Download or read book Regional scale Simulations of the Western US Climate written by J. E. Bossert and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Regional scale Simulations of the Western United States Climate written by and published by . This book was released on 1991 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mesoscale models can provide a sufficiently detailed regional climatology. From these pioneering studies, we were inspired to begin to develop regional climatologies with the Colorado State University Regional Atmospheric Modeling System (CSU-RAMS). Our major goal is to develop a better understanding of the hydrologic cycle in the mountainous, arid west. An advantage of using the RAMS code is that we can generate detailed descriptions of precipitation processes, which will hopefully translate into realistic surface yields of both rain and snow. In the ensuing sections, we first describe the model and its microphysics parameterizations, then continue with our methodology for incorporating large-scale data into the model grid. Preliminary results demonstrating the mesoscale variation of precipitation over the mountainous western US are then presented. The model framework for the present study incorporates a three-dimensional, terrain-following non-hydrostatic version of the code. The simulation includes topography derived from a 5-minute global data set with a silhouette averaging scheme that preserves realistic topography heights. This height data is then interpolated to the model grid. 13 refs., 8 figs.
Download or read book Regional scale Simulations of the Western US Climate written by and published by . This book was released on 1991 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the past two decades the meteorological community has witnessed the evolution of general circulation models (GCMs) from studies attempting to simulate realistic large-scale dynamical regimes and energy transports to present investigations examining future climate change scenarios. From these pioneering studies, we were inspired to begin to develop regional climatologies with the Colorado State University Regional Atmospheric Modeling System (CSU-RAMS). Our major goal is to develop a better understanding of the hydrologic cycle in the mountainous, and west. An advantage of using the RAMS code is that we can generate detailed descriptions of precipitation processes, which will hopefully translate into realistic surface yields of both rain and snow. In the ensuing sections, we first describe the model and its microphysics parameterizations, then continue with our methodology for incorporating large-scale data into the model grid. Preliminary results demonstrating the mesoscale variation of precipitation over the mountainous western US are then presented.
Download or read book Large Ensembles of Regional Climate Simulations Over the Western United States written by Sihan Li and published by . This book was released on 2017 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large ensembles of regional climate simulations were generated from the weather@home distributed volunteer computing project over the western US domain. Weather@home uses the U.K. Met Office Hadley Centre’s regional climate model HadRM3P (~0.22°) nested within the atmospheric global model HadAM3P (1.875 longitude° by 1.25 latitude°). Simulations from HadRM3P were evaluated against observational datasets, and were found to be able to faithfully reproduce various properties of the recent past climate of the western US. In an effort to explore local anthropogenically forced climate responses, especially precipitation response, over the complex terrain, western US climate was simulated for the recent past (1986-2014) and future (2031-2059). The large initial-condition ensemble of regional climate simulations provides detailed information of precipitation changes at local grid point level, with high signal-to-noise ratio, while results from the host global climate model are analyzed for synoptic-scale mechanisms driving the regional changes. Both winter and summer precipitation changes have a large dynamic origin. Winter precipitation changes are associated with a southeastward extension of the Aleutian low-pressure center and strengthening and eastward expansion of the upper subtropical jet stream. Summer precipitation changes are associated with a high-pressure anomaly centered over the northwest at the 500-hPa level, contributing to drying in the northwest, and the wetting in the southwest is associated with stronger increase in water vapor. The pattern of circulation change associated with changes in extreme (wet) monthly precipitation is similar to that for changes in mean monthly precipitation, but the changes are more intense. The changes of extreme precipitation vary spatially, with the least relative increase in Western Oregon-Washington, and the most relative increase in the Great Basin. Precipitation increase more on the leeward side of the Cascade Range than on the windward side, and this difference across mountain barrier is present in changes of both seasonal mean and extreme precipitation, suggesting common physical drivers. These large ensembles also present unique datasets to thoroughly assess the impact of internal variability on climate projections from a high-resolution regional model. We quantify the magnitude of changes forced by increasing greenhouse gas concentrations relative to internal variability and find that simulations spanning 10 to 30 years (the timespans used in the majority of published studies of regional climate modeling) often lead to unfounded confidence in results because of low grid-point level signal-to-noise ratios that furthermore vary considerably by season, variable and location. We offer a rule of thumb for determining the minimum adequate ensemble size N[subscript min] to detect a response to anthropogenic forcing in different climate variables, and a minimum adequate ensemble size N[subscript min(delta x)] required for detecting spatial heterogeneity of such responses. Our results underscore the problem that increasing model resolution without increasing ensemble size does not necessarily advance the understanding of regional and local climate response to anthropogenic forcing. To summarize, the combination of high resolution over the complex terrain of western US and large numbers of simulations allow us to explore the effects of local and regional climate change in a way not otherwise possible.
Download or read book Simulations of Present and Future Climates in the Western U S with Four Nested Regional Climate Models written by and published by . This book was released on 2004 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: We analyze simulations of present and future climates in the western U.S. performed with four regional climate models (RCMs) nested within two global ocean-atmosphere climate models. Our primary goal is to assess the range of regional climate responses to increased greenhouse gases in available RCM simulations. The four RCMs used different geographical domains, different increased greenhouse gas scenarios for future-climate simulations, and (in some cases) different lateral boundary conditions. For simulations of the present climate, we compare RCM results to observations and to results of the GCM that provided lateral boundary conditions to the RCM. For future-climate (increased greenhouse gas) simulations, we compare RCM results to each other and to results of the driving GCMs. When results are spatially averaged over the western U.S., we find that the results of each RCM closely follow those of the driving GCM in the same region, in both present and future climates. In present-climate simulations, the RCMs have biases in spatially-averaged simulated precipitation and near-surface temperature that seem to be very close to those of the driving GCMs. In future-climate simulations, the spatially-averaged RCM-projected responses in precipitation and near-surface temperature are also very close to those of the respective driving GCMs. Precipitation responses predicted by the RCMs are in many regions not statistically significant compared to interannual variability. Where the predicted precipitation responses are statistically significant, they are positive. The models agree that near-surface temperatures will increase, but do not agree on the spatial pattern of this increase. The four RCMs produce very different estimates of water content of snow in the present climate, and of the change in this water content in response to increased greenhouse gases.
Download or read book A Strategy for Assessing Potential Future Changes in Climate Hydrology and Vegetation in the Western United States written by Robert Stephen Thompson and published by . This book was released on 1998 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Third Atmospheric Radiation Measurement ARM Science Team Meeting written by and published by . This book was released on 1994 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Climate Trends Over the Alpine Region written by Atsumu Ohmura and published by vdf Hochschulverlag AG. This book was released on 1996 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mit dt. und franz. Zusammenfass.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 700 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-06 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the Second Atmospheric Radiation Measurement ARM Science Team Meeting October 26 30 1991 Denver Colorado written by and published by . This book was released on 1992 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Initial Climate Change Scenario for the Western United States written by Arnett S. Dennis and published by . This book was released on 1991 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Report written by and published by . This book was released on 2000 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Regional Scale Climate Change written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This collaborative proposal addressed key issues in understanding the Earth's climate system, as highlighted by the U.S. Climate Science Program. The research focused on documenting past climatic changes and on assessing future climatic changes based on suites of global and regional climate models. Geographically, our emphasis was on the mountainous regions of the world, with a particular focus on the Neotropics of Central America and the Hawaiian Islands. Mountain regions are zones where large variations in ecosystems occur due to the strong climate zonation forced by the topography. These areas are particularly susceptible to changes in critical ecological thresholds, and we conducted studies of changes in phonological indicators based on various climatic thresholds.
Download or read book Climate Model Simulations of Spatiotemporal Western North American Hydroclimate Variability During the Medieval Climate Anomaly and Little Ice Age written by Steven Simon and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Despite the immense impacts that large, modern North American droughts, such as those of the 1930s and 1950s, had on economic, social, environmental, and agricultural systems, they were ultimately shorter in duration than the multidecadal to centennial scale megadroughts that affected North America, in particular the western United States,during the Medieval Climate Anomaly (MCA, ~ 850-1300 AD)and the Little Ice Age (LIA, ~1450-1850 AD. Although various proxy records have been used to reconstruct the timing of these MCA and LIA megadroughts in the western United States, there still exists great uncertainty in the magnitude and spatial coherence of such droughts in various cross sections of western North America (i.e. the Pacific Northwest region),especially on decadal to centennial timescales. This uncertainty motivated the following study to establish a causal link between the climate forcing that induced these megadroughts and the spatiotemporal response of regional North American hydroclimates,such as those of the Pacific Northwest, American Southwest, and the Great Plains,to this forcing. This study seeks to establish a better understanding of the influence of tropical Pacific,tropical Indian, extratropical North Pacific, and North Atlantic sea surface temperatures (SSTs) on North American drought during the MCA (950-1250 AD) and LIA (1400-1700 AD). We force NCAR's Community Atmosphere Model version 5.1.1 (CAM 5), as part of a special configuration of the fully coupled Community Earth Systems Model version 1.0.5 (CESM 1.0.5), with prescribed proxy-reconstructed tropical Pacific, tropical Indian, extratropical North Pacific, and North Atlantic SST anomalies from the MCA and LIA, in order to investigate the influence that these SST anomalies had on the spatiotemporal patterns of drought in North America. To isolate the effects of individual and multiple ocean basin SSTs on the North American climate system, the conducted model experiments use a variety of SST permutations in the tropical Pacific, tropical Indian, extratropical North Pacific, and North Atlantic basins as climate forcing. In order to quantify the spatiotemporal response of the western North American hydroclimate system to these SST forcing permutations, precipitation data derived from the MCA and LIA model experiments are presented here as MCA anomalies relative to the LIA reference period. The spatiotemporal precipitation patterns from the model experiments indicate that in the Pacific Northwest, the MCA and LIA were anomalously wet and dry periods, respectively, a finding that is largely supported by the available lake sediment proxy records. This pattern contrasts with the dry MCA/wet LIA pattern diagnosed in model experiments for the U.S. Southwest and Great Plains regions and indicated by tree ring-based proxy data. Thus, the CAM 5 model experiments confirm the wet/dry meridional precipitation dipole pattern suggested by proxy data for the western U.S. during the MCA and LIA and highlight the role that the natural variability of tropical Pacific, tropical Indian, extratropical North Pacific, and North Atlantic SSTs played in driving this spatiotemporal climate pattern and its related teleconnections. Lastly, this study conducts a diagnosis of the physical mechanisms of causality which link the remote SST forcing specified by any given MCA and LIA model experiment and the regional atmospheric response in western North America. This diagnosis ultimately reveals that the simulated MCA-LIA tropospheric circulation anomalies (sea level pressure, mid-tropospheric vertical velocity, and upper-tropospheric geopotential height fields) associated with the MCA megadroughts dynamically support the prevalent western North American MCA-LIA precipitation anomaly patterns identified in the conducted model experiments, and exhibit spatial coherency, in the horizontal and vertical, resembling those of tropically-forced Rossby wave train-like structures which link remote SST forcing regions with local, regional response regions in the western North American troposphere.
Download or read book Climate Change and Energy Policy written by L. Rosen and published by Springer Science & Business Media. This book was released on 1992-05-01 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first conference of its kind explicitly designed to encourage the integration of the climate change community with the energy policy- making and research communities. The book looks at climate change on many levels including its economic impact and its effect on energy technologies. Of interest to energy researchers and policy makers.
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.
