A Generalized Method of Resolving Disturbances into Progressive and Retrogressive Waves by Space Fourier and Time Cross-Spectral Analyses

Hayashi, Yoshikazu

doi:10.2151/jmsj1965.49.2_125

Cited by 196 publications

(165 citation statements)

References 8 publications

Supporting

Mentioning

149

Contrasting

Order By: Relevance

“…Moreover, the present computational scheme is more efficient and can more easily be automated than that of the wavenumber transform method of Hayashi (1980) which must discard all the frequencies except for the tuning frequency of the frequencyshifted wavenumbers. EPS=* for twice-daily data =0 for once-daily data WA(I, J)=w(tl, *) for daytime or odd day, WD(I, J)=w(tl, *) for nighttime or even day, M=m(0 *M *NX/2), NF=*n(-N*NF*N), and F=f=*n/N for twice-daily data =* n/(2N) for once-daily data.…”

Section: Summary and Remarksmentioning

confidence: 99%

“…In order to estimate space-time spectra correctly from uneven twice-daily data sampled by a polar-orbiting satellite, the wavenumber transform method (Hayashi, 1980) is modified by the use of a nonorthogonal Fourier inversion. The space-time spectra are obtained from the time-Fourier coefficients of the space-Fourier transforms of the asynoptic field with respect to its frequency-shifted wavenumber.…”

Section: Introductionmentioning

confidence: 99%

“…In Part I (Hayashi, 1983), the non-orthogonal Fourier transform method (Salby, 1982) is simplified by transforming frequency only. In the present paper (Part II), the wavenumber transform method (Hayashi, 1980) is also modified by use of the nonorthogonal Fourier inversion in order to eliminate the aliasing errors due to uneven twice-daily data.…”

Section: Introductionmentioning

confidence: 99%

“…In the present paper (Part II), the wavenumber transform method (Hayashi, 1980) is also modified by use of the nonorthogonal Fourier inversion in order to eliminate the aliasing errors due to uneven twice-daily data. Also, a more efficient computational scheme is given.…”

Section: Introductionmentioning

confidence: 99%

“…3a of Hayashi, 1980) rather than on the same standard date (see Fig. 2 of Hayashi, 1980). In order to reduce leakage, the original time series data should be tapered at each end (see Section 2.6 of Part I).…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Modified Methods of Estimating Space-Time Spectra from Polar-orbiting Satellite Data

Hayashi

1983

Journal of the Meteorological Society of Japan

Self Cite

View full text Add to dashboard Cite

In order to estimate space-time spectra correctly from uneven twice-daily data sampled by a polar-orbiting satellite, the wavenumber transform method (Hayashi, 1980) is modified by the use of a nonorthogonal Fourier inversion. The space-time spectra are obtained from the time-Fourier coefficients of the space-Fourier transforms of the asynoptic field with respect to its frequency-shifted wavenumber.Since this method requires the spatial interpolation of asynoptic data, it is effective only for ultralong waves. The wavenumberfrequency aliasing characteristics are examined and the computer code is exemplified.

show abstract

Section: Summary and Remarksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Modified Methods of Estimating Space-Time Spectra from Polar-orbiting Satellite Data

Hayashi

1983

Journal of the Meteorological Society of Japan

Self Cite

View full text Add to dashboard Cite

show abstract

Intraseasonal and interannual variability of the quasi 2 day wave in the Northern Hemisphere summer mesosphere

McCormack

Coy

Singer

2014

J. Geophys. Res. Atmos.

View full text Add to dashboard Cite

This study uses global synoptic meteorological fields from a high‐altitude data assimilation system to investigate the quasi 2 day wave (Q2DW) and migrating diurnal tide during the Northern Hemisphere (NH) summers of 2007–2009. By applying a two‐dimensional fast Fourier transform to meridional wind and temperature fields, we identify Q2DW source regions and diagnose propagation of Q2DW activity into the upper mesosphere and lower thermosphere. We find that the Q2DW in NH summer is composed primarily of westward propagating zonal wave number 3 and wave number 4 components that originate within baroclinically unstable regions along the equatorward flank of the summer midlatitude easterly jet. The amplitude of the wave number 3 Q2DW tends to peak in July while the amplitude of the wave number 4 Q2DW tends to peak in late June and again in early August. The seasonal mean Q2DW amplitudes are largest in 2009, when the amplitude of the migrating diurnal tide in the upper mesosphere near 30°N was relatively weak. However, there is no evidence of rapid amplification of the Q2DW via nonlinear interaction with the diurnal tide. Instead, variations of Q2DW amplitudes during NH summer appear to be linked to variations in the strength and location of the mesospheric easterly jet from one summer to the next, with a stronger jet producing larger Q2DW amplitudes. Linear instability model calculations based on the assimilated wind fields indicate that the fastest‐growing modes are zonal wave numbers 3 and 4 with periods near 2 days that originate in the vicinity of the easterly jet.

show abstract

Modulation of monsoon intraseasonal oscillations in the recent warming period

et al. 2014

View full text Add to dashboard Cite

The Indian Ocean sea surface temperature (SST) during the boreal summer has shown a significant warming of 0.3°C in the recent decade (2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010) compared to a former decade (1979)(1980)(1981)(1982)(1983)(1984)(1985)(1986)(1987)(1988), and it is most pronounced in the central tropical Indian Ocean. By using reanalysis and satellite-derived data sets, we investigated how the monsoon intraseasonal oscillation (MISO) over the South Asian summer monsoon (ASM) region has been influenced by the recent warming in the Indian Ocean. It is found that the MISO variance has increased over the ASM region in the recent period compared with the earlier decade. It is also noted that the characteristic northward propagation of the MISO has slowed over 2001-2010, resembling more of a standing oscillation near the equator. Mechanisms implicated in the observed MISO changes are explored by conducting several model sensitivity experiments with an atmospheric general circulation model. The model experiments suggest that the mean SST increase over the Indian Ocean, and the associated changes in the air-sea interaction, the increased mean moisture convergence, and changes in the large-scale circulation are responsible for the changes in the characteristics of the MISO. The influence of the recent Indian Ocean warming on the MISO characteristics must be understood fully since they determine the seasonal amount of rainfall over the Indian subcontinent. An examination of future projections of the MISO using the MPI-ESM-LR model from the Coupled Model Intercomparison Project phase 5 archive also gives consistent result.

show abstract

A Generalized Method of Resolving Disturbances into Progressive and Retrogressive Waves by Space Fourier and Time Cross-Spectral Analyses

Cited by 196 publications

References 8 publications

Modified Methods of Estimating Space-Time Spectra from Polar-orbiting Satellite Data

Modified Methods of Estimating Space-Time Spectra from Polar-orbiting Satellite Data

Intraseasonal and interannual variability of the quasi 2 day wave in the Northern Hemisphere summer mesosphere

Modulation of monsoon intraseasonal oscillations in the recent warming period

Contact Info

Product

Resources

About