Astronomy and Space Sciences / v.38, no.2, 2021 , pp. 135-143 More about this Journal
Abstract
We report, for the first time, the afternoon (i.e., from noon to sunset time) observations of the northern mid-latitude E-region field-aligned irregularities (FAIs) made by the very high frequency (VHF) coherent backscatter radar operated continuously since 29 December 2009 at Daejeon (36.18°N, 127.14°E, 26.7°N dip latitude) in South Korea. We present the statistical characteristics of the mid-latitude afternoon E-region FAIs based on the continuous radar observations. Echo signal-to-noise ratio (SNR) of the afternoon E-region FAIs is found to be as high as 35 dB, mostly occurring around 100-135 km altitudes. Most spectral widths of the afternoon echoes are close to zero, indicating that the irregularities during the afternoon time are not related to turbulent plasma motions. The occurrence of afternoon E-regional FAI is observed with significant seasonal variation, with a maximum in summer and a minimum in winter. Furthermore, to investigate the afternoon E-region FAIs-Sporadic E (Es) relationship, the FAIs have also been compared with Es parameters based on observations made from an ionosonde located at Icheon (37.14°N, 127.54°E, 27.7°N dip latitude), which is 100 km north of Daejeon. The virtual height of Es (h'Es) is mainly in the height range of 105 km to 110 km, which is 5 km to 10 km greater than the bottom of the FAI. There is no relationship between the FAI SNR and the highest frequencies (ftEs) (or blanket frequencies (fbEs)). SNR of FAIs, however, is found to be related well with (ftEs-fbEs).
Keywords
very high frequency (VHF) coherent backscatter radar; afternoon E-region irregularities; mid-latitude;
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1 Patra AK, Rao PB, High-resolution radar measurements of turbulent structure in the low-latitude E region, J. Geophys. Res. 104, 24667-24673, (1999). http://doi.org/10.1029/1999JA900303   DOI
2 Patra AK, Venkateswara Rao N, Phanikumar DV, Chandra H, Das U, et al., A study on the low-latitude daytime E region plasma irregularities using coordinated VHF radar, rocket-borne, and ionosonde observations, J. Geophys. Res. 114, A11301 (2009). https://doi.org/10.1029/2009JA014501   DOI
3 Phanikumar DV, Patra AK, Kwak YS, Kim KH, Yellaiah G, Low latitude E-region irregularities studied using Gadanki radar, ionosonde and in situ measured electron density, Astrophys. Space Sci. 323, 225-233 (2009). https://doi.org/10.1007/s10509-009-0066-y   DOI
4 Yamamoto M, Komoda N, Fukao S, Tsunoda RT, Ogawa T, et al., Spatial structure of the E region field-aligned irregularities revealed by the MU radar, Radio Sci. 29, 337-347 (1994). https://doi.org/10.1029/93RS01846   DOI
5 Saito S, Yamamoto M, Fukao S, Marumoto M, Tsunoda RT, Radar observations of field-aligned plasma irregularities in the SEEK-2 campaign, Ann. Geophys. 23, 2307-2318 (2005). https://doi.org/10.5194/angeo-23-2307-2005   DOI
6 Tsunoda RT, Fukao S, Yamamoto M, Hamasaki T, First 24.5-MHz radar measurements of quasi-periodic backscatter from field-aligned irregularities in midlatitude sporadic E, Geophys. Res. Lett. 25, 1765-1768 (1998). https://doi.org/10.1029/98GL01086   DOI
7 Whitehead JD, Recent work on mid-latitude and equatorial sporadic-E, J. Atmos. Terr. Phys. 51, 401-424 (1989). https://doi.org/10.1016/0021-9169(89)90122-0   DOI
8 Woodman RF, Yamamoto M, Fukao S, Gravity wave modulation of gradient drift instabilities in mid-latitude sporadic E irregularities, Geophys. Res. Lett. 18, 1197-1200 (1991). https://doi.org/10.1029/91GL01159   DOI
9 Yamamoto M, Fukao S, Ogawa T, Tsuda T, Kato S, A morphological study on mid-latitude E-region field-aligned irregularities observed with the MU radar, J. Atmos. Terr. Phys. 54, 769-777 (1992). https://doi.org/10.1016/0021-9169(92)90115-2   DOI
10 Yamamoto M, Fukao S, Tsunoda RT, Pfaff RF, Hayakawa H, SEEK-2 (Sporadic-E Experiment over Kyushu 2)-project outline, and significance, Ann. Geophys. 23, 2295-2305 (2005). https://doi.org/10.5194/angeo-23-2295-2005   DOI
11 Yamamoto M, Itsuki T, Kishimoto T, Tsunoda RT, Pfaff RF, et al., Comparison of E-region electric fields observed with a sounding rocket and a Doppler radar in the SEEK campaign, Geophys. Res. Lett. 25, 1773-1776 (1998). https://doi.org/10.1029/98GL01055   DOI
12 Yang TY, Kwak YS, Kil H, Lee YS, Lee WK, et al., Occurrence climatology of F region field-aligned irregularities in middle latitudes as observed by a 40.8 MHz coherent scatter radar in Daejeon, South Korea, J. Geophys. Res. 120, 10107-10115 (2015). https://doi.org/10.1002/2015JA021885   DOI
13 Fukao S, Sato T, Tsuda T, Kato S, Wakasugi K, et al., The MU radar with an active phased array system: 1. antenna and power amplifiers, Radio Sci. 20, 1155-1168 (1985a). https://doi.org/10.1029/RS020i006p01155   DOI
14 Ecklund WL, Carter DA, Balsley BB, Gradient drift irregularities in mid-latitude sporadic E, J. Geophys. Res. 86, 858-862 (1981). https://doi.org/10.1029/JA086iA02p00858   DOI
15 Fejer BG, Kelley MC, Ionospheric irregularities, Rev. Geophys. 18, 401-454, (1980). http://doi.org/10.1029/RG018i002p00401   DOI
16 Fukao S, Oliver WL, Onishi Y, Takami T, Sato T, et al., F-region seasonal behavior as measured by the MU radar, J. Atmos. Terr. Phys. 53, 599-618, (1991). http://doi.org/10.1016/0021-9169(91)90088-O   DOI
17 Hussey GC, Schlegel K, Haldoupis C, Simultaneous 50-MHz coherent backscatter and digital ionosonde observations in the midlatitude E region, J. Geophys. Res. 103, 6991-7001 (1998). https://doi.org/10.1029/97JA03089   DOI
18 Fukao S, Tsuda T, Sato T, Kato S, Wakasugi K, et al., The MU radar with an active phased array system: 2. in-house equipment, Radio Sci. 20, 1169-1176 (1985b). https://doi.org/10.1029/RS020i006p01169   DOI
19 Fukao S, Yamamoto M, Tsunoda, RT, Hayakawa H, The SEEK (Sporadic-E Experiment over Kyushu) campaign, Geophys. Res. Lett. 25, 1761-1764 (1998). https://doi.org/10.1029/98GL00932   DOI
20 Haldoupis C, A review of radio studies of auroral E region ionospheric irregularities, Ann. Geophys. 7, 239-258, (1989).
21 Ogawa T, Takahashi O, Otsuka Y, Nozaki K, Yamamoto M, et al., Simultaneous middle and upper atmosphere radar and ionospheric sounder observations of midlatitude E region irregularities and sporadic E layer, J. Geophys. Res. 107, SIA 3-1-SIA 3-13 (2002). https://doi.org/10.1029/2001JA900176   DOI
22 Tsunoda RT, Fukao S, Yamamoto M, On the origin of quasiperiodic radar backscatter from midlatitude sporadic E, Radio Sci. 29, 349-365 (1994). https://doi.org/10.1029/93RS01511   DOI
23 Yamamoto M, Fukao S, Woodman RF, Ogawa T, Tsuda T, et al., Mid-latitude E region field-aligned irregularities observed with the MU radar, J. Geophys. Res. 96, 15943-15949 (1991). https://doi.org/10.1029/91JA01321   DOI
24 Phanikumar DV, Patra AK, Devasia CV, Yellaiah G, Seasonal variation of low-latitude E-region plasma irregularities studied using Gadanki radar and ionosonde, Ann. Geophys. 26, 1865-1876 (2008). https://doi.org/10.5194/angeo-26-1865-2008   DOI
25 Otsuka Y, Onoma F, Shiokawa K, Ogawa T, Yamamoto M, et al., Simultaneous observations of nighttime medium-scale traveling ionospheric disturbances and E region field-aligned irregularities at midlatitude, J. Geophys. Res. 112, A06317 (2007). https://doi.org/10.1029/2005JA011548   DOI
26 Kwak YS, Yang TY, Kil H, Phanikumar DV, Heo BH, et al., Characteristics of the E- and F-region field-aligned irregularities in middle latitudes: initial results obtained from the Daejeon 40.8 MHz VHF radar in South Korea, J. Astron. Space Sci. 31, 15-23 (2014). https://doi.org/10.5140/JASS.2014.31.1.15   DOI
27 Lee CC, Liu JY, Pan CJ, Igarashi K, The heights of sporadic-E layer simultaneously observed by the VHF radar and ionosondes in Chung-Li, Geophys. Res. Lett. 27, 641-644 (2000). https://doi.org/10.1029/1999GL003713   DOI
28 Maruyama T, Saito S, Yamamoto M, Fukao S, Simultaneous observation of sporadic E with a rapid-run ionosonde and VHF coherent backscatter radar, Ann. Geophys. 24, 153-162 (2006). https://doi.org/10.5194/angeo-24-153-2006   DOI
29 Ogawa T, Yamamoto M, Fukao S, Middle and upper atmosphere radar observations of turbulence and movement of midlatitude sporadic E irregularities, J. Geophys. Res. 100, 12173-12188 (1995). https://doi.org/10.1029/95JA00261   DOI