scholarly journals Characteristic signatures of Northern Hemisphere blocking events in a Lagrangian flow network representation of the atmospheric circulation

2021 ◽  
Vol 31 (9) ◽  
pp. 093128
Author(s):  
Noémie Ehstand ◽  
Reik V. Donner ◽  
Cristóbal López ◽  
Emilio Hernández-García
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Flow Network ◽  
Network Representation ◽  
Lagrangian Flow

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 Continentality and Oceanity in the Mid and High Latitudes of the Northern Hemisphere and Their Links to Atmospheric Circulation

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Edvinas Stonevicius ◽  
Gintautas Stankunavicius ◽  
Egidijus Rimkus
Keyword(s):  
North America ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Climatic Conditions ◽  
High Latitudes ◽  
Teleconnection Patterns ◽  
The Pacific ◽  
The Impact

The climate continentality or oceanity is one of the main characteristics of the local climatic conditions, which varies with global and regional climate change. This paper analyzes indexes of continentality and oceanity, as well as their variations in the middle and high latitudes of the Northern Hemisphere in the period 1950–2015. Climatology and changes in continentality and oceanity are examined using Conrad’s Continentality Index (CCI) and Kerner’s Oceanity Index (KOI). The impact of Northern Hemisphere teleconnection patterns on continentality/oceanity conditions was also evaluated. According to CCI, continentality is more significant in Northeast Siberia and lower along the Pacific coast of North America as well as in coastal areas in the northern part of the Atlantic Ocean. However, according to KOI, areas of high continentality do not precisely correspond with those of low oceanity, appearing to the south and west of those identified by CCI. The spatial patterns of changes in continentality thus seem to be different. According to CCI, a statistically significant increase in continentality has only been found in Northeast Siberia. In contrast, in the western part of North America and the majority of Asia, continentality has weakened. According to KOI, the climate has become increasingly continental in Northern Europe and the majority of North America and East Asia. Oceanity has increased in the Canadian Arctic Archipelago and in some parts of the Mediterranean region. Changes in continentality were primarily related to the increased temperature of the coldest month as a consequence of changes in atmospheric circulation: the positive phase of North Atlantic Oscillation (NAO) and East Atlantic (EA) patterns has dominated in winter in recent decades. Trends in oceanity may be connected with the diminishing extent of seasonal sea ice and an associated increase in sea surface temperature.

Monsoon dynamics in past and future climates: the Holocene is not an analogue of future projections

2020 ◽  
Author(s):  
Roberta D'Agostino ◽  
Juergen Bader ◽  
Josephine Brown ◽  
Simona Bordoni ◽  
David Ferreira ◽  
...  
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Hydrological Cycle ◽  
Dynamic Responses ◽  
Mean Flow ◽  
The Holocene ◽  
Temperature And Precipitation ◽  
The Future ◽  
Future Warming ◽  
The Relationship

<p><span>In recent decades the paleo-modelling community has sought to identify past warm climates that could provide analogues for greenhouse induced warming. In spite of some similarities in temperature distributions (e.g. Pliocene, Eocene, Cretaceous and summertime Northern Hemisphere mid-Holocene), however, it is unlikely that any past epoch can provide detailed insight into future warming, especially in terms of changes in the hydrological cycle. Reviewing recent work, we show that changes in the atmospheric circulation can dramatically alter the relationship between temperature and precipitation, weakening the possibility for useful climate analogs as envisioned in the literature. We present results of moisture budget decomposition from mid-Holocene and Representative Pathways Scenario RCP8.5, two climates in which monsoons are stronger and wider than the pre-Industrial era. We find that Northern Hemisphere monsoons are much stronger and wider during the Holocene than what projected for the end of the 21st century. This is because the thermodynamic (i.e. moisture changes) and dynamic responses (i.e. mean-flow changes) reinforce each other in the mid-Holocene while they partially cancel out in the future climate. Therefore, the Holocene does not represent an analogue of the future given the opposite dynamical responses in the two climates. Consistent with other studies, our work highlights that changes in atmospheric circulation are the major source of uncertainty for future projection of hydrological cycle, especially at regional scales.</span></p>

scholarly journals Lagrangian Flow Network approach to an open flow model

2017 ◽  
Vol 226 (9) ◽  
pp. 2057-2068 ◽  
Author(s):  
Enrico Ser-Giacomi ◽  
Víctor Rodríguez-Méndez ◽  
Cristóbal López ◽  
Emilio Hernández-García
Keyword(s):  
Flow Model ◽  
Network Approach ◽  
Flow Network ◽  
Open Flow ◽  
Lagrangian Flow

scholarly journals Steady-state aerosol distributions in the extra-tropical, lower stratosphere and the processes that maintain them

2008 ◽  
Vol 8 (1) ◽  
pp. 3665-3692 ◽  
Author(s):  
J. C. Wilson ◽  
S.-H. Lee ◽  
J. M. Reeves ◽  
C. A. Brock ◽  
H. H. Jonsson ◽  
...  
Keyword(s):  
Steady State ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Lower Stratosphere ◽  
Size Distributions ◽  
Aerosol Properties ◽  
Made In

Abstract. Measurements of aerosol, N2O and OCS made in the Northern Hemisphere below 21 km altitude following the eruption of Pinatubo are presented and analyzed. After September 1999, the oxidation of OCS and the sedimentation of particles in the extra-tropical overworld maintain the aerosol in a steady state. This analysis empirically links precursor gas to aerosol abundance throughout this region. These processes are tracked with age-of-air which offers advantages over tracking as a function of latitude and altitude. In the extra-tropical, lowermost stratosphere, normalized volume distributions appear constant in time after the fall of 1999. Exchange with the troposphere is important in understanding aerosol evolution there. Size distributions of volcanically perturbed aerosol are included to distinguish between volcanic and non-volcanic conditions. This analysis suggests that model failures to correctly predict OCS and aerosol properties below 20 km in the Northern Hemisphere extra tropics result from inadequate descriptions of atmospheric circulation.

scholarly journals Sun activity as factor of atmospheric circulation repetition of meridional northern type in northern hemisphere

ScienceRise ◽  
2015 ◽  
Vol 6 (1(11)) ◽  
pp. 49
Author(s):  
Александр Вадимович Холопцев ◽  
Мария Павловна Никифорова
Keyword(s):  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
Sun Activity

The Significance of Anomalies of Atmospheric Circulation Over the North Atlantic in November with Regard to the Temperatures of the Following Winters in New England *

1951 ◽  
Vol 32 (9) ◽  
pp. 319-325 ◽  
Author(s):  
Franz Baur
Keyword(s):  
New England ◽  
Atmospheric Circulation ◽  
Northern Hemisphere ◽  
North Atlantic ◽  
Middle Latitudes ◽  
The North ◽  
The North Atlantic

Seven types are established for forms of the atmospheric circulation in certain portions of “circulation regions” of the middle latitudes of the northern hemisphere. Tendencies of persistence and recurrence are different for each type and are subject to an annual course. Certain rules may be derived from changes in these types.

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