Freshwater Glacial Lake Discharge Events From Eastern North America to the North Atlantic Before, During and After the Younger Dryas

Winter surface air temperature (SAT) over North America exhibits pronounced variability on sub-seasonal-to-interdecadal timescales, but its causes are not fully understood. Here observational and reanalysis data from 1950-2017 are analyzed to investigate these causes. Detrended daily SAT data reveals a known warm-west/cold-east (WWCE) dipole over midlatitude North America and a cold-north/warm-south (CNWS) dipole over eastern North America. It is found that while the North Pacific blocking (PB) is important for the WWCE and CNWS dipoles, they also depend on the phase of the North Atlantic Oscillation (NAO). When a negative-phase NAO (NAO-) concurs with PB, the WWCE dipole is enhanced (compared with the PB alone case) and it also leads to a warm north/cold south dipole anomaly in eastern North America; but when PB occurs with a positive-phase NAO (NAO+), the WWCE dipole weakens and the CNWS dipole is enhanced. In particular, the WWCE dipole is favored by a combination of eastward-displaced PB and NAO- that form a negative Arctic Oscillation. Furthermore, a WWCE dipole can form over midlatitude North America when PB occurs together with southward-displaced NAO+.The PB events concurring with NAO- (NAO+) and SAT WWCE (CNWS) dipole are favored by the El Nio-like (La Nia-like) SST mode, though related to the North Atlantic warm-cold-warm (cold-warm-cold) SST tripole pattern. It is also found that the North Pacific mode tends to enhance the WWCE SAT dipole through increasing PB-NAO- events and producing the WWCE SAT dipole component related to the PB-NAO+ events because the PB and NAO+ form a more zonal wave train in this case.

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Impacts of the North Atlantic Oscillation on Winter Precipitations and Storm Track Variability in Southeast Canada and Northeast US

10.5194/wcd-2020-20 ◽

2020 ◽

Author(s):

Julien Chartrand ◽

Francesco Salvatore Rocco Pausata

Keyword(s):

United States ◽

North America ◽

North Atlantic Oscillation ◽

North Atlantic ◽

Storm Track ◽

The United States ◽

Eastern North America ◽

The North ◽

The North Atlantic ◽

The North Atlantic Oscillation

Abstract. The North Atlantic Oscillation (NAO) affects atmospheric variability from eastern North America to Europe. Although the link between the NAO and winter precipitations in the eastern North America have been the focus of previous work, only few studies have hitherto provided clear physical explanations on these relationships. In this study we revisit and extend the analysis of the effect of the NAO on winter precipitations over a large domain covering southeast Canada and the northeastern United States. Furthermore, here we use the recent ERA5 reanalysis dataset (1979–2018), which currently has the highest available horizontal resolution for a global reanalysis (0.25°), to track extratropical cyclones to delve into the physical processes behind the relationship between NAO and precipitation, snowfall, snowfall-to-precipitation ratio (S/P), and snow cover depth anomalies in the region. In particular, our results show that positive NAO phases are associated with less snowfall over a wide region covering Nova Scotia, New England and the Mid-Atlantic of the United States relative to negative NAO phases. Henceforth, a significant negative correlation is also seen between S/P and the NAO over this region. This is due to a decrease (increase) in cyclogenesis of coastal storms near the United States east coast during positive (negative) NAO phases, as well as a northward (southward) displacement of the mean storm track over North America.

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SynthETC: A Statistical Model for Severe Winter Storm Hazard on Eastern North America

Journal of Climate ◽

10.1175/jcli-d-16-0711.1 ◽

2017 ◽

Vol 30 (14) ◽

pp. 5329-5343 ◽

Cited By ~ 6

Author(s):

Timothy Hall ◽

James F. Booth

Keyword(s):

North America ◽

North Atlantic ◽

Southern Oscillation ◽

Historical Record ◽

Occurrence Rate ◽

Eastern North America ◽

Extratropical Cyclones ◽

Winter Storm ◽

The North ◽

The North Atlantic

The authors develop, evaluate, and apply SynthETC, a statistical–stochastic model of winter extratropical cyclones (ETCs) over eastern North America. SynthETC simulates the life cycle of ETCs from formation to termination, and it can be used to estimate the probability of extreme ETC events beyond the historical record. Two modes of climate variability are used as independent covariates: El Niño–Southern Oscillation (ENSO) Niño-3.4 index and the monthly North Atlantic Oscillation (NAO). SynthETC is used to estimate the annual occurrence rate over sites in eastern North America of intense ETC passage in different ENSO and NAO states. Positive NAO is associated with increased rates over the North Atlantic, while negative NAO is associated with decreased rates over the North Atlantic and increased rates over northern Quebec. Positive ENSO is associated with decreased rates over the North Atlantic, Ontario, and the Canadian maritime, while negative ENSO is associated with increased rates over those regions, as well as the Great Lakes region.

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Combined Influences on North American Winter Air Temperature Variability from North Pacific Blocking and the North Atlantic Oscillation: Subseasonal and Interannual Time Scales

Journal of Climate ◽

10.1175/jcli-d-19-0327.1 ◽

2020 ◽

Vol 33 (16) ◽

pp. 7101-7123 ◽

Cited By ~ 1

Author(s):

Binhe Luo ◽

Dehai Luo ◽

Aiguo Dai ◽

I. Simmonds ◽

Lixin Wu

Keyword(s):

North America ◽

Air Temperature ◽

North Atlantic ◽

North American ◽

North Pacific ◽

Eastern North America ◽

The North ◽

The North Atlantic ◽

The North Atlantic Oscillation ◽

The North Pacific

AbstractWinter surface air temperature (SAT) over North America exhibits pronounced variability on subseasonal, interannual, decadal, and interdecadal time scales. Here, reanalysis data from 1950–2017 are analyzed to investigate the atmospheric and surface ocean conditions associated with its subseasonal to interannual variability. Detrended daily SAT data reveal a known warm west/cold east (WWCE) dipole over midlatitude North America and a cold north/warm south (CNWS) dipole over eastern North America. It is found that while the North Pacific blocking (PB) is important for the WWCE and CNWS dipoles, they also depend on the phase of the North Atlantic Oscillation (NAO). When a negative-phase NAO (NAO−) coincides with PB, the WWCE dipole is enhanced (compared with the PB alone case) and it also leads to a warm north/cold south dipole anomaly in eastern North America; but when PB occurs with a positive-phase NAO (NAO+), the WWCE dipole weakens and the CNWS dipole is enhanced. The PB events concurrent with the NAO− (NAO+) and SAT WWCE (CNWS) dipole are favored by the Pacific El Niño–like (La Niña–like) sea surface temperature mode and the positive (negative) North Pacific mode. The PB-NAO+ has a larger component projecting onto the SAT WWCE dipole during the La Niña winter than during the El Niño winter because a more zonal wave train is formed. Strong North American SAT WWCE dipoles and enhanced projections of PB-NAO+ events onto the SAT WWCE dipole component are also readily seen for the positive North Pacific mode. The North Pacific mode seems to play a bigger role in the North American SAT variability than ENSO.

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FAUNAL RELATIONSHIPS BETWEEN EASTERN NORTH AMERICA AND EUROPE AS SHOWN BY INSECTS

Memoirs of the Entomological Society of Canada ◽

10.4039/entm120144039-1 ◽

1988 ◽

Vol 120 (S144) ◽

pp. 39-53 ◽

Cited By ~ 15

Author(s):

Gerald R. Noonan

Keyword(s):

North America ◽

Late Cretaceous ◽

North Atlantic ◽

North American ◽

Eastern North America ◽

Western North America ◽

The North ◽

The North Atlantic ◽

Fossil Data ◽

Suitable Land

AbstractThe supercontinent of Pangaea, which once included most lands, fragmented during the Mesozoic. By the Late Cretaceous there were two northern land masses that were strikingly different from those of present day: Asiamerica consisting of present western North America and Asia; and Euramerica comprising Europe and eastern North America. Mild climates facilitated the spread of terrestrial organisms within each of these land masses, but epicontinental seas hindered movements between Europe and Asia and between eastern and western North America.The insects of Euramerica presumably once formed a fauna extending from eastern North America to Europe that differed from the fauna of Asiamerica. The opening of the North Atlantic separated insects in Europe from those in eastern North America. This produced vicarious patterns, with some insects of eastern North America now being more closely related phylogenetically to those of Europe than to those of western North America. Most groups of insects have not been examined for such trans-Atlantic vicariances, but studies reviewed in this paper suggest such relationships for some groups of Collembola, Hemiptera, Homoptera, Coleoptera, Diptera, and Hymenoptera.The last suitable land connections between Europe and eastern North America were severed approximately 20–35 million years ago. The insects separated by this severance evolved at different rates. Some groups split in this way have apparently undergone little evolution and have the same species on both sides of the North Atlantic, but other vicarious groups have differentiated into taxa that are now distinct at specific and supra-specific levels.The opening of the North Atlantic probably split both tropical- and temperate-adapted insects in Euramerica. However, without fossil data it is difficult to identify the biogeographical patterns resulting from such splitting of the tropical-adapted groups. Most presently recognized European and eastern North American vicarious patterns of insects were probably caused by division of Euramerica rather than dispersal across Beringia.

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Past and possible future influence of the Atlantic Meridional Overturning Circulation on the climate responsible for concentration of geopolitical power and wealth in the North Atlantic region

Journal of Ocean and Climate Science Technology and Impacts ◽

10.1177/2516019219878561 ◽

2019 ◽

Vol 9 ◽

pp. 251601921987856

Author(s):

L Bruce Railsback

Keyword(s):

North America ◽

North Atlantic ◽

Atmospheric Precipitation ◽

Atlantic Meridional Overturning Circulation ◽

Meridional Overturning Circulation ◽

Eastern North America ◽

Overturning Circulation ◽

The North ◽

Meridional Overturning ◽

The North Atlantic

Previous research has shown that nations that controlled global-scale empires over the most recent centuries and presently possess great per-capita wealth are in Earth’s two largest regions of regular moderate rainfall. That rainfall regime is the pattern of atmospheric precipitation most supportive of agriculture and water-wheel-powered industry, both of which presumably contributed to those nations’ advancement. Those regions of regular moderate rainfall ring the North Atlantic, and this article reviews the evidence that the Gulf Stream delivers warm vapor-releasing water in the upper limb of the Atlantic Meridional Overturning Circulation, generating the distinctive climate of western Europe and eastern North America. Ocean circulation’s control on continental climate has thus contributed significantly to the Euro-American concentration of wealth and geopolitical power that has dominated the last few centuries of human history. However, comparison of the present apparent weakening or failure of the Atlantic Meridional Overturning Circulation with both the early Holocene 8.2 ka event and modeling of the Atlantic Meridional Overturning Circulation’s diminished generation of water vapor suggests that Europe and eastern North America may lose their beneficent climate pattern as rainfall there lessens.

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The distribution of Phyllophora in the North Atlantic and Arctic regions

Canadian Journal of Botany ◽

10.1139/b71-142 ◽

1971 ◽

Vol 49 (6) ◽

pp. 1017-1024 ◽

Cited By ~ 5

Author(s):

P. R. Newroth

Keyword(s):

North America ◽

North Atlantic ◽

Eastern North America ◽

Field Observations ◽

The North ◽

The United Kingdom ◽

Arctic Regions ◽

The North Atlantic ◽

Mediterranean And Black Seas ◽

Made In

The distributions of five species of Phyllophora Greville (Order Gigartinales) were examined in the North Atlantic and Arctic regions. Less detailed distributional observations of Phyllophora were made in the Mediterranean and Black Seas. Distributional records, based on extant specimens from extensive personal field observations in the United Kingdom and eastern North America and from collections in various herbaria, are recorded in tables and on maps; these records are discussed.

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Impacts of the North Atlantic Oscillation on winter precipitations and storm track variability in southeast Canada and the northeast United States

Weather and Climate Dynamics ◽

10.5194/wcd-1-731-2020 ◽

2020 ◽

Vol 1 (2) ◽

pp. 731-744

Author(s):

Julien Chartrand ◽

Francesco S. R. Pausata

Keyword(s):

United States ◽

North America ◽

North Atlantic ◽

Storm Track ◽

The United States ◽

Eastern North America ◽

Heavy Snowfall ◽

The North ◽

The North Atlantic ◽

The North Atlantic Oscillation

Abstract. The North Atlantic Oscillation (NAO) affects atmospheric variability from eastern North America to Europe. Although the link between the NAO and winter precipitations in eastern North America has been the focus of previous work, only few studies have considered extreme precipitation and hitherto provided clear physical explanations on these relationships. In this study we revisit and extend the analysis of the effect of the NAO on mean and heavy winter precipitations over a large domain covering southeast Canada and the northeastern United States. Furthermore, we use the recent ERA5 reanalysis dataset (1979–2018), which currently has the highest available horizontal resolution for a global reanalysis (0.25∘), to track extratropical cyclones to delve into the physical processes behind the relationship between NAO and precipitation, snowfall, snowfall-to-precipitation ratio (S∕P), and snow cover depth anomalies in the region. In particular, our results show that positive NAO phases are associated with less snowfall over a wide region covering Nova Scotia, New England and the Mid-Atlantic of the United States relative to negative NAO phases. Over the same area, the analysis of heavy snowfall revealed that there are up to twice as many heavy snowfall events during negative phases compared to positive phases. Therefore, a significant negative correlation is also seen between S∕P and the NAO over this region. This is due to a decrease (increase) in cyclogenesis of coastal storms near the United States east coast during positive (negative) NAO phases, as well as a northward (southward) displacement of the mean storm track over North America.

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Towards understanding potential atmospheric contributions to abrupt climate changes: Characterizing changes to the North Atlantic eddy-driven jet over the last deglaciation

10.5194/cp-2018-153 ◽

2018 ◽

Author(s):

Heather J. Andres ◽

Lev Tarasov

Keyword(s):

North America ◽

North Atlantic ◽

Wind Forcing ◽

Eastern North America ◽

Last Deglaciation ◽

Sea Ice Extent ◽

The North ◽

The Last Deglaciation ◽

The North Atlantic ◽

Background Climate

Abstract. Abrupt climate shifts of large amplitude were common features of the Earth's climate as it transitioned into and out of the last full glacial state approximately twenty thousand years ago, but their causes are not yet established. Mid-latitudinal atmospheric dynamics may have played an important role in these oscillations through their effects on heat and precipitation distributions, sea ice extent, and wind-driven ocean circulation patterns. This study characterises deglacial winter wind changes over the North Atlantic (NAtl) in a suite of transient deglacial simulations we performed using the PlaSim earth system model, as well as in the TraCE-21ka simulation. We detect multiple instances of NAtl jet transitions that occur within 10 simulation years and a sensitivity of the jet to background climate conditions. Thus, we suggest that changes to the NAtl jet may play a critical role in abrupt glacial climate oscillations. We identify two types of simulated wind changes over the last deglaciation. Firstly, the latitude of the NAtl eddy-driven jet shifts northward over the deglaciation in a sequence of distinct steps. Secondly, the variability of the NAtl jet gradually shifts from a Last Glacial Maximum (LGM) state with a strongly preferred jet latitude and a restricted latitudinal range to one with no single preferred latitude and a range that is at least 11° broader. Changes to the position of the NAtl jet alter the location of the wind forcing driving oceanic surface gyres and the limits of sea ice extent, whereas a shift to a more variable jet reduces the effectiveness of the wind forcing at driving surface ocean transports. The processes controlling these two types of changes differ on the upstream and downstream ends of the NAtl eddy-driven jet. On the upstream side over eastern North America, the elevated ice sheet margin acts as a physical barrier to the winds in both the PlaSim simulations and the TraCE-21ka experiment. This constrains both the position and the latitudinal variability of the jet at LGM, so the jet shifts in sync with ice sheet margin changes. In contrast, the downstream side over the eastern NAtl is more sensitive to the thermal state of the background climate. Our results suggest that knowing the position of the south-eastern margin of the North American ice complex strongly constrains the deglacial position of the jet over eastern North America and the western North Atlantic as well as its variability.

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Empire of the North Atlantic: The Maritime Struggle for North America. Gerald S. Graham

The Journal of Modern History ◽

10.1086/237525 ◽

1952 ◽

Vol 24 (3) ◽

pp. 310-311

Author(s):

G. H. Guttridge

Keyword(s):

North America ◽

North Atlantic ◽

The North ◽

The North Atlantic

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