scholarly journals A nonstationary analysis for investigating the multiscale variability of extreme surges: case of the English Channel coasts

2020 ◽  
Vol 20 (12) ◽  
pp. 3225-3243
Author(s):  
Imen Turki ◽  
Lisa Baulon ◽  
Nicolas Massei ◽  
Benoit Laignel ◽  
Stéphane Costa ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Atlantic Multidecadal Oscillation ◽  
English Channel ◽  
Distribution Models ◽  
Sea Level Pressure ◽  
Physical Mechanisms ◽  
Circulation Change ◽  
Total Variability ◽  
Global Atmospheric Circulation

Abstract. This research examines the nonstationary dynamics of extreme surges along the English Channel coasts and seeks to make their connection to the climate patterns at different timescales by the use of a detailed spectral analysis in order to gain insights into the physical mechanisms relating the global atmospheric circulation to the local-scale variability of the monthly extreme surges. This variability highlights different oscillatory components from the interannual (∼1.5, ∼2–4, ∼5–8 years) to the interdecadal (∼12–16 years) scales with mean explained variances of ∼25 %–32 % and ∼2 %–4 % of the total variability, respectively. Using the two hypotheses that the physical mechanisms of the atmospheric circulation change according to the timescales and their connection with the local variability improves the prediction of the extremes, we have demonstrated statistically significant relationships of ∼1.5, ∼2–4, ∼5–8 and 12–16 years with the different climate oscillations of sea level pressure, zonal wind, North Atlantic Oscillation and Atlantic Multidecadal Oscillation, respectively. Such physical links have been used to implement the parameters of the time-dependent generalized extreme value (GEV) distribution models. The introduced climate information in the GEV parameters has considerably improved the prediction of the different timescales of surges with an explained variance higher than 60 %. This improvement exhibits their non-linear relationship with the large-scale atmospheric circulation.

scholarly journals A nonstationary analysis for investigating the multiscale variability of extreme surges: case of the English Channel coasts

2020 ◽  
Author(s):  
Imen Turki ◽  
Lisa Baulon ◽  
Nicolas Massei ◽  
Benoit Laignel ◽  
Stéphane Costa ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Time Scales ◽  
Large Scale ◽  
Atlantic Multidecadal Oscillation ◽  
English Channel ◽  
Distribution Models ◽  
Physical Mechanisms ◽  
Total Variability ◽  
Global Atmospheric Circulation ◽  
Different Time Scales

Abstract. This research examines the nonstationary dynamics of extreme surges along the English Channel coasts and seeks to make their connection to the climate patterns at different time-scales by the use of a detailed spectral analysis in order to gain insights on the physical mechanisms relating the global atmospheric circulation to the local-scale variability of the monthly extreme surges. The variability of extreme surges highlights different oscillatory components from the interannual (~ 1.5-years, ~ 2–4-years, ~ 5–8-years) to the interdecadal (~ 12–16-years) scales with mean explained variances of ~ 25–32 % and ~ 2–4 % of the total variability, respectively. Using the two hypotheses that the physical mechanisms of the atmospheric circulation change according to the timescales and their connection with the local variability improves the prediction of the extremes, we have demonstrated statistically significant correlations between ~ 1.5-years, ~ 2–4-years, and ~ 5–8-years and 12–16-years with the different climate oscillations of Sea-Level Pressure, Zonal Wind, North Atlantic Oscillation and Atlantic Multidecadal Oscillation, respectively. Such physical links have been used to implement the parameters of the time-dependent GEV distribution models. The introduced climate information in the GEV parameters has considerably improved the prediction of the different time-scales of surges with an explained variance higher than 30 %. This improvement exhibits their nonlinear relationship with the large-scale atmospheric circulation.

scholarly journals Temperature extremes in Europe: overview of their driving atmospheric patterns

2012 ◽  
Vol 12 (5) ◽  
pp. 1671-1691 ◽  
Author(s):  
C. Andrade ◽  
S. M. Leite ◽  
J. A. Santos
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Principal Component ◽  
Temperature Extremes ◽  
Cold Night ◽  
Sea Level Pressure ◽  
Atmospheric Flow ◽  
Atlantic Sector ◽  
Driving Mechanisms ◽  
Large Scale Atmospheric Circulation

Abstract. As temperature extremes have a deep impact on environment, hydrology, agriculture, society and economy, the analysis of the mechanisms underlying their occurrence, including their relationships with the large-scale atmospheric circulation, is particularly pertinent and is discussed here for Europe and in the period 1961–2010 (50 yr). For this aim, a canonical correlation analysis, coupled with a principal component analysis (BPCCA), is applied between the monthly mean sea level pressure fields, defined within a large Euro-Atlantic sector, and the monthly occurrences of two temperature extreme indices (TN10p – cold nights and TX90p – warm days) in Europe. Each co-variability mode represents a large-scale forcing on the occurrence of temperature extremes. North Atlantic Oscillation-like patterns and strong anomalies in the atmospheric flow westwards of the British Isles are leading couplings between large-scale atmospheric circulation and winter, spring and autumn occurrences of both cold nights and warm days in Europe. Although summer couplings depict lower coherence between warm and cold events, important atmospheric anomalies are key driving mechanisms. For a better characterization of the extremes, the main features of the statistical distributions of the absolute minima (TNN) and maxima (TXX) are also examined for each season. Furthermore, statistically significant downward (upward) trends are detected in the cold night (warm day) occurrences over the period 1961–2010 throughout Europe, particularly in summer, which is in clear agreement with the overall warming.

scholarly journals The Dynamical Influence of the Atlantic Multidecadal Oscillation on Continental Climate

2017 ◽  
Vol 30 (18) ◽  
pp. 7213-7230 ◽  
Author(s):  
Christopher H. O’Reilly ◽  
Tim Woollings ◽  
Laure Zanna
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Surface Air Temperature ◽  
Atlantic Multidecadal Oscillation ◽  
The North ◽  
Sst Variability ◽  
Western Sahel ◽  
Prediction Systems ◽  
Sahel Region

Abstract The Atlantic multidecadal oscillation (AMO) in sea surface temperature (SST) has been shown to influence the climate of the surrounding continents. However, it is unclear to what extent the observed impact of the AMO is related to the thermodynamical influence of the SST variability or the changes in large-scale atmospheric circulation. Here, an analog method is used to decompose the observed impact of the AMO into dynamical and residual components of surface air temperature (SAT) and precipitation over the adjacent continents. Over Europe the influence of the AMO is clearest during the summer, when the warm SAT anomalies are interpreted to be primarily thermodynamically driven by warm upstream SST anomalies but also amplified by the anomalous atmospheric circulation. The overall precipitation response to the AMO in summer is generally less significant than the SAT but is mostly dynamically driven. The decomposition is also applied to the North American summer and the Sahel rainy season. Both dynamical and residual influences on the anomalous precipitation over the Sahel are substantial, with the former dominating over the western Sahel region and the latter being largest over the eastern Sahel region. The results have potential implications for understanding the spread in AMO variability in coupled climate models and decadal prediction systems.

scholarly journals Jetwash-induced  vortices and climate change   

2021 ◽  
Author(s):  
Wesley Schouw ◽  
Prof. Gunter Pauli
Keyword(s):  
Climate Change ◽  
Public Policy ◽  
Atmospheric Circulation ◽  
Human Population ◽  
Large Scale ◽  
Popular Press ◽  
Greenhouse Gasses ◽  
Wake Turbulence ◽  
Global Atmospheric Circulation ◽  
Life On Earth

This article introduces factors contributing significantly to climate change that have been largely neglected in both the scientific and popular press. These factors have immediate implications for public policy directed at slowing, halting and even reversing climate change and its effects. This article argues that in addition to the known contributions made by greenhouse gasses, climate change is also driven by shifts in the patterns of global atmospheric circulation which are influenced by persistent, large-scale vortices caused by the wake turbulence left by commercial air traffic. Because this traffic is highly concentrated along the most frequently traveled routes, the vortices aircraft create have transformed into semi-permanent atmospheric circulation which have widespread effects on how the atmosphere traps and releases heat. It is also possible that these changes alter the loss of water from the atmosphere. This would endanger all life on earth, not just the human population.

scholarly journals Stable isotope investigation of groundwater recharge in the Carpathian Mountains, East-Central Europe

2018 ◽  
Author(s):  
Carmen-Andreea Bădăluță ◽  
Aurel Perșoiu ◽  
Monica Ionita ◽  
Viorica Nagavciuc ◽  
Petruț-Ionel Bistricean
Keyword(s):  
Atmospheric Circulation ◽  
Large Scale ◽  
Precipitation Amount ◽  
Winter Season ◽  
Atlantic Multidecadal Oscillation ◽  
The Arctic ◽  
Altitude Effect ◽  
Mountain Area ◽  
The North ◽  
Large Scale Atmospheric Circulation

Abstract. Rapid growth in water usage in NW Romania has led to an increased pressure on the available water resources; however, the relationships between precipitation, surface and groundwater in the region are poorly understood. Here, we have analyzed the stable isotopes of oxygen and hydrogen in precipitation, river and groundwater to gain information on moisture sources feeding precipitation in the area and establish the main links between the large-scale atmospheric circulation, precipitation amount and discharge. Thus, in this study we have analyzed 157 groundwater samples, 64 precipitation samples from two collection sites (one in mountain area and another one in plateau area) and 54 rivers samples from two rivers. Furthermore, we have directly linked the changes in the isotopic composition of the d-excess parameter in the precipitation with the processes linked to large-scale atmospheric circulation. Isotopes in precipitation water resulted in two LMWLs (δ2H = 7.4*δ18O + 2.7 at 350 m asl and δ2H = 8.1*δ18O + 12.4 at 1530 m asl), with a clear seasonal signal, further enhanced by secondary evaporative processes in summer. Moisture in the lowlands was mostly delivered along easterly trajectories, while that in the mountain area from the westerlies. Surface water analyses show the same trend as precipitation, but with reduced amplitude between summer and winter values. Throughout the winter season, the δprec is strongly related with different climate teleconnection patterns like the East Atlantic (EA), the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO), while during summer, the δprec shows a strong correlation with the Atlantic Multidecadal Oscillation (AMO) and the summer EA. Maps of δ18O and d-excess distribution in groundwaters show a depletive trend from NW to SE, generated in principal by topography. The waters in the aquifers show no clear patterns and altitude effect.

Responses of the Tropical Atmospheric Circulation to Climate Change and Connection to the Hydrological Cycle

2018 ◽  
Vol 46 (1) ◽  
pp. 549-580 ◽  
Author(s):  
Jian Ma ◽  
Robin Chadwick ◽  
Kyong-Hwan Seo ◽  
Changming Dong ◽  
Gang Huang ◽  
...  
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
Large Scale ◽  
Hydrological Cycle ◽  
Regional Climate ◽  
Climate Projections ◽  
Local Circulation ◽  
Surface Warming ◽  
Circulation Change ◽  
The Tropics

This review describes the climate change–induced responses of the tropical atmospheric circulation and their impacts on the hydrological cycle. We depict the theoretically predicted changes and diagnose physical mechanisms for observational and model-projected trends in large-scale and regional climate. The tropical circulation slows down with moisture and stratification changes, connecting to a poleward expansion of the Hadley cells and a shift of the intertropical convergence zone. Redistributions of regional precipitation consist of thermodynamic and dynamical components, including a strong offset between moisture increase and circulation weakening throughout the tropics. This allows other dynamical processes to dominate local circulation changes, such as a surface warming pattern effect over oceans and multiple mechanisms over land. To improve reliability in climate projections, more fundamental understandings of pattern formation, circulation change, and the balance of various processes redistributing land rainfall are suggested to be important.

scholarly journals The jet stream and climate change   

2021 ◽  
Author(s):  
Wesley Schouw ◽  
Prof. Gunter Pauli
Keyword(s):  
Climate Change ◽  
Public Policy ◽  
Atmospheric Circulation ◽  
Human Population ◽  
Large Scale ◽  
Jet Stream ◽  
Greenhouse Gasses ◽  
Wake Turbulence ◽  
Global Atmospheric Circulation ◽  
Life On Earth

This article introduces factors contributing significantly to climate change that have been largely neglected in both the scientific and popular press. These factors have immediate implications for public policy directed at slowing, halting and even reversing climate change and its effects. This article argues that in addition to the known contributions made by greenhouse gasses, climate change is also driven by shifts in the patterns of global atmospheric circulation which are influenced by persistent, large-scale vortices caused by the wake turbulence left by commercial air traffic. Because this traffic is highly concentrated along the most frequently traveled routes, the vortices aircraft create have transformed into semi-permanent atmospheric circulation which have widespread effects on how the atmosphere traps and releases heat. It is also possible that these changes alter the loss of water from the atmosphere. This would endanger all life on earth, not just the human population.

scholarly journals Springtime connections between the large-scale sea-level pressure field and gust wind speed over Iberia and the Balearics

2011 ◽  
Vol 11 (1) ◽  
pp. 191-203 ◽  
Author(s):  
M. L. Martín ◽  
F. Valero ◽  
A. Pascual ◽  
A. Morata ◽  
M. Y. Luna
Keyword(s):  
Atmospheric Circulation ◽  
North Atlantic ◽  
Large Scale ◽  
Pressure Field ◽  
Wind Gust ◽  
Sea Level Pressure ◽  
Wind Speeds ◽  
The North ◽  
Wind Gusts ◽  
The North Atlantic

Abstract. This paper investigates, by means of Singular Value Decomposition analysis, the springtime relationships between the mean sea-level pressure field over the North Atlantic and the regional wind gusts over the Iberian Peninsula, identifying the main atmospheric circulation patterns linked to gust wind speed anomaly configurations. The statistical significance of the obtained modes is investigated by means of Monte Carlo approach. The analysis highlighted that the covariability is dominated by two main large-scale features of the atmospheric circulation over the North Atlantic. The first mode relates to Iberian gust wind speeds to the Scandinavian pattern (SCAND), linking the large-scale pattern to above-normal wind gusts. The second covariability mode, associated with the North Atlantic Oscillation (NAO) pattern, correlates with maximum wind speeds over Iberia. An enhanced spring NAO pattern is related to positive (negative) wind gust correlations over northern (southern) Iberia. To find true relationships between large-scale atmospheric field and the gust wind speeds, composite maps were built up to give an average atmospheric circulation associated with coherent wind gust variability over Iberia.

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