Author: Erica E. BickfordPublisher:
ISBN:
Category :
Languages : en
Pages : 188
Book Description
Quantification of Land-atmosphere Coupling and Implications for Drought Persistence in Observations and Model Simulations of 20th Century Climate and 21st Century Climate Change
Author: Erica E. BickfordFrom Ground Measurements to Global Models: Temporal and Spatial Characteristics of Drought and Extreme Precipitation Under Historical and Future Global Warming
Author: Danielle Elie ToumaPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Drought and extreme precipitation events lead to devastating damages to human and natural systems. The characteristics of these extreme climate events, including the frequency, intensity, and spatial extent of extreme wet conditions or extreme dry conditions can shape the risk posed to a region by an event. There has been substantial evidence that global warming has altered and will continue to alter atmospheric, land, and ocean conditions, which in turn lead to changes in the characteristics of extreme climate events. Additional anthropogenic emissions are expected to modify the ocean, land, and atmosphere in the future, though the role that these changes will have on future extreme precipitation and drought events is still uncertain. In my dissertation, I employ a multitude of observed and modeled climate datasets available to quantify the characteristics of drought and extreme wet events under past and future anthropogenic warming. By systematically quantifying the intensity, frequency, duration and spatial extent of extreme climate events across datasets, I aim to provide a climatological assessment of extreme climate event characteristics, and identify spatial or temporal variations of these characteristics. The findings from this dissertation will allow further insight into the impact past and future global warming have on extreme climate events, and subsequently, the risks to human and natural systems. In my first chapter, I investigate the expected changes in the frequency, duration, and spatial extent of drought over the globe in the 21st century under increased anthropogenic warming. To capture drought index-based uncertainty, I calculate four different drought indices which use precipitation, runoff, and moisture deficit, and to capture model-based uncertainty, I use climate simulations from 15 global climate models (GCMs) in the CMIP5 database. By comparing drought characteristics in the historical (1961-2005) simulations to the RCP 8.5 scenario (2010-2099) simulations, I show increases in the frequency and spatial extent of drought over the 21st century. These increases over the tropics and subtropics, reaching 80 more percentage points in the spatial extent and 40 more drought events, are robust among climate models when using deficit-based drought indices, but less robust when using precipitation or runoff-based indices. Given that deficit-based indices directly account for variations in temperature, these indices capture the significant increases in temperature simulated under high levels of anthropogenic emissions throughout the 21st century. These findings suggest that there is an increasing risk in drought stresses in many regions given the current trajectory of greenhouse gas emissions and associated warming temperatures. In my second chapter, I develop a geostatistical method to assess the spatial extent, or length scales, of extreme precipitation in GCHN-D station data. A climatological assessment over the US from 1965-2014 reveals significant seasonal and regional variations in the length scales of extreme daily precipitation. The eastern half of the US has daily extreme precipitation length scales reaching 400km during the winter months, but the length scales are halved during the summer months. The Northwest region, on the other hand, has little seasonal variation, with short extreme precipitation length scales of approximately 150km year-round. Though the magnitude of extreme precipitation length scales can be sensitive to certain choices in my method, the seasonal and regional variations remain relatively intact and can plausibly be explained by well-known atmospheric phenomena. This chapter introduces a valuable framework that can be used to quantify changes in the spatial extents of extreme climate events in the US and globally, and examine the impacts of varying spatial extents of extreme precipitation events on human and natural systems. In my third chapter, I use the geostatistical method I developed in my second chapter to quantify the intensity and length scales of tropical cyclone precipitation (TCP) along US-landfalling Atlantic tropical cyclone tracks from 1900-2017. Using GHCN-D precipitation station data and HURDAT2 tropical cyclone track data, I find significant variations in TCP intensity and length scales across different tropical cyclone strengths. TCP intensity and length scales are largest along major hurricane tracks. The highest values of TCP intensity (more than 150 mm/day) are found along major hurricane tracks, and the TCP intensity distribution is shifted positively during the weaker phases along the tracks. During these weaker phases, I also find the longest TCP length scales. However, the longest length scales of extreme TCP (> 75 mm/day) are found during the strongest phases. TCP intensity and length scales are significantly smaller along tropical storm and minor hurricane tracks. I also find varied changes in TCP intensity and length scales between the first and second halves of the 20th century. The upper quartiles of minor hurricane and tropical storm TCP intensity have significantly increased, alongside significant increases in the extent of extreme TCP. The intensity and extent of extreme TCP during major hurricanes have significantly decreased. The climatology of TCP intensity and length scales can be linked to the strength, speed, and symmetry of a tropical cyclone, as well as interactions with the land surface and topography. Moreover, the changes in TCP intensity and length scales can be explained by changes in precipitable water and vertical wind shear. This chapter provides important insights into the intensity and spatial extent of precipitation across different tropical cyclone strengths, allowing us to better understand the possible changes in TCP under future global warming. Taken together, these chapters advance our understanding of the risks posed by extreme climate events, and inform future research directions in this area of climate science. Given that these events cause severe losses to communities and their surrounding ecosystems, it is imperative that we advance our ability to address the effects of extreme climate events.
Global Environmental Change
Author: National Research CouncilPublisher: National Academies Press
ISBN: 0309174325
Category : Science
Languages : en
Pages : 621
Book Description
How can we understand and rise to the environmental challenges of global change? One clear answer is to understand the science of global change, not solely in terms of the processes that control changes in climate and the composition of the atmosphere, but in how ecosystems and human society interact with these changes. In the last two decades of the twentieth century, a number of such research effortsâ€"supported by computer and satellite technologyâ€"have been launched. Yet many opportunities for integration remain unexploited, and many fundamental questions remain about the earth's capacity to support a growing human population. This volume encourages a renewed commitment to understanding global change and sets a direction for research in the decade ahead. Through case studies the book explores what can be learned from the lessons of the past 20 years and what are the outstanding scientific questions. Highlights include: Research imperatives and strategies for investigators in the areas of atmospheric chemistry, climate, ecosystem studies, and human dimensions of global change. The context of climate change, including lessons to be gleaned from paleoclimatology. Human responses toâ€"and forcing ofâ€"projected global change. This book offers a comprehensive overview of global change research to date and provides a framework for answering urgent questions.
Thriving on Our Changing Planet
Author: National Academies of Sciences, Engineering, and MedicinePublisher: National Academies Press
ISBN: 0309467578
Category : Science
Languages : en
Pages : 717
Book Description
We live on a dynamic Earth shaped by both natural processes and the impacts of humans on their environment. It is in our collective interest to observe and understand our planet, and to predict future behavior to the extent possible, in order to effectively manage resources, successfully respond to threats from natural and human-induced environmental change, and capitalize on the opportunities â€" social, economic, security, and more â€" that such knowledge can bring. By continuously monitoring and exploring Earth, developing a deep understanding of its evolving behavior, and characterizing the processes that shape and reshape the environment in which we live, we not only advance knowledge and basic discovery about our planet, but we further develop the foundation upon which benefits to society are built. Thriving on Our Changing Planet presents prioritized science, applications, and observations, along with related strategic and programmatic guidance, to support the U.S. civil space Earth observation program over the coming decade.
Hydrological Drought
Author: Lena M. TallaksenPublisher: Elsevier
ISBN: 9780444517678
Category : Computers
Languages : en
Pages : 626
Book Description
The majority of the examples are taken from regions where the rivers run most of the year.
Attribution of Extreme Weather Events in the Context of Climate Change
Author: National Academies of Sciences, Engineering, and MedicinePublisher: National Academies Press
ISBN: 0309380979
Category : Science
Languages : en
Pages : 187
Book Description
As climate has warmed over recent years, a new pattern of more frequent and more intense weather events has unfolded across the globe. Climate models simulate such changes in extreme events, and some of the reasons for the changes are well understood. Warming increases the likelihood of extremely hot days and nights, favors increased atmospheric moisture that may result in more frequent heavy rainfall and snowfall, and leads to evaporation that can exacerbate droughts. Even with evidence of these broad trends, scientists cautioned in the past that individual weather events couldn't be attributed to climate change. Now, with advances in understanding the climate science behind extreme events and the science of extreme event attribution, such blanket statements may not be accurate. The relatively young science of extreme event attribution seeks to tease out the influence of human-cause climate change from other factors, such as natural sources of variability like El Niño, as contributors to individual extreme events. Event attribution can answer questions about how much climate change influenced the probability or intensity of a specific type of weather event. As event attribution capabilities improve, they could help inform choices about assessing and managing risk, and in guiding climate adaptation strategies. This report examines the current state of science of extreme weather attribution, and identifies ways to move the science forward to improve attribution capabilities.
Climate Change 2014
Author: Groupe d'experts intergouvernemental sur l'évolution du climatPublisher:
ISBN: 9789291691432
Category :
Languages : en
Pages : 151
Book Description
Natural Climate Variability on Decade-to-Century Time Scales
Author: National Research CouncilPublisher: National Academies Press
ISBN: 0309054494
Category : Science
Languages : en
Pages : 645
Book Description
This volume reflects the current state of scientific knowledge about natural climate variability on decade-to-century time scales. It covers a wide range of relevant subjects, including the characteristics of the atmosphere and ocean environments as well as the methods used to describe and analyze them, such as proxy data and numerical models. They clearly demonstrate the range, persistence, and magnitude of climate variability as represented by many different indicators. Not only do natural climate variations have important socioeconomic effects, but they must be better understood before possible anthropogenic effects (from greenhouse gas emissions, for instance) can be evaluated. A topical essay introduces each of the disciplines represented, providing the nonscientist with a perspective on the field and linking the papers to the larger issues in climate research. In its conclusions section, the book evaluates progress in the different areas and makes recommendations for the direction and conduct of future climate research. This book, while consisting of technical papers, is also accessible to the interested layperson.
Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation
Author: Intergovernmental Panel on Climate ChangePublisher: Cambridge University Press
ISBN: 1107025060
Category : Business & Economics
Languages : en
Pages : 593
Book Description
Extreme weather and climate events, interacting with exposed and vulnerable human and natural systems, can lead to disasters. This Special Report explores the social as well as physical dimensions of weather- and climate-related disasters, considering opportunities for managing risks at local to international scales. SREX was approved and accepted by the Intergovernmental Panel on Climate Change (IPCC) on 18 November 2011 in Kampala, Uganda.
Meteorological Drought
Author: Wayne C. PalmerPublisher:
ISBN:
Category : Climatology
Languages : en
Pages : 68
Book Description
The underlying concept of the paper is that the amount of precipitation required for the near-normal operation of the established economy of an area during some stated period is dependent on the average climate of the area and on the prevailing meteorological conditions both during and preceding the month or period in question. A method for computing this required precipitation is demonstrated.