Source Parameter Estimates from Radiosonde Data.

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Source Parameter Estimates from Radiosonde Data.

• by
• Marvin A. Geller - Stony Brook University
• Jie Gong - Stony Brook University
• Ling Wang - Colorado Research Associates

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• The holy grail in gravity wave research is to
  develop a practical, physically justified gravity
  wave parameterization for use in general
  circulation models.
• McLandress and Scinocca (JAS, 1995, 2394-2413)
  compared the performance of a number of gravity
  wave parameterization schemes and concluded that
  they gave very similar results if their wave
  breaking occurred as similar altitudes. This
  implies that determination of the source spectrum
  is the most important thing.

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• In a series of two papers (Vincent and Alexander,
  JGR, 105, 17,971-17,982 and Alexander and
  Vincent, JGR, 105, 17,983-17,993) derived time
  series of gravity wave energy and vertical flux
  of zonal momentum from high vertical-resolution
  radiosonde data for 6-years of data from Cocos
  Island
• (12 0S, 97 0E). They then did a best fit
  analysis to determine the gravity wave source
  spectrum that was most consistent with these
  results.

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From Alexander and Vincent (2000)
Dashed Line - Antisymmetric, Isotropic
Solid Line - Gaussian, c 0
Dash-Dot Line - Antisymmetric,
anisotropic (moving mountain) Pfister
et al., 1993, JGR
Dotted Line Gaussian, c u0
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• In his PhD thesis, Dr. Ling Wang did a similar
  analysis for 21 US radiosonde sites. He found
  that using the techniques of Alexander and
  Vincent (2000), he could get good fits to the
  time series for a four-year time series for lower
  stratosphere gravity wave energy and vertical
  flux of zonal momentum for 9 of these sites.
• Ms. Jie Gong, a Stony Brook PhD student, is
  extending this work to all of the 93 US
  radiosonde sites for an 8-year time series.
  Here, I show some early results.

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High Correlation Examples
St. Paul Island, AK
Koror/Palau Island
r 0.633
r 0.564
r 0.577
r 0.553
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Low Correlation Examples
Yap Island
Wilmington, OH
r 0.510
r 0.874
r 0.324
r 0.380
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Some Conclusions

• Among the 93 stations for which we have data, 4
  lack sufficiently complete data to be analyzed.
• Correlations have been calculated for 62 of these
  stations, and 31 have absolute values for the
  correlation, ?r? gt 0.25, between the lower
  stratospheric gravity wave energy and the
  vertical momentum flux of and ?r? gt 0.34 for
  the correlation between the source flux and the
  simulated momentum flux, which Dr. Ling Wang
  found to be necessary to get a good fit (Et -gt
  ?r? gt 0.5,
• mom. flux -gt ?r? gt 0.3, all with the same
  intermittency).
• 3. Simulations have been run so far for 32
  stations, out of which a good fit is found for
  19 of these, all of which satisfy Wangs criteria.

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Some Conclusions (continued)

• Correlation for Et ?r? gt 0.5 can be obtained for
  all the simulated 32 stations with at least one
  combination of parameters.
• The B1 spectral shape tends to give the best
  fit for ? gt 30 0N, while the B4 spectral shape
  tends to give the best fit for
• ? lt 30 0N.
• For the B1 type, ?x generally increases with
  latitude, while theres no obvious trend for the
  B4 types.
• All the good fit simulations are obtained with
  a source altitude of 17.75 km.