Cross-Spectral Analysis of Sunspots and Monthly Mean Temperature and Precipitation for the Contiguous United States

Hancock, Daniel J.; Yarger, Douglas N.

doi:10.1175/1520-0469(1979)036<0746:csaosa>2.0.co;2

Cited by 16 publications

(23 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The possibility that any apparent solar-weather relationships observed in isolated cases is produced by chance cannot be ruled out entirely. This observation differs from the results of Hancock and Yarger (1979) who obtained statistically significant relationships between double sunspot cycle and drought in the midwest United States, but agrees with the findings of Gerety et al. (1977).…”

Section: (C) Drought and Sunspot Cyclesupporting

confidence: 72%

“…Whether the sunspot cycle or its Hale cycle found in the drought series by other researchers (e.g. Thompson, 1973;Hancock and Yarger, 1979;Mitchell et al, 1979 among others) are really persistent features of drought occurrence in the region of study is difficult to determine. It is however possible that lack of significant evidence of solar-drought connection presented in this study is a function of the sample size used and the period of study.…”

Section: Discussionmentioning

confidence: 87%

See 1 more Smart Citation

Power spectra and coherence of drought in the interior plains

Oladipo

1987

J. Climatol.

View full text Add to dashboard Cite

Mean growing season (April-September) precipitation series at 407 stations in the Interior Plains of North America, dating back to 1985 in some stations, are used to derive a Bhalme and Mooley-type drought index for the region. Linear trend, representing first order non-stationarity, is first removed from the drought series. Then the periodogram via the Fast Fourier Transform (FFT), Maximum Entropy (ME) and Non-Integer (NI) spectral techniques are applied to search for significant periodicities in the temporal characteristics of the drought series. Cross-spectral technique is also used to characterize the extent of spectral coherence in the drought series.It is found that no significant power in drought is present at periods greater than about 6 years. Spectra of drought in the Interior Plains are dominated by three peaks in the quasi-biennial, quasi-triennial and quasi-5-year oscillations. The periodic 18.6-year lunar nodal cycle obtained by others for the Drought Area Index (DAI) for the region is completely absent in the spectra of the analysed drought index series. Also the well-known 11-year sunspot cycle is only evident in the drought index series for a few of the stations. In general there is an ill-defined drought recurrence interval.Moreover the areal extent of peaks contained within these oscillations do not indicate any significant spatial coherence. These periodicities can be evident at one station while being absent at another a few hundred kilometres away. On the basis of the spectral results, it is concluded that obtained significant periodicities are only short-lived time variabilities in drought as recorded by individual stations and do not represent any persistent drought characteristics over a broad geographical region. A cross-spectral analysis of the drought series with sunspot numbers shows no evidence to indicate a significant relation between drought and the single sunspot cycle. In general, the growing season drought series in the Interior Plains displays only what appears to be a random variation, with the possible superimposition of the quasi-biennial oscillation.KEY WORDS Drought Periodogram maximum entropy and non-integer spectral techniques Drought spectral coherence Cycles

show abstract

Section: (C) Drought and Sunspot Cyclesupporting

confidence: 72%

Section: Discussionmentioning

confidence: 87%

Power spectra and coherence of drought in the interior plains

Oladipo

1987

J. Climatol.

View full text Add to dashboard Cite

show abstract

“…New statistical methods and modem computers are being used to tackle hitherto unmanageable calculations in order to test the reality of the effects and put this in proper perspective.It has been argued that there is little or no reliable evidence for significant correlations of either the 11-or 22-year sunspot cycles with variations of weather or climate (Gerety et al 1977;Pittock 1978). However, among the long-term solar effects, evidence for an approximately 22-year cycle, twice the period of the sunspot cycle, has been found in several climatological variables (Mitchell et al 1979;Dicke 1979;Hancock and Yarger 1979;Bhalme and Mooley 1980;Weinbeck and Yarger 1981;Williams 1981). The 22-year cycle is supposed to arise as a result of the alternate changes in the polarity of the leading sunspots in a given solar hemisphere in successive 11-year cycles.…”

mentioning

confidence: 99%

The Double (Hale) Sunspot Cycle and Floods and Droughts in India

Bhalme

Jadhav

1984

Weather

View full text Add to dashboard Cite

H E quest for the possible relationships between sunspots and weatherlclimate T began even before Schwabe, a German astronomer, discovered the sunspot cycle in 1843. In spite of the controversy surrounding the claimed effects of sunspot cycles on weather and climate, consideration is being given to the possible implication for climatological forecasts. In recent years there has been a major revival of interest on the problems of the sun-weathedclimate relationships. New statistical methods and modem computers are being used to tackle hitherto unmanageable calculations in order to test the reality of the effects and put this in proper perspective.It has been argued that there is little or no reliable evidence for significant correlations of either the 11-or 22-year sunspot cycles with variations of weather or climate (Gerety et al. 1977;Pittock 1978). However, among the long-term solar effects, evidence for an approximately 22-year cycle, twice the period of the sunspot cycle, has been found in several climatological variables (Mitchell et al. 1979;Dicke 1979;Hancock and Yarger 1979;Bhalme and Mooley 1980;Weinbeck and Yarger 1981;Williams 1981). The 22-year cycle is supposed to arise as a result of the alternate changes in the polarity of the leading sunspots in a given solar hemisphere in successive 11-year cycles. Thus the true sunspot cycle is 22 years rather than 11 years when the altematioil of sign of spot magnetic fields is considered. The 22-year quasi-cycle of sunspot activity is often termed the double sunspot cycle or Hale sunspot cycle. A recent work by Bhalme and Mooley (1981) provides evidence of an approximately 22-year cycle in the fluctuations of flood area indices over India for the 89-year period 1891-1979, showing strong coherence with the double (Hale) sunspot cycle. Furthermore, they were able to demonstrate the consistent occurrence of large-scale flood events in the major sunspot cycle by harmonic dial analysis. This finding receives support from the study of Ananthakrishnan and Parthasarathy (1983) who found statistically significant excess rainfall years around the peak phase of alternate sunspot cycles.The present note illustrates the association found between the occurrences of large-scale flood events in India and the double (Hale) sunspot cycle by separating drought and Aood years in a single diagram of the sunspot curve and by statistical analysis of the data. METHOD FOR IDENTIFICATION OF DROUGHTS AND FLOODSBhalme and Mooley (1980) developed an objective numerical drought index, based on the monthly monsoon (June-September) rainfall over an area and a duration for assessment of drought intensity. The basic assumption in the development of the index is that plant life and established human activities are geared to the long-term mean monthly rainfall of the area of the specific period and that the deviation from the mean monthly rainfall determines the drought characteristics. The drought index equation is I k = 0.5 Ik-1 + Mk/48.55(1)where Ik, Ik-1 are the drought intensities of the kt...

show abstract

“…This makes causative mechanisms virtually impossible to detect. Hancock and Yarger (1979) On the other hand, Gerety, et al (1977) icant coherencies of 10, 5, or 1% at any of 22-, 11-, or 5.5year periods. Also, phases of the few significant stations occur randomly about a harmonic dial.…”

Section: Literature Reviewmentioning

confidence: 99%

“…Transform analysis. Squared coherencies and phases then were determined using a five-point uniform filter (Hancock and Yarger, 1979). The 10, 5, and 1% significance levels of coherency for the five point uniform filter are 0.44, 0.53, and 0.68, respec tively (Fuller, 1976).…”

Section: Literature Reviewmentioning

confidence: 99%

Periodic variability from long-term weather records

Weinbeck

View full text Add to dashboard Cite

Ratio values of largest periodogram ordinate 16 to average Coherency and phase results of cross-spectral 32 analysis of temperature index series and sunspot number Superposed epoch analyses of selected area-65 index series Single station area network covering the conti-71 nental United States, 1906-1960 single station U. S. area network for extended 74 period, 1873-1977 Distribution types and Willett-period defi-85 nitions Years pertaining to distribution types for 85 station precipitation records Spatial variability accounted for by eigen-90 vectors associated with largest eigenvalues Area-index series having significant 10.5-or 94 21-year coherencies with the aa-index series Cross-spectral coherencies of area-index series 96 with geomagnetic-activity series for 84-and 88year periods

show abstract

Cross-Spectral Analysis of Sunspots and Monthly Mean Temperature and Precipitation for the Contiguous United States

Cited by 16 publications

References 0 publications

Power spectra and coherence of drought in the interior plains

Power spectra and coherence of drought in the interior plains

The Double (Hale) Sunspot Cycle and Floods and Droughts in India

Periodic variability from long-term weather records

Contact Info

Product

Resources

About