Equatorial 150-km irregularities observed at Pohnpei

On the characteristics of 150-km echoes observed in the Brazilian longitude sector by the 30 MHz São Luı́s radar

We present long-overdue details about the intensity and spectral characteristics of 150-km echoes observed by the São Luı́s radar in Brazil. The São Luı́s observations show that the echoes usually come from multiple scattering layers that descend in altitude before local noon, and ascend during afternoon hours, similar to what has been found in observations made in other longitude sectors. The la...

Day-to-day correlation of equatorial electrojet at two stations separated by 2000 km

Day-to-day fluctuations of the daily range of the geomagnetic field H at the equatorial electrojet stations Ancon (ANC, 77.0 W) and Sao Luis (SLZ, 44.2 W) are described for the period January–June 1993. The H field started increasing between midnight and sunrise, reaching a peak shortly before noon. The daily range of H was maximum during March and April and minimum during June. Regardless of t...

William Osler at 150.

A global radio frequency noise survey as observed by the FORTE satellite at 800 km altitude

[1] We present a global radio frequency noise survey observed from the Fast on-Orbit Recording of Transient Events (FORTE) satellite at 800 km altitude. This is a survey of squared amplitudes (R) in 44 frequency subbands spaced by 0.5 MHz centered at 38 MHz (‘‘low band’’) and 44 subbands spaced by 0.5 MHz centered at 130 MHz (‘‘high band’’). We define 13 geographic regions and analyze signal-fr...

Periodicity of Downward Longwave Radiation at an Equatorial Location

A good understanding of the diverse mechanisms in the atmosphere is required in modelling the climate. In this study, the diurnal and seasonal patterns of all-sky downward longwave radiation (DLR) at Ilorin (8o 32l N, 4o 34l E), Nigeria were investigated alongside relative humidity (RH) and temperature. The average diurnal pattern of DLR gives an arc that begins by increasing gradually with som...