Plays for assessment in Region IV, Rocky Mountains and Northern Great Plains as of October 4, 1993; 1995 National Assessment of oil and gas

1993 ◽  
Author(s):  
D. L. Gautier ◽  
K.L. Varnes
Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1121
Author(s):  
Carlos J. Bucaram ◽  
Frank M. Bowman

Oil and gas production in the Bakken region increased dramatically during the past decade. A WRF-Chem modeling study of the Northern Great Plains was conducted for a July 2010 baseline scenario prior to the largest of these production increases. Simulations using the RACM-MADE/SORGAM, CBMZ-MOSAIC, and MOZART-MOSAIC chemistry-aerosol mechanisms were compared to each other and against ground level observations. All three gas-aerosol modules produced similar prediction results for O3, and NO2, with moderate correlation to hourly measurements and monthly average values overpredicted by 20% for O3 and underpredicted by 5% for NO2. Monthly average PM2.5 concentrations were relatively accurate, but correlation to hourly measurements was very low and PM2.5 subspecies exhibited high variability with a mix of over and underpredictions depending on the mechanism. Pollutant concentrations were relatively low across the mostly rural study domain, especially in the Bakken region. Results from this work can be used as a basis of comparison for studies of more recent time periods that include increased oil and gas-related emissions.


2014 ◽  
Vol 128 (2) ◽  
pp. 204
Author(s):  
Paul Hendricks ◽  
Susan Lenard

Range maps for Pygmy Shrew (Sorex hoyi) show a large hiatus over much of the northern Great Plains between the Rocky Mountains and eastern North Dakota. We report a new record of the Pygmy Shrew in northeastern Montana, review previous records for the state and adjacent regions bordering Montana to the north and east, and suggest that the range boundary in the northern Great Plains be redrawn farther south to include all of Montana north of the Missouri River. This is consistent with the known range of the Pygmy Shrew in eastern North Dakota and South Dakota, where the species has been documented only north and east of the Missouri River, although records are still lacking from north of the Missouri River in northwestern North Dakota and adjacent regions of Canada. Pygmy Shrews will probably be found at additional localities in prairie regions of Canada adjacent to Montana, most likely in association with prairie pothole wetlands, river bottom riparian vegetation, and hardwood draws.


2008 ◽  
Vol 70 (2) ◽  
pp. 188-197 ◽  
Author(s):  
Thomas W.D. Edwards ◽  
S. Jean Birks ◽  
Brian H. Luckman ◽  
Glen M. MacDonald

AbstractModelling of tree-ring δ13C and δ18O data from the Columbia Icefield area in the eastern Rocky Mountains of western Canada provides fuller understanding of climatic and hydrologic variability over the past 1000 yr in this region, based on reconstruction of changes in growth season atmospheric relative humidity (RHgrs), winter temperature (Twin) and the precipitation δ18O–Twin relation. The Little Ice Age (~ AD 1530s–1890s) is marked by low RHgrs and Twin and a δ18O–Twin relation offset from that of the present, reflecting enhanced meridional circulation and persistent influence of Arctic air masses. Independent proxy hydrologic evidence suggests that snowmelt sustained relatively abundant streamflow at this time in rivers draining the eastern Rockies. In contrast, the early millennium was marked by higher RHgrs and Twin and a δ18O–Twin relation like that of the 20th century, consistent with pervasive influence of Pacific air masses because of strong zonal circulation. Especially mild conditions prevailed during the “Medieval Climate Anomaly” ~ AD 1100–1250, corresponding with evidence for reduced discharge in rivers draining the eastern Rockies and extensive hydrological drought in neighbouring western USA.


2018 ◽  
Vol 14 (8) ◽  
pp. 1195-1212 ◽  
Author(s):  
Vachel A. Carter ◽  
Jacqueline J. Shinker ◽  
Jonathon Preece

Abstract. Droughts are a naturally re-occurring phenomena that result in economic and societal losses. Yet, the most historic droughts that occurred in the 1930s and 1950s in the Great Plains and western United States were both shorter in duration and less severe than megadroughts that have plagued the region in the past. Roughly 4200 years ago, a ∼150-year long megadrought occurred in the central Rocky Mountains, as indicated by sedimentary pollen evidence documenting a brief and unique change in vegetation composition from Long Lake, southeastern Wyoming. Neighbouring the central Rocky Mountains, several dune fields reactivated in the western Great Plains around this time period illustrating a severe regional drought. While sedimentary pollen provides evidence of past drought, paleoecological evidence does not provide context for the climate mechanisms that may have caused the drought. Thus, a modern climate analogue technique was applied to the sedimentary pollen and regional dune reactivation evidence identified from the region to provide a conceptual framework for exploring possible mechanisms responsible for the observed ecological changes. The modern climate analogues of 2002/2012 illustrate that warm and dry conditions persisted through the growing season and were associated with anomalously higher-than-normal geopotential heights centred over the Great Plains. In the spring, higher-than-normal heights suppressed moisture transport via the low-level jet from the Gulf of Mexico creating a more southwesterly component of flow. In the summer, higher-than-normal heights persisted over the northern Great Plains resulting in a wind shift with an easterly component of flow, drawing in dry continental air into the study region. In both cases, lower-than-normal moisture in the atmosphere (via 850 mbar specific humidity) inhibited uplift and potential precipitation. Thus, if the present scenario existed during the 4.2 ka drought, the associated climatic responses are consistent with local and regional proxy data suggesting regional drought conditions in the central Rocky Mountains and western Great Plains.


1989 ◽  
Vol 31 (1) ◽  
pp. 57-73 ◽  
Author(s):  
Cathy W. Barnosky

AbstractTwo pollen records from the northern Great Plains of Montana portray vegetational and climatic changes during the last 12,200 yr in a region where few other data are available. A 6.4-m core from Guardipee Lake, east of the Rocky Mountains in the area formerly covered by the Two Medicine glacial lobe, contains the Glacier Peak G and Mt. St. Helens Jy volcanic ashes. Pollen percentage data are dominated byPinus, Poaceae,Artemisia, and Chenopodiaceae/Amaranthaceae. High nonarboreal percentages and small amounts ofJuniperus, Alnus, Salix, andPopuluspollen in sediments deposited between ca. 12,200 and ca. 9300 yr B.P. suggest a temperate grassland with shrubs growing locally in mesic settings. After ca. 9300 yr B.P. an increase in Chenopodiaceae/Amaranthaceae pollen and a concomitant decline inArtemisiaindicate the development of more xerophytic grassland and the beginning of the altithermal period. The lake probably was intermittently dry thoughout the Holocene. A high sedimentation rate and the presence of cereal taxa characterize the last ca. 100 yr of Euroamerican settlement. Lost Lake at the northern margin of the Highwood Mountains yielded a 16.94-m core with no volcanic ashes that spans the last 9400 yr. High amounts of Chenopodiaceae/Amaranthaceae,Artemisia, and Poaceae pollen, from ca. 9400 to ca. 6000 yr B.P., suggest the presence of xeric grassland and a climate drier than at present. After ca. 6000 yr B.P. Chenopodiaceae/Amaranthaceae values declined andArtemisia, Poaceae,Pinus, Picea, Salix, Alnus, andBetulaincreased. The inferred spread of shrubs in wet habitats at this time and the expansion of forest in nearby mountain ranges indicate the end of the altithermal period and the onset of cooler/moister conditions.


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