Investigation of Vertical Winds in the High‐Latitude Thermosphere: Horizontal Wind Divergence and Local Heating Using Tristatic SDI Observations

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Thermospheric vertical winds () in the high‐latitude regions play a key role in ionosphere–thermosphere coupling, and previous work has predicted a linear relationship between and divergence of horizontal winds (). However, this relationship remains controversial since most observational studies have relied on single‐station measurements. We analyze 17 tristatic Scanning Doppler Imager (SDI) observations over Alaska during geomagnetically disturbed periods to investigate the relationship among F‐region vertical winds, , and energy deposition. All events show correlations (>0.2) between vertical winds and horizontal wind divergence. Only 5 of 17 events show that the neutral density scale heights () estimated from the divergence of horizontal winds () are approximately twice as large as those estimated from the SDI neutral temperature and MSIS model (), while the other events show comparable scale heights. These differences in the two scale heights reflect additional local heating contributions to the observed vertical winds. In these 5 events, the auroral emission intensity ratio () shows the strongest association with vertical wind variations, whereas Joule heating rates are weakly correlated. Also, vertical winds in the lower and upper thermospheres are positively correlated. These results suggest that soft electron precipitation plays a more significant role than E‐region Joule heating in driving vertical winds and enhancing the coupling of E‐ and F‐regions. Furthermore, heating contributions are intermittently observed within the auroral oval, implying the mesoscale spatial variability of energy deposition.