Shortperiod Waves in the Equatorial Middle Atmosphere

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• Synoptic mapping of long asynoptic data sequences
• Example using TIMED/SABER temperature data
• Salbys Fast-Fourier Synoptic Mapping
• Extension to arbitrarily long data sequences
• Compare with models
• WACCM3 with different convective
  parameterizations
• Compare wave forcing in model vs. observational
  estimates
• HIRDLS data
• Higher vertical resolution
• Ozone and water vapor (?)

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Interpolation to common s-coordinates

• At yaw maneuvers, the value of the s-coordinate
  shifts slightly, as shown on the right
• To analyze data sequences longer than one yaw
  cycle, the observations are interpolated to
  common ascending and descending s-coordinates
• The data are interpolated across gaps associated
  with yaw maneuvers
• The analysis then proceeds as usual but it can
  be extended to arbitrarily long sequences of
  data. Here we will show results for 1-year
  sequences.

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Equatorial waves Equatorial Spectra(z,?) for m
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• high-frequency Kevin waves
• low-frequency Kelvin waves
• diurnal tide
• non-sun-synchronous tide

• Note sign convention
• positive frequencies ltgt westward
• negative frequencies ltgt eastward
• frequencies are given in cycles/day (cpd)

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Examples of Kelvin wave structures
These waves are presumed to play a role in
forcing the QBO
These wave structures are obtained via Hayashi
(1971) coherence analysis. Only locations with
significance level gt 1 ? are plotted. Note
different latitude scales.
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Spectra (z,?), m1, Equator
Low-frequency m1 Kelvin waves (t 20 days) and
the QBO
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Amplitude(t,z) of m1 Kelvin waves at the Equator
amplitude in frequency range 0.08 to 0.025 cpd,
or t  1240 days eastward
note the clear relationship between wave
amplitude and QBO phase at z 2 5.5 s.h.
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Work with WACCM highlights the importance of the
parameterization of convection
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Model calculations vs. SABER observations of
temperature at 10 mb in the Tropics
WACCM Tietdke

• Spectra in WACCM and SABER observations are
  remarkably similar overall
• But relative amplitude of east- vs.
  west-propagating (arrows) waves appears smaller
  in SABER compared to WACCM
• Vertical resolution too coarse in SABER? Can
  HIRDLS data help here?

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Possible Applications of HIRDLS data

• Confirm SABER results for equatorial waves
• Does higher vertical resolution in SABER enhance
  the detectability of westward-propagating waves
  (inertia-gravity, Rossby gravity)?
• Use HIRDLS and SABER data to quantify wave
  driving compare with model results
• Can ozone and water vapor data be used to look
  for the signature of the QBO in minor
  constituents?