scholarly journals Local wave activity budgets of the wintertime Northern Hemisphere: Implication for the Pacific and Atlantic storm tracks

2017 ◽  
Vol 44 (11) ◽  
pp. 5673-5682 ◽  
Author(s):  
Clare S. Y. Huang ◽  
Noboru Nakamura
Keyword(s):  
Northern Hemisphere ◽  
Wave Activity ◽  
Storm Tracks ◽  
Activity Budgets ◽  
The Pacific ◽  
Local Wave

scholarly journals Wave Events: Climatology, Trends, and Relationship to Northern Hemisphere Winter Blocking and Weather Extremes

2017 ◽  
Vol 30 (15) ◽  
pp. 5675-5697 ◽  
Author(s):  
Patrick Martineau ◽  
Gang Chen ◽  
D. Alex Burrows
Keyword(s):  
East Asia ◽  
Northern Hemisphere ◽  
Spatial Relationship ◽  
Finite Amplitude ◽  
Wave Activity ◽  
Weather Extremes ◽  
Large Wave ◽  
The Pacific ◽  
Local Wave ◽  
Hemisphere Winter

Diagnostics of finite-amplitude local wave activity (LWA) are applied to the 500-hPa geopotential height field to diagnose persistent synoptic weather events of anomalously large wave activity in the Northern Hemisphere. By considering the cyclonic and anticyclonic components of LWA separately, persistent weather systems associated with large-amplitude troughs and ridges are detected. While anticyclonic wave events are predominantly found over Europe and Alaska, cyclonic wave events usually occur over East Asia and northeastern Canada. Those preferred regions correspond to the location of planetary-scale ridges and troughs, which contribute, together with transient anomalies, to the formation of wave events. Although wave events are not blocking events per definition, they are typically associated with increased blocking in their vicinity. Their spatial relationship to blocking, however, varies depending on their cyclonic or anticyclonic nature and the type of wave-breaking signatures. Wave events are also shown to be accompanied by warm or cold temperature extremes, whose spatial pattern depends on the type of events, cyclonic or anticyclonic, and the sector affected. Trends in the frequency of wave events indicate that cyclonic wave events and the associated cold extremes affecting East Asia have become more frequent in recent decades and could be linked to recent trends toward La Niña–like conditions in the Pacific and trends toward the negative phase of Arctic Oscillation.

scholarly journals The Annual Cycle of Northern Hemisphere Storm Tracks. Part I: Seasons

2019 ◽  
Vol 32 (6) ◽  
pp. 1743-1760 ◽  
Author(s):  
B. J. Hoskins ◽  
K. I. Hodges
Keyword(s):  
Northern Hemisphere ◽  
Annual Cycle ◽  
Storm Track ◽  
Lower Troposphere ◽  
Meridional Wind ◽  
Diagnostic Techniques ◽  
Storm Tracks ◽  
The Pacific ◽  
Wide Range ◽  
Close Relationship

Abstract In this paper and Part II a comprehensive picture of the annual cycle of the Northern Hemisphere storm tracks is presented and discussed for the first time. It is based on both feature tracking and Eulerian-based diagnostics, applied to vorticity and meridional wind in the upper and lower troposphere. Here, the storm tracks, as diagnosed using both variables and both diagnostic techniques, are presented for the four seasons for each of the two levels. The oceanic storm tracks retain much of their winter mean intensity in spring with only a small change in their latitude. In the summer they are much weaker, particularly in the Pacific and are generally farther poleward. In autumn the intensities are larger again, comparable with those in spring, but the latitude is still nearer to that of summer. However, in the lower troposphere in the eastern ocean basins the tracking metrics show northern and southern tracks that change little with latitude through the year. The Pacific midwinter minimum is seen in upper-troposphere standard deviation diagnostics, but a richer picture is obtained using tracking. In winter there are high intensities over a wide range of latitudes in the central and eastern Pacific, and the western Pacific has high track density but weak intensity. In the lower troposphere all the diagnostics show that the strength of the Pacific and Atlantic storm tracks are generally quite uniform over the autumn–winter–spring period. There is a close relationship between the upper-tropospheric storm track, particularly that based on vorticity, and tropopause-level winds and temperature gradients. In the lower troposphere, in winter the oceanic storm tracks are in the region of the strong meridional SST gradients, but in summer they are located in regions of small or even reversed SST gradients. However, over North America the lower-tropospheric baroclinicity and the upstream portion of the Atlantic storm track stay together throughout the year.

scholarly journals Are the Northern Hemisphere Winter Storm Tracks Significantly Correlated?

2004 ◽  
Vol 17 (21) ◽  
pp. 4230-4244 ◽  
Author(s):  
Edmund K. M. Chang
Keyword(s):  
Northern Hemisphere ◽  
Storm Track ◽  
Reanalysis Data ◽  
Storm Tracks ◽  
The Pacific ◽  
Aircraft Observations ◽  
Highly Correlated ◽  
Hemisphere Winter ◽  
Aircraft Data ◽  
Northern Hemisphere Winter

Abstract In this study, the correlation between the Northern Hemisphere winter Pacific and Atlantic storm tracks is examined using the NCEP–NCAR reanalysis and the 40-yr ECMWF Re-Analysis (ERA-40), as well as unassimilated aircraft observations. By examining month-to-month variability in the 250-hPa meridional velocity variance, the correlation between the two storm track peaks is found to be as high as 0.5 during the winters between 1975/76 and 1998/99. Here, it is shown that the correlation between the two storm tracks can be clearly detected from the aircraft data. Further analyses of the reanalysis data show that the correlation can also be seen in other eddy variance and covariance statistics, including the poleward heat flux at the 700-hPa level. The correlation between the two storm tracks, as seen in both reanalysis datasets, is shown to be much weaker during the period 1957/58–1971/72, suggesting a possible regime transition from largely uncorrelated storm tracks to highly correlated storm tracks during the 1970s. However, during this earlier period, the number of aircraft observations is insufficient to verify the low correlation seen in the reanalyses. Thus, low biases in the reanalyses during the earlier period cannot be ruled out. An ensemble of four GCM simulations performed using the GFDL GCM forced by global observed SST variations between 1950 and 1995 has also been examined. The correlation between the two storm tracks in the GCM simulations is much lower (0.18) than that observed, even if the analysis is restricted to the GCM simulations from the period 1975/76–1994/95. A Monte Carlo test shows that the observed correlation and the GCM correlation are statistically distinct at the 1% level. Correlations between the Southern Hemisphere summer Pacific and Atlantic storm tracks have also been examined based on the reanalyses datasets. The results suggest that the amplitude of the SH summer Pacific and Atlantic storm tracks are not significantly correlated, showing that seeding of the Atlantic storm track by the Pacific storm track does not necessarily lead to significant correlations between the two storm tracks.

scholarly journals Northern Hemisphere Extratropical Cyclones in a Warming Climate in the HiGEM High-Resolution Climate Model

2011 ◽  
Vol 24 (20) ◽  
pp. 5336-5352 ◽  
Author(s):  
Jennifer L. Catto ◽  
Len C. Shaffrey ◽  
Kevin I. Hodges
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Storm Tracks ◽  
Cyclone Intensity ◽  
The North ◽  
Warming Climate ◽  
The Pacific ◽  
The North Atlantic ◽  
Mean Climate ◽  
Enhanced Surface

Abstract Changes to the Northern Hemisphere winter (December–February) extratropical storm tracks and cyclones in a warming climate are investigated. Two idealized climate change experiments with the High Resolution Global Environmental Model version 1.1 (HiGEM1.1), a doubled CO2 and a quadrupled CO2 experiment, are compared against a present-day control run. An objective feature tracking method is used and a focus is given to regional changes. The climatology of extratropical storm tracks from the control run is shown to be in good agreement with the 40-yr European Centre for Medium-Range Weather Forecasts Re-Analysis (ERA-40), while the frequency distribution of cyclone intensity also compares well. In both simulations the mean climate changes are generally consistent with the simulations of the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) models, with strongly enhanced surface warming at the winter pole and reduced lower-tropospheric warming over the North Atlantic Ocean associated with the slowdown of the meridional overturning circulation. The circulation changes in the North Atlantic are different between the two idealized simulations with different CO2 forcings. In the North Atlantic the storm tracks are influenced by the slowdown of the MOC, the enhanced surface polar warming, and the enhanced upper tropical-troposphere warming, giving a northeastward shift of the storm tracks in the 2 × CO2 experiment but no shift in the 4 × CO2 experiment. Over the Pacific, in the 2 × CO2 experiment, changes in the mean climate are associated with local temperature changes, while in the 4 × CO2 experiment the changes in the Pacific are impacted by the weakened tropical circulation. The storm-track changes are consistent with the shifts in the zonal wind. Total cyclone numbers are found to decrease over the Northern Hemisphere with increasing CO2 forcing. Changes in cyclone intensity are found using 850-hPa vorticity, mean sea level pressure, and 850-hPa winds. The intensity of the Northern Hemisphere cyclones is found to decrease relative to the control.

scholarly journals INVESTIGATION OF STORM TRACKS IN NORTHERN HEMISPHERE

2019 ◽  
Vol 1 (4) ◽  
pp. 145-152
Author(s):  
P. Vargin ◽  
◽  
Y. Martynova ◽  
E. Volodin ◽  
S. Коstrykin ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Storm Tracks

scholarly journals Antarctic ice-shelf calving triggered by the Honshu (Japan) earthquake and tsunami, March 2011

2011 ◽  
Vol 57 (205) ◽  
pp. 785-788 ◽  
Author(s):  
Kelly M. Brunt ◽  
Emile A. Okal ◽  
Douglas R. MacAyeal
Keyword(s):  
Pacific Ocean ◽  
Northern Hemisphere ◽  
European Space Agency ◽  
Observational Evidence ◽  
Ice Shelf ◽  
Wave Impact ◽  
Space Agency ◽  
The Pacific ◽  
The Pacific Ocean ◽  
The Antarctic

AbstractWe use European Space Agency Envisat data to present the first observational evidence that a Northern Hemisphere tsunami triggered Antarctic ice-shelf calving more than 13 000 km away. The Honshu tsunami of 11 March 2011 traversed the Pacific Ocean in <18 hours where it impinged on the Sulzberger Ice Shelf, resulting in the calving of 125 km2 of ice from a shelf front that had previously been stable for >46 years. This event further illustrates the growing evidence of ocean-wave impact on Antarctic calving and emphasizes the teleconnection between the Antarctic ice sheet and events as far away as the Northern Hemisphere.

On the influence of ENSO complexity on Pan-Pacific coastal wave extremes

2021 ◽  
Vol 118 (47) ◽  
pp. e2115599118
Author(s):  
Julien Boucharel ◽  
Rafael Almar ◽  
Elodie Kestenare ◽  
Fei-Fei Jin
Keyword(s):  
Southern Oscillation ◽  
Wave Activity ◽  
Spatial Behavior ◽  
Coastal Hazards ◽  
Climate Control ◽  
Enso Events ◽  
The Pacific ◽  
Coastal Impacts ◽  
Climate Mode

Wind-generated waves are dominant drivers of coastal dynamics and vulnerability, which have considerable impacts on littoral ecosystems and socioeconomic activities. It is therefore paramount to improve coastal hazards predictions through the better understanding of connections between wave activity and climate variability. In the Pacific, the dominant climate mode is El Niño Southern Oscillation (ENSO), which has known a renaissance of scientific interest leading to great theoretical advances in the past decade. Yet studies on ENSO’s coastal impacts still rely on the oversimplified picture of the canonical dipole across the Pacific. Here, we consider the full ENSO variety to delineate its essential teleconnection pathways to tropical and extratropical storminess. These robust seasonally modulated relationships allow us to develop a mathematical model of coastal wave modulation essentially driven by ENSO’s complex temporal and spatial behavior. Accounting for this nonlinear climate control on Pan-Pacific wave activity leads to a much better characterization of waves’ seasonal to interannual variability (+25% in explained variance) and intensity of extremes (+60% for strong ENSO events), therefore paving the way for significantly more accurate forecasts than formerly possible with the previous baseline understanding of ENSO’s influence on coastal hazards.

scholarly journals Northern Hemisphere Stationary Waves in a Changing Climate

2019 ◽  
Vol 5 (4) ◽  
pp. 372-389 ◽  
Author(s):  
Robert C. J. Wills ◽  
Rachel H. White ◽  
Xavier J. Levine
Keyword(s):  
Climate Change ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Climate Models ◽  
Regional Climate ◽  
Stationary Wave ◽  
Future Research ◽  
Stationary Waves ◽  
The Pacific ◽  
Longitudinal Variations

Abstract Purpose of Review Stationary waves are planetary-scale longitudinal variations in the time-averaged atmospheric circulation. Here, we consider the projected response of Northern Hemisphere stationary waves to climate change in winter and summer. We discuss how the response varies across different metrics, identify robust responses, and review proposed mechanisms. Recent Findings Climate models project shifts in the prevailing wind patterns, with corresponding impacts on regional precipitation, temperature, and extreme events. Recent work has improved our understanding of the links between stationary waves and regional climate and identified robust stationary wave responses to climate change, which include an increased zonal lengthscale in winter, a poleward shift of the wintertime circulation over the Pacific, a weakening of monsoonal circulations, and an overall weakening of stationary wave circulations, particularly their divergent component and quasi-stationary disturbances. Summary Numerous factors influence Northern Hemisphere stationary waves, and mechanistic theories exist for only a few aspects of the stationary wave response to climate change. Idealized studies have proven useful for understanding the climate responses of particular atmospheric circulation features and should be a continued focus of future research.

scholarly journals Northern hemisphere winter storm tracks of the Eemian interglacial and the last glacial inception

2007 ◽  
Vol 3 (2) ◽  
pp. 181-192 ◽  
Author(s):  
F. Kaspar ◽  
T. Spangehl ◽  
U. Cubasch
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Storm Track ◽  
Storm Tracks ◽  
Winter Storm ◽  
The North ◽  
The North Atlantic ◽  
Hemisphere Winter ◽  
Eemian Interglacial ◽  
The Last Glacial

Abstract. Climate simulations of the Eemian interglacial and the last glacial inception have been performed by forcing a coupled ocean-atmosphere general circulation model with insolation patterns of these periods. The parameters of the Earth's orbit have been set to conditions of 125 000 and 115 000 years before present (yr BP). Compared to today, these dates represent periods with enhanced and weakened seasonality of insolation in the northern hemisphere. Here we analyse the simulated change in northern hemisphere winter storm tracks. The change in the orbital configuration has a strong impact on the meridional temperature gradients and therefore on strength and location of the storm tracks. The North Atlantic storm track is strengthened, shifted northward and extends further to the east in the simulation for the Eemian at 125 kyr BP. As one consequence, the northern parts of Europe experience an increase in winter precipitation. The frequency of winter storm days increases over large parts of the North Atlantic including the British Isles and the coastal zones of north-western Europe. Opposite but weaker changes in storm track activity are simulated for 115 kyr BP.

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