SA33A-02
UV Observations of Hemispheric Asymmetry

Wednesday, 16 December 2015: 13:55
2016 (Moscone West)
Robert K Schaefer1, Larry J Paxton2, Brian C Wolven1, Yongliang Zhang3 and Giuseppe Romeo2, (1)The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, United States, (2)Applied Physics Laboratory Johns Hopkins, Laurel, MD, United States, (3)Johns Hopkins University, Baltimore, MD, United States
Abstract:
Asymmetry in the auroral patterns can be an important diagnostic for understanding the dynamics of solar wind interaction with the magnetosphere-ionosphere-thermosphere system (e.g., Newel and Meng, 1998; Fillingrim et al., 2005). Molecular nitrogen emission in the UV Lyman-Birge-Hopfield bands can be used to determine energy flux and electron mean energy (Sotirelis, et al, 2013) and thereby Hall and Pederson integrated conductances (Gjerloev, et al., 2014). UV imagery provided by the 4 SSUSI instruments on the Defense Meteorological Satellite Program (DMSP) F16-F19 spacecraft provide two dimensional maps of this emission at different local times. Often there are near simultaneous observations of both poles by some combination of the satellites. (see figure 1) The SSUSI auroral data products are well suited to this study, as they have the following features.:

- dayglow has been subtracted on dayside aurora

- electron energy flux and mean energy are pre-calculated

- individual arcs have been identified through image processing.

In order to intercompare data from multiple satellites, we must first ensure that the instrument calibrations are consistent. In this work we show that the instruments are consistently calibrated, and that results generated from the SSUSI data products can be trusted. Several examples of storm time asymmetries captured by the SSUSI instruments will be discussed.

Fillingim, M. O., G. K. Parks, H. U. Frey, T. J. Immel, and S. B. Mende (2005), Hemispheric asymmetry of the afternoon electron aurora, Geophys. Res. Lett., 32, L03113, doi:10.1029/2004GL021635.

Gjerloev, J., Schaefer, R., Paxton, L, and Zhang, Y. (2014), A comprehensive empirical model of the ionospheric conductivity derived from SSUSI/GUVI, SuperMAG and SuperDARN data, SM51G-4339, Fall 2014 AGU meeting, San Francisco.

Newell, P. T., and C.-I. Meng (1988), Hemispherical asymmetry in cusp precipitation near solstices, J. Geophys. Res., 93(A4), 2643–2648, doi:10.1029/JA093iA04p02643.

Sotirelis, T., Korth, H., Hsieh, S. - Y., Zhang, Y., Morrison, D., and Paxton, L., (2013), “Empirical relationship between electron precipitation and far-ultraviolet auroral emissions from DMSP observations”, Journal of Geophysical Research: Space Physics, vol. 118, no. 3, pp. 1203 - 1209.

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