Supplementary Movies:
Quasi-resonant amplification of planetary waves and recent Northern
Hemisphere weather extremes
Petoukhov, V., Rahmstorf, S., Petri, S., Schellnhuber, H. J. (2013):
Quasi-resonant amplification of planetary waves and recent Northern Hemisphere weather extremes.
Proceedings of the National Academy of Sciences, published ahead of print March 1, 2013.
[doi:10.1073/pnas.1222000110] http://www.pnas.org/cgi/doi/10.1073/pnas.1222000110
Data for the movies was downloaded on Nov 29 2011 13:44
37.5N to 57.5 N
180 W to 180 E
300 mb to 300 mb
May-Sep 1980-2011
Processing
Processing with CDO
to create different aggregations over time intervals.
For the running-mean aggregations, the date information shown is the date of
the middle contributing time step in the original data.
Calculation of fft(), ifft(), dct(), Spectrum Amplitudes and Phases with Matlab.
Calculation of meridional averages and visualisation with ferret.
Meridional windfield on 300 mb, between 37.5N and 57.5N, 180W to 180E.
For every July of the years 1980-2011, the daily means are aggregated into monthly means.
This movie shows a synopsis of the meridional windfield, its meridional
average, and of the discrete spectrum amplitude and phase of the meridional
average.
Each picture corresponds to July of one year, thus it is not a continous time
series, but should best be viewed image after image.
For compactness, the presentation as movie format was choosen instead of a
collection of 32 single images.
Amplitude of waves number 5, 6, 7, 8 of the meridional average of meridional
wind at 300 mb, between 37.5N and 57.5N, 180W to 180E.
The daily means are aggregated into 15-day running means during June-August
of 1980-2011.
The date shown is the date of the middle contributing time step in the original data.
15-day running means of Derivative over time of phases of waves number 5, 6, 7, 8
of the meridional average of meridional
wind at 300 mb, between 37.5N and 57.5N, 180W to 180E.
The daily values are aggregated into 15-day running means during June-August
of 1980-2011.
The date shown is the date of the middle contributing time step in the original
data.
The derivative was computed as difference between preceding and following time
step, divided by time difference.
Because of the periodicity of the wave, a large phase change in one direction
is equivalent to a small change in the opposite direction. Thus, the changes
were ``wrapped'' to the interval -PI .. +PI.
Daily values of Derivative over time of phases of waves number 5, 6, 7, 8
of the meridional average of meridional
wind at 300 mb, between 37.5N and 57.5N, 180W to 180E.
See description of Movie 4 about the calculation of the derivatives.
Time series 1980-2011 of amplitudes of fourier components of monthly means of
meridionally averaged meridionally wind at 300 mb, between 37.5N and 57.5N, 35W
to 45E, for wave number (A) 7, (B) 6, (C) 8. July values in green, August values
in blue.
Inclined dashed straight lines show linear regressions;
horizontal dashed lines show 1.5 standard deviation from the 1980-2011 monthly
climatology (90% confidence level).
(Unfortunately, in the PNG format shown here, the dashed lines appear
solid. The appearance is correct in the EPS and PDF formats.)
Separate figures for July and August data, each
showing linear regression, standard deviation, as well as envelope curves that
mark the 90% confidence level for linear regression.
Latitudinal distributions of K_{s}^{2}a^{2} for two
time periods of extreme weather, and `normal' August 1993. See paper
text for further explanations.
and as PDF (7.97x7.97cm)and as EPS
(Unfortunately, in the PNG format shown above, the dashed lines appear
solid. However, note the thin vs. filled arrow heads.
The appearance is correct in the EPS and PDF formats.)
Latitudinal distribution for zonally averaged monthly averaged (A, top) zonal wind at
300 hPa and (B, bottom) temperature at 850 hPa, for 1980-2011 August
climatology, for extreme August 2003, and for 'normal' August 1993.
Effective forcing due to temperature and orography, normalized to its
climatology, and weighted with cosine of latitude,
averaged over the latitudinal range 37.5N - 47.5N.
The figure shows the amplitudes for waves 6,7,8 plotted over time, monthly
values for July (A) and for August (B).
Wind and temperature data from NOAA NCEP-NCAR CDAS-1
Reanalysis. Topography data from GLOBE.
Reference for the wind and temperature data sets:
Kalnay, E., M. Kanamitsu, R. Kistler, W. Collins, D. Deaven, L. Gandin,
M. Iredell, S. Saha, G. White, J. Woollen, Y. Zhu, A. Leetmaa, B. Reynolds,
M. Chelliah, W. Ebisuzaki, W. Higgins, J. Janowiak, K. C. Mo, C. Ropelewski,
J. Wang, R. Jenne, and D. Joseph. The NCEP/NCAR 40-Year Reanalysis
Project. Bulletin of the American Meteorological Society 77(3), pp 437-471, March, 1996.
http://dx.doi.org/10.1175/1520-0477(1996)077%3C0437:TNYRP%3E2.0.CO;2
Reference for the GLOBE topography data set:
Hastings, David A., and Paula K. Dunbar, 1999. Global Land One-kilometer Base Elevation (GLOBE) Digital Elevation Model, Documentation, Volume 1.0. Key to Geophysical Records Documentation (KGRD) 34. National Oceanic and Atmospheric Administration, National Geophysical Data Center, 325 Broadway, Boulder, Colorado 80303, U.S.A.