Climatic variability in the eastern United States over the past millennium from Chesapeake Bay sediments

Geology ◽  
2000 ◽  
Vol 28 (1) ◽  
pp. 3 ◽  
Author(s):  
T. Cronin ◽  
D. Willard ◽  
A. Karlsen ◽  
S. Ishman ◽  
S. Verardo ◽  
...  
Geology ◽  
2000 ◽  
Vol 28 (1) ◽  
pp. 3-6 ◽  
Author(s):  
T. Cronin ◽  
D. Willard ◽  
A. Karlsen ◽  
S. Ishman ◽  
S. Verardo ◽  
...  

2019 ◽  
Author(s):  
Michael Toomey ◽  
◽  
Nicole D'Entremont ◽  
Emma Armstrong ◽  
Thomas Cronin ◽  
...  

1977 ◽  
Author(s):  
William A. Baker

The logo for this Third Chesapeake Sailing Yacht Symposium, the profile of a rakish sailing log canoe superimposed on that of a modern racing sloop, vividly illustrates the difference between the past and the present. Some might say good riddance to the past but there are many good reasons for trying to preserve something of our maritime heritage, not only the larger vessels such as the whaler Charles w. Morgan and the U. S. Corvette Constellation, but the smaller working watercraft as well. Although the Constellation was built in the Bay region, she was designed as a normal ocean-going ship for naval service; she has none of the unique features of Bay naval architecture hence is outside of the scope of this paper. In the days of our grandfathers the Chesapeake Bay region was the home of a multitude of watercraft employed for a wide variety of pursuits from general freighting to crabbing. There were rams, pungies, schooners, sloops, bugeyes, brogans, canoes, bateaux, skiffs, and scows. Of the skiffs alone, it is said that fourteen different designs were recognized on the Bay. While large numbers of these working boats and vessels have disappeared, it is only on Chesapeake Bay, of all the waters of the United States, that a fair variety of local watercraft can be found. Here there is still a chance of preserving for posterity more than isolated examples.


2019 ◽  
Vol 91 (2A) ◽  
pp. 660-676 ◽  
Author(s):  
John E. Ebel ◽  
Martin C. Chapman ◽  
Won-Young Kim ◽  
Mitchell Withers

Abstract The central and eastern United States (CEUS) is an area of generally low-to-moderate seismic hazard with a number of large cities with high seismic risk, a history of occasional damaging earthquakes, and seismic activity induced by wastewater disposal. Seismic monitoring in the CEUS, which began at the beginning 1900s, has undergone many changes through time. Over the past two decades, broadband digital seismic stations connected by internet communications have become widespread. Modern data processing systems to automatically locate earthquakes and assign event magnitudes in near-real time have become the norm, and, since the inception of the Advanced National Seismic System in 2000, more than 10,000 earthquakes have been located and cataloged. Continuously recorded digital seismic data at 100 samples per second are allowing new avenues of research into earthquake source parameters, ground-motion excitation, and seismic wave propagation. Unfortunately, over the past two decades the number of regional seismic network (RSN) centers has diminished due to consolidations and terminations, as funding has tightened. Nevertheless, the public in different parts of the CEUS still looks to local experts for information when earthquakes take place or when they have questions about earthquakes and seismic hazard. The current RSNs must evolve to encompass the need for local seismic information centers and to serve the needs of present and future research into the causes and effects of CEUS earthquakes.


Botany ◽  
2010 ◽  
Vol 88 (4) ◽  
pp. 336-344 ◽  
Author(s):  
Norton G. Miller ◽  
Sean C. Robinson

The moss Ptychomitrium serratum (C. Müll. Hal. ex Schimp.) Besch., is native to Mexico and parts of western Texas and southern New Mexico, and it is a rare adventive in the area from East Texas and Louisiana to Missouri, Tennessee, South Carolina, and northward to locations near the coast in New York State and Massachusetts. In the adventive part of this calcicole’s range, all collections are from the past 50 years. Concrete, mortar, and rarely asphalt shingle are its only known substrata in this region, which contrasts sharply with its common occurrence on limestone in the native portion of its range. These observations indicate recent, perhaps on-going, immigration into the eastern United States and dispersal from established populations in this region. This monoicous moss commonly produces spores, which are its primary means of spread. Given the low density occurrences in the adventive portion of the range of P. serratum, dispersal may be generally northeastward from Mexico – Texas – New Mexico, following northeastward storm tracks in the southern and eastern United States. The apparently recent spread of this moss does not show obvious reliance on any direct human activity.


2008 ◽  
Vol 276 (1658) ◽  
pp. 823-831 ◽  
Author(s):  
Zhibin Zhang ◽  
Bernard Cazelles ◽  
Huidong Tian ◽  
Leif Christian Stige ◽  
Achim Bräuning ◽  
...  

Global warming is currently of great concern. Yet the ecological effects of low-frequency climate variations remain largely unknown. Recent analyses of interdecadal variability in population abundance of the Oriental migratory locust ( Locusta migratoria manilensis ) in China have revealed negative associations with temperature and positive associations with Yangtze drought and flood frequencies during the past millennium (AD 957–1956). In order to shed new light on the causal relationships between locust abundance, floods, droughts and temperature in ancient China, we used wavelet analysis to explore how the coherencies between the different variables at different frequencies have been changed during the past millennium. We find consistent in-phase coherencies between locusts and drought/flood frequencies, and out-of-phase coherencies between locusts and temperature and between drought/flood and temperature at period components of 160–170 years. Similar results are obtained when historical data of drought/flood frequencies of the Yangtze Delta region are used, despite flood data showing a weak and somewhat inconsistent association with other factors. We suggest that previously unreported periodic cooling of 160–170-year intervals dominate climatic variability in China through the past millennium, the cooling events promoting locust plagues by enhancing temperature-associated drought/flood events. Our results signify a rare example of possible benign effects of global warming on the regional risk of natural disasters such as flood/drought events and outbreaks of pest insects.


2008 ◽  
Vol 21 (9) ◽  
pp. 1850-1862 ◽  
Author(s):  
Pavel Ya Groisman ◽  
Richard W. Knight

Abstract A disproportionate increase in precipitation coming from intense rain events, in the situation of general warming (thus, an extension of the vegetation period with intensive transpiration), and an insignificant change in total precipitation could lead to an increase in the frequency of a potentially serious type of extreme events: prolonged periods without precipitation (even when the mean seasonal rainfall totals increase). This paper investigates whether this development is already occurring during the past several decades over the conterminous United States, for the same period when changes in frequency of intense precipitation events are being observed. Lengthy strings of “dry” days without sizeable (>1.0 mm) precipitation were assessed only during the warm season (defined as a period when mean daily temperature is above the 5°C threshold) when water is intensively used for transpiration and prolonged periods without sizable rainfall represent a hazard for terrestrial ecosystem’s health and agriculture. During the past four decades, the mean duration of prolonged dry episodes (1 month or longer in the eastern United States and 2 months or longer in the southwestern United States) has significantly increased. As a consequence the return period of 1-month-long dry episodes over the eastern United States has reduced more than twofold from 15 to 6–7 yr. The longer average duration of dry episodes has occurred during a relatively wet period across the country but is not observed over the northwestern United States.


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