Adaptive Smoothing Method For Computer Derivation of K-Indices

Abstract

S U M M A R Y This paper gives a new method for automatic calculation of K-indices by computer. The general philosophy of the method is the simulation of the hand-scaling procedure. The simple theory, based on the least-squares method with additional limitation of the second derivatives, is outlined. The method has two steps; in the second step the weighting factors are introduced to avoid errors connected with large variations. We call this method the Adaptive Smoothing (AS). The method was applied to data from three observatories, Belsk, Nurmijarvi and Sodankyla, for the period 1985 January 1 to 1986 February 28. The agreement with results from the hand-scaled method was 75-84 per cent. The percentage of the differences larger than one unit was less than 0.3 per cent.

Analysis of magnetic data of ground station network during strong magnetic storms

“…The traditional approaches and methods of time series analysis are not sufficiently effective to solve this problem [8][9][10]. At the present time, modern mathematical methods and information technologies in this field are intensively developing [2][3][4][5][6][7][11][12][13][14][15][16][17]. Algorithms to isolate the interferences during the primary processing of magnetic data [2,13] and methods for the anomaly detection during magnetic storms [2,13] were developed on the basis of DataMining approaches.…”

“…In the work [19], the wavelet transform is used to study the connection between shortperiod oscillations of the geomagnetic field, the parameters of the solar wind and the interplanetary field during magnetic storms. Problems of removing noise and eliminating the periodic component of the field caused by the Earth rotation are solved on the basis of the wavelet transform [16,17]. Automatic algorithm to determine the periods of the initial phase of a magnetic storm based on the discrete wavelet transform was proposed (15).…”

First Steps Towards K Indices from South Atlantic Observatories: Port Stanley Observatory

“…In 1991 the British Geological Survey (BGS) adopted a method for computing K indices for the three UK observatories (Clark, 1992) based on Nowożyński et al (1991), one of the four IAGA-sanctioned methods. This paper describes recent attempts to begin producing computer generated K indices for PST.…”

Method of analysis of geomagnetic data based on wavelet transform and threshold functions

“…Traditional methods for data analysis applying basic models of time series, different techniques of smoothing and Fourier analysis methods are not effective enough to investigate fast unsteady processes. As it was noted in the papers [15][16][17][18], they do not allow one to identify thin local features characterizing short-period oscillations during increased geomagnetic activity and to estimate their dynamic characteristics before and during storms. At present, modern mathematic methods and technologies are intensively developing in this area [3-9, 14, 18-25].…”