scholarly journals A U.S. CLIVAR Project to Assess and Compare the Responses of Global Climate Models to Drought-Related SST Forcing Patterns: Overview and Results

2009 ◽  
Vol 22 (19) ◽  
pp. 5251-5272 ◽  
Author(s):  
Siegfried Schubert ◽  
David Gutzler ◽  
Hailan Wang ◽  
Aiguo Dai ◽  
Tom Delworth ◽  
...  
Keyword(s):  
United States ◽  
Southern Oscillation ◽  
Global Climate ◽  
Global Climate Model ◽  
The United States ◽  
Signal To Noise ◽  
The Pacific ◽  
Precipitation Response ◽  
Sst Forcing ◽  
The Impact

Abstract The U.S. Climate Variability and Predictability (CLIVAR) working group on drought recently initiated a series of global climate model simulations forced with idealized SST anomaly patterns, designed to address a number of uncertainties regarding the impact of SST forcing and the role of land–atmosphere feedbacks on regional drought. The runs were carried out with five different atmospheric general circulation models (AGCMs) and one coupled atmosphere–ocean model in which the model was continuously nudged to the imposed SST forcing. This paper provides an overview of the experiments and some initial results focusing on the responses to the leading patterns of annual mean SST variability consisting of a Pacific El Niño–Southern Oscillation (ENSO)-like pattern, a pattern that resembles the Atlantic multidecadal oscillation (AMO), and a global trend pattern. One of the key findings is that all of the AGCMs produce broadly similar (though different in detail) precipitation responses to the Pacific forcing pattern, with a cold Pacific leading to reduced precipitation and a warm Pacific leading to enhanced precipitation over most of the United States. While the response to the Atlantic pattern is less robust, there is general agreement among the models that the largest precipitation response over the United States tends to occur when the two oceans have anomalies of opposite signs. Further highlights of the response over the United States to the Pacific forcing include precipitation signal-to-noise ratios that peak in spring, and surface temperature signal-to-noise ratios that are both lower and show less agreement among the models than those found for the precipitation response. The response to the positive SST trend forcing pattern is an overall surface warming over the world’s land areas, with substantial regional variations that are in part reproduced in runs forced with a globally uniform SST trend forcing. The precipitation response to the trend forcing is weak in all of the models. It is hoped that these early results, as well as those reported in the other contributions to this special issue on drought, will serve to stimulate further analysis of these simulations, as well as suggest new research on the physical mechanisms contributing to hydroclimatic variability and change throughout the world.

scholarly journals The Impact of Obliquity Change on El Niño Southern Oscillation (ENSO) and La Niña Climate Episodes

2022 ◽  
Author(s):  
Paul C. Rivera
Keyword(s):  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Global Climate Model ◽  
La Niña ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
La Nina ◽  
The Impact

An alternative physical mechanism is proposed to describe the occurrence of the episodic El Nino Southern Oscillation (ENSO) and La Nina climatic phenomena. This is based on the earthquake-perturbed obliquity change (EPOCH) model previously discovered as a major cause of the global climate change problem. Massive quakes impart a very strong oceanic force that can move the moon which in turn pulls the earth’s axis and change the planetary obliquity. Analysis of the annual geomagnetic north-pole shift and global seismic data revealed this previously undiscovered force. Using a higher obliquity in the global climate model EdGCM and constant greenhouse gas forcing showed that the seismic-induced polar motion and associated enhanced obliquity could be the major mechanism governing the mysterious climate anomalies attributed to El Nino and La Nina cycles.

scholarly journals Trends in Downward Solar Radiation at the Surface over North America from Climate Model Projections and Implications for Solar Energy

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Gerardo Andres Saenz ◽  
Huei-Ping Huang
Keyword(s):  
United States ◽  
North America ◽  
Solar Radiation ◽  
Solar Energy ◽  
Climate Model ◽  
Global Climate Model ◽  
The United States ◽  
Model Simulations ◽  
Climate Model Simulations ◽  
The Impact

The projected changes in the downward solar radiation at the surface over North America for late 21st century are deduced from global climate model simulations with greenhouse-gas (GHG) forcing. A robust trend is found in winter over the United States, which exhibits a simple pattern of a decrease of sunlight over Northern USA. and an increase of sunlight over Southern USA. This structure was identified in both the seasonal mean and the mean climatology at different times of the day. It is broadly consistent with the known poleward shift of storm tracks in winter in climate model simulations with GHG forcing. The centennial trend of the downward shortwave radiation at the surface in Northern USA. is on the order of 10% of the climatological value for the January monthly mean, and slightly over 10% at the time when it is midday in the United States. This indicates a nonnegligible influence of the GHG forcing on solar energy in the long term. Nevertheless, when dividing the 10% by a century, in the near term, the impact of the GHG forcing is relatively minor such that the estimate of solar power potential using present-day climatology will remain useful in the coming decades.

scholarly journals Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles

2019 ◽  
Vol 32 (9) ◽  
pp. 2591-2603 ◽  
Author(s):  
Emily Hogan ◽  
Robert E. Nicholas ◽  
Klaus Keller ◽  
Stephanie Eilts ◽  
Ryan L. Sriver
Keyword(s):  
United States ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Extreme Temperature ◽  
The United States ◽  
Temperature Extremes ◽  
Warm Temperature ◽  
Climate Model Ensembles ◽  
Model Ensembles

Abstract Extreme temperature events can have considerable negative impacts on sectors such as health, agriculture, and transportation. Observational evidence indicates the severity and frequency of warm extremes are increasing over much of the United States, but there are sizeable challenges both in estimating extreme temperature changes and in quantifying the relevant associated uncertainties. This study provides a simple statistical framework using a block maxima approach to analyze the representation of warm temperature extremes in several recent global climate model ensembles. Uncertainties due to structural model differences, grid resolution, and internal variability are characterized and discussed. Results show that models and ensembles differ greatly in the representation of extreme temperature over the United States, and variability in tail events is dependent on time and anthropogenic warming, which can influence estimates of return periods and distribution parameter estimates using generalized extreme value (GEV) distributions. These effects can considerably influence the uncertainty of model hindcasts and projections of extremes. Several idealized regional applications are highlighted for evaluating ensemble skill and trends, based on quantile analysis and root-mean-square errors in the overall sample and the upper tail. The results are relevant to regional climate assessments that use global model outputs and that are sensitive to extreme warm temperature. Accompanying this manuscript is a simple toolkit using the R statistical programming language for characterizing extreme events in gridded datasets.

Shaping Forces, Networks, and Local Influences

2017 ◽  
Author(s):  
Nancy Yunhwa Rao
Keyword(s):  
United States ◽  
North America ◽  
Historical Context ◽  
The United States ◽  
Chinese Opera ◽  
Nation States ◽  
The Pacific ◽  
Chinese Theater ◽  
The Many ◽  
The Impact

This chapter surveys the historical context of the 1920s renaissance of Chinese opera theaters in the United States, including social, economic, cultural, and political forces of nation-states that helped shape the Chinese theater network linking China, the United States, Canada, and Cuba. It represents an important shift of the discourse of American musical history from the traditional focus of Atlantic World to that of the Pacific, presenting Chinatown theaters of North America as products of complex transnational forces. It also considers the symbolic significance of language and the impact of transnational network. The chapter therefore challenges the traditional characterization of the Chinese theater community as recalcitrant, demonstrating the many ways in which Chinese and Chinese American performers, owners, and patrons were active participants in the cultural milieu of North America in this period.

scholarly journals Quantifying the Impact of Climate Change on Flexible Pavement Performance and Lifetime in the United States

2019 ◽  
Vol 2673 (1) ◽  
pp. 110-122 ◽  
Author(s):  
Anne M. K. Stoner ◽  
Jo Sias Daniel ◽  
Jennifer M. Jacobs ◽  
Katharine Hayhoe ◽  
Ian Scott-Fleming
Keyword(s):  
Climate Change ◽  
United States ◽  
Global Climate Model ◽  
Flexible Pavement ◽  
The United States ◽  
Pavement Design ◽  
Pavement Performance ◽  
Climate Projections ◽  
Impact Of Climate Change ◽  
The Impact

Flexible pavement design requires considering a variety of factors including the materials used, variations in water tables, traffic levels, and the climatic conditions the road will experience over its lifetime. Most pavement designs are based on historical climate variables such as temperature and precipitation that are already changing across much of the United States, and do not reflect projected trends. As pavements are typically designed to last 20 years or more, designs that do not account for current and future trends can result in reduced performance. However, incorporating climate projections into pavement design is not a trivial exercise. Significant mismatches in both spatial and temporal scale challenge the integration of the latest global climate model simulations into pavement models. This study provides a national-level overview of what the impact of climate change to flexible pavement could look like, and where regional focus should be placed. It also demonstrates a new approach to developing high-resolution spatial and temporal projections that generates hourly information at the scale of individual weather stations, and applies this as input to the AASHTOWare Pavement ME Design™ model. The impact of three different future climates on pavement performance and time to reach failure thresholds in 24 locations across the United States are quantified. Changes to projected pavement performance differ by location, but nearly all result in decreased performance under current design standards. The largest increases in distress are observed for permanent deformation measures, especially toward the end of the century under greater increases in temperature.

Ecological Education: Extending the Definition of Environmental Education

1999 ◽  
Vol 15 ◽  
pp. 139-146 ◽  
Author(s):  
Gregory A. Smith ◽  
Dilafruz R. Williams
Keyword(s):  
United States ◽  
Environmental Education ◽  
Global Climate ◽  
Cultural Beliefs ◽  
The United States ◽  
Natural World ◽  
Environmental Crisis ◽  
Ecological Education ◽  
Human Beings ◽  
The Impact

Except in small measure, environmental education in the United States has not yet challenged the status quo of Western notions of progress or monoculturalism, or recognized that moving through the environmental crisis may require significant shifts in generally unquestioned cultural attitudes and beliefs. In the U.S., environmental education has instead tended to focus on information regarding environmental problems and to explore topics such as endangered species, global climate change, or the water quality of local streams and rivers. Even this has become a source of controversy in the United States since the mid-1990s as a coalition of right-wing organizations has mounted a well-coordinated political campaign charging environmental educators with bias and a failure to present both sides of controversial issues (Sanera & Shaw 1996, Independent Commission on Environmental Education 1997). Despite this, we believe that if environmental education is to live up to its promise as a vehicle for developing a citizenry capable of making wise decisions about the impact of human activities on the environment, examining and altering fundamental cultural beliefs and practices that are contributing to the degradation of the planet's natural systems will be imperative.We have chosen to call this extended form of environmental education ecological education. For us, ecological education connotes an emphasis on the inescapable embeddedness of human beings in natural settings and the responsibilities that arise from this relationship. Rather than seeing nature as other—a set of phenomena capable of being manipulated like parts of a machine—the practice of ecological education requires viewing human beings as one part of the natural world and human cultures as an outgrowth of interactions between our species and particular places. We believe that the development of sustainable cultures will in fact require widespread acceptance of a relationship between humans and the earth grounded in moral sentiments that arise from the willingness to care. As Indian physicist and ecofeminist Vandana Shiva writes, the term ‘sustainability’ implies the ability and willingness ‘to support, bear weight of, hold up, enable to last out, give strength to, endure without giving way’ (Shiva 1992, p. 191).

scholarly journals The impact of monthly variation of the Pacific–North America (PNA) teleconnection pattern on wintertime surface-layer aerosol concentrations in the United States

2016 ◽  
Vol 16 (8) ◽  
pp. 4927-4943 ◽  
Author(s):  
Jin Feng ◽  
Hong Liao ◽  
Jianping Li
Keyword(s):  
United States ◽  
Surface Layer ◽  
Air Quality ◽  
North America ◽  
Organic Carbon ◽  
Black Carbon ◽  
The United States ◽  
The Pacific ◽  
The Us ◽  
The Impact

Abstract. The Pacific–North America teleconnection (PNA) is the leading general circulation pattern in the troposphere over the region of North Pacific to North America during wintertime. This study examined the impacts of monthly variations of the PNA phase (positive or negative phase) on wintertime surface-layer aerosol concentrations in the United States (US) by analyzing observations during 1999–2013 from the Air Quality System of the Environmental Protection Agency (EPA-AQS) and the model results for 1986–2006 from the global three-dimensional Goddard Earth Observing System (GEOS) chemical transport model (GEOS-Chem). The composite analyses on the EPA-AQS observations over 1999–2013 showed that the average concentrations of PM2.5, sulfate, nitrate, ammonium, organic carbon, and black carbon aerosols over the US were higher in the PNA positive phases (25 % of the winter months examined, and this fraction of months had the highest positive PNA index values) than in the PNA negative phases (25 % of the winter months examined, and this fraction of months had the highest negative PNA index values) by 1.0 µg m−3 (8.7 %), 0.01 µg m−3 (0.5 %), 0.3 µg m−3 (29.1 %), 0.1 µg m−3 (11.9 %), 0.6 µg m−3 (13.5 %), and 0.2 µg m−3 (27.8 %), respectively. The simulated geographical patterns of the differences in concentrations of all aerosol species between the PNA positive and negative phases were similar to observations. Based on the GEOS-Chem simulation, the pattern correlation coefficients were calculated to show the impacts of PNA-induced variations in meteorological fields on aerosol concentrations. The PNA phase was found (i) to influence sulfate concentrations mainly through changes in planetary boundary layer height (PBLH), precipitation (PR), and temperature; (ii) to influence nitrate concentrations mainly through changes in temperature; and (iii) to influence concentrations of ammonium, organic carbon, and black carbon mainly through changes in PR and PBLH. Results from this work have important implications for the understanding and prediction of air quality in the US.

scholarly journals On the Role of SST Forcing in the 2011 and 2012 Extreme U.S. Heat and Drought: A Study in Contrasts

2014 ◽  
Vol 15 (3) ◽  
pp. 1255-1273 ◽  
Author(s):  
Hailan Wang ◽  
Siegfried Schubert ◽  
Randal Koster ◽  
Yoo-Geun Ham ◽  
Max Suarez
Keyword(s):  
United States ◽  
General Circulation ◽  
Rapid Development ◽  
The United States ◽  
Tropical Pacific ◽  
Extreme Heat ◽  
The Pacific ◽  
Sst Forcing ◽  
The Tropical Pacific

Abstract This study compares the extreme heat and drought that developed over the United States in 2011 and 2012 with a focus on the role of sea surface temperature (SST) forcing. Experiments with the NASA Goddard Earth Observing System, version 5 (GEOS-5), atmospheric general circulation model show that the winter/spring response over the United States to the Pacific SST is remarkably similar for the two years despite substantial differences in the tropical Pacific SST. As such, the pronounced winter and early spring temperature differences between the two years (warmth confined to the south in 2011 and covering much of the continent in 2012) primarily reflect differences in the contributions from the Atlantic and Indian Oceans, with both acting to cool the east and upper Midwest during 2011, while during 2012 the Indian Ocean reinforced the Pacific-driven, continental-wide warming and the Atlantic played a less important role. During late spring and summer of 2011, the tropical Pacific SST forced a continued warming and drying over the southern United States, though considerably weaker than observed. Nevertheless, the observed 2011 anomalies fall well within the model’s intraensemble spread. In contrast, the observed rapid development of intense heat and drying over the central United States during June and July 2012 falls on the margins of the model’s intraensemble spread, with the response to the SST giving little indication that 2012 would produce record-breaking precipitation deficits and heat. A diagnosis of the 2012 observed circulation anomalies shows that the most extreme heat and drought was tied to the development of a stationary Rossby wave and an associated anomalous upper-tropospheric high maintained by weather transients.

scholarly journals The Impact of El Niño–Southern Oscillation (ENSO) on Winter and Early Spring U.S. Tornado Outbreaks

2017 ◽  
Vol 56 (9) ◽  
pp. 2455-2478 ◽  
Author(s):  
Ashton Robinson Cook ◽  
Lance M. Leslie ◽  
David B. Parsons ◽  
Joseph T. Schaefer
Keyword(s):  
United States ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
The United States ◽  
Early Spring ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
The Impact ◽  
Tornado Outbreaks

AbstractIn recent years, the potential of seasonal outlooks for tornadoes has attracted the attention of researchers. Previous studies on this topic have focused mainly on the influence of global circulation patterns [e.g., El Niño–Southern Oscillation (ENSO), North Atlantic Oscillation, or Pacific decadal oscillation] on spring tornadoes. However, these studies have yielded conflicting results of the roles of these climate drivers on tornado intensity and frequency. The present study seeks to establish linkages between ENSO and tornado outbreaks over the United States during winter and early spring. These linkages are established in two ways: 1) statistically, by relating raw counts of tornadoes in outbreaks (defined as six or more tornadoes in a 24-h period in the United States east of the Rocky Mountains), and their destructive potential, to sea surface temperature anomalies observed in the Niño-3.4 region, and 2) qualitatively, by relating ENSO to shifts in synoptic-scale atmospheric phenomena that contribute to tornado outbreaks. The latter approach is critical for interpreting the statistical relationships, thereby avoiding the deficiencies in a few of the previous studies that did not provide physical explanations relating ENSO to shifts in tornado activity. The results suggest that shifts in tornado occurrence are clearly related to ENSO. In particular, La Niña conditions consistently foster more frequent and intense tornado activity in comparison with El Niño, particularly at higher latitudes. Furthermore, it is found that tornado activity changes are tied not only to the location and intensity of the subtropical jet during individual outbreaks but also to the positions of surface cyclones, low-level jet streams, and instability axes.

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