The latitudinal distribution of magnetic activity in Canada

Abstract

Hourly ranges in the principal horizontal field component have been measured for sixteen Canadian IGY magnetic observatories and variation stations. The latitudinal variation of disturbance measured by this index has been determined seasonally and as a function of disturbance. One station, Alert, at the northern end of Ellesmere Island, confirms the existence in these longitudes of an apparently narrow zone or area of enhanced magnetic activity, as defined by this measure of disturbance. Semipersistent structure is also apparent in the principal auroral zone in the meridian sections of magnetic activity. Diurnal occurrence patterns, amplitude‐frequency plots, the diurnal variation of the mean disturbance field, and the physical significance of this range index have been investigated in an attempt to explain this apparent inner maximum of magnetic activity. More homogeneous very high latitude data are required to determine the morphology of the anomalous region found.

Removing magnetic activity from high latitude magnetic repeat station observations.

“…Numerous studies have characterized both the spatial and temporal disturbation of magnetic disturbances at northern latitudes (see for example WHITHAM and LOOMER, 1957;WHITHAM et al, 1960;LOOMER and WHITHAM,1963; LOOMER and JANSEN VAN BEEK, 1969, 1973LOOMER, 1979). In and south of the aurora!…”

A new type of magnetic activity forecast for high geomagnetic latitudes.

“…This is a natural physical time interval in the context of this study. WHITHAM et al (1960) discussed the relative merits of various measures of magnetic activity at high latitudes and concluded by selecting the hourly ranges in magnetic field components for their studies. Other more sophisticated indices have been developed, such as the AEindex, but in general they are not available on atimely basis and often require data from a number of stations.…”

“…The level and character of magnetic activity vary greatly with geomagnetic latitude (e.g. WHITHAM et al, 1960;MOE and NEBERGALL,1969;CAMPBELL, 1973). To incorporate this latitudinal dependence into the geomagnetic activity forecasts, HRUSKA (1983) recommended the use of a three-zone forecast for the three dominant magnetic zones in Canada.…”

Geomagnetic Observations of Fletcher's Ice Island (T-3), Arctic Ocean

“…The hourly range of the principal horizontal component has been used as an index of disturbance at high latitudes by Canadian and Russian workers (Whitham et al, 1960). The extension of this index to shorter periods provides a simple method to obtain a rough but reproducible spectral decomposition of the data.…”

“…These correspond to the midnight and morning rV xima common at high latitudes (see for example, Whitham et al, 1960). Most of the work on disturbance in the Arctic Ocean has been done by Russian workers.…”