The Experts below are selected from a list of 16236 Experts worldwide ranked by ideXlab platform
R Erdelyi - One of the best experts on this subject based on the ideXlab platform.
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drivers and potential predictability of summer time north atlantic polar front Jet variability
Climate Dynamics, 2017Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:The variability of the North Atlantic polar front Jet Stream is crucial in determining summer weather around the North Atlantic basin. Recent extreme summers in western Europe and North America have highlighted the need for greater understanding of this variability, in order to aid seasonal forecasting and mitigate societal, environmental and economic impacts. Here we find that simple linear regression and composite models based on a few predictable factors are able to explain up to 35 % of summertime Jet Stream speed and latitude variability from 1955 onwards. Sea surface temperature forcings impact predominantly on Jet speed, whereas solar and cryospheric forcings appear to influence Jet latitude. The cryospheric associations come from the previous autumn, suggesting the survival of an ice-induced signal through the winter season, whereas solar influences lead Jet variability by a few years. Regression models covering the earlier part of the twentieth century are much less effective, presumably due to decreased availability of data, and increased uncertainty in observational reanalyses. Wavelet coherence analysis identifies that associations fluctuate over the study period but it is not clear whether this is just internal variability or genuine non-stationarity. Finally we identify areas for future research.
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drivers of north atlantic polar front Jet Stream variability
International Journal of Climatology, 2015Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:Polar front Jet Stream variability is responsible for instances of extreme weather and is crucial for regional climate change. The North Atlantic Polar Front Jet Stream is of particular significance to the heavily populated areas of western Europe and eastern North America as storm track variability, atmospheric modes of variability such as the North Atlantic Oscillation (NAO), temperature and rainfall are all intimately linked with Jet Stream changes. Although seasonal and interannual variability are often attributed to internal variability, there are several possible drivers of polar front Jet Stream changes that are reviewed in this study. Cryospheric effects from sea-ice extent and snow cover, oceanic effects from North Atlantic sea-surface temperatures and tropical influences such as the El-NiA±o Southern Oscillation, and stratospheric effects due to stratospheric circulation variability, solar variability, volcanic eruptions and the Quasi-Biennial Oscillation are all identified in the literature as factors that impact on the Atlantic Polar Front Jet Stream. These drivers of Jet Stream variability can oppose or reinforce one another, and there are some indications of possible nonlinear interactions between them. We also review the modelling of Jet Stream variability. While a consensus has now been reached that some observed drivers can be reproduced in climate models, we conclude that improved understanding of more recently identified drivers of the Atlantic extratropical Jet Stream is crucial for making progress in regional climate predictions on all timescales from months to decades ahead. © 2015 Royal Meteorological Society.
Adam A Scaife - One of the best experts on this subject based on the ideXlab platform.
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drivers and potential predictability of summer time north atlantic polar front Jet variability
Climate Dynamics, 2017Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:The variability of the North Atlantic polar front Jet Stream is crucial in determining summer weather around the North Atlantic basin. Recent extreme summers in western Europe and North America have highlighted the need for greater understanding of this variability, in order to aid seasonal forecasting and mitigate societal, environmental and economic impacts. Here we find that simple linear regression and composite models based on a few predictable factors are able to explain up to 35 % of summertime Jet Stream speed and latitude variability from 1955 onwards. Sea surface temperature forcings impact predominantly on Jet speed, whereas solar and cryospheric forcings appear to influence Jet latitude. The cryospheric associations come from the previous autumn, suggesting the survival of an ice-induced signal through the winter season, whereas solar influences lead Jet variability by a few years. Regression models covering the earlier part of the twentieth century are much less effective, presumably due to decreased availability of data, and increased uncertainty in observational reanalyses. Wavelet coherence analysis identifies that associations fluctuate over the study period but it is not clear whether this is just internal variability or genuine non-stationarity. Finally we identify areas for future research.
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drivers of north atlantic polar front Jet Stream variability
International Journal of Climatology, 2015Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:Polar front Jet Stream variability is responsible for instances of extreme weather and is crucial for regional climate change. The North Atlantic Polar Front Jet Stream is of particular significance to the heavily populated areas of western Europe and eastern North America as storm track variability, atmospheric modes of variability such as the North Atlantic Oscillation (NAO), temperature and rainfall are all intimately linked with Jet Stream changes. Although seasonal and interannual variability are often attributed to internal variability, there are several possible drivers of polar front Jet Stream changes that are reviewed in this study. Cryospheric effects from sea-ice extent and snow cover, oceanic effects from North Atlantic sea-surface temperatures and tropical influences such as the El-NiA±o Southern Oscillation, and stratospheric effects due to stratospheric circulation variability, solar variability, volcanic eruptions and the Quasi-Biennial Oscillation are all identified in the literature as factors that impact on the Atlantic Polar Front Jet Stream. These drivers of Jet Stream variability can oppose or reinforce one another, and there are some indications of possible nonlinear interactions between them. We also review the modelling of Jet Stream variability. While a consensus has now been reached that some observed drivers can be reproduced in climate models, we conclude that improved understanding of more recently identified drivers of the Atlantic extratropical Jet Stream is crucial for making progress in regional climate predictions on all timescales from months to decades ahead. © 2015 Royal Meteorological Society.
Richard Hall - One of the best experts on this subject based on the ideXlab platform.
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drivers and potential predictability of summer time north atlantic polar front Jet variability
Climate Dynamics, 2017Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:The variability of the North Atlantic polar front Jet Stream is crucial in determining summer weather around the North Atlantic basin. Recent extreme summers in western Europe and North America have highlighted the need for greater understanding of this variability, in order to aid seasonal forecasting and mitigate societal, environmental and economic impacts. Here we find that simple linear regression and composite models based on a few predictable factors are able to explain up to 35 % of summertime Jet Stream speed and latitude variability from 1955 onwards. Sea surface temperature forcings impact predominantly on Jet speed, whereas solar and cryospheric forcings appear to influence Jet latitude. The cryospheric associations come from the previous autumn, suggesting the survival of an ice-induced signal through the winter season, whereas solar influences lead Jet variability by a few years. Regression models covering the earlier part of the twentieth century are much less effective, presumably due to decreased availability of data, and increased uncertainty in observational reanalyses. Wavelet coherence analysis identifies that associations fluctuate over the study period but it is not clear whether this is just internal variability or genuine non-stationarity. Finally we identify areas for future research.
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drivers of north atlantic polar front Jet Stream variability
International Journal of Climatology, 2015Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:Polar front Jet Stream variability is responsible for instances of extreme weather and is crucial for regional climate change. The North Atlantic Polar Front Jet Stream is of particular significance to the heavily populated areas of western Europe and eastern North America as storm track variability, atmospheric modes of variability such as the North Atlantic Oscillation (NAO), temperature and rainfall are all intimately linked with Jet Stream changes. Although seasonal and interannual variability are often attributed to internal variability, there are several possible drivers of polar front Jet Stream changes that are reviewed in this study. Cryospheric effects from sea-ice extent and snow cover, oceanic effects from North Atlantic sea-surface temperatures and tropical influences such as the El-NiA±o Southern Oscillation, and stratospheric effects due to stratospheric circulation variability, solar variability, volcanic eruptions and the Quasi-Biennial Oscillation are all identified in the literature as factors that impact on the Atlantic Polar Front Jet Stream. These drivers of Jet Stream variability can oppose or reinforce one another, and there are some indications of possible nonlinear interactions between them. We also review the modelling of Jet Stream variability. While a consensus has now been reached that some observed drivers can be reproduced in climate models, we conclude that improved understanding of more recently identified drivers of the Atlantic extratropical Jet Stream is crucial for making progress in regional climate predictions on all timescales from months to decades ahead. © 2015 Royal Meteorological Society.
Weiwen Wang - One of the best experts on this subject based on the ideXlab platform.
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summer high temperature extremes in southeast china associated with the east asian Jet Stream and circumglobal teleconnection
Journal of Geophysical Research, 2013Co-Authors: Soi Kun Fong, Weiwen Wang, Xin Wang, Wen Zhou, Ka Cheng LeongAbstract:High temperature extremes (HTEs) have received increasing attention due to their rising impacts on human mortality, regional economies, and ecosystems. In this study, HTEs are defined as days with daily maximum temperature above the 90th percentile derived from a specific climatological period. Occurrences of summer HTEs in Southeast China (south of 35 degrees N and east of 105 degrees E) associated with atmospheric anomalies are investigated. Two key domains in the upper level that are associated with HTE variation, the exit and the tail of the East Asian Jet Stream (EAJS), are identified. Poleward displacement of the exit is associated with warming tropospheric temperatures over East Asia and tends to be linked with high HTE frequency, while enhancement of the tail is associated with cooling tropospheric temperatures in the northern Pacific and tends to be linked with low HTE frequency. A possible reflection effect of the stratosphere on cool summers in Southeast China is proposed. Furthermore, these two domains are in essence two sectors of the phase-locked circumglobal teleconnection (CGT) pattern in the Northern Hemisphere. Linkages are found between HTEs in Southeast China and precipitation anomalies in the Indian summer monsoon region, and also in extratropical regions such as northeastern Europe. These teleconnections are set up through the CGT pattern associated with the westerly Jet in the midlatitudes. These findings may be a source of variability and predictability of HTEs in Southeast China.
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summer high temperature extremes in southeast china associated with the east asian Jet Stream and circumglobal teleconnection
Journal of Geophysical Research, 2013Co-Authors: Soi Kun Fong, Weiwen Wang, Xin Wang, Wen Zhou, Ka Cheng LeongAbstract:High temperature extremes (HTEs) have received increasing attention due to their rising impacts on human mortality, regional economies, and ecosystems. In this study, HTEs are defined as days with daily maximum temperature above the 90th percentile derived from a specific climatological period. Occurrences of summer HTEs in Southeast China (south of 35 degrees N and east of 105 degrees E) associated with atmospheric anomalies are investigated. Two key domains in the upper level that are associated with HTE variation, the exit and the tail of the East Asian Jet Stream (EAJS), are identified. Poleward displacement of the exit is associated with warming tropospheric temperatures over East Asia and tends to be linked with high HTE frequency, while enhancement of the tail is associated with cooling tropospheric temperatures in the northern Pacific and tends to be linked with low HTE frequency. A possible reflection effect of the stratosphere on cool summers in Southeast China is proposed. Furthermore, these two domains are in essence two sectors of the phase-locked circumglobal teleconnection (CGT) pattern in the Northern Hemisphere. Linkages are found between HTEs in Southeast China and precipitation anomalies in the Indian summer monsoon region, and also in extratropical regions such as northeastern Europe. These teleconnections are set up through the CGT pattern associated with the westerly Jet in the midlatitudes. These findings may be a source of variability and predictability of HTEs in Southeast China.
Edward Hanna - One of the best experts on this subject based on the ideXlab platform.
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drivers and potential predictability of summer time north atlantic polar front Jet variability
Climate Dynamics, 2017Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:The variability of the North Atlantic polar front Jet Stream is crucial in determining summer weather around the North Atlantic basin. Recent extreme summers in western Europe and North America have highlighted the need for greater understanding of this variability, in order to aid seasonal forecasting and mitigate societal, environmental and economic impacts. Here we find that simple linear regression and composite models based on a few predictable factors are able to explain up to 35 % of summertime Jet Stream speed and latitude variability from 1955 onwards. Sea surface temperature forcings impact predominantly on Jet speed, whereas solar and cryospheric forcings appear to influence Jet latitude. The cryospheric associations come from the previous autumn, suggesting the survival of an ice-induced signal through the winter season, whereas solar influences lead Jet variability by a few years. Regression models covering the earlier part of the twentieth century are much less effective, presumably due to decreased availability of data, and increased uncertainty in observational reanalyses. Wavelet coherence analysis identifies that associations fluctuate over the study period but it is not clear whether this is just internal variability or genuine non-stationarity. Finally we identify areas for future research.
-
drivers of north atlantic polar front Jet Stream variability
International Journal of Climatology, 2015Co-Authors: Richard Hall, R Erdelyi, Edward Hanna, Julie M Jones, Adam A ScaifeAbstract:Polar front Jet Stream variability is responsible for instances of extreme weather and is crucial for regional climate change. The North Atlantic Polar Front Jet Stream is of particular significance to the heavily populated areas of western Europe and eastern North America as storm track variability, atmospheric modes of variability such as the North Atlantic Oscillation (NAO), temperature and rainfall are all intimately linked with Jet Stream changes. Although seasonal and interannual variability are often attributed to internal variability, there are several possible drivers of polar front Jet Stream changes that are reviewed in this study. Cryospheric effects from sea-ice extent and snow cover, oceanic effects from North Atlantic sea-surface temperatures and tropical influences such as the El-NiA±o Southern Oscillation, and stratospheric effects due to stratospheric circulation variability, solar variability, volcanic eruptions and the Quasi-Biennial Oscillation are all identified in the literature as factors that impact on the Atlantic Polar Front Jet Stream. These drivers of Jet Stream variability can oppose or reinforce one another, and there are some indications of possible nonlinear interactions between them. We also review the modelling of Jet Stream variability. While a consensus has now been reached that some observed drivers can be reproduced in climate models, we conclude that improved understanding of more recently identified drivers of the Atlantic extratropical Jet Stream is crucial for making progress in regional climate predictions on all timescales from months to decades ahead. © 2015 Royal Meteorological Society.