Mofazzal H. Khondekar

NONLINEARITY AND CHAOS IN 8B SOLAR NEUTRINO FLUX SIGNALS FROM SUDBURY NEUTRINO OBSERVATORY

The Sudbury neutrino observatory (SNO) detects 8B solar neutrino fluxes from both the D2O and Salt detector. In the present analysis we have taken into consideration the flux data from 2nd November, 1999 to 27th May, 2001 from the D2O detector and that from 26th July, 2001 to 28th August, 2003 from the Salt detector. We have applied Delay Vector Variance analysis, 0-1 test, correlation dimension analysis, largest Lyapunov exponent method, recurrence plot and recurrence quantification analysis to explore the complexity and chaosity in these two time series. Present study reveals deterministic chaotic behaviour of these two signals which in turn suggests that long-term forecasting is not possible for these two signals but short-term forecasting can be made provided the model for the process dynamics is known to us.

Complexity in Solar Irradiance From the Earth Radiation Budget Satellite

In this paper, a search is made to detect any sort of nonlinearity and chaos in the solar irradiance data from the Earth Radiation Budget Satellite during the time period from October 15, 1984 to October 15, 2003 in order to investigate the inherent complexity in it. In this paper, delay vector variance analysis has been applied to trace the nonlinearity; whereas 0-1 test, correlation dimension analysis, information entropy, recurrence plot, and recurrence quantification analysis have been used to explore the signature of chaos in the present time series. Present investigation reveals that though nonlinearity is significantly present in the signal, chaotic behavior is not really observed in it.

Memory persistency and nonlinearity in daily mean dew point across India

Enterprising endeavour has been taken in this work to realize and estimate the persistence in memory of the daily mean dew point time series obtained from seven different weather stations viz. Kolkata, Chennai (Madras), New Delhi, Mumbai (Bombay), Bhopal, Agartala and Ahmedabad representing different geographical zones in India. Hurst exponent values reveal an anti-persistent behaviour of these dew point series. To affirm the Hurst exponent values, five different scaling methods have been used and the corresponding results are compared to synthesize a finer and reliable conclusion out of it. The present analysis also bespeaks that the variation in daily mean dew point is governed by a non-stationary process with stationary increments. The delay vector variance (DVV) method has been exploited to investigate nonlinearity, and the present calculation confirms the presence of deterministic nonlinear profile in the daily mean dew point time series of the seven stations.

Wavelet Based Fractal Analysis of Solar Wind Speed Signal

In the present work, the Solar Wind Speed (SWS) time series has been considered for study. Here, the intention of the authors is to investigate the presence of multifractality within the signal. Continuous wavelet transforms modulus maxima method has been employed in this purpose. The span of the time series of SWS, which is under consideration, is of 2492 days from 01/01/1997 to 28/10/2003. Finally, the Singularity spectrum is drawn to qualitatively evaluate the level of multifractality present within the SWS signal.