scholarly journals Effect of enhanced manganese oxidation in the hyporheic zone on basin-scale geochemical mass balance

1998 ◽  
Vol 34 (4) ◽  
pp. 623-636 ◽  
Author(s):  
Judson W. Harvey ◽  
Christopher C. Fuller
Keyword(s):  
Mass Balance ◽  
Hyporheic Zone ◽  
Manganese Oxidation ◽  
Basin Scale ◽  
Geochemical Mass Balance

scholarly journals The influence of water–rock interactions on household well water in an area of high prevalence chronic kidney disease of unknown aetiology (CKDu)

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Liza K. McDonough ◽  
Karina T. Meredith ◽  
Chandima Nikagolla ◽  
Richard B. Banati
Keyword(s):  
Water Quality ◽  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Water Chemistry ◽  
Mass Balance ◽  
Stable Carbon Isotopes ◽  
Environmental Isotopes ◽  
Well Water ◽  
High Prevalence ◽  
Geochemical Mass Balance

AbstractPoor drinking water quality in household wells is hypothesised as being a potential contributor to the high prevalence of chronic kidney disease of uncertain aetiology (CKDu) among the farming communities of the Medawachchiya area, Anuradhapura, Sri Lanka. One of the natural processes that can affect water quality is the dissolution of minerals contained within an aquifer by water–rock interactions (WRIs). Here we present a comprehensive assessment of WRIs and their influence on the water chemistry in household wells and spring waters in the Medawachchiya area by combining measurements of environmental isotopes, such as strontium, lithium and stable carbon isotopes and inorganic chemistry parameters, and modelling geochemical mass balance reactions between rainfall and groundwater samples. Our results reveal the presence of strontium, dissolved from both silicate and carbonate minerals, with high isotopic (87Sr/86Sr) ratios of up to 0.7316. Geochemical mass balance modelling and prior 87Sr/86Sr studies on the Wanni Complex bedrock suggest these strontium values may be the result of biotite dissolution. We also identify lithium and uranium contributed from the dissolution of silicates, albeit at concentrations too low to constitute a known health risk. In contrast, the levels of magnesium and calcium in our samples are high and demonstrate that, despite the felsic bedrock, well water chemistry in the Medawachchiya area is dominated by carbonate dissolution.

scholarly journals Quantifying weathering on variable rocks, an extension of geochemical mass balance: Critical zone and landscape evolution

2017 ◽  
Vol 42 (14) ◽  
pp. 2457-2468 ◽  
Author(s):  
Beth A. Fisher ◽  
Aaron K. Rendahl ◽  
Anthony K. Aufdenkampe ◽  
Kyungsoo Yoo
Keyword(s):  
Mass Balance ◽  
Landscape Evolution ◽  
Critical Zone ◽  
Geochemical Mass Balance

scholarly journals An estimate of glacier mass balance for the Chandra basin, western Himalaya, for the period 1984–2012

2017 ◽  
Vol 58 (75pt2) ◽  
pp. 99-109 ◽  
Author(s):  
Sayli Atul Tawde ◽  
Anil V. Kulkarni ◽  
Govindasamy Bala
Keyword(s):  
Mass Balance ◽  
Water Resource Management ◽  
Western Himalaya ◽  
Ratio Method ◽  
Glacier Mass Balance ◽  
Equilibrium Line Altitude ◽  
Temperature Index ◽  
Field Investigations ◽  
Basin Scale ◽  
Accumulation Area Ratio

ABSTRACTAn improved understanding of fresh water stored in the Himalaya is crucial for water resource management in South Asia and can be inferred from glacier mass-balance estimates. However, field investigations in the rugged Himalaya are limited to a few individual glaciers and short duration. Therefore, we have recently developed an approach that combines satellite-derived snowlines, a temperature-index melt model and the accumulation-area ratio method to estimate annual mass balance of glaciers at basin scale and for a long period. In this investigation, the mass balance of 146 glaciers in the Chandra basin, western Himalaya, is estimated from 1984 to 2012. We estimate the trend in equilibrium line altitude of the basin as +113 m decade−1and the mean mass balance as −0.61 ± 0.46 m w.e. a−1. Our basin-wide mass-balance estimates are in agreement with the geodetic method during 1999–2012. Sensitivity analysis suggests that a 20% increase in precipitation can offset changes in mass balance for a 1 °C temperature rise. A water loss of 18% of the total basin volume is estimated, and 67% for small and low-altitude glaciers during 1984–2012, indicating a looming water scarcity crisis for villages in this valley.

Climate parameters influencing satellite-based volume and elevation changes of the Antarctic ice sheet

2020 ◽  
Author(s):  
Athul Kaitheri ◽  
Anthony Mémin ◽  
Frédérique Rémy
Keyword(s):  
Mass Balance ◽  
Ice Sheet ◽  
Snow Accumulation ◽  
Amundsen Sea ◽  
Antarctic Ice Sheet ◽  
Changing Climate ◽  
Basin Scale ◽  
Elevation Changes ◽  
The Antarctic ◽  
Grace Mission

<p>Precisely quantifying the Antarctic Ice Sheet (AIS) mass balance remains a challenge as several processes compete at differing degrees in the basin-scale with regional variations. Understanding of changes in AIS has been largely based on observations from various altimetry missions and Gravity Recovery And Climate Experiment (GRACE) missions due to its scale and coverage. Analysis of linear trends in surface height variations of AIS since the early 1990s showed multiple variabilities in the rate of changes over the period of time. These observations are a reflection of various underlying ice sheet processes. Therefore understanding the processes that interact on the ice sheet is important to precisely determine the response of the ice sheet to a rapidly changing climate.</p><p>Changing climate constitutes variations in major short term processes including snow accumulation and surface melting. Variations in accumulation rate and temperature at the ice sheet surface cause changes in the firn compaction (FC) rate. Variations in the FC rate change the AIS thickness, that should be detected from altimetry, but do not change its mass, as observed by the GRACE mission. We focus our study on the seasonal and interannual changes in the elevation and mass of the AIS. We use surface elevation changes from Envisat data and gravity changes derived from the latest GRACE solutions between 10/2002 and 10/2010. As mass changes observed using the GRACE mission is strongly impacted by long term isostasy, as it involves mantle mass redistribution, we remove from all dataset an 8-year trend. We use weather variable historical data solutions including surface mass balance, temperature and wind velocities from the regional climate model RACMO2.3p2 as input to an FC model to estimate AIS elevation changes. We obtain a very good correlation between height change estimates from GRACE, Envisat and RACMO2.3p2 at several places such as along the coast of Dronning Maud Land, Wilkes land and Amundsen sea sector. Considerable differences in Oates and Mac Robertson regions, with a strong seasonal signal in Envisat estimates, reflect spatial variability in physical parameters of the surface of the AIS due to climate parameter changes such as winds.</p>

scholarly journals Downscaled surface mass balance in Antarctica: impacts of subsurface processes and large-scale atmospheric circulation

2021 ◽  
Author(s):  
Nicolaj Hansen ◽  
Peter L. Langen ◽  
Fredrik Boberg ◽  
Rene Forsberg ◽  
Sebastian B. Simonsen ◽  
...  
Keyword(s):  
Mass Balance ◽  
Total Mass ◽  
Large Scale ◽  
Climate Model ◽  
Regional Climate ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
Lagrangian Framework ◽  
Basin Scale ◽  
The Antarctic

Abstract. Antarctic surface mass balance (SMB) is largely determined by precipitation over the continent and subject to regional climate variability related to the Southern Annular Mode (SAM) and other climatic drivers at the large scale. Locally however, firn and snow pack processes are important in determining SMB and the total mass balance of Antarctica and global sea level. Here, we examine factors that influence Antarctic SMB and attempt to reconcile the outcome with estimates for total mass balance determined from the GRACE satellites. This is done by having the regional climate model HIRHAM5 forcing two versions of an offline subsurface model, to estimate Antarctic ice sheet (AIS) SMB from 1980 to 2017. The Lagrangian subsurface model estimates AIS SMB of 2473.5 ± 114.4 Gt per year, while the Eulerian subsurface model variant results in slightly higher modelled SMB of 2564.8 ± 113.7 Gt per year. The majority of this difference in modelled SMB is due to melt and refreezing over ice shelves and demonstrates the importance of firn modelling in areas with substantial melt. Both the Eulerian and the Lagrangian SMB estimates are within uncertainty ranges of each other and within the range of other SMB studies. However, the Lagrangian version has better statistics when modelling the densities. There is a mean bias in modelled density of −24.0 ± 18.4 kg m−3 and −8.2 ± 15.3 kg m−3 for layers less than 550 kg m−3 for the Eulerian and Lagrangian framework, respectively. For layers with a density above 550 kg m−3 the bias is −31.7 ± 23.4 kg m−3 and −35.0 ± 23.7 kg m−3 for the Eulerian and Lagrangian framework, respectively. The mean firn 10 m temperature bias is 0.42–0.52 °C. Further, analysis of the relationship between SMB in individual drainage basins and the SAM, is carried out using a bootstrapping approach. This shows a robust relationship between SAM and SMB in half of the basins (13 out of 27). In general, when SAM is positive there is a lower SMB over the Plateau and a higher SMB on the westerly side of the Antarctic Peninsula, and vice versa when the SAM is negative. Finally, we compare the modelled SMB to GRACE data by subtracting the solid ice discharge, and find that there is a good agreement in East Antarctica, but large disagreements over the Antarctic Peninsula.There is a large difference between published estimates of discharge that make it challenging to use mass reconciliation in evaluating SMB models on the basin scale.

scholarly journals High-resolution interactive modelling of the mountain glacier–atmosphere interface: an application over the Karakoram

2013 ◽  
Vol 7 (1) ◽  
pp. 103-144 ◽  
Author(s):  
E. Collier ◽  
T. Mölg ◽  
F. Maussion ◽  
D. Scherer ◽  
C. Mayer ◽  
...  
Keyword(s):  
High Resolution ◽  
Mass Balance ◽  
Land Surface ◽  
Traditional Approach ◽  
Coupled Model ◽  
Glacier Mass Balance ◽  
Glacier Surface ◽  
Mountain Glacier ◽  
Near Surface ◽  
Basin Scale

Abstract. The traditional approach to simulations of alpine glacier mass balance (MB) has been one-way, or offline, thus precluding feedbacks from changing glacier surface conditions on the atmospheric forcing. In addition, alpine glaciers have been only simply, if at all, represented in atmospheric models to date. Here, we extend a recently presented, novel technique for simulating glacier–atmosphere interactions without the need for statistical downscaling, through the use of a coupled high-resolution mesoscale atmospheric and physically-based mass balance modelling system that includes glacier MB and energy balance feedbacks to the atmosphere. We compare the model results over the Karakoram region of the northwestern Himalaya with both remote sensing data and in situ glaciological and meteorological measurements for the ablation season of 2004. We find that interactive coupling has a localized but appreciable impact on the near-surface meteorological forcing data and that incorporation of MB processes improves the simulation of variables such as land surface temperature and snow albedo. Furthermore, including feedbacks from the MB model has a non-negligible effect on simulated mass balance, reducing modelled ablation, on average, by 0.1 m w.e. (−6.0%) to a total of −1.5 m w.e. between 25 June–31 August 2004. The interactively coupled model shows promise as a new, multi-scale tool for explicitly resolving atmospheric-MB processes of mountain glaciers at the basin scale.

scholarly journals Groundwater Dominates Water Fluxes in a Headwater Catchment During Drought

2021 ◽  
Vol 3 ◽  
Author(s):  
Robin Kaule ◽  
Benjamin S. Gilfedder
Keyword(s):  
Water Balance ◽  
Mass Balance ◽  
Hyporheic Zone ◽  
Low Flow ◽  
Extreme Weather Events ◽  
Spatial And Temporal Variability ◽  
Climate Change Scenarios ◽  
Ongoing Research ◽  
Drought Period ◽  
Headwater Catchment

Headwaters make up a large part of the global stream length. They are also especially sensitive to droughts, which affect the stream's water balance, chemistry, and ecology. Climate change scenarios predict an increasing frequency of extreme weather events. For streams, rivers, and their catchments, this implies a higher intensity and frequency of severer droughts and floods. It is likely that during drought streams depend to a significant extent on groundwater to maintain flow. This study contributes to ongoing research on the effects of drought on headwater catchments and the role of groundwater in the water balance of these systems. Monthly Radon (222Rn) measurements combined with mass balance calculations were used to quantify the spatial and temporal variability of groundwater influx to the Mähringsbach, a headwater catchment in northern Bavaria, Germany. Sampling was conducted in 2019 and 2020, a multi-year drought period, with 2019 being the seventh driest year since the start of records. Thus measurements covered a broad range of flow regimes (0.04 m3 s−1 to ~ 3 m3 s−1). 222Rn activities ranged between ~500 Bq m−3 and ~8,500 Bq m−3 in the headwater, while further downstream, the activities and variability in activities were lower (~500 Bq m−3 to ~2,000 Bq m−3). Results from the 222Rn mass balance showed that in the headwater reaches, the proportion of groundwater varied between 10 and 70 %, while further downstream, it ranged between only 0 and 30%. There was a clear negative correlation between river discharge and the proportion of groundwater inflow to the stream. Less than 10% of the total discharge was derived from groundwater during high flow conditions, while under low flow in the headwater reaches, it increased to 70%. We conclude that aquatic ecosystems in headwaters become increasingly dependent on groundwater during drought periods as a source of water. This dependency will increase in the summer months given current climate predictions. This knowledge should be used to develop, refine, and apply management strategies for streams and the important habitats located in stream sediments (hyporheic zone) under a changing climate.

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