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Folders: ROOT > ScienceBase Catalog > USGS National Research Program > USGS National Research Program Projects > Predict the Variability and Recent Changes in the Hydrologic Cycle to Natural and Human-Induced Climatic Influences ( Show all descendants )

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Lundquist, J.D., Dettinger, M., Stewart, I., and Cayan, D., 2009, Variability and trends in spring runoff in the western United States, in Wagner, F. ed., Climate warming in western North America/Evidence and environmental effects: University of Utah Press, p. 63-76,
Categories: Publication; Types: Citation
In many meteorological and climatological modeling applications, the availability of ensembles of predictions containing very large numbers of members would substantially ease statistical analyses and validations. This study describes and demonstrates an objective approach for generating large ensembles of “additional” realizations from smaller ensembles, where the additional ensemble members share important first-and second-order statistical characteristics and some dynamic relations within the original ensemble. By decomposing the original ensemble members into assuredly independent time-series components (using a form of principal component decomposition) that can then be resampled randomly and recombined, the...
Cayan, D.C, Bromirski, P., Hayhoe, K., Tyree, M., Dettinger, M., and Flick, R., 2006: Projecting Future Sea Level: Climate Action Team Reports to the Governor and Legislature, publication # CEC-500-2005-202-SF, 53 p. (on-line report in pdf format, 1.59 MB)
Categories: Publication; Types: Citation
A new method for frequency analysis of hydrologic time series was developed to facilitate the estimation and reconstruction of individual or groups of frequencies from hydrologic time-series and facilitate the comparison of these isolated time-series components across data types, between different hydrologic settings within a watershed, between watersheds, and across frequencies. While climate-related variations in inflow to and outflow from aquifers have often been neglected, the development and management of ground-water and surface-water resources has required the inclusion of the assessment of the effects of climatic variability on the supply and demand and sustainability of use. The regional assessment of climatic...
Climate over the watershed of the San Francisco Bay Delta estuary system varies on a wide range of space and time scales, and affects downstream estuarine ecosystems. The historical climate has included mild to severe droughts and torrential rains accompanied by flooding, providing important lessons for present-day resource managers. Paleoclimate records spanning the last 10,000 years, synthesized across the Estuary, watershed and key regions beyond, provide a basis for increased understanding of how variable California’s climate can be and how it affects the Bay Delta system. This review of paleoclimate records reveals a gradual warming and drying in California from about 10,000 years to about 4,000 years before...
The highly variable timing of streamflow in snowmelt-dominated basins across western North America is an important consequence, and indicator, of climate fluctuations. Changes in the timing of snowmelt-derived streamflow from 1948 to 2002 were investigated in a network of 302 western North America gauges by examining the center of mass for flow, spring pulse onset dates, and seasonal fractional flows through trend and principal component analyses. Statistical analysis of the streamflow timing measures with Pacific climate indicators identified local and key large-scale processes that govern the regionally coherent parts of the changes and their relative importance. Widespread and regionally coherent trends toward...
Categories: Publication; Types: Citation
Persistent spring and summer northerly surface winds are the defining climatological feature of the western coast of North America, especially south of the Oregon coast. Northerly surface winds are important for upwelling and a vast array of other biological, oceanic, and atmospheric processes. Intermittence in northerly coastal surface wind is characterized and wind events are quantitatively defined using coastal buoy data south of Cape Mendocino on the northern California coast. The defined wind events are then used as a basis for composites in order to explain the spatial evolution of various atmospheric and oceanic processes. Wind events involve large-scale changes in the three-dimensional atmospheric circulation...
Categories: Publication; Types: Citation; Tags: coast, events, wind
We present a new, non-flux corrected AOGCM, GENMOM, that combines the GENESIS version 3 atmospheric GCM (Global Environmental and Ecological Simulation of Interactive Systems) and MOM2 (Modular Ocean Model version 2) nominally at T31 resolution. We evaluate GENMOM by comparison with reanalysis products (e.g., NCEP2) and three models used in the IPCC AR4 assessment. GENMOM produces a global temperature bias of 0.6 °C. Atmospheric features such as the jet stream structure and major semi-permanent sea level pressure centers are well simulated as is the mean planetary-scale wind structure that is needed to produce the correct position of stormtracks. Most ocean surface currents are reproduced except where they are not...
Categories: Publication; Types: Citation
Changes in water temperatures caused by climate change in California’s Sacramento–San Joaquin Delta will affect the ecosystem through physiological rates of fishes and invertebrates. This study presents statistical models that can be used to forecast water temperature within the Delta as a response to atmospheric conditions. The daily average model performed well ( R 2 values greater than 0.93 during verification periods) for all stations within the Delta and San Francisco Bay provided there was at least 1 year of calibration data. To provide long-term projections of Delta water temperature, we forced the model with downscaled data from climate scenarios. Based on these projections, the ecological implications for...
Dettinger, M.D., and Earman, S., 2007, Western ground water and climate change - Pivotal to supply sustainability or vulnerable in its own right?: Ground Water News and Views, Association of Ground Water Scientists and Engineers Newsletter, v. 4, no. 1, p. 4-5. (on-line article in pdf format)
Categories: Publication; Types: Citation
Observations have shown that the hydrological cycle of the western United States changed significantly over the last half of the 20th century. We present a regional, multivariable climate change detection and attribution study, using a high-resolution hydrologic model forced by global climate models, focusing on the changes that have already affected this primarily arid region with a large and growing population. The results show that up to 60% of the climate-related trends of river flow, winter air temperature, and snow pack between 1950 and 1999 are human-induced. These results are robust to perturbation of study variates and methods. They portend, in conjunction with previous work, a coming crisis in water supply...
Categories: Publication; Types: Citation
The uncertainties associated with climate-change projections for California are unlikely to disappear any time soon, and yet important long-term decisions will be needed to accommodate those potential changes. Projection uncertainties have typically been addressed by analysis of a few scenarios, chosen based on availability or to capture the extreme cases among available projections. However, by focusing on more common projections rather than the most extreme projections (using a new resampling method), new insights into current projections emerge: (1) uncertainties associated with future greenhouse-gas emissions are comparable with the differences among climate models, so that neither source of uncertainties should...
Cayan, D., VanScoy, M., Dettinger, M.D., and Helly, J., 2003, The wireless watershed at the Santa Margarita Ecological Reserve: Southwest Hydrology, v. 2, no. 5, p. 18-19. (on-line article, in pdf format)
Categories: Publication; Types: Citation
Hidalgo, H.G., Dettinger, M.D., and Cayan, D.C., 2008, Downscaling With Constructed Analogues: Daily Precipitation and Temperature Fields Over The United States: California Energy Commission Report CEC-500-2007-123, 62 p. (on-line abstract or on-line report in pdf format, 2200 KB)
Categories: Publication; Types: Citation
This U.S. Geological Survey (USGS) Global Change Science Strategy expands on the Climate Variability and Change science component of the USGS 2007 Science Strategy, ‘Facing Tomorrow‘s Challenges: USGS Science in the Coming Decade‘ (U.S. Geological Survey, 2007). Here we embrace the broad definition of global change provided in the U.S. Global Change Research Act of 1990 (Public Law 101-606, 104 Stat. 3096-3104)-‘Changes in the global environment (including alterations in climate, land productivity, oceans or other water resources, atmospheric chemistry, and ecological systems) that may alter the capacity of Earth to sustain life‘-with a focus on climate and land-use change. Global change science is a well-defined...
Categories: Publication; Types: Citation