Characterizing Climate-Change Impacts on the 1.5-yr Flood Flow in Selected Basins across the United States: A Probabilistic Approach

2011 ◽  
Vol 15 (18) ◽  
pp. 1-16 ◽  
Author(s):  
John F. Walker ◽  
Lauren E. Hay ◽  
Steven L. Markstrom ◽  
Michael D. Dettinger
Keyword(s):  
Climate Change ◽  
United States ◽  
Probabilistic Approach ◽  
The United States ◽  
Empirical Orthogonal Functions ◽  
First Century ◽  
Climate Projections ◽  
Climate Change Scenarios ◽  
Twenty First Century ◽  
Temporal Shifts

Abstract The U.S. Geological Survey Precipitation-Runoff Modeling System (PRMS) model was applied to basins in 14 different hydroclimatic regions to determine the sensitivity and variability of the freshwater resources of the United States in the face of current climate-change projections. Rather than attempting to choose a most likely scenario from the results of the Intergovernmental Panel on Climate Change, an ensemble of climate simulations from five models under three emissions scenarios each was used to drive the basin models. Climate-change scenarios were generated for PRMS by modifying historical precipitation and temperature inputs; mean monthly climate change was derived by calculating changes in mean climates from current to various future decades in the ensemble of climate projections. Empirical orthogonal functions (EOFs) were fitted to the PRMS model output driven by the ensemble of climate projections and provided a basis for randomly (but representatively) generating realizations of hydrologic response to future climates. For each realization, the 1.5-yr flood was calculated to represent a flow important for sediment transport and channel geomorphology. The empirical probability density function (pdf) of the 1.5-yr flood was estimated using the results across the realizations for each basin. Of the 14 basins studied, 9 showed clear temporal shifts in the pdfs of the 1.5-yr flood projected into the twenty-first century. In the western United States, where the annual peak discharges are heavily influenced by snowmelt, three basins show at least a 10% increase in the 1.5-yr flood in the twenty-first century; the remaining two basins demonstrate increases in the 1.5-yr flood, but the temporal shifts in the pdfs and the percent changes are not as distinct. Four basins in the eastern Rockies/central United States show at least a 10% decrease in the 1.5-yr flood; the remaining two basins demonstrate decreases in the 1.5-yr flood, but the temporal shifts in the pdfs and the percent changes are not as distinct. Two basins in the eastern United States show at least a 10% decrease in the 1.5-yr flood; the remaining basin shows little or no change in the 1.5-yr flood.

scholarly journals Watershed-Scale Response to Climate Change through the Twenty-First Century for Selected Basins across the United States

2011 ◽  
Vol 15 (17) ◽  
pp. 1-37 ◽  
Author(s):  
Lauren E. Hay ◽  
Steven L. Markstrom ◽  
Christian Ward-Garrison
Keyword(s):  
Climate Change ◽  
United States ◽  
Coupled Model ◽  
The United States ◽  
Lessons Learned ◽  
First Century ◽  
Emission Scenarios ◽  
Watershed Model ◽  
Geographical Regions ◽  
Twenty First Century

Abstract The hydrologic response of different climate-change emission scenarios for the twenty-first century were evaluated in 14 basins from different hydroclimatic regions across the United States using the Precipitation-Runoff Modeling System (PRMS), a process-based, distributed-parameter watershed model. This study involves four major steps: 1) setup and calibration of the PRMS model in 14 basins across the United States by local U.S. Geological Survey personnel; 2) statistical downscaling of the World Climate Research Programme’s Coupled Model Intercomparison Project phase 3 climate-change emission scenarios to create PRMS input files that reflect these emission scenarios; 3) run PRMS for the climate-change emission scenarios for the 14 basins; and 4) evaluation of the PRMS output. This paper presents an overview of this project, details of the methodology, results from the 14 basin simulations, and interpretation of these results. A key finding is that the hydrological response of the different geographical regions of the United States to potential climate change may be very different, depending on the dominant physical processes of that particular region. Also considered is the tremendous amount of uncertainty present in the climate emission scenarios and how this uncertainty propagates through the hydrologic simulations. This paper concludes with a discussion of the lessons learned and potential for future work.

scholarly journals Physical Mechanisms Related to Climate-Induced Drying of Two Semiarid Watersheds in the Southwestern United States

2014 ◽  
Vol 15 (4) ◽  
pp. 1404-1418 ◽  
Author(s):  
Seshadri Rajagopal ◽  
Francina Dominguez ◽  
Hoshin V. Gupta ◽  
Peter A. Troch ◽  
Christopher L. Castro
Keyword(s):  
United States ◽  
The United States ◽  
Hydrologic Model ◽  
First Century ◽  
Climate Projections ◽  
Southwestern United States ◽  
Study Region ◽  
Model Average ◽  
Basin Scale ◽  
Twenty First Century

Abstract Water managers across the United States face the need to make informed policy decisions regarding long-term impacts of climate change on water resources. To provide a scientifically informed basis for this, the evolution of important components of the basin-scale water balance through the end of the twenty-first century is estimated. Bias-corrected and spatially downscaled climate projections, from phase 3 of the Coupled Model Intercomparison Project (CMIP3) of the World Climate Research Programme, were used to drive a spatially distributed Variable Infiltration Capacity (VIC) model of hydrologic processes in the Salt–Verde basin in the southwestern United States. From the suite of CMIP3 models, the authors select a five-model subset, including three that best reproduce the historical climatology for the study region, plus two others to represent wetter and drier than model average conditions, so as to represent the range of GCM prediction uncertainty. For each GCM, data for three emission scenarios (A1B, A2, and B1) were used to drive the hydrologic model into the future. The projections of this model ensemble indicate a statistically significant 25% decrease in streamflow by the end of the twenty-first century. The primary cause for this change is due to projected decreases in winter precipitation accompanied by significant (temperature driven) reductions in storage of snow and increased winter evaporation. The results show that water management in central Arizona is highly likely to be impacted by changes in regional climate.

Synoptic-Statistical Approach to Regional Downscaling of IPCC Twenty-First-Century Climate Projections: Seasonal Rainfall over the Hawaiian Islands*

2009 ◽  
Vol 22 (16) ◽  
pp. 4261-4280 ◽  
Author(s):  
Oliver Timm ◽  
Henry F. Diaz
Keyword(s):  
Climate Change ◽  
Statistical Downscaling ◽  
Hawaiian Islands ◽  
Dry Season ◽  
First Century ◽  
Climate Projections ◽  
Climate Change Scenarios ◽  
Wet Season ◽  
Near Surface ◽  
Twenty First Century

Abstract A linear statistical downscaling technique is applied to the projection of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) climate change scenarios onto Hawaiian rainfall for the late twenty-first century. Hawaii’s regional rainfall is largely controlled by the strength of the trade winds. During the winter months, disturbances in the westerlies can produce heavy rainfall throughout the islands. A diagnostic analysis of sea level pressure (SLP), near-surface winds, and rainfall measurements at 134 weather observing stations around the islands characterize the correlations between the circulation and rainfall during the nominal wet season (November–April) and dry season (May–October). A comparison of the base climate twentieth-century AR4 model simulations with reanalysis data for the period 1970–2000 is used to define objective selection criterion for the AR4 models. Six out of 21 available models were chosen for the statistical downscaling. These were chosen on the basis of their ability to more realistically simulate the modern large-scale circulation fields in the Hawaiian Islands region. For the AR4 A1B emission scenario, the six analyzed models show important changes in the wind fields around Hawaii by the late twenty-first century. Two models clearly indicate opposite signs in the anomalies. One model projects 20%–30% rainfall increase over the islands; the other model suggests a rainfall decrease of about 10%–20% during the wet season. It is concluded from the six-model ensemble that the most likely scenario for Hawaii is a 5%–10% reduction of the wet-season precipitation and a 5% increase during the dry season, as a result of changes in the wind field. The authors discuss the sources of uncertainties in the projected rainfall changes and consider future improvements of the statistical downscaling work and implications for dynamical downscaling methods.

scholarly journals Probability-Weighted Ensembles of U.S. County-Level Climate Projections for Climate Risk Analysis

2016 ◽  
Vol 55 (10) ◽  
pp. 2301-2322 ◽  
Author(s):  
D. J. Rasmussen ◽  
Malte Meinshausen ◽  
Robert E. Kopp
Keyword(s):  
United States ◽  
Joint Probability ◽  
Coupled Model ◽  
The United States ◽  
First Century ◽  
Climate Projections ◽  
Intergovernmental Panel ◽  
Temperature And Precipitation ◽  
Twenty First Century ◽  
Mixed Ensemble

AbstractQuantitative assessment of climate change risk requires a method for constructing probabilistic time series of changes in physical climate parameters. Here, two such methods, surrogate/model mixed ensemble (SMME) and Monte Carlo pattern/residual (MCPR), are developed and then are applied to construct joint probability density functions (PDFs) of temperature and precipitation change over the twenty-first century for every county in the United States. Both methods produce likely (67% probability) temperature and precipitation projections that are consistent with the Intergovernmental Panel on Climate Change’s interpretation of an equal-weighted Coupled Model Intercomparison Project phase 5 (CMIP5) ensemble but also provide full PDFs that include tail estimates. For example, both methods indicate that, under “Representative Concentration Pathway” 8.5, there is a 5% chance that the contiguous United States could warm by at least 8°C between 1981–2010 and 2080–99. Variance decomposition of SMME and MCPR projections indicates that background variability dominates uncertainty in the early twenty-first century whereas forcing-driven changes emerge in the second half of the twenty-first century. By separating CMIP5 projections into unforced and forced components using linear regression, these methods generate estimates of unforced variability from existing CMIP5 projections without requiring the computationally expensive use of multiple realizations of a single GCM.

scholarly journals Statistical Comparisons of Watershed-Scale Response to Climate Change in Selected Basins across the United States

2011 ◽  
Vol 15 (14) ◽  
pp. 1-26 ◽  
Author(s):  
John Risley ◽  
Hamid Moradkhani ◽  
Lauren Hay ◽  
Steve Markstrom
Keyword(s):  
Climate Change ◽  
United States ◽  
The United States ◽  
First Century ◽  
Energy Output ◽  
Daily Streamflow ◽  
Watershed Models ◽  
Monthly Streamflow ◽  
Twenty First Century ◽  
The Impact

Abstract In an earlier global climate-change study, air temperature and precipitation data for the entire twenty-first century simulated from five general circulation models were used as input to precalibrated watershed models for 14 selected basins across the United States. Simulated daily streamflow and energy output from the watershed models were used to compute a range of statistics. With a side-by-side comparison of the statistical analyses for the 14 basins, regional climatic and hydrologic trends over the twenty-first century could be qualitatively identified. Low-flow statistics (95% exceedance, 7-day mean annual minimum, and summer mean monthly streamflow) decreased for almost all basins. Annual maximum daily streamflow also decreased in all the basins, except for all four basins in California and the Pacific Northwest. An analysis of the supply of available energy and water for the basins indicated that ratios of evaporation to precipitation and potential evapotranspiration to precipitation for most of the basins will increase. Probability density functions (PDFs) were developed to assess the uncertainty and multimodality in the impact of climate change on mean annual streamflow variability. Kolmogorov–Smirnov tests showed significant differences between the beginning and ending twenty-first-century PDFs for most of the basins, with the exception of four basins that are located in the western United States. Almost none of the basin PDFs were normally distributed, and two basins in the upper Midwest had PDFs that were extremely dispersed and skewed.

Biosurveillance: A Modern Look

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
James Lee Brooks
Keyword(s):  
United States ◽  
Homeland Security ◽  
The United States ◽  
First Century ◽  
Direct Result ◽  
Current State ◽  
Twenty First Century ◽  
Security Operations

AbstractThe early part of the twenty-first century saw a revolution in the field of Homeland Security. The 9/11 attacks, shortly followed thereafter by the Anthrax Attacks, served as a wakeup call to the United States and showed the inadequacy of the current state of the nation’s Homeland Security operations. Biodefense, and as a direct result Biosurveillance, changed dramatically after these tragedies, planting the seeds of fear in the minds of Americans. They were shown that not only could the United States be attacked at any time, but the weapon could be an invisible disease-causing agent.

Assess 21st century Flash Drought in the United States using high resolution regional climate models

2021 ◽  
Author(s):  
Brandi Gamelin ◽  
Jiali Wang ◽  
V. Rao Kotamarthi
Keyword(s):  
Climate Change ◽  
United States ◽  
Soil Moisture ◽  
Climate Models ◽  
Wrf Model ◽  
The United States ◽  
Future Climate Change ◽  
Climate Change Scenarios ◽  
Regional Variability ◽  
Groundwater Levels

<p>Flash droughts are the rapid intensification of drought conditions generally associated with increased temperatures and decreased precipitation on short time scales.  Consequently, flash droughts are responsible for reduced soil moisture which contributes to diminished agricultural yields and lower groundwater levels. Drought management, especially flash drought in the United States is vital to address the human and economic impact of crop loss, diminished water resources and increased wildfire risk. In previous research, climate change scenarios show increased growing season (i.e. frost-free days) and drying in soil moisture over most of the United States by 2100. Understanding projected flash drought is important to assess regional variability, frequency and intensity of flash droughts under future climate change scenarios. Data for this work was produced with the Weather Research and Forecasting (WRF) model. Initial and boundary conditions for the model were supplied by CCSM4, GFDL-ESM2G, and HadGEM2-ES and based on the 8.5 Representative Concentration Pathway (RCP8.5). The WRF model was downscaled to a 12 km spatial resolution for three climate time frames: 1995-2004 (Historical), 2045-2054 (Mid), and 2085-2094 (Late).  A key characteristic of flash drought is the rapid onset and intensification of dry conditions. For this, we identify onset with vapor pressure deficit during each time frame. Known flash drought cases during the Historical run are identified and compared to flash droughts in the Mid and Late 21<sup>st</sup> century.</p>

Conclusion: Sincerity Dreams

2017 ◽  
Author(s):  
Ellen Rutten
Keyword(s):  
United States ◽  
Popular Culture ◽  
Western Europe ◽  
The United States ◽  
First Century ◽  
Contemporary Culture ◽  
Cultural Paradigms ◽  
Twenty First Century ◽  
Inclusive Analysis

This conclusion reflects on today's dreams of renewing or revitalizing sincerity and rejects the notion that they are outdated or do not deserve any of our attention. It cites the work of several scholars to show that sincerity is anything but obsolete in twenty-first-century popular culture. Indeed, today's strivings to renew sincerity have not been neglected by scholars such as R. Jay Magill Jr., Epstein, and Yurchak. The rhetoric on new sincerity has been addressed in thoughtful analyses of contemporary culture that have helped the author in crafting a comprehensive and geographically inclusive analysis of present-day sincerity rhetoric. In post-Communist Russia, debates on a shift to late or post-postmodern cultural paradigms are thriving with at least as much fervor as—and possibly more than—in Western Europe or the United States. This conclusion discusses the newly gained insights which the author's sincerity study offers.

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