scholarly journals Tropical glacier meltwater contribution to stream discharge: a case study in the Cordillera Blanca, Peru

2003 ◽  
Vol 49 (165) ◽  
pp. 271-281 ◽  
Author(s):  
Bryan G. Mark ◽  
Geoffrey O. Seltzer
Keyword(s):  
Stream Flow ◽  
Cordillera Blanca ◽  
Stream Discharge ◽  
Glacier Meltwater ◽  
Glacier Melt ◽  
The Pacific ◽  
Glacier Melting ◽  
Glacier Ice ◽  
Stream Geochemistry ◽  
Annual Discharge

AbstractDischarge measurements, climate observations and hydrochemical samples gathered monthly (1998/99) in the Yanamarey and Uruashraju glacier-fed catchments of the Cordillera Blanca, Peru, permit an analysis of the glacier meltwater contribution to stream-flow. These glacier catchments feed the Río Santa, which discharges into the Pacific Ocean. Based on a water-balance computation, glacier melt contributes an estimated 35% of the average discharge from the catchments. For comparison, a volumetric end-member mixing model of oxygen isotopes shows glacier melt contributes 30–45% to the total annual discharge. Based on stream geochemistry, discharge from the Yanamarey glacier catchment provides 30% of the annual volume discharged from the Querococha watershed, which is <10% glacierized. By analogy, the larger Río Santa watershed, also <10% glacierized, receives at least 12% of its annual discharge from melting glacier ice. Tributary watersheds to the Río Santa with larger fractions of glacier cover have less variable runoff and enhanced discharge, demonstrating that the glaciers effectively buffer stream discharge seasonally. With continued glacier melting, stream-flow will likely become more variable, and there will be less dry-season runoff.

scholarly journals Glacier melting and precipitation trends detected by surface area changes in Himalayan ponds

2016 ◽  
Vol 10 (4) ◽  
pp. 1433-1448 ◽  
Author(s):  
Franco Salerno ◽  
Sudeep Thakuri ◽  
Nicolas Guyennon ◽  
Gaetano Viviano ◽  
Gianni Tartari
Keyword(s):  
Surface Area ◽  
Landsat Imagery ◽  
High Elevation ◽  
Maximum Temperature ◽  
Study Region ◽  
Glacier Shrinkage ◽  
Glacier Melt ◽  
Glacier Melting ◽  
Glacier Ice ◽  
Climatic Time Series

Abstract. Climatic time series for high-elevation Himalayan regions are decidedly scarce. Although glacier shrinkage is now sufficiently well described, the changes in precipitation and temperature at these elevations are less clear. This contribution shows that the surface area variations of unconnected glacial ponds, i.e. ponds not directly connected to glacier ice, but that may have a glacier located in their hydrological basin, can be considered as suitable proxies for detecting past changes in the main hydrological components of the water balance. On the south side of Mt Everest, glacier melt and precipitation have been found to be the main drivers of unconnected pond surface area changes (detected mainly with Landsat imagery). In general, unconnected ponds have decreased significantly by approximately 10 &amp;pm; 5 % in terms of surface area over the last 50 years (1963–2013 period) in the study region. Here, an increase in precipitation occurred until the mid-1990s followed by a decrease until recent years. Until the 1990s, glacier melt was constant. An increase occurred in the early 2000s, while a declining trend in maximum temperature has caused a reduction in the glacier melt during recent years.

scholarly journals Supraglacial Re-Sedimentation from Melt-Water Streams on to Snow Overlying Glacier Ice, Sylgjujökull, West Vatnajökull, Iceland

1982 ◽  
Vol 28 (99) ◽  
pp. 365-375 ◽  
Author(s):  
Julian A. Dowdeswell
Keyword(s):  
Grain Size ◽  
Volcanic Ash ◽  
Marginal Zone ◽  
Suspended Load ◽  
Sediment Deposition ◽  
Stream Discharge ◽  
Glacier Terminus ◽  
Melt Water ◽  
Glacier Ice ◽  
The Relationship

AbstractSediment deposition on to snow overlying glacier ice occurs in a marginal zone extending 200–300 m up-glacier from the terminus of Sylgjujökull. Debris on ice above the marginal snow zone comes from debris-rich layers, and 85% of this debris falls between 1 and 4ϕ, the characteristic grain-size of volcanic ash within Icelandic glaciers. The ash is transported down-glacier as suspended load in melt-water streams at concentrations between 61 and 430 mg l−1, and loads from 0.2 to 32.7 g s−1. A diurnal hysteretic loop is present in the relationship between suspended sediment and discharge for one stream.Supraglacial streams flow from relatively impermeable ice on to more permeable snow near the glacier terminus. As they move across the snow, stream discharge (up to 0.1 m3s−1on ice) is reduced and debris is re-sedimented as linear debris trains 1–3 cm thick and orientated orthogonal to the glacier margin. Since sediment deposition reduces the permeability of the snow substrate, the debris trains are successively extended across the snow cover at rates of up to 36.5 m d−1. If the debris is then let down on to glacier ice, linear dirt-cone assemblages may be produced. Re-sedimented debris trains are of little stratigraphic significance if deposited pro-glacially.

Remote semiautomatic instrumentation for intermittent streamflow measurement and suspended sediment sampling

1984 ◽  
Vol 11 (4) ◽  
pp. 993-996 ◽  
Author(s):  
John L. Honsaker ◽  
Ian A. Campbell ◽  
R. B. Bryan
Keyword(s):  
Solar Cells ◽  
Key Words ◽  
Suspended Sediment ◽  
Stream Flow ◽  
Intermittent Stream ◽  
Battery Charging ◽  
Stream Discharge ◽  
Ephemeral Channels ◽  
Solar Battery ◽  
Sediment Sampling

Stream discharge and suspended sediment in ephemeral channels are measured by battery-powered instruments adapted for control by detection of rainfall. Solar cells recharge batteries between flow events. Key words: instruments, ephemeral channel, intermittent stream flow, suspended sediment, rain-activated, solar battery charging.

scholarly journals Monitoring Tropical Debris Covered Glacier Dynamics from High Resolution Unmanned Aerial Vehicle Photogrammetry, Cordillera Blanca, Peru

2017 ◽  
Author(s):  
Oliver Wigmore ◽  
Bryan Mark
Keyword(s):  
High Resolution ◽  
Low Cost ◽  
Glacier Change ◽  
Glacier Surface ◽  
Cordillera Blanca ◽  
Glacier Tongue ◽  
Mountain Glaciers ◽  
Quality Of Water ◽  
Glacier Ice ◽  
Proglacial Lake

Abstract. The glaciers of the Cordillera Blanca Peru are rapidly retreating as a result of climate change, altering timing, quantity and quality of water available to downstream users. Furthermore, increases in the number and size of proglacial lakes associated with these melting glaciers is increasing potential exposure to glacier lake outburst floods (GLOFs). Understanding how these glaciers are changing and their connection to proglacial lake systems is thus of critical importance. Most satellite data are too coarse for studying small mountain glaciers and are often affected by cloud cover, while traditional airborne photogrammetry and LiDAR are costly. Recent developments have made Unmanned Aerial Vehicles (UAVs) a viable and potentially transformative method for studying glacier change at high spatial resolution, on demand and at relatively low cost. Using a custom designed hexacopter built for high altitude (4000–6000 m asl) operation we completed repeat aerial surveys (2014 and 2015) of the debris covered Llaca glacier tongue and proglacial lake system. High resolution orthomosaics (5 cm) and digital elevation models (DEMs) (10 cm) were produced and their accuracy assessed. Analysis of these datasets reveals highly heterogeneous patterns of glacier change. The most rapid areas of ice loss were associated with exposed ice cliffs and melt water ponds on the glacier surface. Considerable subsidence and low surface velocities were also measured on the sediments within the pro-glacial lake, indicating the presence of extensive regions of buried ice and continued connection to the glacier tongue. Only limited horizontal retreat of the glacier tongue was observed, indicating that simple measurements of changes in aerial extent are inadequate for understanding actual changes in glacier ice quantity.

scholarly journals Data assimilation in integrated hydrological modelling in the presence of observation bias

2015 ◽  
Vol 12 (8) ◽  
pp. 8131-8173 ◽  
Author(s):  
J. Rasmussen ◽  
H. Madsen ◽  
K. H. Jensen ◽  
J. C. Refsgaard
Keyword(s):  
Parameter Estimation ◽  
Kalman Filter ◽  
Stream Flow ◽  
Groundwater Modeling ◽  
Optimal Parameter ◽  
Estimation Methods ◽  
Model Parameters ◽  
Stream Discharge ◽  
Groundwater Head ◽  
Observation Bias

Abstract. The use of bias-aware Kalman filters for estimating and correcting observation bias in groundwater head observations is evaluated using both synthetic and real observations. In the synthetic test, groundwater head observations with a constant bias and unbiased stream discharge observations are assimilated in a catchment scale integrated hydrological model with the aim of updating stream discharge and groundwater head, as well as several model parameters relating to both stream flow and groundwater modeling. The Colored Noise Kalman filter (ColKF) and the Separate bias Kalman filter (SepKF) are tested and evaluated for correcting the observation biases. The study found that both methods were able to estimate most of the biases and that using any of the two bias estimation methods resulted in significant improvements over using a bias-unaware Kalman Filter. While the convergence of the ColKF was significantly faster than the convergence of the SepKF, a much larger ensemble size was required as the estimation of biases would otherwise fail. Real observations of groundwater head and stream discharge were also assimilated, resulting in improved stream flow modeling in terms of an increased Nash-Sutcliffe coefficient while no clear improvement in groundwater head modeling was observed. Both the ColKF and the SepKF tended to underestimate the biases, which resulted in drifting model behavior and sub-optimal parameter estimation, but both methods provided better state updating and parameter estimation than using a bias-unaware filter.

Analysis of Discharge Variability in the Naryn River Basin, Kyrgyzstan

2020 ◽  
Vol 3 (2) ◽  
pp. 90-106
Author(s):  
Merim Pamirbek K ◽  
Chen X ◽  
Sainath Aher ◽  
Alamanov Salamat ◽  
Pragati Deshmukh ◽  
...  
Keyword(s):  
Land Use ◽  
Flow Regime ◽  
River Basin ◽  
Stream Flow ◽  
Negative Relationship ◽  
Exceedance Probability ◽  
Climatic Fluctuations ◽  
Discharge Data ◽  
Spatio Temporal ◽  
Annual Discharge

Changing climate and land-use practices influencing the natural stream flow processes in the Naryn river basin of Kyrgyzstan. Variations in stream flow regime over 33-years (1980 to 2012) were investigated using daily discharge data of three hydro-stations (Naryn, Ych-Terek and Uzunakmat), located in the Naryn River Basin. Mean monthly discharge (MMD), mean annual discharge (MAD), standard deviation (SD) and coefficient of variation (CV) were calculated to know the spatio-temporal variability. Similarly, Pearson’s correlation coefficient (r) was used to know the relationship between discharge and rainfall. Advanced time-series graph, exceedance probability and frequency distribution were computed using Hydrognomon (V.4.0.3) software to observe the variability and trends in discharge. The results from statistical calculations and software-based computations highlight the monthly, annual, and long term spatio-temporal discharge variability, extreme events, distribution and changes in stream flow records. This study preciously creates the frequency and trends of seasonal discharge, annual discharge cycle, and range of highest and lowest discharge flows. The weak and negative relationship (-0.2121, -0.4238) between rainfall and discharge propose for more investigation of climatic parameters and the topography of Tian Shan Mountain perhaps influencing discharge variability due to melting of glacier at high altitude. The flow regime of the Naryn river basin over the past 33-years perhaps changed due to climatic fluctuations, with the seasonal snowmelt timing (Post-Spring, Summer, Pri-Autumn), precipitations period (March-October), and large-scale land-use alterations.

scholarly journals Evaluation of an ice ablation model to estimate the contribution of melting glacier ice to annual discharge in the Nepal Himalaya

2013 ◽  
Vol 49 (9) ◽  
pp. 5117-5133 ◽  
Author(s):  
Adina E. Racoviteanu ◽  
Richard Armstrong ◽  
Mark W. Williams
Keyword(s):  
Nepal Himalaya ◽  
Glacier Ice ◽  
Annual Discharge ◽  
Ablation Model
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