7. Applications for Prediction
(a) In a majority of spectra, periodicities up to 4 years contribute up to 50% of total variance (Table 3) and is in agreement with model prediction (Equation 14) The model also predicts that,periodicities upto 9.5 years contribute upto 95% of total variance(Equation 15). Dominant periodicities ,such as the widely documented QBO,ENSO and decadal scale fluctuations may be used for predictability studies.
(b) Universal spectrum for atmospheric interannual variability provides precise quantification for the apparently irregular natural variability.The concept of universal spectrum for fluctuations rules out linear secular trends in meteorological parameters with regard to climate change.Global warming, either natural or man - made (industrialization related) will result in enhancement of fluctuations of all scales(Equation 3).The following studies indicate intensification of space-time fluctuations in atmospheric flows in recent years(since 1970s). IPCC (Intergovernmental Panel on Climate Change) report shows that recent increases have been found in the intensity of the winter atmospheric circulation over the extratropical Pacific and Atlantic(Houghton et al., 1992,1996 References) and are consistent with model predicted climate change.There have been relatively more frequent El Nino episodes since 1976/77 with only rare excursions into the other extreme(La Nina episodes)(Houghton et al., 1996 References). An assessment of ENSO - scale secular variability shows that ENSO - scale variance is relatively large in recent decades(Wang and Ropelewski,1995 References). Hurrel and Van Loon(1994 References) have reported a delayed breakdown of the polar vortex in the troposphere and lower stratosphere after the late 1970s coincident with the beginning of the ozone deficit in the Antarctic spring.It is possible that enhanced vertical mixing(Equations 6 and 7) inside the polar vortex may contribute to the ozone loss.Regions of enhanced convective activity in the monsoon regime are found to be associated with lower levels of atmospheric columnar total ozone content(Hingane and Patil,1996 References).Incidentally ,it was found that enhancement of background noise,i.e. energy input into the eddy continuum results in amplification of faint signals in electrical circuits(Brown,1996 References).
The cell dynamical system model for atmospheric flows presented in this paper is applicable in general to all turbulent fluid flows.
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