scholarly journals Significant enhancements of nitrogen oxides, black carbon, and ozone in the North Atlantic lower free troposphere resulting from North American boreal wildfires

2006 ◽  
Vol 111 (D23) ◽  
Author(s):  
M. Val Martín ◽  
R. E. Honrath ◽  
R. C. Owen ◽  
G. Pfister ◽  
P. Fialho ◽  
...  
Keyword(s):  
Nitrogen Oxides ◽  
Black Carbon ◽  
North Atlantic ◽  
North American ◽  
Free Troposphere ◽  
The North ◽  
The North Atlantic

scholarly journals Impact of North America on the aerosol composition in the North Atlantic free troposphere

2017 ◽  
Vol 17 (12) ◽  
pp. 7387-7404 ◽  
Author(s):  
M. Isabel García ◽  
Sergio Rodríguez ◽  
Andrés Alastuey
Keyword(s):  
Organic Matter ◽  
North America ◽  
North Atlantic ◽  
North American ◽  
Sea Salt ◽  
Free Troposphere ◽  
Aerosol Composition ◽  
The North ◽  
The North Atlantic

Abstract. In the AEROATLAN project we study the composition of aerosols collected over  ∼  5 years at Izaña Observatory (located at  ∼  2400 m a.s.l. in Tenerife, the Canary Islands) under the prevailing westerly airflows typical of the North Atlantic free troposphere at subtropical latitudes and midlatitudes. Mass concentrations of sub-10 µm aerosols (PM10) carried by westerly winds to Izaña, after transatlantic transport, are typically within the range 1.2 and 4.2 µg m−3 (20th and 80th percentiles). The main contributors to background levels of aerosols (PM10 within the 1st–50th percentiles  =  0.15–2.54 µg m−3) are North American dust (53 %), non-sea-salt sulfate (14 %) and organic matter (18 %). High PM10 events (75th–95th percentiles  ≈  4.0–9.0 µg m−3) are prompted by dust (56 %), organic matter (24 %) and non-sea-salt sulfate (9 %). These aerosol components experience a seasonal evolution explained by (i) their spatial distribution in North America and (ii) the seasonal shift of the North American outflow, which migrates from low latitudes in winter (∼  32° N, January–March) to high latitudes in summer (∼  52° N, August–September). The westerlies carry maximum loads of non-sea-salt sulfate, ammonium and organic matter in spring (March–May), of North American dust from midwinter to mid-spring (February–May) and of elemental carbon in summer (August–September). Our results suggest that a significant fraction of organic aerosols may be linked to sources other than combustion (e.g. biogenic); further studies are necessary for this topic. The present study suggests that long-term evolution of the aerosol composition in the North Atlantic free troposphere will be influenced by air quality policies and the use of soils (potential dust emitter) in North America.

scholarly journals Impact of North America on the aerosol composition in the North Atlantic free troposphere

2017 ◽  
Author(s):  
M. Isabel García ◽  
Sergio Rodríguez ◽  
Andrés Alastuey
Keyword(s):  
Organic Matter ◽  
North America ◽  
North Atlantic ◽  
North American ◽  
Free Troposphere ◽  
Aerosol Composition ◽  
The North ◽  
Westerly Winds ◽  
The North Atlantic

Abstract. In the AEROATLAN project we study the composition of aerosols collected over ~ 5 years at Izaña Observatory (located at ~ 2400 m a.s.l. in Tenerife, the Canary Islands) under the prevailing westerly airflows typical of the North Atlantic free troposphere at subtropical and mid-latitudes. Mass concentrations of sub10-µm aerosols (PM10) carried by westerly winds to Izaña, after transatlantic transport, are typically within the range 1.2 and 4.2 µg m−3 (20th and 80th percentiles). The main contributors to background levels of aerosols (PM10 within the 1st–50th percentiles = 0.15–2.54 µg m−3) are North American dust (53 %), non-sea-salt-SO4= (14 %) and organic matter (18 %). High PM10 events (75th–95th percentiles ≈ 4.0–9.0 µg m−3) and are prompted by dust (56 %), organic matter (24 %) and nss-SO4= (9 %). These aerosol components experience a seasonal evolution explained by (i) their spatial distribution in North America and (ii) the seasonal shift of the North American outflow, which migrates from low latitudes in winter (~ 32º N, January–March) to high latitudes in summer (~ 52º N, August–September). The westerlies carry maximum loads of nss-sulphate, ammonium and organic matter in spring (March–May), of North American dust from mid-winter to mid-spring (February–May) and of elemental carbon in summer (August–September). Our results suggest that a significant fraction of organic aerosols may be linked to sources other than combustion (e.g. biogenic); further studies are necessary for this topic. The present study evidences how long-term evolution of the aerosol composition in the North Atlantic free troposphere will be influenced by air quality policies and the use of soils (potential dust emitter) in North America.

Beyond the Cold War Chessboard

Worldview ◽  
1974 ◽  
Vol 17 (6) ◽  
pp. 21-22
Author(s):  
John W. Holmes
Keyword(s):  
United States ◽  
Cold War ◽  
North Atlantic ◽  
North American ◽  
The Other ◽  
The North ◽  
Common Interests ◽  
The North Atlantic ◽  
The Cold War

The problem in judging M. Servan-Schreiber's message is that he reaches some sound conclusions on the basis of dubious premises, from which he derives recommendations which could be disastrous.There may be some satisfaction in seeing a Frenchman concerned with le défi, russe instead of le défi américain, but his interpretation of one is as crude as was his interpretation of the other. The shock of revelation that there are common interests of the Atlantic countries in economic as well as strategic matters is understandably more startling to a Frenchman than to others. It was all set out in 1949 in Article 2 of the North Atlantic Treaty and was restated eloquently in 1973 by Mr. Kissinger. But last spring European leaders were included to see the latter as a self-interested plea from a weak United States to a prosperous Europe. The North American countries were reminded that their role in Europe was simply to defend it on request.

The Vinland Adventure: A North Atlantic Perspective

1982 ◽  
Vol 2 (4) ◽  
pp. 285-308 ◽  
Author(s):  
Thomas H. Mc Govern
Keyword(s):  
Native Americans ◽  
North Atlantic ◽  
North American ◽  
American Continent ◽  
North American Continent ◽  
The North ◽  
Geographical Factors ◽  
The North Atlantic ◽  
Adaptive Shifts ◽  
Early Phases

During the Viking period, Norse seafarers from Greenland attempted to plant a settlement on the North American continent. This Vinland settlement faltered in its early phases and was not successful. Its failure may be best understood from the broader perspective of the Scandinavian expansion across the North Atlantic islands which began ca. AD 800. Adaptive shifts in the older North Atlantic colonies, geographical factors, and the resistance of Native Americans may have combined to doom this Western-most medieval colony.

Timing and duration of North American glacial lake discharges and the Younger Dryas climate reversal

2011 ◽  
Vol 75 (3) ◽  
pp. 541-551 ◽  
Author(s):  
John A. Rayburn ◽  
Thomas M. Cronin ◽  
David A. Franzi ◽  
Peter L.K. Knuepfer ◽  
Debra A. Willard
Keyword(s):  
Ocean Circulation ◽  
North Atlantic ◽  
North American ◽  
Younger Dryas ◽  
Ice Cores ◽  
Cold Event ◽  
Lawrence Estuary ◽  
The North ◽  
The North Atlantic ◽  
Proglacial Lake

AbstractRadiocarbon-dated sediment cores from the Champlain Valley (northeastern USA) contain stratigraphic and micropaleontologic evidence for multiple, high-magnitude, freshwater discharges from North American proglacial lakes to the North Atlantic. Of particular interest are two large, closely spaced outflows that entered the North Atlantic Ocean via the St. Lawrence estuary about 13,200–12,900 cal yr BP, near the beginning of the Younger Dryas cold event. We estimate from varve chronology, sedimentation rates and proglacial lake volumes that the duration of the first outflow was less than 1 yr and its discharge was approximately 0.1 Sv (1 Sverdrup = 106 m3 s−1). The second outflow lasted about a century with a sustained discharge sufficient to keep the Champlain Sea relatively fresh for its duration. According to climate models, both outflows may have had sufficient discharge, duration and timing to affect meridional ocean circulation and climate. In this report we compare the proglacial lake discharge record in the Champlain and St. Lawrence valleys to paleoclimate records from Greenland Ice cores and Cariaco Basin and discuss the two-step nature of the inception of the Younger Dryas.

A Unified Nonlinear Multiscale Interaction Model of Pacific–North American Teleconnection Patterns

2020 ◽  
Vol 77 (4) ◽  
pp. 1387-1414
Author(s):  
Dehai Luo ◽  
Yao Ge ◽  
Wenqi Zhang ◽  
Aiguo Dai
Keyword(s):  
North Atlantic ◽  
North American ◽  
Wave Train ◽  
Interaction Model ◽  
Energy Dispersion ◽  
Pacific North American ◽  
The North ◽  
The North Atlantic ◽  
The Difference ◽  
Multiscale Interaction

Abstract In this paper, reanalysis data are first analyzed to reveal that the individual negative (positive)-phase Pacific–North American pattern (PNA) or PNA− (PNA+) has a lifetime of 10–20 days, is characterized by strong (weak) westerly jet stream meanders, and exhibits clear wave train structures, whereas the PNA− with rapid retrogression tends to have longer lifetime and larger amplitude than the PNA+ with slow retrogression. In contrast, the wave train structure of the North Atlantic Oscillation (NAO) is less distinct, and the positive (negative)-phase NAO shows eastward (westward) movement around a higher latitude than the PNA. Moreover, it is found that the PNA wave train occurs under a larger background meridional potential vorticity gradient (PVy) over the North Pacific than that over the North Atlantic for the NAO. A unified nonlinear multiscale interaction (UNMI) model is then developed to explain why the PNA as a nonlinear wave packet has such characteristics and its large difference from the NAO. The model results reveal that the larger background PVy for the PNA (due to its location at lower latitudes) leads to its larger energy dispersion and weaker nonlinearity than the NAO, thus explaining why the PNA (NAO) is largely a linear (nonlinear) process with a strong (weak) wave train structure, though it is regarded as a nonlinear initial-value problem. The smaller PVy for the PNA− than for the PNA+ leads to lower energy dispersion and stronger nonlinearity for PNA−, which allows it to maintain larger amplitude and have a longer lifetime than the PNA+. Thus, the difference in the background PVy is responsible for the asymmetry between the two phases of PNA and the difference between the PNA and NAO.

Merchant Organization and Maritime Trade in the North Atlantic, 1660-1815

1998 ◽  
Keyword(s):  
International Trade ◽  
Early Modern ◽  
North Atlantic ◽  
North American ◽  
Early Modern Period ◽  
Economic Life ◽  
The North ◽  
Modern Period ◽  
Modern Economic ◽  
The North Atlantic

This journal presents the challenges faced by maritime merchants operating in the North Atlantic in the early modern period, and examines the opportunities, aspirations, and methods utilised in the pursuit of profitable trade. The journal collects nine essays and a reflective conclusion, which cumulatively explore the major themes of trade within empires; growth of trade; new initiatives within trade empires; government initiatives in relation to maritime mercantile trade; merchant migration; and changes in international trade. The journal attempts to provide scholarly insight and perspectives into early modern economic life, through the maritime mercantile activities of various European and North American nations.

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