The OI 630.0 and 557.7nm dayglow measured by WINDII and modeled by TRANSCAR

Abstract

Abstract. A 1-D fluid/kinetic code is used to model WIND Imaging Interferometer measurements of the atomic oxygen ( 3 P-1 D) red and ( 1 D-1 S) green thermospheric dayglows at 630.0 nm and 557.7 nm. This modelling is performed for different latitude and solar zenith angle conditions, in order to reproduce the measurements all along the satellite orbit. Results are successfully compared to the interferometer's observations, reproducing the measured volume emission rates, together with the maximum emission altitude. A good agreement is found regardless of the position considered along the satellite orbit, meaning that the solar flux and the solar zenith angle influences were successfully taken into account. Together with this model study, a four-year red and green oxygen lines set of WINDII data is analysed with regards to those geophysical parameters. Correlations between volume emission rates and solar flux are evaluated and it is found that the MgI I index is better suited to this kind of study than the f 10.7 decimetric index.

Influence of geomagnetic activity on the O I 630.0 and 557.7 nm dayglow

“…On the left side of Figure 2, from top to bottom, are shown the exospheric temperature, the concentration ratios (concentrations at Ap = 200 over concentrations at Ap = 10) for O and O 2 , and the electron density at an altitude of 250 km. These parameters are plotted versus the solar zenith angle (SZA), which is one of the main parameters that influences the intensity of the dayglow [see Culot et al , 2004]. On the right side of Figure 2 are shown the red line peak intensity (taken at the altitude of the maximum) and peak altitude, together with the preponderant production processes at SZA = 50°, the solar zenith angle for which the largest changes are observed with respect to magnetic activity.…”

A new method for studying the thermospheric density variability derived from CHAMP/STAR accelerometer data for magnetically active conditions

“…Indeed, have used the Mg II index for constructing their DTM2000 empirical model. On the other hand, Culot et al (2004) have also shown that Mg II was a better proxy to model the red and green line emission at thermospheric altitudes during magnetic quiet periods. Figure 7 (upper panel) shows the comparison between the CHAMP density c 1 projection coefficient (red line) and those computed with the actual (black line) and quiet (blue line) model using Mg II instead of F10.7 as a proxy for the Solar activity.…”

Solar influence on the redline dayglow emission under equinox conditions

“…The O( 1 D) state is mainly populated by the following reactions (Culot et al, 2004;Tyagi and Singh, 2000;Link and Swaminathan, 1992;Bates, 1990;Solomon and Abreu, 1989): Table 1 Reaction rate coefficients used in the modeling of 630.0 nm dayglow emission.…”