First simultaneous measurements of neutral and ionized iron densities in the upper mesosphere

Abstract

We report on the results of a multi‐instrument study of a sporadic Fe layer and a sporadic E layer which took place in the night of September 20, 1991, at the Andøya Rocket Range (69°N, 16°E). A ground‐based lidar was used to measure mesospheric Fe densities, while simultaneously rocket‐borne probes and an ion mass spectrometer measured the profile of total ion density and ion composition, respectively. All instruments observed the sporadic layers near 97 km altitude. Radar tracking of chaff clouds established the wind field in the 90‐ to 100‐km region with high spatial resolution, while the EISCAT incoherent scatter radar measured the E fields in the F region. The major ion in the sporadic E layer turned out to be Mg+. The narrow Fe+ layer was 1 km lower than the sporadic Fe+ layer. The ratio of densities [Fe+]/[Fe] in the peaks of the sporadic layers was found to be 1.75.

Sporadic Ca and Ca<sup>+</sup> layers at mid-latitudes: Simultaneous observations and implications for their formation

“…For the case of sodium, Friedman et al (2000) report on Na enrichments below 97 km without the occurrence of Na + layers in the same volume. Height differences between ionized and neutral sporadic metal layers have been reported by Alpers et al (1993) and Gardner et al (1993). Alpers et al (1993) measured the altitude of a Fe s layer by lidar and that of a simultaneous Fe + s layer by a rocket-borne mass spectrometer.…”

“…Height differences between ionized and neutral sporadic metal layers have been reported by Alpers et al (1993) and Gardner et al (1993). Alpers et al (1993) measured the altitude of a Fe s layer by lidar and that of a simultaneous Fe + s layer by a rocket-borne mass spectrometer. They found the neutral layer 1 km higher than the ionized layer.…”

“…von , Alpers et al (1993), Kirkwood and von Zahn (1993), Clemesha (1995)). For the case of fast conversion of Ca ions to Ca atoms, the seasonal variations of both species are expected to correlate positively.…”

“…Still, a strong link between the neutral and the ionized sporadic metal layers is generally assumed (e.g. Alpers et al, 1993;Qian et al, 1998). For the case of Ca atoms and Ca + ions, this link can be studied time-resolved by ground-based lidar observations.…”

Global transport and localized layering of metallic ions in the upper atmospherer

“…Similar rocket measurements were reported by Narcisi and Bailey (1965) and Narcisi (1967), including a¯ight during the Leonid meteor shower which conclusively demonstrated that meteor ablation is the mechanism responsible for production of metallic ions in the upper atmosphere. Numerous other rocket¯ights have subsequently provided data on metallic ion distributions (i.e., Young et al, 1967;Aiken and Goldberg, 1973;Aiken et al, 1974Aiken et al, , 1977Goldberg and Witt, 1977;Zbinden et al, 1975;Alpers et al, 1993). Some of these provided evidence for connections between metallic ion layers and sporadic-E (E s ), and others attempted to establish connections between metallic ion cluster molecules and the formation of noctilucent clouds.…”