Discrete high‐density plasma structures in the Earth's ionosphere that convect across the polar cap from the dayside to nightside are known as polar cap patches. This high‐latitude phenomenon can ...interfere and disrupt satellite and high‐frequency (HF) communications when the associated sharp electron density gradients are encountered, and therefore, accurate modeling and forecasting of such events would be greatly beneficial. In this study, we have utilized the assimilative Global Positioning System Ionospheric Inversion (GPSII) method to reconstruct the high‐latitude ionosphere utilizing data from Global Navigation Satellite System (GNSS) receivers, vertical ionosondes, the Resolute Bay Incoherent Scatter Radar (RISR‐N), in situ satellite data, and Super Dual Auroral Radar Network (SuperDARN) radars. The novel method of assimilating RISR‐N and SuperDARN ground scatter measurements helps to increase the limited number of observations at high latitudes. The reconstructed polar cap patches are shown to correspond with ground‐ and spaced‐based observations, illustrating the ability of utilizing GPSII to study the complex high‐latitude region.
Key Points
Using the Global Positioning System Ionospheric Inversion (GPSII) method, we reconstructed the high‐latitude ionosphere on 22 January 2012
Polar cap patches were observed in the ionospheric reconstructions
The reconstructed patches corresponded well to ground‐based and space‐based ionospheric observations
Clouds of vaporized samarium (Sm) were released during sounding rocket flights from the Reagan Test Site, Kwajalein Atoll in May 2013 as part of the Metal Oxide Space Cloud (MOSC) experiment. A ...network of ground‐based sensors observed the resulting clouds from five locations in the Republic of the Marshall Islands. Of primary interest was an examination of the extent to which a tailored radio frequency (RF) propagation environment could be generated through artificial ionospheric modification. The MOSC experiment consisted of launches near dusk on two separate evenings each releasing ~6 kg of Sm vapor at altitudes near 170 km and 180 km. Localized plasma clouds were generated through a combination of photoionization and chemi‐ionization (Sm + O → SmO+ + e–) processes producing signatures visible in optical sensors, incoherent scatter radar, and in high‐frequency (HF) diagnostics. Here we present an overview of the experiment payloads, document the flight characteristics, and describe the experimental measurements conducted throughout the 2 week launch window. Multi‐instrument analysis including incoherent scatter observations, HF soundings, RF beacon measurements, and optical data provided the opportunity for a comprehensive characterization of the physical, spectral, and plasma density composition of the artificial plasma clouds as a function of space and time. A series of companion papers submitted along with this experimental overview provide more detail on the individual elements for interested readers.
Key Points
An overview of the 2013 Metal Oxide Space Cloud (MOSC) sounding rocket experiment from Kwajalein Atoll
A comprehensive diagnosis of artificial plasma clouds generated through release of samarium vapor in the upper atmosphere
Artificial modification of the radio frequency propagation environment
Hines discusses a number of strategies for involving viewers in a work of art. Hines' painting process begins with a solid, believable structure based on an accurate drawing as a foundation for less ...defined, painterly areas which give the painting depth without sacrificing an overall lifelike look.
PDF
