scholarly journals Seasonal and spatial patterns of mercury wet deposition in the United States: Constraints on the contribution from North American anthropogenic sources

2008 ◽  
Vol 42 (21) ◽  
pp. 5193-5204 ◽  
Author(s):  
Noelle E. Selin ◽  
Daniel J. Jacob
Keyword(s):  
United States ◽  
Spatial Patterns ◽  
North American ◽  
Wet Deposition ◽  
The United States ◽  
Anthropogenic Sources

scholarly journals Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

2013 ◽  
Vol 13 (4) ◽  
pp. 9849-9893 ◽  
Author(s):  
H. Lei ◽  
X.-Z. Liang ◽  
D. J. Wuebbles ◽  
Z. Tao
Keyword(s):  
United States ◽  
Air Quality ◽  
Wet Deposition ◽  
Total Mercury ◽  
The United States ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Mercury Deposition ◽  
Transpacific Transport ◽  
Mercury Cycle

Abstract. Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry). The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg) in three forms: elemental mercury (Hg(0)), reactive mercury (Hg(II)), and particulate mercury (PHg). Emissions of mercury include those from human, land, ocean, biomass burning and volcano related sources. Land emissions are calculated based on surface solar radiation flux and skin temperature. A simplified air–sea mercury exchange scheme is used to calculate emissions from the oceans. The chemistry mechanism includes the oxidation of Hg(0) in gaseous phase by ozone with temperature dependence, OH, H2O2 and chlorine. Aqueous chemistry includes both oxidation and reduction of Hg(0). Transport and deposition of mercury species are calculated through adapting the original formulations in CAM-Chem. The CAM-Chem model with mercury is driven by present meteorology to simulate the present mercury air quality during the 1999–2001 periods. The resulting surface concentrations of total gaseous mercury (TGM) are then compared with the observations from worldwide sites. Simulated wet depositions of mercury over the continental United States are compared to the observations from 26 Mercury Deposition Network stations to test the wet deposition simulations. The evaluations of gaseous concentrations and wet deposition confirm a strong capability for the CAM-Chem mercury mechanism to simulate the atmospheric mercury cycle. The results also indicate that mercury pollution in East Asia and Southern Africa is very significant with TGM concentrations above 3.0 ng m−3. The comparison to wet deposition indicates that wet deposition patterns of mercury are more affected by the spatial variability of precipitation. The sensitivity experiments show that 22% of total mercury deposition and 25% of TGM concentrations in the United States are resulted from domestic anthropogenic sources, but only 9% of total mercury deposition and 7% of TGM concentrations are contributed by transpacific transport. However, the contributions of domestic and transpacific sources on the western United States levels of mercury are of comparable magnitude.

scholarly journals Dynamics, Variability, and Change in Seasonal Precipitation Reconstructions for North America

2020 ◽  
Vol 33 (8) ◽  
pp. 3173-3195 ◽  
Author(s):  
David W. Stahle ◽  
Edward R. Cook ◽  
Dorian J. Burnette ◽  
Max C. A. Torbenson ◽  
Ian M. Howard ◽  
...  
Keyword(s):  
United States ◽  
North America ◽  
Spatial Patterns ◽  
North American ◽  
Arctic Oscillation ◽  
Warm Season ◽  
The United States ◽  
The Arctic ◽  
Seasonal Precipitation ◽  
The Arctic Oscillation

AbstractCool- and warm-season precipitation totals have been reconstructed on a gridded basis for North America using 439 tree-ring chronologies correlated with December–April totals and 547 different chronologies correlated with May–July totals. These discrete seasonal chronologies are not significantly correlated with the alternate season; the December–April reconstructions are skillful over most of the southern and western United States and north-central Mexico, and the May–July estimates have skill over most of the United States, southwestern Canada, and northeastern Mexico. Both the strong continent-wide El Niño–Southern Oscillation (ENSO) signal embedded in the cool-season reconstructions and the Arctic Oscillation signal registered by the warm-season estimates faithfully reproduce the sign, intensity, and spatial patterns of these ocean–atmospheric influences on North American precipitation as recorded with instrumental data. The reconstructions are included in the North American Seasonal Precipitation Atlas (NASPA) and provide insight into decadal droughts and pluvials. They indicate that the sixteenth-century megadrought, the most severe and sustained North American drought of the past 500 years, was the combined result of three distinct seasonal droughts, each bearing unique spatial patterns potentially associated with seasonal forcing from ENSO, the Arctic Oscillation, and the Atlantic multidecadal oscillation. Significant 200–500-yr-long trends toward increased precipitation have been detected in the cool- and warm-season reconstructions for eastern North America. These seasonal precipitation changes appear to be part of the positive moisture trend measured in other paleoclimate proxies for the eastern area that began as a result of natural forcing before the industrial revolution and may have recently been enhanced by anthropogenic climate change.

scholarly journals Model analyses of atmospheric mercury: present air quality and effects of transpacific transport on the United States

2013 ◽  
Vol 13 (21) ◽  
pp. 10807-10825 ◽  
Author(s):  
H. Lei ◽  
X.-Z. Liang ◽  
D. J. Wuebbles ◽  
Z. Tao
Keyword(s):  
United States ◽  
Air Quality ◽  
Wet Deposition ◽  
Total Mercury ◽  
The United States ◽  
Atmospheric Mercury ◽  
Anthropogenic Sources ◽  
Mercury Deposition ◽  
Transpacific Transport ◽  
Mercury Cycle

Abstract. Atmospheric mercury is a toxic air and water pollutant that is of significant concern because of its effects on human health and ecosystems. A mechanistic representation of the atmospheric mercury cycle is developed for the state-of-the-art global climate-chemistry model, CAM-Chem (Community Atmospheric Model with Chemistry). The model simulates the emission, transport, transformation and deposition of atmospheric mercury (Hg) in three forms: elemental mercury (Hg(0)), reactive mercury (Hg(II)), and particulate mercury (PHg). Emissions of mercury include those from human, land, ocean, biomass burning and volcano related sources. Land emissions are calculated based on surface solar radiation flux and skin temperature. A simplified air–sea mercury exchange scheme is used to calculate emissions from the oceans. The chemistry mechanism includes the oxidation of Hg(0) in gaseous phase by ozone with temperature dependence, OH, H2O2 and chlorine. Aqueous chemistry includes both oxidation and reduction of Hg(0). Transport and deposition of mercury species are calculated through adapting the original formulations in CAM-Chem. The CAM-Chem model with mercury is driven by present meteorology to simulate the present mercury air quality during the 1999–2001 period. The resulting surface concentrations of total gaseous mercury (TGM) are then compared with the observations from worldwide sites. Simulated wet depositions of mercury over the continental United States are compared to the observations from 26 Mercury Deposition Network stations to test the wet deposition simulations. The evaluations of gaseous concentrations and wet deposition confirm a strong capability for the CAM-Chem mercury mechanism to simulate the atmospheric mercury cycle. The general reproduction of global TGM concentrations and the overestimation on South Africa indicate that model simulations of TGM are seriously affected by emissions. The comparison to wet deposition indicates that wet deposition patterns of mercury are more affected by the spatial variability of precipitation. The sensitivity experiments show that 22% of total mercury deposition and 25% of TGM concentrations in the United States result from domestic anthropogenic sources, but only 9% of total mercury deposition and 7% of TGM concentrations are contributed by transpacific transport. However, the contributions of domestic and transpacific sources on the western United States levels of mercury are of comparable magnitude.

Benjamin Henry Latrobe and the nomenclature of two North American fishes

1987 ◽  
Vol 14 (1) ◽  
pp. 85-88
Author(s):  
CHARLOTTE M PORTER
Keyword(s):  
United States ◽  
North American ◽  
The United States ◽  
American Shad ◽  
New Name ◽  
The Common ◽  
Fish Louse

A curious error affects the names of three North American clupeids—the Alewife, American Shad, and Menhaden. The Alewife was first described by the British-born American architect, Benjamin Henry Latrobe in 1799, just two years after what is generally acknowledged as the earliest description of any ichthyological species published in the United States. Latrobe also described the ‘fish louse’, the common isopod parasite of the Alewife, with the new name, Oniscus praegustator. Expressing an enthusiasm for American independence typical of his generation, Latrobe humorously proposed the name Clupea tyrannus for the Alewife because the fish, like all tyrants, had parasites or hangers-on.

scholarly journals “The Future of Archaeology Is Antiracist”: Archaeology in the Time of Black Lives Matter

2021 ◽  
pp. 1-20
Author(s):  
Ayana Omilade Flewellen ◽  
Justin P. Dunnavant ◽  
Alicia Odewale ◽  
Alexandra Jones ◽  
Tsione Wolde-Michael ◽  
...  
Keyword(s):  
United States ◽  
North American ◽  
The United States ◽  
Heritage Preservation ◽  
Social Unrest ◽  
Black Lives Matter ◽  
The North ◽  
Road Map ◽  
The Social ◽  
The Future

This forum builds on the discussion stimulated during an online salon in which the authors participated on June 25, 2020, entitled “Archaeology in the Time of Black Lives Matter,” and which was cosponsored by the Society of Black Archaeologists (SBA), the North American Theoretical Archaeology Group (TAG), and the Columbia Center for Archaeology. The online salon reflected on the social unrest that gripped the United States in the spring of 2020, gauged the history and conditions leading up to it, and considered its rippling throughout the disciplines of archaeology and heritage preservation. Within the forum, the authors go beyond reporting the generative conversation that took place in June by presenting a road map for an antiracist archaeology in which antiblackness is dismantled.

Notice of transfer of figured specimens of North American Devonian cyclocystoids

1993 ◽  
Vol 67 (1) ◽  
pp. 151-151
Author(s):  
R. William Orr ◽  
Richard H. Fluegeman
Keyword(s):  
United States ◽  
New York ◽  
North American ◽  
The United States ◽  
State University ◽  
Ball State University ◽  
Geological Museum ◽  
University College ◽  
University Of Cincinnati ◽  
The University

In 1990 (Fluegeman and Orr) the writers published a short study on known North American cyclocystoids. This enigmatic group is best represented in the United States Devonian by only two specimens, both illustrated in the 1990 report. Previously, the Cortland, New York, specimen initially described by Heaslip (1969) was housed at State University College at Cortland, New York, and the Logansport, Indiana, specimen was housed at Ball State University, Muncie, Indiana. Both institutions recognize the importance of permanently placing these rare specimens in a proper paleontologic repository with other cyclocystoids. Therefore, these two specimens have been transferred to the curated paleontologic collection at the University of Cincinnati Geological Museum where they can be readily studied by future workers in association with a good assemblage of Ordovician specimens of the Cyclocystoidea.

Financial Returns in Major League Soccer

2021 ◽  
pp. 152700252110227
Author(s):  
John Charles Bradbury
Keyword(s):  
United States ◽  
Ownership Structure ◽  
North American ◽  
Consumer Demand ◽  
Professional Sports ◽  
The United States ◽  
Professional Soccer ◽  
Major League Soccer ◽  
Major League ◽  
Sports Leagues

Major League Soccer (MLS) is the top-tier professional soccer league serving the United States and Canada. This study examines factors hypothesized to impact consumer demand for professional sports on team revenue in this nascent league. The estimates are consistent with positive returns to performance, novelty effects from newer teams, and varying impacts from roster quality and composition. Other factors hypothesized to be important for MLS teams (e.g., stadium quality and market demographics) are not associated with team revenue. The estimates are similar to findings in other major North American sports leagues, even though MLS operates with a unique single-entity ownership structure that has the potential to disincentivize individual team investments by league owners.

A SYNOPSIS OF THE NORTH AMERICAN SPECIES OF SYNDIPNUS (HYMEN., ICHNEUMONIDAE)

1940 ◽  
Vol 72 (7) ◽  
pp. 135-145 ◽  
Author(s):  
G. Stuart Walley
Keyword(s):  
United States ◽  
North American ◽  
The United States ◽  
North American Species ◽  
National Museum ◽  
United States National Museum ◽  
The North

As noted below the two North American species described in Syndipnus by workers appear to belong in other genrra. In Europe the gunus is represented by nearly a score of species and has been reviewed in recent years by two writers (1, 2). North American collections contain very few representatives of the genus; after combining the material in the National Collection with that from the United States National Museum, the latter kindly loaned to me by Mr. R. A. Cushman, only thirty-seven specimens are available for study.

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