scholarly journals Recent Eurasian river discharge to the Arctic Ocean in the context of longer-term dendrohydrological records

2007 ◽  
Vol 112 (G4) ◽  
pp. n/a-n/a ◽  
Author(s):  
G. M. MacDonald ◽  
K. V. Kremenetski ◽  
L. C. Smith ◽  
H. G. Hidalgo
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
The Arctic ◽  
The Arctic Ocean

scholarly journals Cryospheric Impacts of Soviet River Diversion Schemes

1984 ◽  
Vol 5 ◽  
pp. 61-68 ◽  
Author(s):  
T. Holt ◽  
P. M. Kelly ◽  
B. S. G. Cherry
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
River Discharge ◽  
Large Scale ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
The Arctic Ocean ◽  
The Impact

Soviet plans to divert water from rivers flowing into the Arctic Ocean have led to research into the impact of a reduction in discharge on Arctic sea ice. We consider the mechanisms by which discharge reductions might affect sea-ice cover and then test various hypotheses related to these mechanisms. We find several large areas over which sea-ice concentration correlates significantly with variations in river discharge, supporting two particular hypotheses. The first hypothesis concerns the area where the initial impacts are likely to which is the Kara Sea. Reduced riverflow is associated occur, with decreased sea-ice concentration in October, at the time of ice formation. This is believed to be the result of decreased freshening of the surface layer. The second hypothesis concerns possible effects on the large-scale current system of the Arctic Ocean and, in particular, on the inflow of Atlantic and Pacific water. These effects occur as a result of changes in the strength of northward-flowing gradient currents associated with variations in river discharge. Although it is still not certain that substantial transfers of riverflow will take place, it is concluded that the possibility of significant cryospheric effects and, hence, large-scale climate impact should not be neglected.

scholarly journals On the biogeochemical signature of the Lena River from its headwaters to the Arctic Ocean

2011 ◽  
Vol 8 (2) ◽  
pp. 2093-2143 ◽  
Author(s):  
I. P. Semiletov ◽  
I. I. Pipko ◽  
N. E. Shakhova ◽  
O. V. Dudarev ◽  
S. P. Pugach ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Arctic Ocean ◽  
River Discharge ◽  
Total Carbon ◽  
The Arctic ◽  
Time Shift ◽  
Laptev Sea ◽  
Lena River ◽  
The Arctic Ocean ◽  
The Laptev Sea

Abstract. The Lena River integrates biogeochemical signals from its vast drainage basin and its signal reaches far out over the Arctic Ocean. Transformation of riverine organic carbon into mineral carbon, and mineral carbon into the organic form in the Lena River watershed, can be considered a quasi-equilibrated processes. Increasing the Lena discharge causes opposite effects on total organic (TOC) and inorganic (TCO2) carbon: TOC concentration increases, while TCO2 concentration decreases. Significant inter-annual variability in mean values of TCO2, TOC, and their sum (TC) has been found. This variability is determined by changes in land hydrology which cause differences in the Lena River discharge, because a negative correlation may be found between TC in September and mean discharge in August (a time shift of about one month is required for water to travel from Yakutsk to the Laptev Sea). Total carbon entering the sea with the Lena discharge is estimated to be almost 10 Tg C y−1. The annual Lena River discharge of particulate organic carbon (POC) may be equal to 0.38 Tg (moderate to high estimate). If we instead accept Lisytsin's (1994) statement concerning the precipitation of 85–95% of total particulate matter (PM) (and POC) on the marginal "filter", then only about 0.03–0.04 Tg of POC reaches the Laptev Sea from the Lena River. The Lena's POC export would then be two orders of magnitude less than the annual input of eroded terrestrial carbon onto the shelf of the Laptev and East Siberian seas, which is about 4 Tg. The Lena River is characterized by relatively high concentrations of primary greenhouse gases: CO2 and dissolved CH4. During all seasons the river is supersaturated in CO2 compared to the atmosphere: up to 1.5–2 fold in summer, and 4–5 fold in winter. This results in a narrow zone of significant CO2 supersaturation in the adjacent coastal sea. Spots of dissolved CH4 in the Lena delta channels may reach 100 nM, but the CH4 concentration decreases to 5–20 nM towards the sea, which suggests only a minor role of riverborne export of CH4 for the East Siberian Arctic Shelf (ESAS) CH4 budget in coastal waters. Instead, the seabed appears to be the source that provides most of the CH4 to the Arctic Ocean.

scholarly journals Climate change and the Arctic hydrologic cycle as calculated by a global coupled atmosphere–ocean model

1995 ◽  
Vol 21 ◽  
pp. 91-95 ◽  
Author(s):  
James R. Miller ◽  
Gary L. Russell
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
Surface Air Temperature ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
Hydrologic Cycle ◽  
Transient Simulation ◽  
The Arctic ◽  
Glacial Ice ◽  
The Arctic Ocean

A global coupled atmosphere–ocean model is used to examine the hydrologic cycle of the Arctic Ocean. The model has a horizontal resolution of 4° × 5°, nine vertical layers in the atmosphere and 13 in the ocean. River discharge into the Arctic Ocean is included by allowing runoff from each continental grid box to flow downstream according to a specified direction file and a speed that depends on topography. A 74 year control simulation of the present climate is used to examine variability of the hydrologic cycle, including precipitation, sea ice, glacial ice and river discharge. A 74 year transient simulation in which atmospheric CO2increases each year at a compound rate оf 1% is then used to examine potential changes in the hydrologic cycle. Among these changes are a 4°C increase in mean annual surface air temperature in the Arctic Ocean, a decrease in ice cover which begins after 35 years, and increases in river discharge and cloud cover. There is little change in the net difference between precipitation and evaporation. Also in the transient simulation, glacial ice on Greenland decreases relative to the control.

scholarly journals Increasing River Discharge to the Arctic Ocean

Science ◽  
2002 ◽  
Vol 298 (5601) ◽  
pp. 2171-2173 ◽  
Author(s):  
B. J. Peterson
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
The Arctic ◽  
The Arctic Ocean

scholarly journals Unprecedented acceleration of winter discharge of Upper Yenisei River inferred from tree rings

2021 ◽  
Author(s):  
Irina Panyushkina ◽  
David M Meko ◽  
Alexander Shiklomanov ◽  
Richard D Thaxton ◽  
Vladimyr Myglan ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
Ring Width ◽  
Ocean Modeling ◽  
The Arctic ◽  
Yenisei River ◽  
South Siberia ◽  
The Arctic Ocean ◽  
The Yenisei River ◽  
The Impact

Abstract The Yenisei River is the largest contributor of freshwater and energy fluxes among all rivers draining to the Arctic Ocean. Modeling long-term variability of Eurasian runoff to the Arctic Ocean is complicated by the considerable variability of river discharge in time and space, and the monitoring constraints imposed by a sparse gauged-flow network and paucity of satellite data. We quantify tree growth response to river discharge at the upper reaches of the Yenisei River in Tuva, South Siberia. Two regression models built from eight tree-ring width chronologies of Larix sibirica are applied to reconstruct winter (Nov–Apr) discharge for the period 1784-1997 (214 years), and annual (Oct–Sept) discharge for the period 1701–2000 (300 years). The Nov–Apr model explains 52% of the discharge variance whereas Oct–Sept explains 26% for the calibration intervals 1927–1997 and 1927-2000, respectively. This new hydrological archive doubles the length of the instrumental discharge record at the Kyzyl gauge and resets the temporal background of discharge variability back to 1784. The reconstruction finds a remarkable 80% upsurge in winter flow over the last 25 years, which is unprecedented in the last 214 years. In contrast, annual discharge fluctuated normally for this system, with only a 7% increase over the last 25 years. Water balance modeling with CRU data manifests a significant discrepancy between decadal variability of the gauged flow and climate data after 1960. We discuss the impact on the baseflow rate change of both the accelerating permafrost warming in the discontinuous zone of South Siberia and widespread forest fires. The winter discharge accounts for only one-third of the annual flow, yet the persistent 25-year upsurge is alarming. This trend is likely caused by Arctic Amplification, which can be further magnified by increased winter flow delivering significantly more freshwater to the Kara Sea during the cold season.

scholarly journals Using Remotely Sensed Sea Surface Salinity and Colored Detrital Matter to Characterize Freshened Surface Layers in the Kara and Laptev Seas during the Ice-Free Season

2021 ◽  
Vol 13 (19) ◽  
pp. 3828
Author(s):  
Marta Umbert ◽  
Carolina Gabarro ◽  
Estrella Olmedo ◽  
Rafael Gonçalves-Araujo ◽  
Sebastien Guimbard ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
River Runoff ◽  
River Discharge ◽  
Active Material ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
The Arctic ◽  
Optical Data ◽  
Surface Salinity ◽  
The Arctic Ocean

The overall volume of freshwater entering the Arctic Ocean has been growing as glaciers melt and river runoff increases. Since 1980, a 20% increase in river runoff has been observed in the Arctic system. As the discharges of the Ob, Yenisei, and Lena rivers are an important source of freshwater in the Kara and Laptev Seas, an increase in river discharge might have a significant impact on the upper ocean circulation. The fresh river water mixes with ocean water and forms a large freshened surface layer (FSL), which carries high loads of dissolved organic matter and suspended matter into the Arctic Ocean. Optically active material (e.g., phytoplankton and detrital matter) are spread out into plumes, which are evident in satellite data. Russian river signatures in the Kara and Laptev Seas are also evident in recent SMOS Sea Surface Salinity (SSS) Arctic products. In this study, we compare the new Arctic+ SSS products, produced at the Barcelona Expert Center, with the Ocean Color absorption coefficient of colored detrital matter (CDM) in the Kara and Laptev Seas for the period 2011–2019. The SSS and CDM are found to be strongly negatively correlated in the regions of freshwater influence, with regression coefficients between −0.72 and −0.91 in the studied period. Exploiting this linear correlation, we estimate the SSS back to 1998 using two techniques: one assuming that the relationship between the CDM and SSS varies regionally in the river-influenced areas, and another assuming that it does not. We use the 22-year time-series of reconstructed SSS to estimate the interannual variability of the extension of the FSL in the Kara and Laptev Seas as well as their freshwater content. For the Kara and Laptev Seas, we use 32 and 28 psu as reference salinities, and 26 and 24 psu isohalines as FSL boundaries, respectively. The average FSL extension in the Kara Sea is 2089–2611 km2, with a typical freshwater content of 11.84–14.02 km3. The Laptev Sea has a slightly higher mean FSL extension of 2320–2686 km2 and a freshwater content of 10.15–12.44 km3. The yearly mean freshwater content and extension of the FSL, computed from SMOS SSS and Optical data, is (as expected) found to co-vary with in situ measurements of river discharge from the Arctic Great Rivers Observatory database, demonstrating the potential of SMOS SSS to better monitor the river discharge changes in Eurasia and to understand the Arctic freshwater system during the ice-free season.

scholarly journals Uncertainty in the impacts of projected climate change on the hydrology of a subarctic environment: Liard River Basin

2010 ◽  
Vol 7 (3) ◽  
pp. 3129-3157 ◽  
Author(s):  
R. Thorne
Keyword(s):  
Arctic Ocean ◽  
River Discharge ◽  
Annual Runoff ◽  
The Arctic ◽  
Climate Projections ◽  
Mountainous Regions ◽  
The Arctic Ocean ◽  
The Impact ◽  
Global Mean ◽  
Mackenzie River

Abstract. Freshwater inputs from the Mackenzie River into the Arctic Ocean contribute to the control of oceanic dynamics and sea ice cover duration. Half of the annual runoff from the Mackenzie River drains from mountainous regions, where the Liard River, with a drainage area of 275 000 km2, is especially influential. The impact of projected atmospheric warming on the discharge of the Liard River is unclear. Here, uncertainty in climate projections associated with GCM structure (2 °C prescribed warming) and magnitude of increases in global mean air temperature (1 to 6 °C) on the river discharge are assessed using SLURP, a well-tested hydrological model. Most climate projections indicate (1) warming in this subarctic environment that is greater than the global mean and (2) an increase in precipitation across the basin. These changes lead to an earlier spring freshet (1 to 12 days earlier), a decrease in summer runoff (up to 22%) due to enhanced evaporation, and an increase in autumn flow (up to 48%), leading to higher annual discharge and more freshwater input from the Liard River to the Arctic Ocean. All simulations project that the subarctic nival regime will be preserved in the future but the magnitude of changes in river discharge is highly uncertain (ranging from a decrease of 3% to an increase of 15% in annual runoff), due to differences in GCM projections of basin-wide temperature and precipitation.

scholarly journals Cryospheric Impacts of Soviet River Diversion Schemes

1984 ◽  
Vol 5 ◽  
pp. 61-68 ◽  
Author(s):  
T. Holt ◽  
P. M. Kelly ◽  
B. S. G. Cherry
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
River Discharge ◽  
Large Scale ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Ice Concentration ◽  
The Arctic Ocean ◽  
The Impact

Soviet plans to divert water from rivers flowing into the Arctic Ocean have led to research into the impact of a reduction in discharge on Arctic sea ice. We consider the mechanisms by which discharge reductions might affect sea-ice cover and then test various hypotheses related to these mechanisms. We find several large areas over which sea-ice concentration correlates significantly with variations in river discharge, supporting two particular hypotheses. The first hypothesis concerns the area where the initial impacts are likely to which is the Kara Sea. Reduced riverflow is associated occur, with decreased sea-ice concentration in October, at the time of ice formation. This is believed to be the result of decreased freshening of the surface layer. The second hypothesis concerns possible effects on the large-scale current system of the Arctic Ocean and, in particular, on the inflow of Atlantic and Pacific water. These effects occur as a result of changes in the strength of northward-flowing gradient currents associated with variations in river discharge. Although it is still not certain that substantial transfers of riverflow will take place, it is concluded that the possibility of significant cryospheric effects and, hence, large-scale climate impact should not be neglected.

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