Mezen Bay—a key area for understanding Weichselian glaciations in northern Russia

Sediment successions in coastal cliffs around Mezen Bay, southeastern White Sea, record an unusually detailed history of former glaciations, interstadial marine and fluvial events from the Weichselian. A regional glaciation model for the Weichselian is based on new data from the Mezen Bay area and previously published data from adjacent areas. Following the Mikulinian (Eemian) interglacial a shelf‐centred glaciation in the Kara Sea is reflected in proglacial conditions at 100–90 ka. A local ice‐cap over the Timan ridge existed between 75 and 65 ka. Renewed glaciation in the Kara Sea spread southwestwards around 60 ka only, interrupted by a marine inundation, before it advanced to its maximum position at about 55–50 ka. After a prolonged ice‐free period, the Scandinavian ice‐sheet invaded the area from the west and terminated east of Mezen Bay about 17 ka. The previously published evidence of a large ice‐dammed lake in the central Arkhangelsk region, Lake Komi, finds no support in this study. Copyright © 2003 John Wiley & Sons, Ltd.     

Glacial rebound and sea-level change in the British Isles

Observations of sea levels around the coastline of the British Isles for the past 10,000–15,000 years exhibit a major regional variation and provide an important data base for testing models of glacial rebound as well as models of the Late Devensian ice sheet. A high-resolution rebound model has been developed which is consistent with both the spatial and temporal patterns of sea-level change and which demonstrates that the observations are the result of (i) the glacio-isostatic crustal rebound in response to the unloading of the ice sheet over Britain and, to a lesser degree, of the ice sheet over Fennoscandia, and (ii) the rise in sea-level from the melting Late Pleistocene ice sheets, including the response of the crust to the water loading (the hydro-isostatic effect). The agreement between model and observations is such that there is no need to invoke vertical crustal movements for Great Britain and Ireland of other than glacio-hydro-isostatic origin. The rebound contributions are important throughout the region and nowhere is it sufficiently small for the sea-level change to approximate the eustatic sea-level rise. The observational data distribution around the periphery as well as from sites near the centre of the former ice sheet is sufficient to permit constraints to be established on both earth model parameters specifying the mantle viscosity and lithospheric thickness and the extent and volume of the ice sheet at the time of the last glaciation. Preliminary solutions are presented which indicate an upper mantle viscosity of (3–5)10²⁰ Pas, a lithospheric thickness of about 100 km or less, and an ice model that was not confluent with the Scandinavian ice sheet during the last glaciation and whose maximum thickness over Scotland is unlikely to have exceeded about 1500 m.     

The Solar Flare of November 4, 2001, and Its Manifestations in Energetic Particles from Coronas-F Data

Based on X-ray, gamma-ray, and charged-particle measurements with several instruments onboard the Coronas-F satellite and on ACE and GOES experimental data presented on the Internet, we investigate the parameters of the solar flare of November 4, 2001, and the energetic-particle fluxes produced by it in circumterrestrial space. The increase in relativistic-electron fluxes for about 1.5 days points to a moving source (shock front). The structure of the energetic-particles fluxes in the second half of November 5, 2001, can be explained by the passage of the coronal mass ejection that was ejected on November 1, 2001, and that interacted with the shock wave from the flare of November 4, 2001.     

Über die Schreibung russischer Namen

Ohne Zusammenfassung     

Wide-band multi-spectral space for color representation

This paper develops a wide-band multi-spectral space for color representation with Aitken PCA algorithm. This novel mathematical space using the broad-band spectra matching method aims at improving the accuracy of color representation as well as reducing costs for processing and storing multi-spectral images. The results show that the space can present our experimental original spectral spaces (i. e. Munsell color matt and DIN-6164 color chips) with high efficiency, and that the spanning space with three eigenvectors can present the original space at more than 98% CSCR, and when 5 eigenvectors are used it can cover almost the whole original spaces.     

Graph theory for analyzing pair-wise data: application to geophysical model parameters estimated from interferometric synthetic aperture radar data at Okmok volcano,Alaska

Graph theory is useful for analyzing time-dependent model parameters estimated from interferometric synthetic aperture radar (InSAR) data in the temporal domain. Plotting acquisition dates (epochs) as vertices and pair-wise interferometric combinations as edges defines an incidence graph. The edge-vertex incidence matrix and the normalized edge Laplacian matrix are factors in the covariance matrix for the pair-wise data. Using empirical measures of residual scatter in the pair-wise observations, we estimate the relative variance at each epoch by inverting the covariance of the pair-wise data. We evaluate the rank deficiency of the corresponding least-squares problem via the edge-vertex incidence matrix. We implement our method in a MATLAB software package called GraphTreeTA available on GitHub (https://github.com/feigl/gipht). We apply temporal adjustment to the data set described in Lu et al. (Geophys Res Solid Earth 110, 2005) at Okmok volcano, Alaska, which erupted most recently in 1997 and 2008. The data set contains 44 differential volumetric changes and uncertainties estimated from interferograms between 1997 and 2004. Estimates show that approximately half of the magma volume lost during the 1997 eruption was recovered by the summer of 2003. Between June 2002 and September 2003, the estimated rate of volumetric increase is \((6.2 \, \pm \, 0.6) \times 10^6~\mathrm{m}^3/\mathrm{year} \). Our preferred model provides a reasonable fit that is compatible with viscoelastic relaxation in the five years following the 1997 eruption. Although we demonstrate the approach using volumetric rates of change, our formulation in terms of incidence graphs applies to any quantity derived from pair-wise differences, such as range change, range gradient, or atmospheric delay.     

Opportunistic natural experiments using digital telemetry: a transit disruption case study

ABSTRACT

In the past decade society has entered a technological period characterized by handheld computing that supports input and processing from numerous sensors. Today’s mobile phones offer the ability to integrate input from sensors monitoring various external and internal sources (e.g., accelerometer, magnetometer, microphone, GPS, wireless Internet, and Bluetooth). Furthermore, these raw inputs can be integrated and processed in ways that can offer novel representations of human behaviour. As a result, new opportunities to examine and better understand human spatial behaviour are available; one such application is the constant monitoring of a group of people over an extended period of time. Such a research setting lends itself to natural experiments that emerge as a result of regular and on-going observations. We report here on the observation of a natural experiment that took place in the context of a month-long monitoring study of 28 participants using mobile phone-based ubiquitous sensor monitoring. The implications for public health and transportation planning are discussed.     

Polarimetric NIR reflectance measurements of regolith simulants at zero phase angle

Polarimetric reflectance measurements have been made at a wavelength of for a suite of predominantly lunar regolith simulants in support of development efforts for the BepiColombo Laser Altimeter (BELA). Measurements were made using an instrument at the University of Bern, Switzerland, that has been modified to accommodate photometric characterizations of laboratory samples down to 0^° phase angle (g) with linearly polarized illumination and a linearly polarized receiver. The data reveal opposition surges that are dominated by polarization state-conserving reflectance terms for all samples. Relative strengths of the trans-state reflectance terms are lowest for the darkest samples, suggesting that multiple scattering is responsible for state conversions. Normal albedo measurements of the lunar simulants range from 0.13 to 0.22 at zero illumination angle (i=0^°). The total reflectance of the regolith simulants at g=0^° were found to decrease with increasing i, which is inconsistent with predictions of reflectance models for Mercury. However, the g=0^° reflectance remains higher at i>0^° than would be expected for a gray Lambert surface that is scaled to the g=i=0^° reflectance value. Polarization ratios for reflectance under polarized illumination but unconstrained emission show that the samples scatter light in the in-plane polarization state more efficiently than in the transverse state at g=0^° and i>0^°. The opposite is true for g>0^° polarization ratios, which indicate that transverse polarized illumination scatters more efficiently at high g. The polarization effect appears to correlate with the sample's characteristic grain size, but the statistical basis of this trend is weak. The implications of these measurements upon the performance of the BELA instrument are discussed.