Climatological study of the daytime occurrence of the 3-meter EEJ plasma irregularities over Jicamarca close to the solar minimum (2007 and 2008)

Abstract

We have developed algorithms for conducting a seasonal statistical study of the occurrence of plasma irregularities in the Peruvian sector as a function of height and local time, covering two years of data (2007 and 2008) close to the solar minimum. This study was performed based on radar measurements carried out at the Jicamarca Radio Observatory (JRO), which is located in Lima-Peru (11.57• S, 76.52, under the magnetic equator. The statistical analysis runs over daily Range Time Intensity (RTI) maps obtained with the radar operating in the Jicamarca Unattended Long-term Investigations of the Ionosphere and Atmosphere (JULIA) mode. Our results revealed relevant features of the diurnal variation of the plasma irregularities embedded in the equatorial electrojet, such as: a more often occurring presence of the 3-m irregularities during equinox, and a descent of the scattering profile in the morning hours, followed by its ascent in the afternoon.

Equatorial E region electric fields at the dip equator: 2. Seasonal variabilities and effects over Brazil due to the secular variation of the magnetic equator

“…The Sq foci in both the Northern and Southern Hemispheres shift toward the equator during equinox (the EEJ intensity will increase) and shift toward the poles during solstice (the EEJ intensity decreases), explaining the strengthening and weakening of the EEJ during these seasons. In the Brazilian sector, however, the EEJ has one prominent peak centering around the December and January months both during solar maximum and minimum, and the strength of the EEJ is minimum during Southern (Northern) Hemisphere winter (summer) (May–August) [ Chapman and Rao , ; Doumouya et al , ; Okeke and Hamano , ; Denardini et al , ; Shume et al , ; Guizelli et al , ]. An important factor that influences this result is certainly the large magnetic declination angle in the Brazilian sector as compared with the Peruvian sector.…”

Day‐to‐day variability of equatorial electrojet and its role on the day‐to‐day characteristics of the equatorial ionization anomaly over the Indian and Brazilian sectors

“…Reviews on EEJ and CEJ have been made by different researchers [Richmond, 1973;Kane, 1976;Mayaud, 1977;Forbes, 1981;Reddy, 1981Reddy, , 1989Stening, 1985;Rastogi, 1989;Mazaudier et al, 1993;Doumouya et al, 1998;Mazaudier et al, 2005]. During the past few decades, theoretical and scientific models of the ionospheric dynamo have been developed to explain the mechanism of the EEJ flow and its morphology [Sugiura and Cain, 1966;Sugiura and Poros, 1969;Richmond, 1973;Kane and Trivedi, 1982;Stening, 1985;Reddy, 1989;Chandra et al, 2000;Rabiu et al, 2007;Denardini et al, 2009;Abbas et al, 2012;Rastogi et al, 2013;Guizelli et al, 2013]. Electrojet characteristics have also been simulated by assuming simple current configurations such as line current [Forbush and Casaverde, 1961], thin-band current [Chapman, 1951] and fourth degree current distribution [Fambitakoye, 1976], and thick current distribution [Onwumechili, 1967].…”

E region electric field dependence of the solar activity

“…[, ] and Guizelli et al . [] investigated the regional differences about the EEJ in the Brazilian and Peruvian sector.…”

“…Also, specifically about the responses of the E regions electric field (EF), drivers of the EEJ, to storm time, significant progress have being made by Denardini et al [2009Denardini et al [ , 2011 to explain the behavior of the plasma irregularities (driven by electric field) to the disturbance dynamo. In addition, Shume et al [2010Shume et al [ , 2011 and Guizelli et al [2013] investigated the regional differences about the EEJ in the Brazilian and Peruvian sector.…”