scholarly journals Large-Scale Pinyon Ips (Ips confusus) Outbreak in Southwestern United States Tied with Elevation and Land Cover

2012 ◽  
Vol 110 (4) ◽  
pp. 194-200 ◽  
Author(s):  
Sabrina J. Kleinman ◽  
Thomas E. DeGomez ◽  
Gary B. Snider ◽  
Kelly E. Williams
Keyword(s):  
United States ◽  
Land Cover ◽  
Large Scale ◽  
Southwestern United States ◽  
Ips Confusus

scholarly journals Multiscale Variability of the Flow during the North American Monsoon Experiment

2007 ◽  
Vol 20 (9) ◽  
pp. 1628-1648 ◽  
Author(s):  
Richard H. Johnson ◽  
Paul E. Ciesielski ◽  
Brian D. McNoldy ◽  
Peter J. Rogers ◽  
Richard K. Taft
Keyword(s):  
United States ◽  
North American ◽  
Gulf Of California ◽  
Large Scale ◽  
Regional Scale ◽  
North American Monsoon ◽  
Return Flow ◽  
Southwestern United States ◽  
The North ◽  
Upper Level

Abstract The 2004 North American Monsoon Experiment (NAME) provided an unprecedented observing network for studying the structure and evolution of the North American monsoon. This paper focuses on multiscale characteristics of the flow during NAME from the large scale to the mesoscale using atmospheric sounding data from the enhanced observing network. The onset of the 2004 summer monsoon over the NAME region accompanied the typical northward shift of the upper-level anticyclone or monsoon high over northern Mexico into the southwestern United States, but in 2004 this shift occurred slightly later than normal and the monsoon high did not extend as far north as usual. Consequently, precipitation over the southwestern United States was slightly below normal, although increased troughiness over the Great Plains contributed to increased rainfall over eastern New Mexico and western Texas. The first major pulse of moisture into the Southwest occurred around 13 July in association with a strong Gulf of California surge. This surge was linked to the westward passages of Tropical Storm Blas to the south and an upper-level inverted trough over northern Texas. The development of Blas appeared to be favored as an easterly wave moved into the eastern Pacific during the active phase of a Madden–Julian oscillation. On the regional scale, sounding data reveal a prominent sea breeze along the east shore of the Gulf of California, with a deep return flow as a consequence of the elevated Sierra Madre Occidental (SMO) immediately to the east. Subsidence produced a dry layer over the gulf, whereas a deep moist layer existed over the west slopes of the SMO. A prominent nocturnal low-level jet was present on most days over the northern gulf. The diurnal cycle of heating and moistening (Q1 and Q2) over the SMO was characterized by deep convective profiles in the mid- to upper troposphere at 1800 LT, followed by stratiform-like profiles at midnight, consistent with the observed diurnal evolution of precipitation over this coastal mountainous region. The analyses in the core NAME domain are based on a gridded dataset derived from atmospheric soundings only and, therefore, should prove useful in validating reanalyses and regional models.

scholarly journals The Impact of Horizontal Resolution on North American Monsoon Gulf of California Moisture Surges in a Suite of Coupled Global Climate Models

2016 ◽  
Vol 29 (21) ◽  
pp. 7911-7936 ◽  
Author(s):  
Salvatore Pascale ◽  
Simona Bordoni ◽  
Sarah B. Kapnick ◽  
Gabriel A. Vecchi ◽  
Liwei Jia ◽  
...  
Keyword(s):  
United States ◽  
North American ◽  
Gulf Of California ◽  
Large Scale ◽  
Horizontal Resolution ◽  
North American Monsoon ◽  
Geophysical Fluid Dynamics Laboratory ◽  
Southwestern United States ◽  
Near Surface ◽  
The Impact

Abstract The impact of atmosphere and ocean horizontal resolution on the climatology of North American monsoon Gulf of California (GoC) moisture surges is examined in a suite of global circulation models (CM2.1, FLOR, CM2.5, CM2.6, and HiFLOR) developed at the Geophysical Fluid Dynamics Laboratory (GFDL). These models feature essentially the same physical parameterizations but differ in horizontal resolution in either the atmosphere (≃200, 50, and 25 km) or the ocean (≃1°, 0.25°, and 0.1°). Increasing horizontal atmospheric resolution from 200 to 50 km results in a drastic improvement in the model’s capability of accurately simulating surge events. The climatological near-surface flow and moisture and precipitation anomalies associated with GoC surges are overall satisfactorily simulated in all higher-resolution models. The number of surge events agrees well with reanalyses, but models tend to underestimate July–August surge-related precipitation and overestimate September surge-related rainfall in the southwestern United States. Large-scale controls supporting the development of GoC surges, such as tropical easterly waves (TEWs), tropical cyclones (TCs), and trans-Pacific Rossby wave trains (RWTs), are also well captured, although models tend to underestimate the TEW and TC magnitude and number. Near-surface GoC surge features and their large-scale forcings (TEWs, TCs, and RWTs) do not appear to be substantially affected by a finer representation of the GoC at higher ocean resolution. However, the substantial reduction of the eastern Pacific warm sea surface temperature bias through flux adjustment in the Forecast-Oriented Low Ocean Resolution (FLOR) model leads to an overall improvement of tropical–extratropical controls on GoC moisture surges and the seasonal cycle of precipitation in the southwestern United States.

scholarly journals Influence of Daily Rainfall Characteristics on Regional Summertime Precipitation over the Southwestern United States

2009 ◽  
Vol 10 (5) ◽  
pp. 1218-1230 ◽  
Author(s):  
Bruce T. Anderson ◽  
Jingyun Wang ◽  
Suchi Gopal ◽  
Guido Salvucci
Keyword(s):  
United States ◽  
Large Scale ◽  
Daily Precipitation ◽  
Daily Rainfall ◽  
Southwestern United States ◽  
Regional Variability ◽  
Rainfall Frequency ◽  
Circulation Patterns ◽  
Precipitation Characteristics ◽  
Precipitation Anomalies

Abstract The regional variability in the summertime precipitation over the southwestern United States is studied using stochastic chain-dependent models generated from 70 yr of station-based daily precipitation observations. To begin, the spatiotemporal structure of the summertime seasonal mean precipitation over the southwestern United States is analyzed using two independent spatial cluster techniques. Four optimal clusters are identified, and their structures are robust across the techniques used. Next, regional chain-dependent models—comprising a previously dependent occurrence chain, an empirical rainfall coverage distribution, and an empirical rainfall amount distribution—are constructed over each subregime and are integrated to simulate the regional daily precipitation evolution across the summer season. Results indicate that generally less than 50% of the observed interannual variance of seasonal precipitation in a given region lies outside the regional chain-dependent models’ stochastic envelope of variability; this observed variance, which is not captured by the stochastic model, is sometimes referred to as the “potentially predictable” variance. In addition, only a small fraction of observed years (between 10% and 20% over a given subregime) contain seasonal mean precipitation anomalies that contribute to this potentially predictable variance. Further results indicate that year-to-year variations in daily rainfall coverage are the largest contributors to potentially predictable seasonal mean rainfall anomalies in most regions, whereas variations in daily rainfall frequency contribute the least. A brief analysis for one region highlights how the identification of years with potentially predictable precipitation characteristics can be used to better understand large-scale circulation patterns that modulate the underlying daily rainfall processes responsible for year-to-year variations in regional rainfall.

scholarly journals Analysis Ready Data: Enabling Analysis of the Landsat Archive

2018 ◽  
Author(s):  
John Dwyer ◽  
David Roy ◽  
Brian Sauer ◽  
Calli Jenkerson ◽  
Hankui Zhang ◽  
...  
Keyword(s):  
United States ◽  
Land Cover ◽  
Large Scale ◽  
The United States ◽  
Poor Quality ◽  
Thematic Mapper ◽  
United States Geological Survey ◽  
Landsat 8 ◽  
Landsat 7 ◽  
Data Provision

Data that have been processed to allow analysis with a minimum of additional user effort are often referred to as Analysis Ready Data (ARD). The ability to perform large scale Landsat analysis relies on the ability to access observations that are geometrically and radiometrically consistent, and have had non-target features (clouds) and poor quality observations flagged so that they can be excluded. The United States Geological Survey (USGS) has processed all of the Landsat 4 and 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 8 Operational Land Imager (OLI) and Thermal Infrared Sensor (TIRS) archive over the conterminous United States (CONUS), Alaska, and Hawaii, into Landsat ARD. The ARD are available to significantly reduce the burden of pre-processing on users of Landsat data. Provision of pre-prepared ARD is intended to make it easier for users to produce Landsat-based maps of land cover and land-cover change and other derived geophysical and biophysical products. The ARD are provided as tiled, georegistered, top of atmosphere and atmospherically corrected products defined in a common equal area projection, accompanied by spatially explicit quality assessment information, and

Climatic Change and Early Population Dynamics in the Southwestern United States

1970 ◽  
Vol 1 (1) ◽  
pp. 59-71 ◽  
Author(s):  
Cynthia Irwin-Williams ◽  
C. Vance Haynes
Keyword(s):  
United States ◽  
Climatic Change ◽  
Large Scale ◽  
Population Control ◽  
Small Scale ◽  
Human Populations ◽  
Southwestern United States ◽  
Human Occupation ◽  
Cultural System ◽  
Early Human

It is becoming increasingly apparent that the pattern of early human occupation of the Southwestern United States was strongly influenced by the major paleoclimatic events of the period 9500 B.C. to A.D. 700. The size of human populations and the distribution of human settlement at both the regional-topographic and large-scale areal level, known from archaeological research, are directly correlated to climatic change documented by the evidence of geology and palynology.The effect of climatic change is felt through the actions and reactions of the economic subsystem and its linkages with other subsystems. These reactions reflect not only the character of the climatic stimulus but also the existing state of the cultural system. Alternate reactions include direct systemic readaptation to the changed environment (through changed technologies, methods of population control, etc.); or small scale or large scale relocation of populations in different local niches, regions, or areas whose character most closely approximates the conditions to which the cultural system was initially adapted.

scholarly journals Land cover change impacts on atmospheric chemistry: simulating projected large-scale tree mortality in the United States

2016 ◽  
Vol 16 (4) ◽  
pp. 2323-2340 ◽  
Author(s):  
Jeffrey A. Geddes ◽  
Colette L. Heald ◽  
Sam J. Silva ◽  
Randall V. Martin
Keyword(s):  
United States ◽  
Land Use ◽  
Air Quality ◽  
Land Cover ◽  
Land Cover Change ◽  
Dry Deposition ◽  
Large Scale ◽  
Tree Mortality ◽  
The United States ◽  
Tropospheric Chemistry

Abstract. Land use and land cover changes impact climate and air quality by altering the exchange of trace gases between the Earth's surface and atmosphere. Large-scale tree mortality that is projected to occur across the United States as a result of insect and disease may therefore have unexplored consequences for tropospheric chemistry. We develop a land use module for the GEOS-Chem global chemical transport model to facilitate simulations involving changes to the land surface, and to improve consistency across land–atmosphere exchange processes. The model is used to test the impact of projected national-scale tree mortality risk through 2027 estimated by the 2012 USDA Forest Service National Insect and Disease Risk Assessment. Changes in biogenic emissions alone decrease monthly mean O3 by up to 0.4 ppb, but reductions in deposition velocity compensate or exceed the effects of emissions yielding a net increase in O3 of more than 1 ppb in some areas. The O3 response to the projected change in emissions is affected by the ratio of baseline NOx : VOC concentrations, suggesting that in addition to the degree of land cover change, tree mortality impacts depend on whether a region is NOx-limited or NOx-saturated. Consequently, air quality (as diagnosed by the number of days that 8 h average O3 exceeds 70 ppb) improves in polluted environments where changes in emissions are more important than changes to dry deposition, but worsens in clean environments where changes to dry deposition are the more important term. The influence of changes in dry deposition demonstrated here underscores the need to evaluate treatments of this physical process in models. Biogenic secondary organic aerosol loadings are significantly affected across the US, decreasing by 5–10 % across many regions, and by more than 25 % locally. Tree mortality could therefore impact background aerosol loadings by between 0.5 and 2 µg m−3. Changes to reactive nitrogen oxide abundance and partitioning are also locally important. The regional effects simulated here are similar in magnitude to other scenarios that consider future biofuel cropping or natural succession, further demonstrating that biosphere–atmosphere exchange should be considered when predicting future air quality and climate. We point to important uncertainties and further development that should be addressed for a more robust understanding of land cover change feedbacks.

The Influence of Eastern Pacific Tropical Cyclone Remnants on the Southwestern United States

2011 ◽  
Vol 139 (1) ◽  
pp. 192-210 ◽  
Author(s):  
Elizabeth A. Ritchie ◽  
Kimberly M. Wood ◽  
David S. Gutzler ◽  
Sarah R. White
Keyword(s):  
United States ◽  
Tropical Cyclone ◽  
Large Scale ◽  
Gulf Coast ◽  
Movement Pattern ◽  
The United States ◽  
Southwestern United States ◽  
Gulf Coast Region ◽  
Tropical Moisture ◽  
Coast Region

Abstract Forty-three eastern North Pacific tropical cyclone remnants with varying impact on the southwestern United States during the period 1992–2005 are investigated. Of these, 35 remnants (81%) brought precipitation to some part of the southwestern United States and the remaining 8 remnants (19%) had precipitation that was almost entirely restricted to Mexico, although cloud cover did advect over the southwestern United States in some of these cases. Although the tropical cyclone–strength winds rapidly diminish upon making landfall, these systems still carry a large quantity of tropical moisture and, upon interaction with mountainous topography, are found to drop up to 30% of the local annual precipitation. Based on common rainfall patterns and large-scale circulation features, the tropical cyclones are grouped into five categories. These include a northern recurving pattern that is more likely to bring rainfall to the southwestern United States; a southern recurving pattern that brings rainfall across northern Mexico and the Gulf Coast region; a largely north and/or northwestward movement pattern that brings rainfall to the west coast of the United States; a group that is blocked from the southwest by a ridge, which limits rainfall to Mexico; and a small group of cases that are not clearly any of the previous four types. Composites of the first four groups are shown and forecasting strategies for each are described.

scholarly journals Land cover change impacts on atmospheric chemistry: simulating projected large-scale tree mortality in the United States

2015 ◽  
Vol 15 (20) ◽  
pp. 29303-29345
Author(s):  
J. A. Geddes ◽  
C. L. Heald ◽  
S. J. Silva ◽  
R. V. Martin
Keyword(s):  
United States ◽  
Land Use ◽  
Air Quality ◽  
Land Cover ◽  
Land Cover Change ◽  
Dry Deposition ◽  
Large Scale ◽  
Tree Mortality ◽  
The United States ◽  
Tropospheric Chemistry

Abstract. Land use and land cover changes impact climate and air quality by altering the exchange of trace gases between the Earth's surface and atmosphere. Large-scale tree mortality that is projected to occur across the United States as a result of insect and disease may therefore have unexplored consequences for tropospheric chemistry. We develop a land use module for the GEOS-Chem global chemical transport model to facilitate simulations involving changes to the land surface, and to improve consistency across land–atmosphere exchange processes. The model is used to test the impact of projected national-scale tree mortality risk through 2027 estimated by the 2012 USDA Forest Service National Insect and Disease Risk Assessment. Changes in biogenic emissions alone decrease monthly mean O3 by up to 0.4 ppb, but reductions in deposition velocity compensate or exceed the effects of emissions yielding a net increase in O3 of more than 1 ppb in some areas. The O3 response to emissions is controlled by the ratio of baseline NOx : VOC concentrations, suggesting that in addition to the degree of land cover change, tree mortality impacts depend on whether a region is NOx-limited or NOx-saturated. Consequently, air quality (as diagnosed by the number of days that average 8 h O3 exceeds 65 ppb) improves in polluted environments where changes in emissions are more important than changes to dry deposition, but worsens in clean environments where changes to dry deposition are the more important term. Biogenic secondary organic aerosol loadings are significantly affected across the US, decreasing by 5–10 % across many regions, and by more than 25 % locally. Tree mortality could therefore impact background aerosol loadings by between 0.5 to 2 μg m−3. Changes to reactive nitrogen oxide abundance and partitioning are also locally important. These simulations suggest that changes in biosphere–atmosphere exchange must be considered when predicting future air quality and climate. We point to important uncertainties and further development that should be addressed for a more robust understanding of land cover change feedbacks.

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