ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2019
    Description: Abstract Tropopause‐penetrating convection is a frequent seasonal feature of the Central United States climate. This convection presents the potential for consistent transport of water vapor into the upper troposphere and lower stratosphere (UTLS) through the lofting of ice, which then sublimates. Water vapor enhancements associated with convective ice lofting have been observed in both in situ and satellite measurements. These water vapor enhancements can increase the probability of sulfate aerosol‐catalyzed heterogeneous reactions that convert reservoir chlorine (HCl and ClONO2) to free radical chlorine (Cl and ClO) that leads to catalytic ozone loss. In addition to water vapor transport, lofted ice may also scavenge nitric acid and further impact the chlorine activation chemistry of the UTLS. We present a photochemical model that resolves the vertical chemical structure of the UTLS to explore the effect of water vapor enhancements and potential additional nitric acid removal. The model is used to define the response of stratospheric column ozone to the range of convective water vapor transported and the temperature variability of the lower stratosphere currently observed over the Central United States in conjunction with potential nitric acid removal and to scenarios of elevated sulfate aerosol surface area density representative of possible future volcanic eruptions or solar radiation management. We find that the effect of HNO3 removal is dependent on the magnitude of nitric acid removal and has the greatest potential to increase chlorine activation and ozone loss under UTLS conditions that weakly favor the chlorine activation heterogeneous reactions by reducing NOx sources.
    Print ISSN: 2169-897X
    Electronic ISSN: 2169-8996
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2013-07-31
    Description: [1]  In this paper we compare time-dependent global ionospheric field-aligned current (FAC) patterns on 10-min time scales inferred from the Active Magnetosphere and Polar Electrodynamics Response Experiment (AMPERE) with the high-resolution Lyon-Fedder-Mobarry (LFM) global magnetohydrodynamic (MHD) model. The improved LFM model yields temporally varying FAC patterns with a fine structure on the sub–100 km scale. The goal of the study is to explore the responses of observed and simulated FAC patterns and underlying magnetic perturbations to a succession of rapid transitions in the solar wind and Interplanetary Magnetic Field (IMF) parameters. To drive the simulations we use the upstream Wind and THEMIS spacecraft measurements recorded on August 3, 2010. For the time interval of interest (~40 mins following the impact of an interplanetary shock), the IMF is characterized by a B Z rotation from southward to northward direction under negative B Y conditions. Through this case study analysis, it is found that the simulations have generally reproduced the salient characteristics of both the morphology and dynamics of the AMPERE FAC patterns. Due to the high resolution of the global model, the peak current densities are found to significantly (by a factor of 2–4) exceed those obtained from AMPERE. As a further quantitative analysis, the low-altitude magnetic perturbations measured by Iridium spacecraft and used to derive the AMPERE 2-D FAC patterns are also compared with the magnetic field variations calculated from the simulations. It is found that outside of localized regions of peak current densities, which mainly occur on the dayside and can fall between the Iridium tracks, the simulated magnetic perturbations closely follow the Iridium measurements. This demonstrates, in particular, that there is no systematic bias in the simulations to overestimate the magnetic perturbations and corresponding FAC densities. Overall, our results demonstrate that, given sufficient resolution, contemporary global MHD models are capable of reproducing observed features of global ionospheric FAC distributions. This, in particular, suggests the feasibility of potential efforts to assimilate AMPERE observations in global magnetospheric models.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 1990-01-01
    Description: The distortions of earthquake ground motions recorded in small instrument shelters as a result of soil‐structure interaction effects are investigated by means of a theoretical parametric study. A total of 12 foundation geometries varying in basal radius, embedment depth and extension above the ground surface and a number of soil profiles including uniform and layered soil models were considered. The results obtained show significant amplification and deamplification of the free‐field ground motion for sufficiently soft soils (β〈200 m/sec) and sufficiently high frequencies (f〉20 Hz). Copyright © 1990 John Wiley & Sons, Ltd
    Print ISSN: 0098-8847
    Electronic ISSN: 1096-9845
    Topics: Architecture, Civil Engineering, Surveying
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2008-07-07
    Description: A reconnaissance slip-rate-estimation technique is needed for hundreds of uncharacterized normal faults in the Great Basin. We use the occurrence and/or absence of primary tectonic geomorphology, alluvial fault scarps and fault facets, to distinguished between categories of faults that have differences of orders of magnitudes in slip rate. Normal faults that lack alluvial fault scarps and fault facets (Type 3) have vertical slip rates on the order of 0.001 m kyr-1. Faults with alluvial fault scarps but that lack active fault facets (Type 2) have vertical slip rates on the order of 0.01 m kyr-1. Faults with active fault facets with a minimum height of 30 m (Type 1) are the most important faults in the Great Basin with respect to seismic hazard, tectonic deformation, and basin development and deposition. These faults generally have vertical slip rates of 0.1 m kyr-1 and faster. For better precision we have developed a relationship between vertical slip rate and maximum basal facet height: Log10 Sv = 0.00248H - 0.938 where Sv is vertical slip rate in m kyr-1 and H is maximum basal facet height in metres. The standard deviation of this relationship is 0.239, which corresponds to plus or minus a multiplicative factor of 1.7 in vertical slip rate. These criteria were used to estimate vertical slip rates for major normal faults in Nevada, USA. Based on the rates and orientations of these faults, seven Quaternary tectonic subprovinces are distinguished. The fastest faults (≥0.5 m kyr-1) are generally located in the Walker Lane belt, perhaps because of higher extension rates created by the addition of strike-slip tectonics. Earthquake occurrence rates based on the faults in Nevada and their estimated slip rates are about a factor of two lower than historical earthquake rates.
    Print ISSN: 0950-091X
    Electronic ISSN: 1365-2117
    Topics: Geosciences
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2000-09-01
    Print ISSN: 0950-091X
    Electronic ISSN: 1365-2117
    Topics: Geosciences
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...