scholarly journals Annual River Runoff Variations and Trends for the Andes Cordillera

2018 ◽  
Vol 19 (7) ◽  
pp. 1167-1189 ◽  
Author(s):  
Sebastian H. Mernild ◽  
Glen E. Liston ◽  
Christopher A. Hiemstra ◽  
Jacob C. Yde ◽  
Gino Casassa
Keyword(s):  
River Runoff ◽  
Annual Runoff ◽  
Spatiotemporal Variability ◽  
Modeling Tools ◽  
Ice Melt ◽  
The Andes ◽  
Glacier Ice ◽  
High Runoff ◽  
Over Time ◽  
Andes Cordillera

Abstract We analyzed modeled river runoff variations west of the Andes Cordillera’s continental divide for 1979/80–2013/14 (35 years). Our foci were annual runoff conditions, runoff origins (rain, snowmelt, and glacier ice), and runoff spatiotemporal variability. Low and high runoff conditions were defined as occurrences that fall outside the 10th (low values) and 90th (high values) percentile values of the period of record. SnowModel and HydroFlow modeling tools were used at 4-km horizontal grid increments and 3-h time intervals. NASA Modern-Era Retrospective Analysis for Research and Applications (MERRA) datasets were used as atmospheric forcing. This modeling system includes evaporation and sublimation from snow-covered surfaces, but it does not take into account evapotranspiration from bare and vegetation-covered soils and from river and lake surfaces. In general for the Andes Cordillera, the simulated runoff decreased before 1997 and increased afterward. This could be due to a model precipitation artifact in the MERRA forcing. If so, this artifact would influence the number of years with low runoff values, which decreased over time, while the number of high runoff values increased over time. For latitudes south of ~40°S, both the greatest decrease in the number of low runoff values and the greatest increase in high runoff values occurred. High runoff values averaged 84% and 58% higher than low values for nonglacierized and glacierized catchments, respectively. Furthermore, for glacierized catchments, 61% and 62% of the runoff originated from rain-derived runoff during low and high runoff extreme years, respectively; 28% and 30% from snowmelt-derived runoff; and 11% and 8% from glacier-ice-melt-derived runoff. As the results could be MERRA dependent, more work with other precipitation forcings and/or in situ measurements is needed to assess whether these are real runoff behaviors or artifacts.

scholarly journals Runoff Variability in the Scott River (SW Spitsbergen) in Summer Seasons 2012–2013 in Comparison with the Period 1986–2009

2016 ◽  
Vol 35 (3) ◽  
pp. 39-50 ◽  
Author(s):  
Łukasz Franczak ◽  
Waldemar Kociuba ◽  
Grzegorz Gajek
Keyword(s):  
River Runoff ◽  
Discharge Rate ◽  
High Variability ◽  
Flow Rates ◽  
Ice Melt ◽  
Glacier Ice ◽  
Runoff Variability ◽  
Daily Discharge ◽  
The Mean

Abstract River runoff variability in the Scott River catchment in the summer seasons 2012 and 2013 has been presented in comparison to the multiannual river runoff in 1986–2009. Both in particular seasons and in the analysed multiannual, high variability of discharge rate was recorded. In the research periods 2012–2013, a total of 11 952 water stages and 20 flow rates were measured in the analysed cross-section for the determination of 83 daylong discharges. The mean multiannual discharge of the Scott River amounted to 0.96 m3·s−1. The value corresponds to a specific runoff of 94.6 dm3·s−1·km2, and the runoff layer 937 mm. The maximum values of daily discharge amounted to 5.07 m3·s−1, and the minimum values to 0.002 m3·s−1. The highest runoff occurs in the second and third decade of July, and in the first and second decade of August. The regime of the river is determined by a group of factors, and particularly meteorological conditions affecting the intensity of ablation, and consequently river runoff volume. We found a significant correlation (0.60 in 2012 and 0.67 in 2013) between the air temperature and the Scott River discharge related to the Scott Glacier ice melt.

INFLUENCE OF LARGE-SCALE ATMOSPHERIC PROCESSES ON SEASONAL RUNOFF OF LARGE SIBERIAN RIVERS

2021 ◽  
pp. 36-47
Author(s):  
L. N. VASILEVSKAYA ◽  
◽  
I. A. LISINA ◽  
D. N. VASILEVSKII ◽  
◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
River Runoff ◽  
Large Scale ◽  
Annual Runoff ◽  
Spring Flood ◽  
Atmospheric Circulation Indices ◽  
Rate Of Increase ◽  
Circulation Indices ◽  
Seasonal Runoff ◽  
Kolyma River

Based on daily runoff volumes of four large Siberian rivers (the Ob, Yenisei, Lena, and Kolyma) for 1936-2018, the regime and changes in the total annual and seasonal runoff are analyzed. High synchronous and asynchronous correlations between monthly river runoff and atmospheric circulation indices of hemispheric and regional scales are revealed. In recent decades, the total annual runoff and its variations have increased (the rate of increase is most pronounced for the Kolyma River). A change in water content within a year is heterogeneous: weak positive trends are characteristic of the spring flood runoff and the summer-autumn period, and a significant increase occurred in the winter months. High correlations with a 1-8-month shift made it possible to identify the most informative regions, the atmospheric circulation over which makes a certain contribution to the variance of river runoff.

DATA RECOVERY OF ANNUAL RIVER RUNOFF IN THE SYRDARYA RIVER BASIN

2021 ◽  
Vol 100 (1) ◽  
pp. 17-26
Author(s):  
T. Kazakbayeva ◽  
Keyword(s):  
River Basin ◽  
River Runoff ◽  
Annual Runoff ◽  
Data Recovery ◽  
Base Period ◽  
Quantitative Estimates ◽  
Integral Curves ◽  
Analogue Method ◽  
Runoff Rate ◽  
Variability Index

The data recovery of the annual runoff was carried out and correlation dependences were obtained, which were used to calculate the runoff rate for each of the selected rivers in the Syrdariya river basin. Differential integral curves were constructed from the runoff data using the variability index. When restoring the missing data on the annual runoff, the river-analogue method was applied. The actual series of observations are given for a longterm period. The base period was chosen from 1960 to 2015. Quantitative estimates of the effectiveness of bringing the average values to a multi-year period are also provided.

Fe Skarn, Iron Oxide Cu-Au, and Manto Cu-(Ag) Deposits in the Andes Cordillera of Southwest Mendoza Province (34 -36 S), Argentina

2007 ◽  
Vol 16 (3-4) ◽  
pp. 233-265 ◽  
Author(s):  
M.B. Franchini ◽  
R.E. de Barrio ◽  
M.J. Pons ◽  
I.B. Schalamuk ◽  
F.J. Rios ◽  
...  
Keyword(s):  
Iron Oxide ◽  
The Andes ◽  
Andes Cordillera

scholarly journals Data-driven catchment classification: application to the PUB problem

2011 ◽  
Vol 8 (1) ◽  
pp. 391-427 ◽  
Author(s):  
M. Di Prinzio ◽  
A. Castellarin ◽  
E. Toth
Keyword(s):  
Cross Validation ◽  
Principal Component ◽  
Annual Runoff ◽  
Data Driven ◽  
Spatiotemporal Variability ◽  
Ungauged Basins ◽  
Streamflow Prediction ◽  
Streamflow Regime ◽  
Predictions In Ungauged Basins ◽  
Unsupervised Neural Networks

Abstract. Objective criteria for catchment classification are identified by the scientific community among the key research topics for improving the interpretation and representation of the spatiotemporal variability of streamflow. A promising approach to catchment classification makes use of unsupervised neural networks (Self Organising Maps, SOM's), which organise input data through non-linear techniques depending on the intrinsic similarity of the data themselves. Our study considers ~300 Italian catchments scattered nationwide, for which several descriptors of the streamflow regime and geomorphoclimatic characteristics are available. We qualitatively and quantitatively compare in the context of PUB (Prediction in Ungauged Basins) a reference classification, RC, with four alternative classifications, AC's. RC was identified by using indices of the streamflow regime as input to SOM, whereas AC's were identified on the basis of catchment descriptors that can be derived for ungauged basins. One AC directly adopts the available catchment descriptors as input to SOM. The remaining AC's are identified by applying SOM to two sets of derived variables obtained by applying Principal Component Analysis (PCA, second AC) and Canonical Correlation Analysis (CCA, third and fourth ACs) to the available catchment descriptors. First, we measure the similarity between each AC and RC. Second, we use AC's and RC to regionalize several streamflow indices and we compare AC's with RC in terms of accuracy of streamflow prediction. In particular, we perform an extensive cross-validation to quantify nationwide the accuracy of predictions in ungauged basins of mean annual runoff, mean annual flood, and flood quantiles associated with given exceedance probabilities. Results of the study show that CCA can significantly improve the effectiveness of SOM classifications for the PUB problem.

The «rainfall-runoff» system and its long-term fluctuations in the Siverskyi Donets River Basin (Ukraine)

2021 ◽  
Author(s):  
Hanna Bolbot ◽  
Vasyl Grebin
Keyword(s):  
Climate Change ◽  
Water Resources ◽  
River Basin ◽  
Air Temperature ◽  
River Runoff ◽  
Annual Runoff ◽  
Annual Precipitation ◽  
Spring Flood ◽  
Current Period

<p>The current patterns estimation of the water regime under climate change is one of the most urgent tasks in Ukraine and the world. Such changes are determined by fluctuations in the main climatic characteristics - precipitation and air temperature, which are defined the value of evaporation. These parameters influence on the annual runoff distribution and long-term runoff fluctuations. In particular, the annual precipitation redistribution is reflected in the corresponding changes in the river runoff.<br>The assessment of the current state and nature of changes in precipitation and river runoff of the Siverskyi Donets River Basin was made by comparing the current period (1991-2018) with the period of the climatological normal (1961-1990).<br>In general, for this area, it was defined the close relationship between the amount of precipitation and the annual runoff. Against the background of insignificant (about 1%) increase of annual precipitation in recent decades, it was revealed their redistribution by seasons and separate months. There is a decrease in precipitation in the cold period (November-February). This causes (along with other factors) a decrease in the amount of snow and, accordingly, the spring flood runoff. There are frequent cases of unexpressed spring floods of the Siverskyi Donets River Basin. The runoff during March-April (the period of spring flood within the Ukrainian part of the basin) decreased by almost a third.<br>The increase of precipitation during May-June causes a corresponding (insignificant) increase in runoff in these months. The shift of the maximum monthly amount of precipitation from May (for the period 1961-1990) to June (in the current period) is observed.<br>There is a certain threat to water supply in the region due to the shift in the minimum monthly amount of precipitation in the warm period from October to August. Compared with October, there is a higher air temperature and, accordingly, higher evaporation in August, which reduces the runoff. Such a situation is solved by rational water resources management of the basin. The possibility of replenishing water resources in the basin through the transfer runoff from the Dnieper (Dnieper-Siverskyi Donets channel) and the annual runoff redistribution in the reservoir system causes some increase in the river runoff of summer months in recent decades. This is also contributed by the activities of the river basin management structures, which control the maintenance water users' of minimum ecological flow downstream the water intakes and hydraulic structures in the rivers of the basin.<br>Therefore, in the period of current climate change, the annual runoff distribution of the Siverskyi Donets River Basin has undergone significant changes, which is related to the annual precipitation redistribution and anthropogenic load on the basin.</p>

scholarly journals Supraglacial debris-transport variability over time: examples from Switzerland and Iceland

1996 ◽  
Vol 22 ◽  
pp. 181-186 ◽  
Author(s):  
W.B. Whalley ◽  
C.F. Palmer ◽  
S.J. Hamilton ◽  
D. Kitchen
Keyword(s):  
19Th Century ◽  
Little Ice Age ◽  
Ice Age ◽  
Debris Transport ◽  
Actual Volume ◽  
Glacier Ice ◽  
Rock Glaciers ◽  
Slow Moving ◽  
The 19Th Century ◽  
Over Time

The volume of debris in the left-lateral, Little Ice Age (LIA:AD1550–1850) moraine of the Feegletscher, Valais, Switzerland was compared with the actual volume being transported currently by the glacier. The latter is smaller by a factor of about two. In Tröllaskagi, north Iceland, a surface cover of debris on top of a very slow moving glacier ice mass (glacier noir, rock glacier) has been dated by lichenometry. The age of the oldest part is commensurate with LIA moraines in the area. Knowing the volume of debris of a given age allows an estimate of the debris supply to the glacier in a given time. Again, there appears to have been a significant reduction in debris to the glacier since the turn of the 19th century. Debris input in the early LIA seems to have been particularly copious and this may be important in the formation of some glacier depositional forms such as rock glaciers.

scholarly journals Artificially Induced Thermokarst in Active Glacier Ice: An Example from North-West British Columbia, Canada

1977 ◽  
Vol 18 (80) ◽  
pp. 437-444
Author(s):  
N. Eyles ◽  
R. J. Rogerson
Keyword(s):  
Waste Water ◽  
British Columbia ◽  
Review Of The Literature ◽  
North West ◽  
Ice Melt ◽  
Basal Ice ◽  
Glacier Ice

AbstractWarm waste water, at 30°C, has been discharged from a copper concentrater on to the active terminal ice of Berendon Glacier, British Columbia, since 1970. As a result, rapid basal ice melt causes the formation of caverns and subsequent collapse features referred to as glacier thermokarst. A review of the literature reveals that such features have been described elsewhere from active ice, and the usual conditions assumed for the development of glacier thermokarst (stagnant, heavily debris-covered ice) should be redefined to include these examples.

scholarly journals The Dynamics of Bird Diversity in the New World

2020 ◽  
Vol 69 (6) ◽  
pp. 1180-1199 ◽  
Author(s):  
Antonin Machac
Keyword(s):  
Species Richness ◽  
New World ◽  
Dominant Role ◽  
Bird Diversity ◽  
Biodiversity Hotspots ◽  
Relative Importance ◽  
Diversification Rates ◽  
The Andes ◽  
The Rich ◽  
Over Time

Abstract Three prominent explanations have been proposed to explain the dramatic differences in species richness across regions and elevations, (i) time for speciation, (ii) diversification rates, and (iii) ecological limits. But the relative importance of these explanations and, especially, their interplay and possible synthesis remain largely elusive. Integrating diversification analyses, null models, and geographic information systems, I study avian richness across regions and elevations of the New World. My results reveal that even though the three explanations are differentially important (with ecological limits playing the dominant role), each contributes uniquely to the formation of richness gradients. Further, my results reveal the likely interplay between the explanations. They indicate that ecological limits hinder the diversification process, such that the accumulation of species within a region gradually slows down over time. Yet, it does not seem to converge toward a hard ceiling on regional richness. Instead, species-rich regions show suppressed, but continued, diversification, coupled with signatures of possible competition (esp. Neotropical lowlands). Conversely, species-poor, newly-colonized regions show fast diversification and weak to no signs of competition (esp. Nearctic highlands). These results held across five families of birds, across grid cells, biomes, and elevations. Together, my findings begin to illuminate the rich, yet highly consistent, interplay of the mechanisms that together shape richness gradients in the New World, including the most species-rich biodiversity hotspots on the planet, the Andes and the Amazon. [Biogeography; community; competition; macroevolution; phylogenetics; richness gradient.]

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