Neutral Density Response to
Sudden Stratospheric Warmings
Tim Fuller-Rowell, Rashid Akmaev, Fei Wu, Houjun Wang,
Mariangel Fedrizzi, Mihail Codrescu, Eduardo Araujo-Pradere,
and Tzu-Wei Fang
CIRES Center for Space Weather
University of Colorado
and
NOAA Space Weather Prediction Center
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
30K
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
SW1
SW2
SW3
TW3
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
Before warming
After warming
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
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GSI: Gridpoint Statistical Interpolation
GFS-GSI is the NCEP operational analysis system for
global and regional NWP
Use 3-D variational (3DVAR) analysis technique
Replace GFS with WAM
Background error statistics were derived from 24 hour
‘tendencies’ (from 1 year continuous run of WAM) to
remove strong diurnal component
Analysis system modified to use IAU to avoid use of
digital filter, which excessively damps tidal propagation to
the thermosphere
Simulate January 2009 period during large SSW
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
70K
WAM-GSI-IAU
Data: ECMWF
Oct 27-28th, 2010
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Annual Meeting
Ter-diurnal tide increased by a
factor of three exceeding the
diurnal and semi-diurnal
components
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
Tidal Analysis
east and west propagating W1, 2, 3, diurnal, semi-diurnal, ter-diurnal
Oct 27-28th, 2010
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Annual Meeting
SW2
Time series of
amplitude of the
various tidal modes
DW1
TW3
Oct 27-28th, 2010
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Annual Meeting
Oct 27-28th, 2010
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Annual Meeting
Evolving wave structure in
lower thermosphere during
sudden stratospheric warming
Jan 14th Wave 2
Oct 27-28th, 2010
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Jan 24th Wave 3
Annual Meeting
Oct 27-28th, 2010
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14th
Density increases by 7% from 14th to 23rd
at 400 km altitude
23rd
Oct 27-28th, 2010
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Oct 27-28th, 2010
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Oct 27-28th, 2010
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WAM winds driving CTIPe electrodynamics
Dayside upward
plasma drift increases
and moves to earlier
local times, then
moves to later local
times
Fejer et al. 2010
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
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GSI: Gridpoint Statistical Interpolation
NCEP operational analysis system for global
and regional models
Use 3-D variational (3DVAR) analysis
technique
Sequential intermittent data assimilation
Background error statistics were derived from 24
hour ‘tendencies’ (from 1 year continuous run of
WAM) to remove strong diurnal component:
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
Day in January 2009 at 00 UTC
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
GSI
Analysis
IAU
Analysis
Forecast
Oct 27-28th, 2010
NADIR MURI
Annual Meeting
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Sudden stratospheric warmings appear to have a
distinct signature on thermospheric density
In the lower thermosphere the ter-diurnal tide
increases in amplitude at the expense of the semidiurnal – possible impact on re-entry
The increase in the ter-diurnal increases the
amplitude of the midnight temperature and density
maxima
The global mean temperature increases by 5 to
10% during an SSW
WAM produces stratospheric warmings naturally
WAM-GSI-IAU can follow real SSW events and
forecast their consequences several days ahead
Oct 27-28th, 2010
NADIR MURI
Annual Meeting