کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4577209 1630004 2012 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Quantifying the effects of glacier conduit geometry and recharge on proglacial hydrograph form
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
پیش نمایش صفحه اول مقاله
Quantifying the effects of glacier conduit geometry and recharge on proglacial hydrograph form
چکیده انگلیسی

SummaryThe configuration of glacier hydrological systems is often inferred from proxy data, such as hydrographs, that are collected in proglacial streams. Seasonal changes in the peakedness of hydrographs are thought to reflect changes in the configuration of the subglacial drainage system. However, the amount of information that proglacial hydrographs contain about drainage system configurations depends critically on the degree to which the drainage systems modify recharge hydrographs. If the drainage system does not modify recharge hydrographs, then proglacial hydrographs primarily reflect the recharge conditions produced by supraglacial inputs. Here, we develop a theoretical framework to determine the circumstances under which glacier drainage systems can modify recharge hydrographs and the circumstances under which recharge pulses pass through glaciers unchanged. We address the capability of single conduits, simple arborescent conduit networks, and linked cavity systems to modify diurnal recharge pulses. Simulations of discharge through large sets of such systems demonstrate that, unless large reservoirs or significant constrictions are present, the discharge hydrographs of simple glacial conduit systems are nearly identical to their recharge hydrographs. Conduit systems tend not to modify hydrographs because the changes in storage within englacial and subglacial conduit networks on short time scales are typically small compared to their ability to transmit water. This finding suggests that proglacial hydrographs reflect a variety of factors, including surface melt rate, surface water transfer, and subglacial water transfer. In many cases the influence of suglacial processes may be relatively minor. As a result, the evolution of proglacial hydrographs cannot be used unambiguously to infer changes in the structure or efficiency of englacial or subglacial hydrological systems, without accurate knowledge of the nature of the recharge hydrograph driving the flow.


► Proglacial hydrographs are poor indicators of subglacial drainage configuration.
► Recharge, rather than system geometry, often determines hydrograph form.
► Hydrograph modulation can be characterized using a hydraulic response time.
► We advance a conceptual model for studying glacial recharge–discharge relations.
► Quantifying recharge is important for interpreting proglacial time series.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Hydrology - Volumes 414–415, 11 January 2012, Pages 59–71
نویسندگان
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