Details

Autor(en) / Beteiligte

• Patra, A. K.
• Pavan Chaitanya, P.
• Durga Rao, M.
• Kamaraj, P.

Titel

First Dual‐Frequency Radar Observations of 150‐km Echoes From Gadanki and Implications

Ist Teil von

• Geophysical research letters, 2018-05, Vol.45 (10), p.4594-4600

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2018

Quelle

Wiley-Blackwell Journals

Beschreibungen/Notizen

• We present the first dual‐frequency overlapping volume radar observations of daytime 150‐km echoes made at 30 and 53 MHz from Gadanki, India. We show remarkably different responses of the 150‐km echoing layers including the spectral characteristics of the echoes at 30 and 53 MHz. Results show that while the echoes in general are remarkably stronger with narrower spectral width at 30 MHz than that of 53 MHz the relationship between radar cross sections at the two frequencies varies depending on the echoing layer. We also show distinctly different spectral broadening in different echoing regions observed by the 53‐MHz radar, which is missing in the 30‐MHz radar observations. These new observations indicate involvement of naturally enhanced incoherent scattering as well as scattering from enhanced electron density fluctuations of plasma instability origin and hence are of utmost importance in understanding the origin of the puzzling 150‐km echoing phenomenon. Plain Language Summary We present the first dual‐frequency overlapping volume radar observations of daytime 150‐km echoes made at 30 and 53 MHz from Gadanki. We show remarkably different responses of the 150‐km echoing layers including the spectral characteristics of the echoes at 30 and 53 MHz clearly suggesting frequency dependence property of the 150‐km echoes, not known before. These observations are new and indicate the role of Naturally Enhanced Incoherent Scattering as well as enhanced electron density fluctuations presumably of plasma instability origin and provide new insight in understanding the origin of the puzzling 150‐km echoing phenomenon. Key Points We present first common volume 30 and 53‐MHz radar observations of 150‐km echoes Results show complex relationship between radar cross sections at the two frequencies Results indicate role of both NEIS and plasma instability in the echoing phenomenon