Maurice Blackmon and two dimensional spectral analysis:

The power and the glory

Joe TribbiaNCAR

No, not that power and glory!

Title Disclaimer

“All history is LIES agreed upon” Napoleon*

*Attributed by Barbara Tuchman

Noted historian

Historical Disclaimer

Celebrate 1st Publication in Atmospheric Science

Early 1970s Transition Particle Physics -- Atmospheric science

One career/hobby for another

Maurice’s One True Vocation

On to the power…..

Computed Spherical harmonic spectra of 500mb height

ComputedSpectra forWinter and Summer1963-72

Many tables with lots of numbers (Power)

Power in Frequency domain vsTwo dimensionalWavenumber (n)

Power for fixedFrequency forEach SphericalHarmonic

Comparison with 1990s

0.5 0.2 0.1 0.3 0.2 0.2 0.2 0.2 0.1 0.1 0.1 0.3 0.4 0.3 0.2 1.0 0.3 0.7 0.5 0.2 0.3 0.2 0.7 0.3 0.3 0.4 0.7 0.5 0.3 0.4 0.5 0.2 0.3 0.9 0.9 1.4 2.4 1.7 0.7 1.3 0.6 0.5 1.0 0.2 1.4 0.9 2.4 0.9 5.7 2.4 1.1 1.3 0.6 0.6 0.2 1.4 0.9 2.2 2.9 5.4 4.8 2.6 2.3 3.0 1.0 0.1 2.7 3.2 1.6 4.0 26.2 33.7 13.9 10.8 1.5 0.7 0.1 1.1 5.5 7.1 22.9 34.8 46.9 20.0 10.2 2.6 0.1 0.0 2.5 1.3 3.3 21.1 66.2 75.5 48.5 7.5 0.6 0.0 0.0 5.2 5.7 6.0 22.3 101.9 47.3 26.8 1.6 0.1 0.0 0.0 2.5 10.7 12.5 37.5 65.3 18.8 6.5 0.1 0.0 0.0 0.0 9.3 19.3 7.9 3.9 48.3 2.9 0.6 0.0 0.0 0.0 0.0 4.6 10.5 5.9 9.7 5.4 0.2 0.0 0.0 0.0 0.0 0.0 10.3 14.6 5.0 1.7 0.7 0.0 0.0 0.0 0.0 0.0 0.0 4.3 3.1 1.0 1.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 13.8 5.2 6.9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 5.5 1.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 10.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

5 day powerWinter ’63-72

5day powerJFM ’90-99

Comparison with 1990s

0.5 0.5 0.7 0.2 0.7 0.3 0.2 0.1 0.2 0.1 0.1 1.1 1.2 1.1 0.9 1.1 0.8 0.6 0.2 0.2 0.1 0.1 1.6 3.3 1.5 0.6 0.2 1.0 0.4 0.4 0.2 0.1 0.1 2.5 2.1 1.3 1.3 1.4 1.2 1.7 0.6 0.3 0.2 0.1 4.3 11.4 5.4 4.0 4.2 2.6 1.5 1.2 0.5 0.2 0.1 3.1 19.7 6.8 13.8 17.4 8.0 1.8 1.5 1.8 1.3 0.1 38.2 72.0 41.3 15.6 6.6 16.3 2.5 6.3 2.3 0.4 0.1 18.8 85.0 68.1 48.5 4.2 12.6 27.2 2.9 3.7 0.3 0.0 44.1 512.0 614.4 191.8 331.4 43.4 28.9 16.5 1.3 0.1 0.0 190.6 286.1 282.2 3032.6 402.3 250.5 14.4 1.6 0.2 0.0 0.0 221.8 416.1 3408.6 1427.7 1031.9 269.8 9.2 0.7 0.0 0.0 0.0 188.5 1125.9 4560.2 7291.8 1058.7 78.2 0.6 0.0 0.0 0.0 0.0 1334.6 4429.1 1568.8 976.4 103.8 16.3 0.0 0.0 0.0 0.0 0.0 901.5 3587.0 4454.9 564.3 32.5 0.0 0.0 0.0 0.0 0.0 0.0 5179.1 7054.1 109.4 11.2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1073.8 634.5 31.1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 816.6 46.8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 10.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0

15 day powerWinter ’63-72

15 day powerJFM ’90-99

Enough power,on to the glory….

Introduced (now classic)bandpass filters

Compare variance with 1990’s

Total Winter RMS Amplitude

Nine yearWinter mean

Total JFM RMSAmplitude

Ten yearJFM mean

Lowpass Regime I (1963-72)Winter RMS amplitude

All waves Regime I

Lowpass Regime I (1990s)JFM RMS amplitude

All waves Regime I

Three Centers of low frequency variability

• Pacific (Blocking and PNA)

• Atlantic (Blocking and NAO)

• Eurasian (?)

• Inspiring research up to present day

Great beginning of 2nd career/hobby

“Well begun is half done”Mary Poppins*

Maurice was just warming up

*Attributed by noted historian

Joe Tribbia