Medium‐scale traveling ionospheric disturbances detected with dense and wide TEC maps over North America

Abstract

[1] Nighttime and daytime medium-scale traveling ionospheric disturbances (MSTIDs) are detected with dense and wide detrended total electron content (TEC) maps over North America using multiple GPS receiver networks. The TEC maps cover a wide region of 60-130°W and 24-54°N (30-65°N in geomagnetic latitude), and have a spatial resolution of 1.05°Â 1.05°in latitude and longitude (0.15°Â 0.15°with 7 Â 7 pixel smoothing) and a temporal resolution of 30 seconds. The TEC maps reveal, for the first time, that the nighttime MSTIDs propagate southwestward with 200 -500 km wavelengths over North America and have wavefronts longer than $2,000 km. We also observe that daytime MSTIDs with 300 -1,000 km wavelengths propagate southeastward until mid-afternoon and southwestward in the late afternoon. In the mid-to-late afternoon, these MSTIDs propagating in the different directions are superimposed. The TEC maps can be a new powerful tool to investigate the MSTIDs.

The first GPS-TEC imaging of the space structure of MS wave packets excited by the solar terminator

“…Thus we build up the dynamic image of disturbances traveling over Japan in AVI format. The said space-time presentation method of ionosphere disturbances for dense USA GPS networks was used in Tsugawa et al (2007). …”

First simultaneous observations of daytime MSTIDs over North America using GPS‐TEC and DEMETER satellite data

“…As of January 2008, more than 1700 receivers are available, each of which calculates and records the slant TEC values every 30 seconds from 5 $ 8 visible GPS satellites with elevation angle larger than 30 degrees. In the TEC map construction, we have employed the same method as that of Tsugawa et al [2007] as follows. Integer cycle ambiguities and instrumental biases contained in each receiver-satellite data set are removed by detrending the data with a 60-minute running average, which is longer than a typical MSTID periodicity (10 $ 60 minutes) [Hunsucker, 1982].…”

A multi-platform investigation of midlatitude sporadic <i>E</i> and its ties to <i>E</i>–<i>F</i> coupling and meteor activity

“…It has been shown that the polarized electric fields that fuel the Cosgrove and Tsunoda (2002) instability can remotely interact with similar fields formed by the Perkins instability (Perkins, 1973) in the F region, using both physical arguments (Cosgrove et al, 2004) and simulations (Cosgrove, 2007;Yokoyama et al, 2009). This E-F coupling instability has been posited to be the origin of southwestwardpropagating traveling ionospheric disturbances (TIDs) seen prominently during summer nighttime in the Northern Hemisphere (e.g., Hernández-Pajares et al, 2006;Tsugawa et al, 2007). The growth rate of the Perkins instability alone has been noted to be too low to generate these F -region wavefronts, making the coupled E-F instability, which has a larger growth rate by a factor of a few (Cosgrove et al, 2004), a more likely candidate.…”