scholarly journals Future Changes in Tropical Cyclone and Easterly Wave Characteristics over Tropical North America

Oceans ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 429-447
Author(s):  
Christian Dominguez ◽  
James M. Done ◽  
Cindy L. Bruyère

Tropical Cyclones (TCs) and Easterly Waves (EWs) are the most important phenomena in Tropical North America. Thus, examining their future changes is crucial for adaptation and mitigation strategies. The Community Earth System Model drove a three-member regional model multi-physics ensemble under the Representative Concentration Pathways 8.5 emission scenario for creating four future scenarios (2020–2030, 2030–2040, 2050–2060, 2080–2090). These future climate runs were analyzed to determine changes in EW and TC features: rainfall, track density, contribution to seasonal rainfall, and tropical cyclogenesis. Our study reveals that a mean increase of at least 40% in the mean annual TC precipitation is projected over northern Mexico and southwestern USA. Slight positive changes in EW track density are projected southwards 10° N over the North Atlantic Ocean for the 2050–2060 and 2080–2090 periods. Over the Eastern Pacific Ocean, a mean increment in the EW activity is projected westwards across the future decades. Furthermore, a mean reduction by up to 60% of EW rainfall, mainly over the Caribbean region, Gulf of Mexico, and central-southern Mexico, is projected for the future decades. Tropical cyclogenesis over both basins slightly changes in future scenarios (not significant). We concluded that these variations could have significant impacts on regional precipitation.

<em>Abstract.</em> - Sea sturgeons are closely related anadromous fishes inhabiting both shores of the North Atlantic Ocean. They are classified in two species: the European sturgeon <em>Acipenser sturio</em> in Europe and the Atlantic sturgeon <em>A. oxyrinchus</em> in North America. The Atlantic sturgeon is further separated into two subspecies: Atlantic sturgeon (North American East Coast populations) <em>A. o. oxyrinchus</em> and Gulf sturgeon <em>A. o. desotoi. </em>Most recent studies of morphology and genetics support these classifications. Furthermore, they produced evidence for a trans-Atlantic colonization event during the early Middle Ages. Atlantic sturgeon colonized Baltic waters, founding a self-reproducing population before they became extinct due to anthropogenic reasons. Today, populations of Atlantic sturgeon are found along the Atlantic Coast from the St. Johns River, Florida to the St. Lawrence River, Quebec, whereas only one relict spawning population of European sturgeon still exists in the Gironde River, France. The evidence of a population of Atlantic sturgeon in Baltic waters requires a detailed comparison of both sea sturgeon species, describing differences and similarities, which may influence the ongoing restoration projects in Europe as well as concerning conservation efforts in North America. This article reviews similarities and differences in the fields of genetics, morphology, and ecological adaptation of European sturgeon and Atlantic sturgeon, concluding that, besides morphological and genetic differences, a wider range of spawning temperatures in Atlantic sturgeon is evident. This wider temperature adaptation may be a selective advantage under fast-changing climatic conditions, possibly the mechanism that enabled the species shift in the Baltic Sea during the Middle Ages.


Paleobiology ◽  
1991 ◽  
Vol 17 (3) ◽  
pp. 266-280 ◽  
Author(s):  
S. David Webb

When the isthmian land bridge triggered the Great American Interchange, a large majority of land-mammal families crossed reciprocally between North and South America at about 2.5 Ma (i.e., Late Pliocene). Initially land-mammal dynamics proceeded as predicted by equilibrium theory, with roughly equal reciprocal mingling on both continents. Also as predicted, the impact of the interchange faded in North America after about 1 m.y. In South America, contrary to such predictions, the interchange became decidedly unbalanced: during the Pleistocene, groups of North American origin continued to diversify at exponential rates. Whereas only about 10% of North American genera are derived from southern immigrants, more than half of the modern mammalian fauna of South America, measured at the generic level, stems from northern immigrants. In addition, extinctions more severely decimated interchange taxa in North America, where six families were lost, than in South America, where only two immigrant families became extinct.This paper presents a two-phase ecogeographic model to explain the asymmetrical results of the land-mammal interchange. During the humid interglacial phase, the tropics were dominated by rain forests, and the principal biotic movement was from Amazonia to Central America and southern Mexico. During the more arid glacial phase, savanna habitats extended broadly right through tropical latitudes. Because the source area in the temperate north was six times as large as that in the south, immigrants from the north outnumbered those from the south. One prediction of this hypothesis is that immigrants from the north generally should reach higher latitudes in South America than the opposing contingent of land-mammal taxa in North America. Another prediction is that successful interchange families from the north should experience much of their phylogenetic diversification in low latitudes of North America before the interchange. Insofar as these predictions can be tested, they appear to be upheld.


2016 ◽  
Vol 29 (2) ◽  
pp. 659-671 ◽  
Author(s):  
Qi Hu ◽  
Michael C. Veres

Abstract This is the second part of a two-part paper that addresses deterministic roles of the sea surface temperature (SST) anomalies associated with the Atlantic multidecadal oscillation (AMO) in variations of atmospheric circulation and precipitation in the Northern Hemisphere, using a sequence of idealized model runs at the spring equinox conditions. This part focuses on the effect of the SST anomalies on North American precipitation. Major results show that, in the model setting closest to the real-world situation, a warm SST anomaly in the North Atlantic Ocean causes suppressed precipitation in central, western, and northern North America but more precipitation in the southeast. A nearly reversed pattern of precipitation anomalies develops in response to the cold SST anomaly. Further examinations of these solutions reveal that the response to the cold SST anomaly is less stable than that to the warm SST anomaly. The former is “dynamically charged” in the sense that positive eddy kinetic energy (EKE) exists over the continent. The lack of precipitation in its southeast is because of an insufficient moisture supply. In addition, the results show that the EKE of the short- (2–6 day) and medium-range (7–10 day) weather-producing processes in North America have nearly opposite signs in response to the same cold SST anomaly. These competing effects of eddies in the dynamically charged environment (elevated sensitivity to moisture) complicate the circulation and precipitation responses to the cold SST anomaly in the North Atlantic and may explain why the model results show more varying precipitation anomalies (also confirmed by statistical test results) during the cold than the warm SST anomaly, as also shown in simulations with more realistic models. Results of this study indicate a need to include the AMO in the right context with other forcings in an effort to improve understanding of interannual-to-multidecadal variations in warm season precipitation in North America.


1991 ◽  
Vol 123 (S158) ◽  
pp. 3-105 ◽  
Author(s):  
D.C. Ferguson ◽  
D.J. Hilburn ◽  
B. Wright

AbstractThe 183 species of Lepidoptera recorded from Bermuda are discussed with respect to their world distribution, origin, long-range dispersal capability, host plants, nomenclature, and the circumstances of their occurrence in Bermuda; most are illustrated. Fifty-nine species are reported from Bermuda for the first time; Oenobotys invinacealis Ferguson (Pyralidae) and Tetanolita mynesalis inaequalis Ferguson (Noctuidae) are described as new. Four new genus–species combinations and four new synonymies are proposed.The Bermuda islands have a distressed fauna dominated by introduced pest species and migrants from the North American mainland and Caribbean Region. About 125 of the 183 recorded species are thought to be established residents; the remainder are assumed to be vagrants. Of approximately 50 resident species identified as probably indigenous, 11 species and three subspecies are endemic, and one of these, Semiothisa ochrifascia (Warren), is believed extinct.All Bermudian Lepidoptera are of American origin except the few introduced Old World species that are nearly cosmopolitan. Like Norfolk Island, Australia, Bermuda has a supersaturated lepidopterous fauna — more recorded species than its land area might support, which can be explained only by a high incidence of migrants and transients. This migratory component is explained relative to long-range movements of the same or congeneric species elsewhere; and hypotheses are proposed concerning the natural history of long-range dispersal in eastern North America and the ability of these moths to reach Bermuda. From a list of 113 species of Lepidoptera identified as frequent south–north migrants on the mainland, 76 are recorded from Bermuda. These include 38 of the 40 best-known cutworm moths of the eastern United States. It is argued that such moths reach Bermuda repeatedly without man's assistance and must regularly travel similar distances in North America.


2015 ◽  
Vol 54 (3) ◽  
pp. 643-657 ◽  
Author(s):  
Jonny W. Malloy ◽  
Daniel S. Krahenbuhl ◽  
Chad E. Bush ◽  
Robert C. Balling ◽  
Michael M. Santoro ◽  
...  

AbstractThis study explores long-term deviations from wind averages, specifically near the surface across central North America and adjoining oceans (25°–50°N, 60°–130°W) for 1979–2012 (408 months) by utilizing the North American Regional Reanalysis 10-m wind climate datasets. Regions where periods of anomalous wind speeds were observed (i.e., 1 standard deviation below/above both the long-term mean annual and mean monthly wind speeds at each grid point) were identified. These two climatic extremes were classified as wind lulls (WLs; below) or wind blows (WBs; above). Major findings for the North American study domain indicate that 1) mean annual wind speeds range from 1–3 m s−1 (Intermountain West) to over 7 m s−1 (offshore the East and West Coasts), 2) mean durations for WLs and WBs are high for much of the southeastern United States and for the open waters of the North Atlantic Ocean, respectively, 3) the longest WL/WB episodes for the majority of locations have historically not exceeded 5 months, 4) WLs and WBs are most common during June and October, respectively, for the upper Midwest, 5) WLs are least frequent over the southwestern United States during the North American monsoon, and 6) no significant anomalous wind trends exist over land or sea.


1985 ◽  
Vol 28 (3) ◽  
pp. 575-596 ◽  
Author(s):  
Philip Lawson

This was how the Public Advertiser greeted the passage of the Quebec Act through parliament in June 1774. It was a remarkable transformation from the ecstasy evident in newspaper reports that greeted the fall of New France in 1760. As early as November 1759 the city of Nottingham singled out the North American campaign as the glorious core of British strategy. Its loyal address congratulated the king ‘particularly upon the defeat of the French army in Canada, and the taking of Quebec; an acquisition not less honourable to your majesty's forces, than destructive of the trade and commerce and power of France in North America’. What occurred in those fourteen years to produce such a stark revision of views on the conquest of New France? The answer can be found partly by surveying the English press for this period. During these years, treatment of Canadian issues in the press displayed quite distinct characteristics that revealed a whole range of attitudes and opinions on the place Canada held in the future of the North American empire. No consensus on this issue ever existed. Debate on Canada mirrored a wider discussion on the future of the polyglot empire acquired at the end of the Seven Years War in 1763. In ranged from the enthusiasm of officials at Westminster to spokesmen of a strain in English thinking that challenged the whole thrust of imperial policy to date.


1989 ◽  
Vol 83 (1) ◽  
pp. 16-18
Author(s):  
M.D. Orlansky

This report offers a brief overview of recent population figures, types of educational programs, and selected topics of present interest and relevance to educators of blind and visually impaired students in the U.S.A., Canada, and the Caribbean. While not intended to be comprehensive or statistically exacting, it is hoped that this discussion will be useful in informing our colleagues in other areas of the world about some of the current concerns of professionals in the North America-Caribbean region.


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