Using Australian records, we studied six isolated geomagnetic storms for the regional effects of their associated magnetic fields, emphasizing the linear regression correlation coefficient between station locations and indices. An innovation used here was to consider both the full magnetic disturbance field and a form of this field with the smoothed storm-time Dst values removed to feature the small variations. Magnetic H-component data from paired stations throughout the continent showed correlation values of +0.90 to +0.97. These results indicate the adequacy of the present density of observatories in Australia and their value for use with aeromagnetic surveys. The planetary magnetic ap index was found to have an inconsistent relationship to Australian H-component fields. The planetary magnetic Dst index was successfully represented by data from four Australian observatories. The discovered capability of Australian magnetic observatories to represent the magnetic storm Dst index in real time, combined with the established lognormal-form characteristic of Dst, means that Australian solar-terrestrial disturbance centers should be able to predict the time to recovery of quieter fields once an on-line Austrialian magnetic field Dst main-phase computation has been made.

Adoption of information and communication technologies and access to the Internet is expanding in Africa, but because of the rapid growth elsewhere, a Digital Divide between Africa and the rest of the world exists, and the gap is growing. In many sub-Saharan African countries, education and research sector suffer some of the worst deficiencies in access to the Internet, despite progress in development of NRENs National Research and Education (cyber) Networks. By contrast, it is widely acknowledged in policy statements from the African Union, the UN, and others that strength in this very sector provides the key to meeting and sustaining Millennium Development Goals. Developed countries with effective cyber-capabilities proclaim the benefits to rich and poor alike arising from the Information Revolution. This is but a dream for many scientists in African institutions. As the world of science becomes increasingly Internet-dependent, so they become increasingly isolated. eGY-Africa is a bottom-up initiative by African scientists and their collaborators to try to reduce this Digital Divide by a campaign of advocacy for better institutional facilities. Four approaches are being taken. The present status of Internet services, problems, and plans are being mapped via a combination of direct measurement of Internet performance (the PingER Project) and a questionnaire-based survey. Information is being gathered on policy statements and initiatives aimed at reducing the Digital Divide, which can be used for arguing the case for better Internet facilities. Groups of concerned scientists are being formed at the national, regional levels in Africa, building on existing networks as much as possible. Opinion in the international science community is being mobilized. Finally, and perhaps most important of all, eGY-Africa is seeking to engage with the many other programs, initiatives, and bodies that share the goal of reducing the Digital Divide either as a direct policy objective, or indirectly as a means to an end, such as the development of an indigenous capability in science and technology for national development. The expectation is that informed opinion from the scientific community at the institutional, national, and international levels can be used to influence the decision makers and donors who are in a position to deliver better Internet capabilities.

We thank James E. Faller for his comment and this opportunity to emphasize one of the main points of our article. Our use of the title “science” on the lintel in Figure 2 was deliberate and pivotal. “Information science” is, of course, not excluded. We are trying to convey the view that information is changing fundamentally the conduct of science research, including observational science.

Lake Johnston cirque contains some of the best subalpine rainforest in Tasmania. Pollen from the sediments shows Lagarostrobos franklinii, which presently reaches 1040 m, may be a glacial relict. Nothofagus cunninghamii–Nothofagus gunnii subalpine rainforest developed between 9000 and 6000 14C yr B.P., with a maximum at 8700 14C yr B.P. After 6000 14C yr B.P. Nothofagus gunnii became more important, and from 3600 14C yr B.P. sclerophyll and heath components increased. Partial burning of the catchment occurred periodically. Early Holocene climate was warmer and wetter than late Holocene climate. The vegetation and climate changes are similar to those recorded from western South Island New Zealand and Chile. Radiocarbon dates give a sedimentation rate of 0.43 mm/yr. Cores are correlated by magnetic susceptibility. Magnetic ages are assigned by matching with the 14C-dated secular variation master curve for southeastern Australia. Magnetic ages are consistent with the 14C chronology when the former are adjusted by 350 years.

A Late-glacial-Holocene pollen record was obtained from a 3.96 m sediment core taken from Lake St Clair, central Tasmania. Modern vegetation and pollen analyses formed the basis for interpretation of the vegetation and climate history. Following deglaciation and before ca. 18 450 yr BP Podocarpus lawrencei coniferous heath and Astelia-Plantago wet alpine herb-field became established at Lake St Clair. A distinct Poaceae-Plantago peak occurs between 18450 and 11210 yr BP and a mean annual temperature depression from ca. 6.2 degreesC to 3 degreesC below present is inferred for this period. The marked reduction in Podocarpus and strong increase of Poaceae suggests reduced precipitation levels during the period of widespread deglaciation (ca. 18.5-11 kyr BP). The local Late Pleistocene-Holocene non-forest to forest biostratigraphical boundary is dated at 11.2 kyr BP. It is characterised by expansion of the subalpine taxa Athrotaxis/Diselma with Nothofagus gunnii, and by the establishment of Nothofagus cunninghamii with Eucalyptus spp. A 'Phyllocladus bulge' prior to the expansion of Nothofagus cunninghamii, reported at other Tasmanian sites, is not present at Lake St Clair. Nothofagus cunninghamii cool temperate rainforest peaked at 7800 yr BP, probably under wetter climatic conditions than present. The maximum development of rainforest in the early-middle Holocene may indicate that the temperature was slightly warmer than present, but the evidence is not definitive. The expansion of Eucalyptus spp. and Poaceae after 6000 yr BP may be partly a disclimax effect as a result of Aboriginal burning, but appears also to reflect reduced precipitation. The changes in vegetation and inferred climate can be explained by major changes in synoptic patterns of southern Australia and the adjacent southwest Pacific. Copyright (C) 2000 John Wiley & Sons, Ltd.

Analysis of pollen, NRM intensity of sediments, and dating of a 397cm core from Lake Selina in western Tasmania provides a detailed record of vegetation and climate changes for the Last Interglacial–Last Glacial cycle. The vegetation record shows that cool temperate rainforest was present during Isotope Substage 5e and during the Holocene. Wet montane forest and subalpine shrublands dominated the early Last Glacial interstades; subalpine–alpine heathlands and herbfield the stadials. Stages 4–2 mainly had grassland, herbland and heath vegetation. There is close correlation between phases of maximum magnetic intensity in the sediments with pollen zones indicating presence of herbaceous vegetation. This suggests erosion of the catchment was greater in the absence of forest or woodland. Climate may have been slightly cooler than present during Substage 5e but the evidence is not definitive. Climate was colder at all times during the Last Glacial Stage until after ca. 14kyr BP. Maximum temperature depression from present during Stage 2 was >3.5°C at Lake Selina, but probably as much as 6.5°C in the West Coast Range. Holocene climate was cool and wet. Comparison of the Lake Selina record, with others in western Tasmania and Victoria, indicate that variations in vegetation during the Last Interglacial–Last Glacial cycle were primarily responses to temperature changes in western Tasmania, and to precipitation changes, particularly summer drought, in western Victoria.

The International Geomagnetic Reference Field (IGRF) is due to be updated from the beginning of the year 2000. IAGA Working Group V‐8, for analysis of the global and regional geomagnetic field and its secular variation, is seeking the following candidate spherical harmonic models: a main field model for the year 2000 (IGRF 2000) with the expected maximum degree and order m=n=10 a secular variation model for the interval 2000–2005 with the expected maximum degree and order m=n=8

This study concerns the use of selected geomagnetic field records to establish the 1990 quiet-day current system (Sq) for Australia and to use the ionospheric current source of Sq for a determination of the Earth’s deep electrical conductivity. The primary data set came from a chain of eight, three-component magnetometer stations that was operated along a north-south line in central Australia. Additional records, necessary for boundary conditions, were added to the data set. A regional spherical harmonic analysis (SHA) allowed the separation of the internal and external field contributions to the Sq variations. Mapping of the equivalent ionospheric current from the external field showed that the Sq contour focus passed near the —30° geomagnetic latitude of central Australia with a 5° latitude variation between winter and summer and a corresponding change from about 80 to 200 kA in strength. A special transfer function allowed the computation of an equivalent conductivity-depth profile of central Australia from the paired external and internal coefficients of the SHA. A regression line through the conductivity estimates gives a profile that starts at 0.025 S/m for a depth of 130 km, rising gradually to about 0.045 S/m at 250 km, then steepens to 0.11 S/m at 360 km and rises moderately to 0.13 S/m at 470 km near the base of the upper mantle. No data were obtained through the mantle transition zone. Computations gave 0.18 S/m in the region of 800 km depth. Previous conductivity models for the upper mantle beneath central Australia, although less specific in values, are consistent with our profile. At depths greater than 500 km, the regression profile is in agreement with the conductivity distribution beneath the Tasman Sea determined from seafloor magnetotellurics, although both measurements lack high resolution at such depths.

Transitional VGP paths recorded in sediments cluster into two antipodal preferred longitude bands that tend to lie 90 degrees away from their site longitudes, the latter also being clustered. VGP paths obtained from lava flow sequences, though much fewer, appear not to show these biases, suggesting a rock-magnetic influence on VGP paths recorded in sediments. Inclination shallowing of detrital magnetic remanence, enhanced under low transitional field strengths, is the most likely candidate. We illustrate the effects of inclination shallowing by applying a simple shallowing model (tan I-R = f tan I-A, where I-A is the inclination of the magnetic remanence and I-A is the inclination of the ambient field) with field variation to hypothetical data sets. Shallowing-induced clustering increases as f decreases and becomes extreme as f approaches 0.1. We have used the model to 'de-shallow' the available set of transitional VGP sediment records for various values of f. The probability that the observations arise from inclination shallowing of a uniform random distribution of paths increases as f decreases. When f drops to 0.13 there is a 50% chance of getting at least as much grouping as observed. To decide if inclination shallowing is a dominant factor in the clustering, we need to know whether such extreme shallowing is widespread in sedimentary records under transitional field conditions. Field and laboratory redeposition data are not yet adequate to resolve this question.

The term “normal field,” used to describe the nontransient part of the geomagnetic field, has largely fallen into disuse, yet, it is a useful term and worthy of revival. The term probably originated from Schmidt [1916] (referred to in Chapman and Bartels, 1940, p. 133), who called 12‐month averages of the geomagnetic field elements the Normalwerte (normal values). Schmidt compared these normal values with his “secular values”—10‐year averages of the field—in order to identify solar cycle effects. He assumed that normal values would average out the shorter‐period contributions of the solar daily variation, lunar variation, and irregular disturbance effects: S, L, and D, respectively, in the notation of Chapman and Bartels [1940].

IAGA Working Group V‐8 (Analysis of the global and regional geomagnetic field and its secular variation) is seeking numerical models of the main‐field and its secular variation as candidates for the 1995 revision of the International Geomagnetic Reference Field. The following spherical harmonic models are required: a definitive main‐field model for epoch 1990.0 (IGRF 1990); an interim main‐field model for epoch 1995.0 (IGRF1995); a secular variation model for the interval 1995.0‐2000.0 (as part of IGRF 1995); and, possibly, a definitive main‐field models at 5‐year epochs from 1900.0 to 1940.0.