William F. Laurance
- Published in print:
- 2005
- Published Online:
- September 2007
- ISBN:
- 9780198567066
- eISBN:
- 9780191717888
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198567066.003.0003
- Subject:
- Biology, Plant Sciences and Forestry
In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (<1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply ...
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In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (<1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply increased tree mortality, altering canopy-gap dynamics, plant-community composition, biomass dynamics, and carbon storage. Fragmented forests are also highly vulnerable to edge-related fires, especially in regions which have periodic droughts or strong dry seasons. At landscape to regional scales (10-1,000 km), habitat fragmentation may have complex effects on forest-climate interactions, with important consequences for atmospheric circulation, water cycling, and precipitation. Positive feedbacks among deforestation, regional climate change, and fire could pose a serious threat for some tropical forests, but the details of such interactions are poorly understood.Less
In the tropics, habitat fragmentation alters forest-climate interactions in diverse ways. On a local scale (<1 km), elevated desiccation and wind disturbance near fragment margins lead to sharply increased tree mortality, altering canopy-gap dynamics, plant-community composition, biomass dynamics, and carbon storage. Fragmented forests are also highly vulnerable to edge-related fires, especially in regions which have periodic droughts or strong dry seasons. At landscape to regional scales (10-1,000 km), habitat fragmentation may have complex effects on forest-climate interactions, with important consequences for atmospheric circulation, water cycling, and precipitation. Positive feedbacks among deforestation, regional climate change, and fire could pose a serious threat for some tropical forests, but the details of such interactions are poorly understood.
Theodore G. Shepherd
- Published in print:
- 2020
- Published Online:
- March 2020
- ISBN:
- 9780198855217
- eISBN:
- 9780191889172
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198855217.003.0004
- Subject:
- Physics, Geophysics, Atmospheric and Environmental Physics
The chapter begins with a phenomenological treatment of the observed atmospheric circulation. It then goes on to discuss how the barotropic model arises as a so-calledbalanced model of the slow, ...
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The chapter begins with a phenomenological treatment of the observed atmospheric circulation. It then goes on to discuss how the barotropic model arises as a so-calledbalanced model of the slow, vorticity-driven dynamics, from the more general shallowwater model which also admits inertia-gravity waves. This is important because large-scale atmospheric turbulence exhibits aspects of both balanced and unbalanced dynamics. Because of the first-order importance of zonal flows in the atmospheric general circulation, the large-scale turbulence is highly inhomogeneous, and is shaped by the nature of the interaction between zonal flows and Rossby waves described eloquently by Michael McIntyre as a wave-turbulence jigsaw puzzle. This motivates a review of the barotropic theory of wave, mean-flow interaction, which is underpinned by the Hamiltonian structure of geophysical fluid dynamics.Less
The chapter begins with a phenomenological treatment of the observed atmospheric circulation. It then goes on to discuss how the barotropic model arises as a so-calledbalanced model of the slow, vorticity-driven dynamics, from the more general shallowwater model which also admits inertia-gravity waves. This is important because large-scale atmospheric turbulence exhibits aspects of both balanced and unbalanced dynamics. Because of the first-order importance of zonal flows in the atmospheric general circulation, the large-scale turbulence is highly inhomogeneous, and is shaped by the nature of the interaction between zonal flows and Rossby waves described eloquently by Michael McIntyre as a wave-turbulence jigsaw puzzle. This motivates a review of the barotropic theory of wave, mean-flow interaction, which is underpinned by the Hamiltonian structure of geophysical fluid dynamics.
Richard A. Minnich
- Published in print:
- 2006
- Published Online:
- March 2012
- ISBN:
- 9780520246058
- eISBN:
- 9780520932272
- Item type:
- chapter
- Publisher:
- University of California Press
- DOI:
- 10.1525/california/9780520246058.003.0002
- Subject:
- Biology, Ecology
This chapter starts by exploring some basic principles of weather. It then describes California’s Mediterranean climate from the standpoint of atmospheric circulation. This is followed by short-term ...
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This chapter starts by exploring some basic principles of weather. It then describes California’s Mediterranean climate from the standpoint of atmospheric circulation. This is followed by short-term weather conditions associated with fire spread, and climate variability and its possible role in fire regimes. The Mediterranean climate results from seasonal changes in global circulation, including California’s marginal position to the jet stream and the presence of cold, upwelling ocean waters offshore. The weather influences fire outcomes by altering vegetation fuel moisture and the efficiency of heat transfer in combustion. The El Niño/Southern Oscillation and the Pacific Decadal Oscillation influence the amount and distribution of water vapor that is evaporated into the air, condensed into clouds, and rained back to earth. The effect of precipitation variability is modulated by patch structure in which changes in regional fire hazard result in only finite portions of stands achieving flammability thresholds.Less
This chapter starts by exploring some basic principles of weather. It then describes California’s Mediterranean climate from the standpoint of atmospheric circulation. This is followed by short-term weather conditions associated with fire spread, and climate variability and its possible role in fire regimes. The Mediterranean climate results from seasonal changes in global circulation, including California’s marginal position to the jet stream and the presence of cold, upwelling ocean waters offshore. The weather influences fire outcomes by altering vegetation fuel moisture and the efficiency of heat transfer in combustion. The El Niño/Southern Oscillation and the Pacific Decadal Oscillation influence the amount and distribution of water vapor that is evaporated into the air, condensed into clouds, and rained back to earth. The effect of precipitation variability is modulated by patch structure in which changes in regional fire hazard result in only finite portions of stands achieving flammability thresholds.
Kevin E. Trenberth and James W. Hurrell
- Published in print:
- 2019
- Published Online:
- September 2019
- ISBN:
- 9780198824268
- eISBN:
- 9780191862809
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198824268.003.0002
- Subject:
- Biology, Ornithology, Animal Biology
The climate is changing from human activities. This has major implications for the future and for human society and ecosystems, including birds. However, it is often masked by natural variability and ...
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The climate is changing from human activities. This has major implications for the future and for human society and ecosystems, including birds. However, it is often masked by natural variability and there is great weather-related variability. This chapter reviews observed changes in climate, with a focus on changes in surface climate including variations in major patterns (modes) of climate variability and teleconnections. Of particular importance are changes in extremes. It describes how natural and anthropogenic drivers of climate change are assessed using climate models and concludes with a brief summary of future projected changes in climate and their impacts.Less
The climate is changing from human activities. This has major implications for the future and for human society and ecosystems, including birds. However, it is often masked by natural variability and there is great weather-related variability. This chapter reviews observed changes in climate, with a focus on changes in surface climate including variations in major patterns (modes) of climate variability and teleconnections. Of particular importance are changes in extremes. It describes how natural and anthropogenic drivers of climate change are assessed using climate models and concludes with a brief summary of future projected changes in climate and their impacts.
Jost Heintzenberg and Robert J. Charlson (eds)
- Published in print:
- 2009
- Published Online:
- August 2013
- ISBN:
- 9780262012874
- eISBN:
- 9780262255448
- Item type:
- book
- Publisher:
- The MIT Press
- DOI:
- 10.7551/mitpress/9780262012874.001.0001
- Subject:
- Environmental Science, Climate
More than half the globe is covered by visible clouds. Clouds control major parts of the Earth’s energy balance, influencing both incoming shortwave solar radiation and outgoing longwave thermal ...
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More than half the globe is covered by visible clouds. Clouds control major parts of the Earth’s energy balance, influencing both incoming shortwave solar radiation and outgoing longwave thermal radiation. Latent heating and cooling related to cloud processes modify atmospheric circulation, and, by modulating sea surface temperatures, clouds affect the oceanic circulation. They are also an essential component of the global water cycle, on which all terrestrial life depends. Yet clouds constitute the most poorly quantified, least understood, and most puzzling aspect of atmospheric science, and thus the largest source of uncertainty in the prediction of climate change. Because they are influenced by climate change, and because complex, unidentified feedback systems are involved, science is faced with many unanswered questions. This book begins by identifying and describing the baffling nature of clouds. It explores the boundaries of current knowledge on the spatial/temporal variability of clouds and cloud-related aerosols, as well as the factors that control clouds, and examines the extent and nature of anthropogenic perturbations. Particular emphasis is placed on the connections of clouds to climate through radiation, dynamics, precipitation, and chemistry, and on the difficulties in understanding the obvious but elusive fact that clouds must be affected by climate change. The book offers recommendations to improve the current state of knowledge and to direct future research in fields ranging from chemistry and theoretical physics to climate modeling and remote satellite sensing.Less
More than half the globe is covered by visible clouds. Clouds control major parts of the Earth’s energy balance, influencing both incoming shortwave solar radiation and outgoing longwave thermal radiation. Latent heating and cooling related to cloud processes modify atmospheric circulation, and, by modulating sea surface temperatures, clouds affect the oceanic circulation. They are also an essential component of the global water cycle, on which all terrestrial life depends. Yet clouds constitute the most poorly quantified, least understood, and most puzzling aspect of atmospheric science, and thus the largest source of uncertainty in the prediction of climate change. Because they are influenced by climate change, and because complex, unidentified feedback systems are involved, science is faced with many unanswered questions. This book begins by identifying and describing the baffling nature of clouds. It explores the boundaries of current knowledge on the spatial/temporal variability of clouds and cloud-related aerosols, as well as the factors that control clouds, and examines the extent and nature of anthropogenic perturbations. Particular emphasis is placed on the connections of clouds to climate through radiation, dynamics, precipitation, and chemistry, and on the difficulties in understanding the obvious but elusive fact that clouds must be affected by climate change. The book offers recommendations to improve the current state of knowledge and to direct future research in fields ranging from chemistry and theoretical physics to climate modeling and remote satellite sensing.
René D. Garreaud and Patricio Aceituno
- Published in print:
- 2007
- Published Online:
- November 2020
- ISBN:
- 9780195313413
- eISBN:
- 9780197562475
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195313413.003.0010
- Subject:
- Earth Sciences and Geography, Physical Geography and Topography
Regional variations in South America’s weather and climate reflect the atmospheric circulation over the continent and adjacent oceans, involving mean ...
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Regional variations in South America’s weather and climate reflect the atmospheric circulation over the continent and adjacent oceans, involving mean climatic conditions and regular cycles, as well as their variability on timescales ranging from less than a few months to longer than a year. Rather than surveying mean climatic conditions and variability over different parts of South America, as provided by Schwerdtfeger and Landsberg (1976) and Hobbs et al. (1998), this chapter presents a physical understanding of the atmospheric phenomena and precipitation patterns that explain the continent’s weather and climate. These atmospheric phenomena are strongly affected by the topographic features and vegetation patterns over the continent, as well as by the slowly varying boundary conditions provided by the adjacent oceans. The diverse patterns of weather, climate, and climatic variability over South America, including tropical, subtropical, and midlatitude features, arise from the long meridional span of the continent, from north of the equator south to 55°S. The Andes cordillera, running continuously along the west coast of the continent, reaches elevations in excess of 4 km from the equator to about 40°S and, therefore, represents a formidable obstacle for tropospheric flow. As shown later, the Andes not only acts as a “climatic wall” with dry conditions to the west and moist conditions to the east in the subtropics (the pattern is reversed in midlatitudes), but it also fosters tropical-extratropical interactions, especially along its eastern side. The Brazilian plateau also tends to block the low-level circulation over subtropical South America. Another important feature is the large area of continental landmass at low latitudes (10°N–20°S), conducive to the development of intense convective activity that supports the world’s largest rain forest in the Amazon basin. The El Niño–Southern Oscillation phenomenon, rooted in the ocean-atmosphere system of the tropical Pacific, has a direct strong influence over most of tropical and subtropical South America. Similarly, sea surface temperature anomalies over the Atlantic Ocean have a profound impact on the climate and weather along the eastern coast of the continent. In this section we describe the long-term annual and monthly mean fields of several meteorological variables.
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Regional variations in South America’s weather and climate reflect the atmospheric circulation over the continent and adjacent oceans, involving mean climatic conditions and regular cycles, as well as their variability on timescales ranging from less than a few months to longer than a year. Rather than surveying mean climatic conditions and variability over different parts of South America, as provided by Schwerdtfeger and Landsberg (1976) and Hobbs et al. (1998), this chapter presents a physical understanding of the atmospheric phenomena and precipitation patterns that explain the continent’s weather and climate. These atmospheric phenomena are strongly affected by the topographic features and vegetation patterns over the continent, as well as by the slowly varying boundary conditions provided by the adjacent oceans. The diverse patterns of weather, climate, and climatic variability over South America, including tropical, subtropical, and midlatitude features, arise from the long meridional span of the continent, from north of the equator south to 55°S. The Andes cordillera, running continuously along the west coast of the continent, reaches elevations in excess of 4 km from the equator to about 40°S and, therefore, represents a formidable obstacle for tropospheric flow. As shown later, the Andes not only acts as a “climatic wall” with dry conditions to the west and moist conditions to the east in the subtropics (the pattern is reversed in midlatitudes), but it also fosters tropical-extratropical interactions, especially along its eastern side. The Brazilian plateau also tends to block the low-level circulation over subtropical South America. Another important feature is the large area of continental landmass at low latitudes (10°N–20°S), conducive to the development of intense convective activity that supports the world’s largest rain forest in the Amazon basin. The El Niño–Southern Oscillation phenomenon, rooted in the ocean-atmosphere system of the tropical Pacific, has a direct strong influence over most of tropical and subtropical South America. Similarly, sea surface temperature anomalies over the Atlantic Ocean have a profound impact on the climate and weather along the eastern coast of the continent. In this section we describe the long-term annual and monthly mean fields of several meteorological variables.
William F. Fitzgerald, Chad R. Hammerschmidt, Daniel R. Engstrom, Prentiss H. Balcom, Carl H. Lamborg, and Chun-Mao Tseng
- Published in print:
- 2014
- Published Online:
- May 2015
- ISBN:
- 9780199860401
- eISBN:
- 9780190267889
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:osobl/9780199860401.003.0009
- Subject:
- Biology, Ecology
This chapter discusses mercury cycling and contamination in the Alaskan arctic. It provides a framework for investigating the behavior and fate of many contaminants in polar regions. It looks into ...
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This chapter discusses mercury cycling and contamination in the Alaskan arctic. It provides a framework for investigating the behavior and fate of many contaminants in polar regions. It looks into the role atmospheric circulation and chemistry in affecting the transport and deposition of both inorganic and organic substrates on local and global scales. It analyzes a series of reports by the Arctic Monitoring and Assessment Program in determining mechanisms that transport contaminants, including mercury, to the arctic and identifies their effects on the arctic ecosystem.Less
This chapter discusses mercury cycling and contamination in the Alaskan arctic. It provides a framework for investigating the behavior and fate of many contaminants in polar regions. It looks into the role atmospheric circulation and chemistry in affecting the transport and deposition of both inorganic and organic substrates on local and global scales. It analyzes a series of reports by the Arctic Monitoring and Assessment Program in determining mechanisms that transport contaminants, including mercury, to the arctic and identifies their effects on the arctic ecosystem.
E. C. Pielou
- Published in print:
- 2001
- Published Online:
- February 2013
- ISBN:
- 9780226668062
- eISBN:
- 9780226668055
- Item type:
- chapter
- Publisher:
- University of Chicago Press
- DOI:
- 10.7208/chicago/9780226668055.003.0005
- Subject:
- Biology, Natural History and Field Guides
Wherever the wind blows, some of its energy is dissipated — converted to entropy — by the shearing of air against air; this happens at all elevations. However, the losses are far greater in the ...
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Wherever the wind blows, some of its energy is dissipated — converted to entropy — by the shearing of air against air; this happens at all elevations. However, the losses are far greater in the lower-most layer because of friction with the surface — the drag of moving air as it passes across land or water. Drag also affects the direction of the wind, making atmospheric circulation far more complicated than it is aloft. This chapter discusses the following: surface winds; vertical movements of the air; water vapor and energy transfers; storms; how atmospheric energy is dissipated; and the energy in a rainstorm.Less
Wherever the wind blows, some of its energy is dissipated — converted to entropy — by the shearing of air against air; this happens at all elevations. However, the losses are far greater in the lower-most layer because of friction with the surface — the drag of moving air as it passes across land or water. Drag also affects the direction of the wind, making atmospheric circulation far more complicated than it is aloft. This chapter discusses the following: surface winds; vertical movements of the air; water vapor and energy transfers; storms; how atmospheric energy is dissipated; and the energy in a rainstorm.
Tim Woollings
- Published in print:
- 2019
- Published Online:
- September 2019
- ISBN:
- 9780198828518
- eISBN:
- 9780191867002
- Item type:
- book
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780198828518.001.0001
- Subject:
- Physics, Geophysics, Atmospheric and Environmental Physics
A number of extreme weather events have struck the Northern Hemisphere in recent years, from scorching heatwaves to desperately cold winters and from floods and storms to droughts and wildfires. Is ...
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A number of extreme weather events have struck the Northern Hemisphere in recent years, from scorching heatwaves to desperately cold winters and from floods and storms to droughts and wildfires. Is this the emerging signal of climate change, and should we expect more of this? Media reports vary widely, but one mysterious agent has risen to prominence in many cases: the jet stream. The story begins on a windswept beach in Barbados, from where we follow the ascent of a weather balloon that will travel all around the world, following the jet stream. From this viewpoint we can observe the effect of the jet in influencing human life around the hemisphere, and witness startling changes emerging. What is the jet stream and how well do we understand it? How does it affect our weather and is it changing? These are the main questions tackled in this book. We learn about how our view of the wind has developed from Aristotle’s early theories up to today’s understanding. The jet is shown to be intimately connected with dramatic contrasts between climate zones and to have played a key historical role in determining patterns of trade. We learn about the basic physics underlying the jet and how this knowledge is incorporated into computer models which predict both tomorrow’s weather and the climate of future decades. We discuss how climate change is expected to affect the jet, and introduce the urgent scientific debate over whether these changes have contributed to recent extreme weather events.Less
A number of extreme weather events have struck the Northern Hemisphere in recent years, from scorching heatwaves to desperately cold winters and from floods and storms to droughts and wildfires. Is this the emerging signal of climate change, and should we expect more of this? Media reports vary widely, but one mysterious agent has risen to prominence in many cases: the jet stream. The story begins on a windswept beach in Barbados, from where we follow the ascent of a weather balloon that will travel all around the world, following the jet stream. From this viewpoint we can observe the effect of the jet in influencing human life around the hemisphere, and witness startling changes emerging. What is the jet stream and how well do we understand it? How does it affect our weather and is it changing? These are the main questions tackled in this book. We learn about how our view of the wind has developed from Aristotle’s early theories up to today’s understanding. The jet is shown to be intimately connected with dramatic contrasts between climate zones and to have played a key historical role in determining patterns of trade. We learn about the basic physics underlying the jet and how this knowledge is incorporated into computer models which predict both tomorrow’s weather and the climate of future decades. We discuss how climate change is expected to affect the jet, and introduce the urgent scientific debate over whether these changes have contributed to recent extreme weather events.
Antony R. Orme
- Published in print:
- 2007
- Published Online:
- November 2020
- ISBN:
- 9780195313413
- eISBN:
- 9780197562475
- Item type:
- chapter
- Publisher:
- Oxford University Press
- DOI:
- 10.1093/oso/9780195313413.003.0008
- Subject:
- Earth Sciences and Geography, Physical Geography and Topography
Tectonism is the science of Earth movements and the rocks and structures involved therein. These movements build the structural framework that supports the ...
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Tectonism is the science of Earth movements and the rocks and structures involved therein. These movements build the structural framework that supports the stage on which surface processes, plants, animals and, most recently, people pursue their various roles under an atmospheric canopy. An appreciation of this tectonic framework is thus a desirable starting point for understanding the physical geography of South America, from its roots in the distant past through the many and varied changes that have shaped the landscapes visible today. Tectonic science recognizes that Earth’s lithosphere comprises rocks of varying density that mobilize as relatively rigid plates, some continental in origin, some oceanic, and some, like the South American plate, amalgams of both continental and oceanic rocks. These plates shift in response to deep-seated forces, such as convection in the upper mantle, and crustal forces involving push and pull mechanics between plates. Crustal motions, augmented by magmatism, erosion, and deposition, in turn generate complex three-dimensional patterns. Although plate architecture has changed over geologic time, Earth’s lithosphere is presently organized into seven major plates, including the South American plate, and numerous smaller plates and slivers. The crustal mobility implicit in plate tectonics often focuses more attention on plate margins than on plate interiors. In this respect, it is usual to distinguish between passive margins, where plates are rifting and diverging, and active margins, where plates are either converging or shearing laterally alongside one another. At passive or divergent margins, such as the present eastern margin of the South American plate, severe crustal deformation is rare but crustal flexuring (epeirogeny), faulting, and volcanism occur as plates shift away from spreading centers, such as the Mid-Atlantic Ridge, where new crust is forming. Despite this lack of severe postrift deformation, however, passive margins commonly involve the separation of highly deformed rocks and structures that were involved in the earlier assembly of continental plates, as shown by similar structural legacies in the facing continental margins of eastern South America and western Africa. At active convergent margins, mountain building (orogeny) commonly results from subduction of oceanic plates, collision of continental plates, or accretion of displaced terranes.
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Tectonism is the science of Earth movements and the rocks and structures involved therein. These movements build the structural framework that supports the stage on which surface processes, plants, animals and, most recently, people pursue their various roles under an atmospheric canopy. An appreciation of this tectonic framework is thus a desirable starting point for understanding the physical geography of South America, from its roots in the distant past through the many and varied changes that have shaped the landscapes visible today. Tectonic science recognizes that Earth’s lithosphere comprises rocks of varying density that mobilize as relatively rigid plates, some continental in origin, some oceanic, and some, like the South American plate, amalgams of both continental and oceanic rocks. These plates shift in response to deep-seated forces, such as convection in the upper mantle, and crustal forces involving push and pull mechanics between plates. Crustal motions, augmented by magmatism, erosion, and deposition, in turn generate complex three-dimensional patterns. Although plate architecture has changed over geologic time, Earth’s lithosphere is presently organized into seven major plates, including the South American plate, and numerous smaller plates and slivers. The crustal mobility implicit in plate tectonics often focuses more attention on plate margins than on plate interiors. In this respect, it is usual to distinguish between passive margins, where plates are rifting and diverging, and active margins, where plates are either converging or shearing laterally alongside one another. At passive or divergent margins, such as the present eastern margin of the South American plate, severe crustal deformation is rare but crustal flexuring (epeirogeny), faulting, and volcanism occur as plates shift away from spreading centers, such as the Mid-Atlantic Ridge, where new crust is forming. Despite this lack of severe postrift deformation, however, passive margins commonly involve the separation of highly deformed rocks and structures that were involved in the earlier assembly of continental plates, as shown by similar structural legacies in the facing continental margins of eastern South America and western Africa. At active convergent margins, mountain building (orogeny) commonly results from subduction of oceanic plates, collision of continental plates, or accretion of displaced terranes.