scholarly journals Effect of gravitational consistency and mass conservation on seasonal surface mass loading models

2005 ◽  
Vol 32 (8) ◽  
Author(s):  
P. J. Clarke
Keyword(s):  
Mass Conservation ◽  
Mass Loading ◽  
Surface Mass

scholarly journals Review on the Macro-Transport Processes Theory for Irregular Pores able to Perform Catalytic Reactions

Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 281 ◽  
Author(s):  
Iván Santamaría-Holek ◽  
Saúl Hernández ◽  
Consuelo García-Alcántara ◽  
Aldo Ledesma-Durán
Keyword(s):  
Porous Media ◽  
Diffusion Coefficients ◽  
Mass Conservation ◽  
Breakthrough Curves ◽  
Transport Processes ◽  
Catalytic Reactions ◽  
Irregular Domains ◽  
Surface Mass ◽  
Physicochemical Basis ◽  
Mass Uptake

We review and generalize a recent theoretical framework that provides a sound physicochemical basis to describe how volume and surface diffusion are affected by adsorption and desorption processes, as well as by catalytic conversion within the space defined by the irregular geometry of the pores in a material. The theory is based on two single-dimensional mass conservation equations for irregular domains deduced for the volumetric (bulk) and surface mass concentrations. It offers a powerful tool for analyzing and modeling mass transport across porous media like zeolites or artificially build materials, since it establishes how the microscopic quantities that refer to the internal details of the geometry, the flow and the interactions within the irregular pore can be translated into macroscopic variables that are currently measured in experiments. The use of the theory in mass uptake experiments is explained in terms of breakthrough curves and effective mass diffusion coefficients which are explicitly related to the internal geometry of the pores.

scholarly journals Basis functions for the consistent and accurate representation of surface mass loading

2017 ◽  
Author(s):  
Peter Clarke ◽  
David Lavallee ◽  
Geoffrey Blewitt ◽  
Tonie van Dam
Keyword(s):  
Basis Functions ◽  
Mass Loading ◽  
Surface Mass ◽  
Accurate Representation

scholarly journals Analysis of the Potential Contributors to Common Mode Error in Chuandian Region of China

2020 ◽  
Vol 12 (5) ◽  
pp. 751
Author(s):  
Weijie Tan ◽  
Junping Chen ◽  
Danan Dong ◽  
Weijing Qu ◽  
Xueqing Xu
Keyword(s):  
Time Series ◽  
Soil Moisture ◽  
Principal Component ◽  
Mass Loading ◽  
Common Mode ◽  
Surface Mass ◽  
Common Mode Error ◽  
Comparison Results ◽  
Wide Range ◽  
Gps Time Series

Common mode error (CME) in Chuandian region of China is derived from 6-year continuous GPS time series and is identified by principal component analysis (PCA) method. It is revealed that the temporal behavior of the CME is not purely random, and contains unmodeled signals such as nonseasonal mass loadings. Its spatial distribution is quite uniform for all GPS sites in the region, and the first principal component, uniformly distributed in the region, has a spatial response of more than 70%. To further explore the potential contributors of CME, daily atmospheric mass loading and soil moisture mass loading effects are evaluated. Our results show that ~15% of CME can be explained by these daily surface mass loadings. The power spectral analysis is used to assess the CME. After removing atmospheric and soil moisture loadings from the CME, the power of the CME reduces in a wide range of frequencies. We also investigate the contribution of CME in GPS filtered residuals time series and it shows the Root Mean Squares (RMSs) of GPS time series are reduced by applying of the mass loading corrections in CME. These comparison results demonstrate that daily atmosphere pressure and the soil moisture mass loadings are a part of contributors to the CME in Chuandian region of China.

scholarly journals Detecting high spatial variability of ice-shelf basal mass balance (Roi Baudouin ice shelf, Antarctica)

2017 ◽  
Author(s):  
Sophie Berger ◽  
Reinhard Drews ◽  
Veit Helm ◽  
Sainan Sun ◽  
Frank Pattyn
Keyword(s):  
Spatial Variability ◽  
Mass Balance ◽  
Mass Conservation ◽  
Atmospheric Model ◽  
Small Scale ◽  
Ice Shelf ◽  
Surface Mass ◽  
Ice Shelves ◽  
Shelf Slope ◽  
Grounding Line

Abstract. Ice shelves control the dynamic mass loss of ice sheets through buttressing and their integrity depends on the spatial variability of their basal mass balance (BMB), i.e., the difference between refreezing and melting. Here, we present a novel technique – based on satellite observations – to capture the small-scale variability in the BMB of ice-shelves. As a case study we apply the methodology to the Roi Baudouin Ice Shelf, Dronning Maud Land, East Antarctica and derive its yearly-averaged BMB at 10 m horizontal gridding. We use mass conservation within a Lagrangian framework based on high-resolution surface velocities, atmospheric-model surface mass balance and hydrostatic ice-thickness fields (derived from TanDEM-X surface elevation). Spatial derivatives are implemented using the total-variation differentiation, which avoids spatial averaging hence loss of spatial resolution. Our BMB field exhibits high detail and ranges from −14.8 to 8.6 m a−1 ice equivalent. Highest melt rates are found close to the grounding line where the basal ice-shelf slope is the steepest. The BMB field agrees well with on-site measurements from phase-sensitive radar, although unresolved spatial variations in firn density determined from profiling radar occur. We show that the surface expression of an englacial lake (0.7 × 1.3 km2 wide and 30 m deep) lowers by 0.5 to 1.4 m a−1, which we tentatively attribute to a transient adaptation to hydrostatic equilibrium. We find evidence for elevated melting beneath ice-shelf channels (with melting being concentrated on the channel's flanks). However, farther downstream from the grounding line, the majority of ice-shelf channels advect passively toward the ice-shelf front. Although the absolute, satellite-based BMB values remain uncertain, we have high confidence in the spatial variability on sub-kilometre scales. This study highlights expected challenges for a full coupling between ice and ocean models.

scholarly journals Relative contribution of surface mass-balance and ice-flux changes to the accelerated thinning of Mer de Glace, French Alps, over1979-2008

2012 ◽  
Vol 58 (209) ◽  
pp. 501-512 ◽  
Author(s):  
Etienne Berthier ◽  
Christian Vincent
Keyword(s):  
Mass Balance ◽  
Cross Sections ◽  
Important Implication ◽  
Mass Conservation ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
French Alps ◽  
Relative Contribution ◽  
Covered Area ◽  
Surface Topographies

AbstractBy subtracting surface topographies from 1979, 1994, 2000 and 2008, we measured icethinning rates increasing from 1 ma-1 (1979-94) to >4 ma-1 (2000-08) on the tongue of Mer de Glace, French Alps. The relative contributions of changes in surface mass balance and ice fluxes to this acceleration in the thinning are estimated using field and remote-sensing measurements. Between 1979-94 and 2000-08, surface mass balance diminished by 1.2mw.e.a-1, mainly because of atmospheric warming. Mass-balance changes induced by the growing debris-covered area and the evolving glacier hypsometry compensated each other. Meanwhile, Mer de Glace slowed down and the ice fluxes through two cross sections at 2200 and 2050ma.s.l. decreased by 60%. Between 1979-94 and 2000-08, two-thirds of the increase in the thinning rates was caused by reduced ice fluxes and one- third by rising surface ablation. However, these numbers need to be interpreted cautiously given our inability to respect mass conservation below our upper cross section. An important implication is that large errors would occur if one term of the continuity equation (e.g. surface mass balance) were deduced from the two others (e.g. elevation and ice-flux changes).

scholarly journals Basis functions for the consistent and accurate representation of surface mass loading

2007 ◽  
Vol 171 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Peter J. Clarke ◽  
David A. Lavallée ◽  
Geoff Blewitt ◽  
Tonie van Dam
Keyword(s):  
Basis Functions ◽  
Mass Loading ◽  
Surface Mass ◽  
Accurate Representation
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