HR: 1330h
AN: SA13A-06    [Abstracts]
TI: Specifying the Upper Atmospheric Drivers Using an Ensemble Kalman Filter
AU: * Minter, C F
EM: cliff.minter@noaa.gov
AF: University of Colorado, R/SEC 325 Broadway, Boulder, CO 80305 United States
AU: Fuller-Rowell, T J
EM: tim.fuller-rowell@noaa.gov
AF: University of Colorado, R/SEC 325 Broadway, Boulder, CO 80305 United States
AU: Codrescu, M V
EM: mihail.codrescu@noaa.gov
AF: University of Colorado, R/SEC 325 Broadway, Boulder, CO 80305 United States
AB: A data assimilation system for specifying the thermospheric composition and density in near real time has been developed over the last several years. Although it is possible to describe the physics of the upper atmospheric forcing, quantifying the time-dependent drivers still remains difficult - particularly during geomagnetic storm conditions. Incorporating the high latitude forcing into the data assimilation system requires knowledge of the spatial and temporal variations of the convection electric field and the auroral precipitation. Innaccurate knowledge of these drivers in data assimilation systems for space weather applications is the current limitation in improving the specification further. Compared with the solar wind parameters that force the magnetosphere, the drivers of the upper atmosphere, although well understood, remain poorly quantified. At best, the globally averaged Joule heating rate at a given time is only known to within a factor of two. At a given location, this uncertainty can rise to a factor of ten. This research endeavors to better quantify the balance between solar and magnetospheric forcing over the range of solar and geomagnetic activity through the implementation of an ensemble Kalman filter. This research plans to use recent advances in meteorology which use the ensemble Kalman filter to specify the drivers for the troposphere. Since the solar heating at low latitudes and the magnetospheric sources at high latitudes control the magnitude and spatial distribution of the global circulation, these drivers strongly affect the neutral composition and density structure, and as a result, the ensemble Kalman filter approach for specifying the drivers may be even better suited for the thermosphere. Further, the improved driver specification, in turn, improves the composition and density specification in the data assimilation system.
DE: 0350 Pressure, density, and temperature
DE: 0355 Thermosphere--composition and chemistry
DE: 0358 Thermosphere--energy deposition
DE: 0394 Instruments and techniques
DE: 2447 Modeling and forecasting
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly