Ionospheric weather forecasting using the LETKF

By Juan Durazo

Arizona State University

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We track the three-dimensional global distribution of electron density in the ionosphere using the
Local Ensemble Kalman Filter (LETKF) and the Thermosphere-Ionosphere-Electrodynamics Global
Circulation Model (TIEGCM) by assimilating globally distributed electron density profiles. The
TIEGCM is a three-dimensional non-linear representation of the coupled ionosphere-thermosphere
system on a global grid with resolution of 5◦ × 5
from 97 km to 600 km in elevation depending on solar activity levels. Observations are obtained from
the COSMIC satellite mission and are assimilated into the ensemble forecast at every hour, using
observations available within 30 minutes of analysis time. The ionosphere-thermosphere system
is strongly driven by external solar and magetospheric forcing, which is represented in TIEGCM
through parametrized input that is specified through auxiliary empirical models. The one way
coupling between the parametrized input and the I-T system poses some challenges for the LETKF
that include estimation of the parameterized forcing and ensemble inflation of the parameters to
adequately represent appropriate ensemble forecast error distribution. Results are validated with
other electron density profiles derived from other satellite missions (CHAMP and GRACE) and
measurements of peak electron density and peak elevation in the F2-layer as given by ionosonde
stations all over the world.


This talk was given on 2-26-15.


Colin James Grudzien

University of North Carolina at Chapel Hill Mathematics