scholarly journals The impact of bark beetle infestation on monoterpene emissions and secondary organic aerosol formation in Western North America

2012 ◽  
Vol 12 (11) ◽  
pp. 29763-29800 ◽  
Author(s):  
A. R. Berg ◽  
C. L. Heald ◽  
K. E. Huff Hartz ◽  
A. G. Hallar ◽  
A. J. H. Meddens ◽  
...  
Keyword(s):  
United States ◽  
British Columbia ◽  
North America ◽  
Bark Beetle ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Western United States ◽  
Mortality Data ◽  
Western North America ◽  
The Impact

Abstract. Over the last decade, extensive beetle outbreaks in Western North America have destroyed over 100 000 km2 of forest throughout British Columbia and the Western United States. Beetle infestations impact monoterpene emissions through both decreased emissions as trees are killed (mortality effect) and increased emissions in trees under attack (attack effect). We use 14 yr of beetle mortality data together with beetle-induced monoterpene concentration data in the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) to investigate the impact of beetle mortality and attack on monoterpene emissions and secondary organic aerosol (SOA) formation in Western North America. Regionally, beetle infestations may have a significant impact on monoterpene emissions and SOA concentrations, with up to a 4-fold increase in monoterpene emissions and up to a 40% increase in SOA concentrations in some years (following a scenario where the attack effect is based on observed lodgepole pine response). Responses to beetle attack depend on the extent of previous mortality and the number of trees under attack in a given year, which can vary greatly over space and time. Simulated enhancements peak in 2004 (British Columbia) and 2008 (US). Responses to beetle attack are shown to be substantially larger (up to a 3-fold localized increase in SOA concentrations) when following a scenario based on bark-beetle attack in spruce trees. Placed in the context of observations from the IMPROVE network, the changes in SOA concentrations due to beetle attack are in most cases small compared to the large annual and interannual variability in total organic aerosol which is driven by wildfire activity in Western North America. This indicates that most beetle-induced SOA changes are not likely detectable in current observation networks; however these changes may impede efforts to achieve natural visibility conditions in the national parks and wilderness areas of the Western United States.

scholarly journals The impact of bark beetle infestations on monoterpene emissions and secondary organic aerosol formation in western North America

2013 ◽  
Vol 13 (6) ◽  
pp. 3149-3161 ◽  
Author(s):  
A. R. Berg ◽  
C. L. Heald ◽  
K. E. Huff Hartz ◽  
A. G. Hallar ◽  
A. J. H. Meddens ◽  
...  
Keyword(s):  
United States ◽  
British Columbia ◽  
North America ◽  
Bark Beetle ◽  
Tree Mortality ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Western United States ◽  
Western North America ◽  
The Impact

Abstract. Over the last decade, extensive beetle outbreaks in western North America have destroyed over 100 000 km2 of forest throughout British Columbia and the western United States. Beetle infestations impact monoterpene emissions through both decreased emissions as trees are killed (mortality effect) and increased emissions in trees under attack (attack effect). We use 14 yr of beetle-induced tree mortality data together with beetle-induced monoterpene emission data in the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM) to investigate the impact of beetle-induced tree mortality and attack on monoterpene emissions and secondary organic aerosol (SOA) formation in western North America. Regionally, beetle infestations may have a significant impact on monoterpene emissions and SOA concentrations, with up to a 4-fold increase in monoterpene emissions and up to a 40% increase in SOA concentrations in some years (in a scenario where the attack effect is based on observed lodgepole pine response). Responses to beetle attack depend on the extent of previous mortality and the number of trees under attack in a given year, which can vary greatly over space and time. Simulated enhancements peak in 2004 (British Columbia) and 2008 (US). Responses to beetle attack are shown to be substantially larger (up to a 3-fold localized increase in summertime SOA concentrations) in a scenario based on bark-beetle attack in spruce trees. Placed in the context of observations from the IMPROVE network, the changes in SOA concentrations due to beetle attack are in most cases small compared to the large annual and interannual variability in total organic aerosol which is driven by wildfire activity in western North America. This indicates that most beetle-induced SOA changes are not likely detectable in current observation networks; however, these changes may impede efforts to achieve natural visibility conditions in the national parks and wilderness areas of the western United States.

Late Cambrian (Furongian; Paibian, Steptoean) agnostoid arthropods from the Cow Head Group, western Newfoundland

2012 ◽  
Vol 86 (2) ◽  
pp. 201-237 ◽  
Author(s):  
Stephen R. Westrop ◽  
Jennifer D. Eoff
Keyword(s):  
United States ◽  
British Columbia ◽  
New Species ◽  
North America ◽  
Western United States ◽  
Type Material ◽  
Head Group ◽  
Western North America ◽  
Late Cambrian

Nine agnostoid species from late Cambrian (Paibian: Steptoean) boulders from the Cow Head Group in western Newfoundland fall into three biostratigraphically distinct faunas. The Glyptagnostus reticulatus Fauna contains only the eponymous species and correlates with the lower part of the Paibian and the basal Steptoean of North America. The “Innitagnostus” inexpectans Fauna is more diverse and likely correlates into part of the lower Steptoean Aphelaspis Zone of western North America. The youngest fauna, the Acmarhachis kindlei n. sp. Fauna, also includes species of Homagnostus and Pseudagnostus, as well as a second new species of Acmarhachis, A. whittingtoni. It probably correlates with the Dunderbergia Zone (mid-Pabian and mid-Steptoean) of the western United States. The Laurentian species Acmarhachis typicalis Resser (1938) and A. acuta (Kobayashi, 1938) are evaluated from restudy of type material, and types of “Innitagnostus” inexpectans (Kobayashi, 1938) from British Columbia are also reillustrated.

SPECIES OF THE GENUS PINALITUS KELTON FOUND IN NORTH AMERICA (HETEROPTERA: MIRIDAE)

1977 ◽  
Vol 109 (12) ◽  
pp. 1549-1554 ◽  
Author(s):  
Leonard A. Kelton
Keyword(s):  
United States ◽  
British Columbia ◽  
North America ◽  
Western United States ◽  
Key To Species ◽  
European Species

AbstractOrthops rubricatus (Fallén), a European species now known to occur in North America, is transferred to the genus Pinalitus Kelton. Pinalitus solivagus (Van Duzee) is reported from British Columbia, and P. utahensis Knight and P. brevirostris Knight are considered to be synonyms of it. Pinalitus rostratus n. sp. is described from Canada and western United States. Pinalitus californicus Knight is transferred to the genus Proba Distant. A key to species is provided.

scholarly journals AN ASSESSMENT OF LATE PLEISTOCENE TO MIDDLE HOLOCENE LAKE LEVEL FLUCTUATIONS IN SURPRISE VALLEY, CALIFORNIA

2018 ◽  
Author(s):  
Daniel Enrique Ibarra
Keyword(s):  
United States ◽  
North America ◽  
Late Pleistocene ◽  
General Circulation ◽  
Lake Level ◽  
Basin And Range ◽  
Future Climate ◽  
Western United States ◽  
Western North America ◽  
Ocean General Circulation

Knowledge of Earth’s climate history and sensitivity, combined with modeling past and future climate, are central to informing policy decisions regarding future climate change. The hydrologic response to future warming scenarios due to increased anthropogenic CO2 emissions remains uncertain. Freshwater availability in the arid western United States is projected to decrease in availability as increased agricultural, urban and industrial uses continue to stress supplies. Motivated by the potential for dramatic future hydrologic changes, studies recording the abrupt transitions between different equilibrium states of natural past climate variability shed light on our understanding of the modern climate system.The presence of pluvial lakes in the Basin and Range Province, in the western United States, during the late Pleistocene (40 to 10 ka) indicates far greater moisture availability during the Pleistocene glacials. This study investigates the timing and magnitude of the most recent pluvial lake cycle that filled Surprise Valley, California using geophysical, geochemical and geochronologic tools. Spanning 31.2 to 4.6 ka, this new lake level record places the highest lake level, at 180 meters above present day playa, at 13.9 ± 1.2 ka. This age appears to be nearly synchronous with highstands of Lake Lahontan to the south and the Chewaucan Basin to the north. Additionally, most of the Basin and Range lake highstands, including Lake Surprise, follow peaks in precipitation minus evapotranspiration (P-ET) by 8-10 kyr. By compiling a diverse set of paleoclimate data available for western North America, I found that the timing and geographic distribution of lake highstands is inconsistent with increased precipitation in response to shifting westerly winds, the current model for the genesis of large lakes in western North America. Rather, lakes levels are more strongly correlated with changes in summer insolation, suggesting that lake highstands were likely facilitated by colder temperatures and increased humidity due to the presence of continental ice sheets and increased atmospheric convergence. I compared the constraints from lake and soil-based records to Atmosphere-Ocean General Circulation Model simulations from the Paleoclimate Model Intercomparison Project 2. Based on model-proxy intercomparison, the Atmosphere-Ocean General Circulation Models, the same models used to also assess future climatic changes, poorly predict hydrologic quantities for the Last Glacial Maximum.

Early Eocene snakeflies (Raphidioptera) of western North America from the Okanagan Highlands and Green River Formation

Zootaxa ◽  
2021 ◽  
Vol 4951 (1) ◽  
pp. 41-79
Author(s):  
S. BRUCE ARCHIBALD ◽  
VLADIMIR N. MAKARKIN
Keyword(s):  
United States ◽  
British Columbia ◽  
North America ◽  
United States Of America ◽  
Green River Formation ◽  
Early Eocene ◽  
Western North America ◽  
Green River ◽  
The Family ◽  
Okanagan Highlands

Four new species of Raphidiidae are described from the early Eocene of western North America: Megaraphidia antiquissima sp. nov. from McAbee, M. ootsa sp. nov. from Driftwood Canyon, M. hopkinsi sp. nov. from the Allenby Formation (all from British Columbia, Canada), M. klondika sp. nov. from Republic (Washington, United States of America). Archiinocellia Handlirsch, 1910, Archiinocellia oligoneura Handlirsch, 1910 from Horsefly River (British Columbia, Canada), and A. protomaculata (Engel, 2011), comb. nov., from the Green River Formation (Colorado, United States of America) are redescribed. Archiinocellia is assigned to Raphidiidae, sit. nov. The apparent absence of sclerotized gonocoxites 9 in the Archiinocellia protomaculata male is probably plesiomorphic at the family level. As some modern snakeflies do not require a cold interval to complete their development and Eocene Inocelliidae and Raphidiidae lived in regions of warm winters (especially A. protomaculata), adaptation to cold winters in many modern snakeflies is a post-Eocene phenomenon. Eocene Raphidiidae of Europe (Priabonian) differ greatly from those of North America (Ypresian and Priabonian). This pattern might reflect dispersal in either direction or ranges established prior to continental separation. Eocene Inocelliidae of Europe (Priabonian), however, are more similar to those of North America (Ypresian and Lutetian). 

scholarly journals Stable isotopic evidence of El Niño-like atmospheric circulation in the Pliocene western United States

2013 ◽  
Vol 9 (2) ◽  
pp. 903-912 ◽  
Author(s):  
M. J. Winnick ◽  
J. M. Welker ◽  
C. P. Chamberlain
Keyword(s):  
United States ◽  
North America ◽  
El Niño ◽  
El Nino ◽  
Storm Track ◽  
Western United States ◽  
Western North America ◽  
Late Pliocene ◽  
Future Warming ◽  
Isotopic Anomalies

Abstract. Understanding how the hydrologic cycle has responded to warmer global temperatures in the past is especially important today as concentrations of CO2 in the atmosphere continue to increase due to human activities. The Pliocene offers an ideal window into a climate system that has equilibrated with current atmospheric pCO2. During the Pliocene the western United States was wetter than modern, an observation at odds with our current understanding of future warming scenarios, which involve the expansion and poleward migration of the subtropical dry zone. Here we compare Pliocene oxygen isotope profiles of pedogenic carbonates across the western US to modern isotopic anomalies in precipitation between phases of the El Niño–Southern Oscillation (ENSO). We find that when accounting for seasonality of carbonate formation, isotopic changes through the late Pliocene match modern precipitation isotopic anomalies in El Niño years. Furthermore, isotopic shifts through the late Pliocene mirror changes through the early Pleistocene, which likely represents the southward migration of the westerly storm track caused by growth of the Laurentide ice sheet. We propose that the westerly storm track migrated northward through the late Pliocene with the development of the modern cold tongue in the east equatorial Pacific, then returned southward with widespread glaciation in the Northern Hemisphere – a scenario supported by terrestrial climate proxies across the US. Together these data support the proposed existence of background El Niño-like conditions in western North America during the warm Pliocene. If the earth behaves similarly with future warming, this observation has important implications with regard to the amount and distribution of precipitation in western North America.

NEW SPFCIES OF HERCOSTOMUS FROM WESTERN NORTH AMERICA (DIPTERA, DOLICHOPODIDAE)

1941 ◽  
Vol 73 (7) ◽  
pp. 127-132 ◽  
Author(s):  
F. C. Harmston ◽  
G. F. Knowlton
Keyword(s):  
United States ◽  
North America ◽  
Western United States ◽  
Western North America ◽  
Undescribed Species ◽  
The Third

The following paper deals with six apparently undescribed species of Hercostomus collected from localities in the western United States and Canada.Hercostomus chaetilamellus n. sp.Male. Length, 4 mm.; of wing, 3.8 mm. Face wide, silvery white. Front silvery white, concolorous with face. Antennae black, the third joint about as long as broad, evenly rounded below. Orbital cilia white, the uppermost bristle black. Palpi and proboscis yellow.

scholarly journals Model evaluation of NO<sub>3</sub> secondary organic aerosol (SOA) source and heterogeneous organic aerosol (OA) sink in the Western United States

2012 ◽  
Vol 12 (2) ◽  
pp. 5189-5223 ◽  
Author(s):  
J. L. Fry ◽  
K. Sackinger
Keyword(s):  
United States ◽  
Secondary Organic Aerosol ◽  
Organic Aerosol ◽  
Chemical Mechanism ◽  
Western United States ◽  
Urban Centers ◽  
Aerosol Composition ◽  
Organic Gases ◽  
Source And Sink ◽  
Loss Rates

Abstract. The relative importance of NO3-initiated source and heterogeneous sink of organic aerosol in the Western United States is investigated using the WRF/Chem regional weather and chemistry model. The model is run for the four individual months, representing the four seasons, of January, May, August, and October, to produce hourly spatial maps of surface concentrations of NO3, organic aerosol (OA), and reactive organic gases (ROG, a sum of alkene species tracked in the lumped chemical mechanism employed). These "baseline" simulations are used in conjunction with literature data on secondary organic aerosol (SOA) mass yields, average organic aerosol composition, and reactive uptake coefficients for NO3 on organic surfaces to predict SOA source and OA heterogeneous loss rates due to reactions initiated by NO3. We find both source and sink rates maximized downwind of urban centers, therefore with a varying location that depends on wind direction. Both source and sink terms are maximum in summer, and SOA source dominates over OA loss by approximately three orders of magnitude, with large day-to-day variability. The NO3 source of SOA is found to be atmospherically significant (peak production rates of 0.4–3.0 μg kg−1 h−1), while the heterogeneous sink of OA via NO3 surface reactions (peak loss rates of 0.11–2.3 × 10−3 μg kg−1 h−1) is likely too small to significantly impact the atmospheric lifetime of either organic aerosol or oxidized nitrogen (NOy).

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