scholarly journals Influence of multidecadal variability on high and low flows: the case of the Seine basin

2020 ◽  
Vol 24 (4) ◽  
pp. 1611-1631
Author(s):  
Rémy Bonnet ◽  
Julien Boé ◽  
Florence Habets
Keyword(s):  
Large Scale ◽  
Hydrological Modeling ◽  
Spring Precipitation ◽  
Seine River ◽  
River Flows ◽  
Multidecadal Variability ◽  
Low Flows ◽  
The North ◽  
Hydrological Variability

Abstract. The multidecadal hydroclimate variations of the Seine basin since the 1850s are investigated. Given the scarcity of long-term hydrological observations, a hydrometeorological reconstruction is developed based on hydrological modeling and a method that combines the results of a downscaled long-term atmospheric reanalysis and local observations of precipitation and temperature. This method improves previous attempts and provides a realistic representation of daily and monthly river flows. This new hydrometeorological reconstruction, available over more than 150 years while maintaining fine spatial and temporal resolutions, provides a tool to improve our understanding of the multidecadal hydrological variability in the Seine basin, as well as its influence on high and low flows. This long-term reconstruction allows analysis of the strong multidecadal variations of the Seine river flows. The main hydrological mechanisms at the origin of these variations are highlighted. Spring precipitation plays a central role by directly influencing not only the multidecadal variability in spring flows but also soil moisture and groundwater recharge, which then regulate summer river flows. These multidecadal hydroclimate variations in the Seine basin are driven by anomalies in large-scale atmospheric circulation, which themselves appear to be influenced by sea surface temperature anomalies over the North Atlantic and the North Pacific. The multidecadal hydroclimate variations also influence high and low flows over the last 150 years. The analysis of two particularly severe historical droughts, the 1921 and the 1949 events, illustrates how long-term hydroclimate variations may impact short-term drought events, particularly through groundwater–river exchanges. The multidecadal hydroclimate variations described in this study, probably of internal origin, could play an important role in the evolution of water resources in the Seine basin in the coming decades. It is therefore essential to take the associated uncertainties into account in future projections.

scholarly journals Influence of multidecadal hydroclimate variations on hydrological extremes: the case of the Seine basin

2019 ◽  
Author(s):  
Rémy Bonnet ◽  
Julien Boé ◽  
Florence Habets
Keyword(s):  
Soil Moisture ◽  
Large Scale ◽  
North Atlantic Ocean ◽  
North Pacific Ocean ◽  
Seine River ◽  
River Flows ◽  
The North ◽  
Hydroclimate Variability ◽  
Extreme Hydrological Events

Abstract. The multidecadal hydroclimate variations of the Seine basin since the 1850s are investigated. Given the scarcity of long term observations of hydrological variables, a hydrometeorological reconstruction is developed based on an method that combines the results of a downscaled long-term atmospheric reanalysis and local observations of precipitation and temperature. This method improves the representation of daily flows as well as at longer time steps. This reconstruction provide therefore an interesting tool to study the multidecadal hydroclimate variability of the Seine basin, as well as its possible influence on extreme hydrological events. Based on this reconstruction, it is shown that the Seine river flows, groundwater and soil moisture, have been influenced by multidecadal variations from the 1850s. Spring precipitations play a central role by directly influencing the multidecadal variability of spring flows, but also soil moisture and groundwater recharge, which then modulate summer river flows. Groundwater controls a large part of the multidecadal variations in river flows, particularly in summer and fall. These hydroclimate variations seem to influence extreme hydrological events. The positive multidecadal phases indeed appear to be more conducive to flooding, with twice as many flood days as in the negative phases while the negative multidecadal phases seems to influenced the droughts intensity. These hydroclimate variations over the Seine basin are driven by anomalies in large scale atmospheric circulations, which themselves appear to be influenced by sea surface temperature anomalies over of the North Atlantic Ocean and the North Pacific Ocean.

Observed Trends in Canada’s Climate and Influence of Low-Frequency Variability Modes

2015 ◽  
Vol 28 (11) ◽  
pp. 4545-4560 ◽  
Author(s):  
L. A. Vincent ◽  
X. Zhang ◽  
R. D. Brown ◽  
Y. Feng ◽  
E. Mekis ◽  
...  
Keyword(s):  
Snow Cover ◽  
Large Scale ◽  
Low Frequency ◽  
Surface Air Temperature ◽  
Spring Precipitation ◽  
The North ◽  
Temperature And Precipitation ◽  
Low Frequency Variability ◽  
Hydroclimatic Variables

Abstract Trends in Canada’s climate are analyzed using recently updated data to provide a comprehensive view of climate variability and long-term changes over the period of instrumental record. Trends in surface air temperature, precipitation, snow cover, and streamflow indices are examined along with the potential impact of low-frequency variability related to large-scale atmospheric and oceanic oscillations on these trends. The results show that temperature has increased significantly in most regions of Canada over the period 1948–2012, with the largest warming occurring in winter and spring. Precipitation has also increased, especially in the north. Changes in other climate and hydroclimatic variables, including a decrease in the amount of precipitation falling as snow in the south, fewer days with snow cover, an earlier start of the spring high-flow season, and an increase in April streamflow, are consistent with the observed warming and precipitation trends. For the period 1900–2012, there are sufficient temperature and precipitation data for trend analysis for southern Canada (south of 60°N) only. During this period, temperature has increased significantly across the region, precipitation has increased, and the amount of precipitation falling as snow has decreased in many areas south of 55°N. The results also show that modes of low-frequency variability modulate the spatial distribution and strength of the trends; however, they alone cannot explain the observed long-term trends in these climate variables.

Landscape development in western and central Dronning Maud Land, East Antarctica

2001 ◽  
Vol 13 (3) ◽  
pp. 302-311 ◽  
Author(s):  
Jens-Ove Näslund
Keyword(s):  
Large Scale ◽  
High Elevation ◽  
Continental Margins ◽  
Landscape Development ◽  
Ice Streams ◽  
The North ◽  
Ice Stream ◽  
Dronning Maud Land ◽  
Break Up

Large-scale bedrock morphology and relief of two key areas, the Jutulsessen Nunatak and the Jutulstraumen ice stream are used to discuss glascial history and landscape development in western and central Dronning Maud Land, Antarctica. Two main landform components were identified: well-defined summit plateau surfaces and a typical alpine glacial landscape. The flat, high-elevation plateau surfaces previously were part of one or several continuous regional planation surfaces. In western Dronning Maud Land, overlying cover rocks of late Palaeozoic age show that the planation surface(s) existed in the early Permian, prior to the break-up of Gondwana. A well-develoment escarpment, a mega landform typical for passive continental margins, bounds the palaeosurface remnants to the north for a distance of at least 700 km. The Cenozoic glacial landscape, incised in the palaeosurface and escarpment, is exemplified by Jutulsessen Nunatak, where a c. 1.2 km deep glacial valley system is developed. However, the prominent Penck-Jutul Trough represents some of the deepest dissection of the palaeosurface. This originally tectonic feature is today occupied by the Jutulstraumen ice stream. New topographic data show that the bed of the Penck-Jutul Trough is situated 1.9±1.1 km below sea level, and that the total landscape relief is at least 4.2 km. Today's relief is a result of several processes, including tectonic faulting, subaerial weathering, fluvial erosion, and glacial erosion. It is probable that erosion by ice streams has deepened the tectonic troughs of Dronning Maud Land since the onset of ice sheet glaciation in the Oligocene, and continues today. An attempt is made to identify major events in the long-term landscape development of Dronning Maud Land, since the break-up of the Gondwana continent.

scholarly journals Climate impacts on multidecadal <i>p</i>CO<sub>2</sub> variability in the North Atlantic: 1948–2009

2015 ◽  
Vol 12 (17) ◽  
pp. 15223-15244
Author(s):  
M. L. Breeden ◽  
G. A. McKinley
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Dissolved Inorganic Carbon ◽  
Atlantic Multidecadal Oscillation ◽  
Climate Impacts ◽  
Co2 Uptake ◽  
Subpolar Gyre ◽  
The North ◽  
The North Atlantic

Abstract. The North Atlantic is the most intense region of ocean CO2 uptake. Here, we investigate multidecadal timescale variability of the partial pressure CO2 (pCO2) that is due to the natural carbon cycle using a regional model forced with realistic climate and pre-industrial atmospheric pCO2 for 1948–2009. Large-scale patterns of natural pCO2 variability are primarily associated with basin-averaged sea surface temperature (SST) that, in turn, is composed of two parts: the Atlantic Multidecadal Oscillation (AMO) and a long-term positive SST trend. The North Atlantic Oscillation (NAO) drives a secondary mode of variability. For the primary mode, positive AMO and the SST trend modify pCO2 with different mechanisms and spatial patterns. Warming with the positive AMO increases subpolar gyre pCO2, but there is also a significant reduction of dissolved inorganic carbon (DIC) due primarily to reduced vertical mixing. The net impact of positive AMO is to reduce pCO2 in the subpolar gyre. Through direct impacts on SST, the net impacts of positive AMO is to increase pCO2 in the subtropical gyre. From 1980 to present, long-term SST warming has amplified AMO impacts on pCO2.

Impact of Seasonality in the North Atlantic Jet Stream and Storm Migration on the Seasonality of Hurricane Translation Speed Changes

2021 ◽  
pp. 1-38
Author(s):  
Xi Guo ◽  
James P. Kossin ◽  
Zhe-Min Tan
Keyword(s):  
North Atlantic ◽  
Atlantic Coast ◽  
Jet Stream ◽  
Translation Speed ◽  
Multidecadal Variability ◽  
The Past ◽  
The North ◽  
Term Variation ◽  
The North Atlantic

AbstractTropical cyclone (TC) translation speed (TCTS) can affect the duration of TC-related disasters, which is critical to coastal and inland areas. The long-term variation of TCTS and their relationship to the variability of the mid-latitude jet stream and storm migration are discussed here for storms near the North Atlantic coast during 1948-2019. Our results reveal the prominent seasonality in the long-term variation of TCTS, which can be largely explained by the seasonality in the covariations of the mid-latitude jet stream and storm locations. Specifically, significant increases of TCTS occur in June and October during the past decades, which may result from the equatorward displacement of the jet stream and poleward migration of storm locations. Prominent slowdown of TCTS is found in August, which is related to the weakened jet strength and equatorward storm migration. In September, the effects of poleward displacement and weakening of the jet stream on TCTS are largely compensated by the poleward storm migration, therefore, no significant change in TCTS is observed. Meanwhile, the multidecadal variability of the Atlantic may contribute to the multidecadal variability of TCTS. Our findings emphasize the significance in taking a seasonality view in discussing the variability and trends of near-coast Atlantic TCTS under climate change.

scholarly journals Improving Meteorological Seasonal Forecasts for Hydrological Modeling in European Winter

2020 ◽  
Vol 59 (2) ◽  
pp. 317-332
Author(s):  
Nicky Stringer ◽  
Jeff Knight ◽  
Hazel Thornton
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Hydrological Modeling ◽  
Strongly Correlated ◽  
Hydrological Models ◽  
Seasonal Forecasts ◽  
The North ◽  
Ensemble Mean ◽  
The North Atlantic Oscillation ◽  
Correlation Skill

AbstractRecent advances in the skill of seasonal forecasts in the extratropics during winter mean they could offer improvements to seasonal hydrological forecasts. However, the signal-to-noise paradox, whereby the variability in the ensemble mean signal is lower than would be expected given its correlation skill, prevents their use to force hydrological models directly. We describe a postprocessing method to adjust for this problem, increasing the size of the predicted signal in the large-scale circulation. This reduces the ratio of predictable components in the North Atlantic Oscillation (NAO) from 3 to 1. We then derive a large ensemble of daily sequences of spatially gridded rainfall that are consistent with the seasonal mean NAO prediction by selecting historical observations conditioned on the adjusted NAO forecasts. Over northern and southwestern Europe, where the NAO is strongly correlated with winter mean rainfall, the variability of the predicted signal in the adjusted rainfall forecasts is consistent with the correlation skill (they have a ratio of predictable components of ~1) and are as skillful as the unadjusted forecasts. The adjusted forecasts show larger predicted deviations from climatology and can be used to better assess the risk of extreme seasonal mean precipitation as well as to force hydrological models.

scholarly journals 'The worst disaster suffered by the people of Scotland in recorded history': climate change, dearth and pathogens in the long 14th century

2015 ◽  
Vol 144 ◽  
pp. 223-244
Author(s):  
Richard Oram
Keyword(s):  
Cultural Change ◽  
Large Scale ◽  
Environmental Data ◽  
Historical Discourse ◽  
Proxy Records ◽  
The North ◽  
Political Upheaval ◽  
The People ◽  
Large Scale Change

Informing historical and archaeological discourse with environmental data culled from documentary and climate proxy records is transforming understanding of political, social economic and cultural change across the North Atlantic and European Atlantic regions generally. Limited record evidence and region-specific proxy data has hindered engagement by historians of medieval Scotland with the exploration of environmental factors as motors for long term and large scale change and adoption of the interdisciplinary methodologies involved in their use. This paper seeks to provide an overview of the potential for such data and methodologies in providing context for the well-rehearsed narratives of political upheaval and socio-economic realignment that have characterised much past Scottish historical discourse.

scholarly journals Multi-decadal river flow variations in France

2014 ◽  
Vol 18 (2) ◽  
pp. 691-708 ◽  
Author(s):  
J. Boé ◽  
F. Habets
Keyword(s):  
Soil Moisture ◽  
Large Scale ◽  
River Flow ◽  
Decadal Variability ◽  
Internal Variability ◽  
Spring Precipitation ◽  
Main Mode ◽  
River Flows ◽  
Decadal Variations ◽  
The Impact

Abstract. In this article, multi-decadal variations in the French hydroclimate are investigated, with a specific focus on river flows. Based on long observed series, it is shown that river flows in France generally exhibit large multi-decadal variations in the instrumental period (defined in this study as the period from the late 19th century to the present), especially in spring. Differences of means between 21 yr periods of the 20th century as large as 40% are indeed found for many gauging stations. Multi-decadal spring river flow variations are associated with variations in spring precipitation and temperature. These multi-decadal variations in precipitation are themselves found to be driven by large-scale atmospheric circulation, more precisely by a multi-decadal oscillation in a sea level pressure dipole between western Europe and the eastern Atlantic. It is suggested that the Atlantic Multidecadal Variability, the main mode of multi-decadal variability in the North Atlantic–Europe sector, controls those variations in large-scale circulation and is therefore the main ultimate driver of multi-decadal variations in spring river flows. Potential multi-decadal variations in river flows in other seasons, and in particular summer, are also noted. As they are not associated with significant surface climate anomalies (i.e. temperature, precipitation) in summer, other mechanisms are investigated based on hydrological simulations. The impact of climate variations in spring on summer soil moisture, and the impact of soil moisture in summer on the runoff-to-precipitation ratio, could potentially play a role in multi-decadal summer river flow variations. The large amplitude of the multi-decadal variations in French river flows suggests that internal variability may play a very important role in the evolution of river flows during the next decades, potentially temporarily limiting, reversing or seriously aggravating the long-term impacts of anthropogenic climate change.

scholarly journals Hydro-businesses: National and Global Demands on the São Francisco River Basin Environment of Brazil

2010 ◽  
Vol 55 (S18) ◽  
pp. 203-233
Author(s):  
Lucigleide Nery Nascimento ◽  
Mimi Larsen Becker
Keyword(s):  
Large Scale ◽  
The United States ◽  
Economic Approach ◽  
Hydro Power ◽  
Federal Policies ◽  
Sao Francisco River ◽  
North East ◽  
The North ◽  
São Francisco River

SummaryThe São Francisco River provided very obvious, close-by forms of sustenance for local communities. Beginning in the mid-1950s, the river became the place for large hydro-electric facilities, large-scale flooding, and population resettlement. A decade later, the federal government began working on pilot irrigation projects that would lead to areas described today as the Brazilian California. Hydro-power for Brazilian cities such as Recife and Salvador and irrigation for grapes and mangoes destined for the United States and Europe are among the eco-system services this river supplies. The purpose of federal policies for the north-east went beyond mitigation of the consequences of droughts, the hydraulic approach, and started to follow an economic approach based upon development; as a consequence, river and user came to be distant from one another. The two major intensive uses of the river, electricity and irrigation, threaten the long-term sustainability of this system.

scholarly journals The long-term variability of extreme sea levels in the German Bight

Ocean Science ◽  
2019 ◽  
Vol 15 (3) ◽  
pp. 651-668 ◽  
Author(s):  
Andreas Lang ◽  
Uwe Mikolajewicz
Keyword(s):  
Sea Level ◽  
German Bight ◽  
Large Scale ◽  
Internal Variability ◽  
Climate System ◽  
System Model ◽  
Tide Gauge Record ◽  
Sea Levels ◽  
The North

Abstract. Extreme high sea levels (ESLs) caused by storm floods constitute a major hazard for coastal regions. We here quantify their long-term variability in the southern German Bight using simulations covering the last 1000 years. To this end, global earth system model simulations from the PMIP3 past1000 project are dynamically scaled down with a regionally coupled climate system model focusing on the North Sea. This approach provides an unprecedented long high-resolution data record that can extend the knowledge of ESL variability based on observations, and allows for the identification of associated large-scale forcing mechanisms in the climate system. While the statistics of simulated ESLs compare well with observations from the tide gauge record at Cuxhaven, we find that simulated ESLs show large variations on interannual to centennial timescales without preferred oscillation periods. As a result of this high internal variability, ESL variations appear to a large extent decoupled from those of the background sea level, and mask any potential signals from solar or volcanic forcing. Comparison with large-scale climate variability shows that periods of high ESL are associated with a sea level pressure dipole between northeastern Scandinavia and the Gulf of Biscay. While this large-scale circulation regime applies to enhanced ESL in the wider region, it differs from the North Atlantic Oscillation pattern that has often been linked to periods of elevated background sea level. The high internal variability with large multidecadal to centennial variations emphasizes the inherent uncertainties related to traditional extreme value estimates based on short data subsets, which fail to account for such long-term variations. We conclude that ESL variations as well as existing estimates of future changes are likely to be dominated by internal variability rather than climate change signals. Thus, larger ensemble simulations will be required to assess future flood risks.

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