Caribbean Ionosphere Campaign, year one: Airglow and plasma observations during two intense mid‐latitude spread‐F events

Abstract

Abstract. A series of campaigns has been carried out in the Caribbean over a one-year period to study intense midlatitude spreaA-F events using a cluster of diversified instrumentation. These events are relatively rare but a number of them have now been captured and will be discussed in this and several companion papers. This paper focuses on 630 nm airglow images obtained by the Cornell All-Sky Imager for two of the more spectacular cases that began on February 17, 1998 and February 17, 1999. In the latter case, and for the first time, a poleward surge of depletion/enhancement airglow zones was captured by radar as well as an airglow imager. In the former case structures grew in place overhead and produced strong VHF F-region backscatter as observed by the CUPRI and University of Illinois radars; the other event, exactly one year later, did not result in detectable 3-m backscatter. The two data sets show quantitatively that the low airglow region is elevated in height and depleted in plasma density and Pedersen conductivity. We suggest an enhanced eastward electric field inside the low conductivity zone may be responsible for the surge. The data also suggest small scale turbulence can only be observed in developing structures.

Midlatitudinal Special Airglow Structures Generated by the Interaction Between Propagating Medium‐Scale Traveling Ionospheric Disturbance and Nighttime Plasma Density Enhancement at Magnetically Quiet Time

“…As a special example, this event is accompanied by a poleward surge of airglow depletion/enhancement and a bifurcation of depletion, during the occurrence of NPDE/NIAEI of the ionosphere near midnight. Aponte et al (2000) further analyzed one of the events reported by Kelley et al (2000) and obtained the same conclusion. Kelley et al (2000) and Garcia, Kelley, Makela, Sultan, et al (2000) previously reported this kind of special midlatitudinal airglow structures, and two of those events were caused by the geomagnetic storm.…”

“…Kelley et al (2000) and Garcia, Kelley, Makela, Sultan, et al (2000) previously reported this kind of special midlatitudinal airglow structures, and two of those events were caused by the geomagnetic storm. As a special example, this event is accompanied by a poleward surge of airglow depletion/enhancement and a bifurcation of depletion, during the occurrence of NPDE/NIAEI of the ionosphere near midnight.…”

Tracking F-region plasma depletion bands using GPS-TEC, incoherent scatter radar, and all-sky imaging at Arecibo

“…(Mendillo et al, 1997;Garcia et al, 2000;Kelley et al, 2000bKelley et al, , 2002Kelley et al, , 2004Shiokawa et al, 2003a, b;Otsuka et al, 2003;Seker et al, 2007). The use of imager and radar together has been the subject of several recent papers: Pi et al (2000) (imager, ISR, FPI), Kelley et al (2000a) (imager, ISR), Kelley et al (2002) (imager, ISR, GPS), Otsuka et al (2003) (imager, MU radar, FPI). However these papers have typically been limited to comparing the radar "image" and the all-sky image by looking at them simultaneously, rather than using the two jointly to infer additional information about the structures being studied.…”

First results from the Penn State Allsky Imager at the Arecibo Observatory

“…It is also highly affected by atmospheric, magnetospheric, and solar events and is often unstable. Thus, there are many different phenomena seen in the ionosphere, such as ducted and gravity waves (Taylor, 1997), bores (Smith et al, 2003), sporadic-E (Mathews et al, 2001a;Kelley et al, 2003), equatorial anomaly (Kelley et al, 2000a), spread-F (ESF) and Plumes (Mendillo et al, 1997;Mathews et al, 2001b;Makela, 2004b;Makela et al, 2004a), plasma bubbles and instabilities, traveling ionospheric disturbances (TIDs) (Mendillo et al, 1997;Kelley et al, 2000b;Kelley et al, 2002), midnight temperature maximum (MTM), and brightness waves (BW) (Herrero and Meriwether, 1980;Colerico et al, 1996;Mendillo et al, 1997).…”