Data assimilation for neutral thermospheric species during geomagnetic storms

摘要: [1] During a geomagnetic storm, Joule heating heats the neutral gas and drives horizontally divergent winds which force upwelling of atmosphere. The heavier molecular species N2 O2, abundant in lower thermosphere, are transported to high altitude where they increase loss rate F region ionosphere. “bulge” enhanced species, or depleted atomic oxygen, is long-lived, returning equilibrium mainly through slow process diffusion. Its longevity, order day, enables global wind system transport composition disturbance over thousands kilometers, driven by combination quiet storm-time fields. In stand-alone physical model formation subsequent movement features depend on accurate specification spatial temporal distribution from magnetosphere knowledge time-dependent fields define transport. Neither sufficiently well known given current observational capability. An alternative approach combine contained with observations thermospheric composition. It has been demonstrated that FUV images can provide reliable estimate magnitude structure oxygen-depleted regions sunlit side Earth. A Kalman filter data assimilation method developed optimally thermosphere This used as one important drivers for Global Assimilation Ionospheric Measurements (GAIM) improve forecast response ionosphere storms.