Download or read book Mid 21st Century Changes to Surface Hydrology Over the Los Angeles Region written by Marla Ann Schwartz and published by . This book was released on 2013 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explores projected mid-21st century changes to surface hydrological fluxes and states in the Los Angeles region at 2km resolution. This work quantifies and describes potential impacts of climate change to precipitation, runoff, evapotranspiration and soil column moisture content in the Los Angeles region. Little previous research has focused on the impacts of climate change to water resources and surface hydrology in this region. We simulate detailed climatologies of surface hydrology for the late 20th century and mid 21st century. By looking at differences between the future and baseline periods, mid-century changes to surface hydrology relative to the late 20th century can be evaluated in our study region. Using dynamical downscaling techniques and the Weather Research and Forecasting (WRF) model, we develop a detailed high-resolution climatology for the Los Angeles region from coarse-resolution North America Regional Reanalysis (NARR) data and output from five "business as usual" global climate model (GCMs) simulations in the Fifth Coupled Model Intercomparison Project (CMIP5) data archive. Output from the dynamical downscaling WRF simulations is then used to force the offline Noah Land Surface Model (Noah & ndashLSM), which simulates near-surface state variables and surface turbulent fluxes. This methodology allows us to assess potential impacts of climate change to surface hydrology in the Los Angeles region at scales relevant to local policy makers or water resources planners.
Download or read book Climate Change and California Surface Hydrology written by Marla Ann Schwartz and published by . This book was released on 2016 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding 21st century changes in California surface hydrology is critical to ensuring enough freshwater resources for the state's municipal, ecological and agricultural purposes and assessing future ecosystem health and wildfire risk. To project 21st century surface hydrology over California - a region with highly complex topography that is not well captured by global climate models (GCMs) - downscaling is necessary. This work projects future changes in surface hydrology over the Los Angeles and Sierra Nevada regions through dynamical and statistical downscaling techniques. Dynamical downscaling is employed over Los Angeles to produce 2-km resolution regional projections for the mid-21st-century under an aggressive warming scenario. These projections reveal annual mean runoff and actual evapotranspiration are nearly insensitive to warming. This insensitivity is an artifact of the region's Mediterranean-type climate: Because the warm season receives almost no precipitation, the strongest warming-induced potential evapotranspiration enhancement coincides with dry soils, severely constraining actual evapotranspiration increases. This surprising result highlights that this important semi-arid region is less susceptible to long-term changes in runoff and soil moisture due to its Mediterranean climate. Over the Sierra Nevada Mountains, dynamical downscaling is used to produce high-resolution (3-km) simulations of end-of-21st-century surface hydroclimate. The high resolution and physical realism of these simulations provides unprecedented detail into the elevational dependence of hydroclimate changes and allows us to examine hydroclimate changes at the watershed level. These downscaled simulations reveal future warming leads to a shift toward significantly earlier snowmelt-driven surface runoff timing at each elevation throughout the Sierra Nevada, particularly in mid-elevations (2000-2750m) in the western and northern Sierra. Moreover, these projections show that any precipitation increases are outweighed by warming induced snowpack reductions and evapotranspiration increases, resulting in statistically significant drying of spring and summer soils and a substantial lengthening of the summer dry period. Relationships and patterns that emerge through dynamical downscaling over the Sierra Nevada are exploited to build simple statistical models that mimic dynamical model behavior. Using this hybrid dynamical-statistical downscaling model, high-resolution end-of-21st-century runoff timing and soil moisture changes are projected for all available GCMs from phase 5 of the Coupled Model Intercomparison Project and the four forcing scenarios adopted by the Intergovernmental Panel on Climate Change's Fifth Assessment Report. These multi-model projections allow us to quantify and characterize ensemble-mean changes and the associated uncertainty due to inter-model GCM spread, as well as the consequences associated with choice of emissions scenario. Averaged across the Sierra, April-September soil moisture is projected to decrease 17.1% in the 35-model ensemble mean under RCP8.5 (with an approximate intermodel range of -12.9% to -21.0%), but only 9.1% with an approximate intermodel range of -5.7% to -12.9%) under RCP4.5, a reasonable mitigation scenario.
Download or read book Assessing Urban Ecosystem Alternatives for Changing Land Use Dynamics in the Los Angeles Region written by Ruth Aliza Engel and published by . This book was released on 2022 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the world has grown increasingly urbanized over the last half-century, management of regional metropolitan landscapes has become more complex. Planning and research efforts alike require an understanding of local conditions and variability within cities. In this study, I examine changing land cover, urban hydrology, and surface temperature within the Los Angeles region. Using a deep convolutional neural network, I disaggregated mixed Landsat pixels to track land cover change over a continuous 35-year record. I found relatively constant urban area but a higher abundance of irrigated tree cover than is commonly detected in long-term remote sensing data. I used the Distributed Hydrology Soil Vegetation Model to examine hydrology in two distinct neighborhoods within Los Angeles, and observed that new urban vegetation in primarily impervious areas reduced precipitation-event runoff but universally increased evapotranspiration more substantially than it did in vegetated areas. Both the hydrologic baseline and the responses to land use change varied substantially across different localities. I assessed the contributions of streets to land surface temperature (LST), and found that localized urban morphology and vegetation, rather than road surface, determine LST. In many cases, large impervious or irrigated pockets dominated neighborhood-scale 1st signatures. Together, these analyses demonstrate that disparate vegetation, irrigation strategies, and building footprints across an urban area have unique interactions that can make regional approaches impractical and ineffective. Rather, urban ecosystem services can be strengthened by local consideration and an understanding of scale.
Download or read book The Effects of Climate Change on Lake Tahoe in the 21st Century written by and published by . This book was released on 2010 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Extreme Hydrological Changes in the Southwestern US Drive Reductions in Water Supply to Southern California by Mid Century written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Southwestern United States has a greater vulnerability to climate change impacts on water security due to a reliance on snowmelt driven imported water. The State of California, which is the most populous and agriculturally productive in the United States, depends on an extensive artificial water storage and conveyance system primarily for irrigated agriculture, municipal and industrial supply and hydropower generation. Here we take an integrative high-resolution ensemble approach to examine near term climate change impacts on all imported and local sources of water supply to Southern California. While annual precipitation is projected to remain the same or slightly increase, rising temperatures result in a shift in precipitation type towards more rainfall, reducing cold season snowpack and earlier snowmelt. Associated with these hydrological changes are substantial increases in both dry and flood event frequency and intensity. On one hand, the greater probability of drought decreases imported water supply availability. On the other hand, earlier snowmelt and significantly stronger winter precipitation events pose increased flood risk requiring water releases from reservoirs for flood control, also potentially decreasing water availability. As a result, lack of timely local water resource expansion coupled with climate change projections and population increases may leave the area in extended periods of shortages.
Download or read book California Drought written by Betsy A. Cody and published by DIANE Publishing. This book was released on 2010-10 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: California experienced severe water supply shortages in 2009, which led to economic disruption across the state, incl. losses in agricultural areas in the western portion of the Central Valley ¿ areas already experiencing declines in the housing industry and the economic downturn in general. At the same time, several fish species whose habitat lie at the heart of California¿s water supply system and throughout its northern rivers are in decline and some face the possibility of extinction. This situation too has had economic implications, resulting in job and income losses in northern California. Contents of this report: (1) Intro.; (2) What is Drought?; (3) Drought in California; (4) Regulatory Restrictions Affecting Water Deliveries; (5) California Water Rights. Illus.
Download or read book Effects of the January and February 1969 Floods on Ground Water in Central and Southern California written by J. L. Hughes and published by . This book was released on 1972 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Thriving on Our Changing Planet written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-01-20 with total page 717 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Dividing the Waters written by William Andrew Blomquist and published by . This book was released on 1992 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Not only are these water supplies not depleted, they are in fact relatively healthy despite California's recent six-year drought.
Download or read book The West without Water written by B. Lynn Ingram and published by Univ of California Press. This book was released on 2013-08-01 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt: The West without Water documents the tumultuous climate of the American West over twenty millennia, with tales of past droughts and deluges and predictions about the impacts of future climate change on water resources. Looking at the region’s current water crisis from the perspective of its climate history, the authors ask the central question of what is "normal" climate for the West, and whether the relatively benign climate of the past century will continue into the future. The West without Water merges climate and paleoclimate research from a wide variety of sources as it introduces readers to key discoveries in cracking the secrets of the region’s climatic past. It demonstrates that extended droughts and catastrophic floods have plagued the West with regularity over the past two millennia and recounts the most disastrous flood in the history of California and the West, which occurred in 1861–62. The authors show that, while the West may have temporarily buffered itself from such harsh climatic swings by creating artificial environments and human landscapes, our modern civilization may be ill-prepared for the future climate changes that are predicted to beset the region. They warn that it is time to face the realities of the past and prepare for a future in which fresh water may be less reliable.
Download or read book Atmospheric Rivers written by F. Martin Ralph and published by Springer Nature. This book was released on 2020-07-10 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the standard reference based on roughly 20 years of research on atmospheric rivers, emphasizing progress made on key research and applications questions and remaining knowledge gaps. The book presents the history of atmospheric-rivers research, the current state of scientific knowledge, tools, and policy-relevant (science-informed) problems that lend themselves to real-world application of the research—and how the topic fits into larger national and global contexts. This book is written by a global team of authors who have conducted and published the majority of critical research on atmospheric rivers over the past years. The book is intended to benefit practitioners in the fields of meteorology, hydrology and related disciplines, including students as well as senior researchers.
Download or read book Watershed Hydrology written by Vijay P. Singh and published by Allied Publishers. This book was released on 2003 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Impacts of Climate Change on Hydrology and Agricultural Pollutant Runoff in California s Central Valley written by Darren L. Ficklin and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Soil and Water Assessment Tool (SWAT) and HYDRUS were used to assess the impact of climate change on the hydrologic cycle (streamflow, surface runoff, groundwater recharge, evapotranspiration, and irrigation water use) and agricultural pollutant runoff (sediment, nitrate, phosphorus, chlorpyrifos, and diazinon) in the Sacramento and San Joaquin River watersheds in California's Central Valley. Five separate studies were constructed. For the first three studies, hydrological responses were modeled in the San Joaquin River watershed using variations of atmospheric CO2 (550 and 970 ppm), temperature (+1.1 and +6.4°C), and precipitation (0%, ±10%, and ±20%) based on Intergovernmental Panel on Climate Change projections. The fourth study used a calibration and an uncertainty analysis technique for the calibration of the Sacramento River watershed. This study confirmed that SWAT was able to capture the large amount of uncertainty within the Sacramento River watershed and successfully simulate streamflow, sediment, nitrate, chlorpyrifos and diazinon loads. The final study used a novel stochastic climate change analysis technique to bracket the 95% confidence interval of potential climate changes. For all studies, increases in precipitation generally changed the hydrological cycle and agricultural runoff proportionally, where increases in precipitation resulted in increases in surface runoff and thus agricultural runoff and vice-versa. Also, for all studies, increasing temperature caused a temporal shift in plant growth patterns and redistributed evapotranspiration and irrigation water demand earlier in the year. Increasing atmospheric CO2 resulted in watershed-wide decreases in evapotranspiration, therefore increasing water yield and streamflow while concurrently decreasing irrigation water use. This research improves the understanding between climate change and hydrology and agricultural pollutant runoff within the Central Valley of California. Theses climate change analyses may be used by water resource managers to evaluate the potential effects of climate change.
Download or read book Sustainable Water and Environmental Management in the California Bay Delta written by National Research Council and published by National Academies Press. This book was released on 2012-10-01 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extensively modified over the last century and a half, California's San Francisco Bay Delta Estuary remains biologically diverse and functions as a central element in California's water supply system. Uncertainties about the future, actions taken under the federal Endangered Species Act (ESA) and companion California statues, and lawsuits have led to conflict concerning the timing and amount of water that can be diverted from the Delta for agriculture, municipal, and industrial purposes and concerning how much water is needed to protect the Delta ecosystem and its component species. Sustainable Water and Environmental Management in the California Bay-Delta focuses on scientific questions, assumptions, and conclusions underlying water-management alternatives and reviews the initial public draft of the Bay Delta Conservation Plan in terms of adequacy of its use of science and adaptive management. In addition, this report identifies the factors that may be contributing to the decline of federally listed species, recommend future water-supple and delivery options that reflect proper consideration of climate change and compatibility with objectives of maintaining a sustainable Bay-Delta ecosystem, advises what degree of restoration of the Delta system is likely to be attainable, and provides metrics that can be used by resource managers to measure progress toward restoration goals.
Download or read book Managing California s Water written by Ellen Hanak and published by Public Policy Instit. of CA. This book was released on 2011 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ecosystems of California written by Harold Mooney and published by Univ of California Press. This book was released on 2016-01-19 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-anticipated reference and sourcebook for CaliforniaÕs remarkable ecological abundance provides an integrated assessment of each major ecosystem typeÑits distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of CaliforniaÕs ecological patterns and the history of the stateÕs various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the stateÕs ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of CaliforniaÕs environment and curious naturalists.
Download or read book Improved Understanding of the Climatic and Anthropogenic Drivers of Groundwater Depletion and Recovery in California s Central Valley written by Sarfaraz Alam and published by . This book was released on 2021 with total page 182 pages. Available in PDF, EPUB and Kindle. Book excerpt: The role of climatic and anthropogenic drivers in groundwater storage depletion and recovery in California's Central Valley has been investigated. Specifically, the dissertation addresses three research questions: (1) How does climate change impact the groundwater storage? (2) Can managed aquifer recharge (MAR) mitigate groundwater overdraft? (3) How much of the drought-caused groundwater overdraft in Central Valley has recovered during the post-drought years and what is the role of climate and water management in the fast versus slow post-drought overdraft recovery? In the first part of the dissertation, integrated hydrologic models have been simulated to predict future groundwater storage changes under multiple climate change scenarios and to evaluate the relative contribution of crop water use and surface water inflow to Central Valley regions. It is shown that climate change will accelerate groundwater depletion in the future and an increase in future crop water use will be the dominant cause of future groundwater decline without mitigation measure. In the second part, the impact of large-scale MAR implementation on groundwater overdraft recovery, flood peak, and low flow have been investigated via numerical experiments. It is shown that MAR has limited capacity to recovery historical groundwater overdraft due to lack of surface water availability in the southern Central Valley (i.e., San Joaquin and Tulare regions). Delivering excess surface water from the delta to the Tulare and San Joaquin region can significantly solve the groundwater overdraft problem. Moreover, MAR can reduce flood peaks, and increase dry season flow. Finally, an ensemble of groundwater storage change estimates has been made using multiple methods and numerical experiments conducted to understand the role of climate and water management to recover drought-caused groundwater overdraft during post-drought years. The result shows that the Central Valley aquifer is not resilient to drought under existing conditions, and it is very challenging to recover drought-caused groundwater overdraft. However, water management measures that restrict groundwater extraction can significantly reduce the groundwater overdraft recovery time.
