A comparison between large-scale irregularities and scintillations in the polar ionosphere

A comparison between large-scale ionospheric irregularities recorded in the global GPS total electron content (TEC) and scintillations observed by Canadian High Arctic Ionospheric Network (CHAIN) are pursued during a geomagnetic storm. Clear irregularities, such as storm enhanced density, middle-latitude trough and polar cap patches, are identified from the TEC maps, together with the modeling auroral oval. At the edges of these irregularities, clear scintillations appeared but their behaviors were different. Phase scintillations (σφ) were much larger than amplitude scintillations (S4) both in the SED segmented area and at the equatorward edge of the middle-latitude trough in post-noon sector, associated with the bursty flows or flow reversals. S4 and σφ were small in the polar cap with small enhancements due to the varied flows with the density gradient at the edges of polar cap patches. While S4 were much larger than σφ in the auroral oval due to the particle precipitations.