Groundwater Fluxes Across Interfaces (2004) / Chapter Skim
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3 Interactions of Groudwater with Climate
3 Interactions of Groudwater with Climate
Pages 32-41
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From page 32... ...
This is particularly true for northern peatiands. The location of the water table determines whether the peat is subjected to aerobic or anaerobic decomposition rates, which are substantially different, and the subsequent release of methane and carbon dioxide." This chapter focuses on three topics: how climate affects groundwater fluxes, how groundwater fluxes affect climate, and how groundwater storage may have potential to indirectly affect the composition of the atmosphere, especially greenhouse gasses.
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From page 33... ...
In more recent times and at shorter time scales, climate variability and change also affect rates of grounowater recharge and discharge. For example, a rising water table may increase the near-surface soil moisture and streamflow, causing major changes in surface vegetation and ecosystems, in the extreme by creating or expanding wetlands and thereby affecting surface processes that influence recharge/discharge rates.
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From page 34... ...
suggests that groundwater may play an important role in the interannual and decadal-scale dynamics of lake levels through stream-aquifer interaction and groundwater discharge. Deep groundwater upwells and discharges to the low end of streams before entering the Great Salt Lake (GSL)
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From page 35... ...
FIGURE 3-1 The spectrum for the historical record of the Great Salt Lake produced from bimonthly volume time series 1847-1997. The labeled, filled circles on the graph represent probable signals above or at the upper range of the noise envelope.
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From page 36... ...
At high elevation, oscillation is tightly bound (i.e., monthly runoff is closely correlated win monthly precipitation and temperature) , reflecting the influence of seasonal conditions, while the low-elevation oscillation for P_T_Q is smeared out, representing the dampening effect of upwelling groundwater.
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From page 37... ...
using a hydrologic model of groundwater-surface calibrated using a modern historical records of hydrologic stresses within the Shingobee watershed in Northern Minnesota. For influence of climate variability on groundwater more recently, lake shore reconstruction through historical data bases can provide important information when linked to historical climate variability.
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From page 38... ...
permit measurement of vertical displacements of the land surface that can be directly indicative of subsurface pressure changes and/or changing groundwater loads. Altimetry may also prove useful for synoptic monitoring of surface-water levels that can be indicative of changes in either discharge or groundwater storage, depending on hydrogeologic framework.
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From page 39... ...
Soil moisture, through its influence on the partitioning of heat and moisture fluxes at the land surface, provides potentially important feedbacks affecting continental precipitation and temperatures by modulating the Bowen ratio and (on climate time scales) vegetation land cover with its effects on albedo and roughness of land surface, which in turn modulate the forms and intensities of heat and momentum fluxes into the atmosphere on a variety of time scales.
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From page 40... ...
EFFECTS ON ATMOSPHERIC COMPOSITION Atmospheric composition determines the atmospheric radiation balance, which determines climate. To the extent that groundwater systems affect atmospheric composition, they will also influence global climate.
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From page 41... ...
In dry places where the water table drops because of the lack of recharge and evaporation, dissolved carbon can also be sequestered as precipitates in the soil zone. The simple mass estimates above suggest that carbon sequestering in groundwater recharge may play an important role in the global cycling of carbon at a time scale important to climate change.
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