Holocene Glaciation in the Mountain Ranges of the Western United States

2018 ◽  
pp. 3-11 ◽  
Author(s):  
R. M. Burke ◽  
P. W. Birkeland
Keyword(s):  
United States ◽  
Western United States ◽  
Mountain Ranges

Pleistocene relief production in Laramide mountain ranges, western United States: Comment and Reply

Geology ◽  
1998 ◽  
Vol 26 (12) ◽  
pp. 1150 ◽  
Author(s):  
Jeffrey P. Schaffer ◽  
Eric E. Small ◽  
Robert S. Anderson
Keyword(s):  
United States ◽  
Western United States ◽  
Mountain Ranges

scholarly journals Ambient Factors Controlling the Wintertime Precipitation Distribution across Mountain Ranges in the Interior Western United States. Part II: Changes in Orographic Precipitation Distribution in a Pseudo–Global Warming Simulation

2019 ◽  
Vol 58 (4) ◽  
pp. 695-715 ◽  
Author(s):  
Xiaoqin Jing ◽  
Bart Geerts ◽  
Yonggang Wang ◽  
Changhai Liu
Keyword(s):  
United States ◽  
Global Warming ◽  
Western United States ◽  
Cmip5 Models ◽  
Cloud Base ◽  
Orographic Precipitation ◽  
Precipitation Distribution ◽  
Mountain Ranges ◽  
Ensemble Mean ◽  
Precipitation Increase

AbstractTwo high-resolution (4 km) regional climate simulations over a 10-yr period are conducted to study the changes in wintertime precipitation distribution across mountain ranges in the interior western United States (IWUS) in a warming climate. One simulation represents the current climate, and another represents an ~2050 climate using a pseudo–global warming approach. The climate perturbations are derived from the ensemble mean of 15 global climate models from phase 5 of the Coupled Model Intercomparison Project (CMIP5). These simulations provide an estimate of average changes in wintertime orographic precipitation enhancement and finescale distribution across mountain ranges. The variability in these changes among CMIP5 models is quantified using statistical downscaling relations between orographic precipitation distribution and upstream conditions, developed in Part I. The CMIP5 guidance indicates a robust warming signal (~2 K) over the IWUS by ~2050 but minor changes in relative humidity and cloud-base height. The IWUS simulations reveal a widespread increase in precipitation on account of higher precipitation rates during winter storms in this warmer climate. This precipitation increase is most significant over the mountains rather than on the surrounding plains. The increase in precipitation rate is largely due to an increase in low-level cross-mountain moisture transport. The application of the statistical relations indicates that individual CMIP5 models disagree about the magnitude and distribution of orographic precipitation change in the IWUS, although most agree with the ensemble-mean-predicted orographic precipitation increase.

Forest Canopy Density Effects on Snowpack across the Climate Gradients of the Western United States Mountain Ranges

2022 ◽  
Author(s):  
Ning Sun ◽  
Hongxiang Yan ◽  
Mark S. Wigmosta ◽  
Jessica Lundquist ◽  
Susan Dickerson‐Lange ◽  
...  
Keyword(s):  
United States ◽  
Forest Canopy ◽  
Western United States ◽  
Canopy Density ◽  
Climate Gradients ◽  
Mountain Ranges ◽  
Density Effects ◽  
Forest Canopy Density

scholarly journals Biomass burning contribution to black carbon in the Western United States Mountain Ranges

2011 ◽  
Vol 11 (21) ◽  
pp. 11253-11266 ◽  
Author(s):  
Y. H. Mao ◽  
Q. B. Li ◽  
L. Zhang ◽  
Y. Chen ◽  
J. T. Randerson ◽  
...  
Keyword(s):  
United States ◽  
Black Carbon ◽  
Biomass Burning ◽  
Forest Fires ◽  
Transport Model ◽  
Reanalysis Data ◽  
Western United States ◽  
Fire Season ◽  
Carbonaceous Aerosols ◽  
Mountain Ranges

Abstract. Forest fires are an important source to carbonaceous aerosols in the Western United States (WUS). We quantify the relative contribution of biomass burning to black carbon (BC) in the WUS mountain ranges by analyzing surface BC observations for 2006 from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network using the GEOS-Chem global chemical transport model. Observed surface BC concentrations show broad maxima during late June to early November. Enhanced potassium concentrations and potassium/sulfur ratios observed during the high-BC events indicate a dominant biomass burning influence during the peak fire season. Model surface BC reproduces the observed day-to day and synoptic variabilities in regions downwind of but near urban centers. Major discrepancies are found at elevated mountainous sites during the July-October fire season when simulated BC concentrations are biased low by a factor of two. We attribute these low biases largely to the underestimated (by more than a factor of two) and temporally misplaced biomass burning emissions of BC in the model. Additionally, we find that the biomass burning contribution to surface BC concentrations in the USA likely was underestimated in a previous study using GEOS-Chem (Park et al., 2003), because of the unusually low planetary boundary layer (PBL) heights in the GEOS-3 meteorological reanalysis data used to drive the model. PBL heights from GEOS-4 and GEOS-5 reanalysis data are comparable to those from the North American Regional Reanalysis (NARR). Model simulations show slightly improved agreements with the observations when driven by GEOS-5 reanalysis data, but model results are still biased low. The use of biomass burning emissions with diurnal cycle, synoptic variability, and plume injection has relatively small impact on the simulated surface BC concentrations in the WUS.

scholarly journals Biomass burning contribution to black carbon in the western United States mountain ranges

2011 ◽  
Vol 11 (5) ◽  
pp. 13425-13467 ◽  
Author(s):  
Y. Mao ◽  
Q. Li ◽  
L. Zhang ◽  
Y. Chen ◽  
J. T. Randerson ◽  
...  
Keyword(s):  
United States ◽  
Black Carbon ◽  
Biomass Burning ◽  
Forest Fires ◽  
Transport Model ◽  
Reanalysis Data ◽  
Western United States ◽  
Fire Season ◽  
Carbonaceous Aerosols ◽  
Mountain Ranges

Abstract. Forest fires are an important source to carbonaceous aerosols in the western United States (WUS). We quantify the relative contribution of biomass burning to black carbon (BC) in the WUS mountain ranges by analyzing surface BC observations for 2006 from the Interagency Monitoring of PROtected Visual Environment (IMPROVE) network using the GEOS-Chem global chemical transport model. Observed surface BC concentrations show broad maxima during late June to early November. Enhanced potassium concentrations and potassium/sulfur ratios observed during the high-BC events indicate a dominant biomass burning influence during the peak fire season. Model surface BC reproduces the observed day-to-day and synoptic variabilities in regions downwind of and near urban centers. Major discrepancies are found at elevated mountainous sites during the July–October when simulated BC concentrations are biased low by a factor of two. We attribute these biases largely to the underestimated and temporally misplaced biomass burning emissions of BC in the model. Additionally, we find that the biomass burning contribution to surface BC concentrations in the US likely was underestimated in a previous study using GEOS-Chem (Park et al., 2003), because of the unusually low planetary boundary layer (PBL) heights and weak precipitation in the GEOS-3 meteorological reanalysis data used to drive the model. PBL heights from GEOS-4 and GEOS-5 reanalysis data are comparable to those from the North American Regional Reanalysis (NARR). Model simulations show improved agreements with the observations when driven by GEOS-5 reanalysis data, but model results are still biased low. The use of biomass burning emissions with diurnal cycle, synoptic variability, and plume injection has relatively small impact on the simulated surface BC concentrations in the WUS.

scholarly journals Distribución altitudinal del género Pinus en el oeste de Estados Unidos de América y México

2017 ◽  
pp. 55
Author(s):  
Richard I. Yeaton
Keyword(s):  
United States ◽  
Resource Partitioning ◽  
Morphological Characteristics ◽  
The Other ◽  
Western United States ◽  
Mountain Ranges ◽  
Species Pairs ◽  
Associated Species ◽  
Species Being ◽  
Altitudinal Distributions

The altitudinal distributions of members of the genus Pinus were studied on mountain ranges in the western United States and Mexico. The community of pines on each mountainside consists of members of three major groupings - long-needled Diploxylon species, short-needled Diploxylon species and Haploxylon species. Long-needled Diploxylon species form a core sequence of altitudinally replacing species over whose distribution are superimposed sequences of members of one of the other two groups. In the northern mountains ranges Haploxylon species formed this second sequence while in the southern ranges short-neddled Diploxylon species assumed this role. Some morphological characteristics of these species were examined and random associations of species pairs generated using these characteristics. The results suggest that resource partitioning between altitudinally associated species does not occur but rather that a successional situatton exists with long-needled Diploxylon species being replaced by either Haploxylon in the norrhern ranges or short-needled Diploxylon species in the southern ranges.

scholarly journals Ambient Factors Controlling the Wintertime Precipitation Distribution Across Mountain Ranges in the Interior Western United States. Part I: Insights from Regional Climate Simulations

2018 ◽  
Vol 57 (8) ◽  
pp. 1931-1954 ◽  
Author(s):  
Xiaoqin Jing ◽  
Bart Geerts ◽  
Yonggang Wang ◽  
Changhai Liu
Keyword(s):  
United States ◽  
Regional Climate ◽  
Western United States ◽  
Precipitation Rate ◽  
Cloud Base ◽  
Precipitation Distribution ◽  
Mountain Ranges ◽  
Low Level ◽  
Teton Range ◽  
Resolution Simulation

AbstractThis study analyzes the control of upstream conditions on the distribution of wintertime precipitation across mountain ranges in the interior western United States using 10 winters of high-resolution regional climate model data. Three mountain ranges, the Wind River Range, the Park Range, and the Teton Range, are selected to explore the statistical relations between the precipitation distribution and upstream wind, stability, and cloud conditions. A 4-km-resolution simulation is used for the former two ranges, and a 1.33-km-resolution simulation driven by the 4-km-resolution simulation is used for the Teton Range, which is smaller and steeper. Across all three mountain ranges, the dominant factor controlling precipitation is the mountain-normal low-level wind speed. Statistically, stronger wind results in heavier precipitation and a lower upwind precipitation fraction. The low-level wind generally veers with height during precipitation events, but the amount of veering does not unambiguously affect the precipitation distribution or intensity. The more the terrain blocks the upstream flow, the more the precipitation shifts toward the upstream side of the mountain and the weaker the overall precipitation rate is. A higher cloud-base temperature and a lower cloud-base height typically are associated with heavier precipitation. Deeper clouds tend to produce heavier precipitation and a slightly lower windward/leeward contrast. Convective precipitation proportionally falls more on the lee slopes than stratiform precipitation. The upstream and macroscale cloud conditions identified herein predict both the mean precipitation rate and the upwind precipitation fraction very well for the three ranges studied here.

scholarly journals New species of Allomyia Banks from the Western United States (Trichoptera: Apataniidae)

Zoosymposia ◽  
2019 ◽  
Vol 14 (1) ◽  
pp. 273-288
Author(s):  
DAVID E. RUITER ◽  
HIROYUKI NISHIMOTO
Keyword(s):  
United States ◽  
New Species ◽  
High Altitude ◽  
North American ◽  
Adult Emergence ◽  
North American Species ◽  
Western United States ◽  
Mountain Ranges

Six new Allomyia species from the western United States are described: Allomyia kondratieffi sp. nov., Allomyia leei sp. nov., Allomyia meachamensis sp. nov., Allomyia sarahae sp. nov., Allomyia sheldoni sp. nov., Allomyia whatcomensis sp. nov. The majority of these species were collected from small headwater, high altitude streams on relatively isolated mountain ranges. These species bring the number of known North American Allomyia to 18. Additional notes on state/county distribution records, taxonomic problems, species diagnostics and adult emergence periods for the 18 North American species are provided.

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