Browsing by Subject "Climatic changes"

Now showing 1 - 5 of 5

Climate modeling of giant planets : the Saturnian seasonal stratosphere
(2008-05) Strong, Shadrian Brittany, 1980-; Lacy, John Howard
Development of a parallel river transport algorithm and applications to climate studies
(2001-12) Branstetter, Marcia Lynne, 1963-; Famiglietti, James S.
The global hydrologic cycle plays a central role in the interactive functioning of the Earth’s climate system. The theme of this study is land-oceanatmosphere interaction. Continental runoff has a notable effect on the global hydrologic cycle, both directly as freshwater forcing on the oceans and indirectly through effects on global patterns of precipitation and coincident feedbacks to continental runoff. To demonstrate this, a series of three projects involving both observations and modeling were completed. The first phase involved the development of a parallel river transport model to deliver runoff from the land surface to the oceans at the appropriate location and time. Within each watershed, the river routing algorithm used cell-to-cell routing by considering the mass balance of surface inflows and outflows. This river transport model was then incorporated into a climate system model. The second and third phases involved the use of a climate system model to investigate the effect of continental runoff. To test the sensitivity of the oceans to freshwater input from runoff, in the second phase, a number of 70-year simulations were conducted, using the ocean and ice components of a highresolution climate model with observed runoff and modeled atmospheric forcing. A half-degree observed runoff data set, consisting of both annual and monthly averages, was used for this forcing. Differences in sea surface temperature and salinity between simulations with and without the addition of runoff were found in the Arctic, Tropical Atlantic, and North Atlantic Oceans. The differences were especially pronounced in the North Atlantic. By affecting sea surface temperatures and salinity, the addition of freshwater from river runoff led to a reduction in North Atlantic Deep Water formation and a corresponding slowdown of heat transport. The third phase used a fully coupled land-ocean-atmosphere-ice model plus the river transport model from the first phase. Two 200-year simulations were conducted, with and without the river component. The simulation with rivers had reduced oceanic meridional heat transport. Reduced convective rainfall and runoff during January in the simulation with rivers indicated a feedback from the continental runoff flux into the oceans back to the land surface.
Hydrologic modeling of the Pecos River basin below Red Bluff Reservoir
(2011-05) Yalcinkaya, Sedat; McKinney, Daene C.; Maidment, David R.
The segment of the Pecos River that extends from Red Bluff Reservoir until it discharges to the Rio Grande/Bravo near Langtry was studied in this project. Hydrologic behavior of the basin was analyzed between 1981 and 2000, the first ten year period for calibration and the second ten year period for validation by using Water Evaluation and Planning Software (WEAP, SEI, 2006). Simulated streamflows were compared with naturalized streamflows (RJBCO, 2003) at two control points, one in the middle of the basin near Girvin and the other one is at the end of the basin near Langtry. The purpose of the project is to create a valid model for water availability simulations in the Pecos River Basin to be used for future water availability simulations considering climate change effects. The basin was divided into two parts in order to evaluate the results, the upper basin and the entire basin (below Red Bluff reservoir) according to the location of control gages. Simulated streamflows closely match the naturalized flows at the Girvin station in the upper basin. Although the results at the Langtry station for the entire basin are not as good as Girvin, the model still reproduces streamflows well enough to represent the hydrologic behavior of the basin, especially for the base flow. Considering the complex geological structure of the Pecos River Basin below Red Bluff Reservoir, the results can be considered satisfactory. The model can be used for future water availability predictions in the basin considering climate change effects.
Modeling climate change impacts on hydrology and water resources : case study Rio Conchos basin
(2011-05) Ingol Blanco, Eusebio Mercedes; McKinney, Daene C.; Maidment, David R.; Charbeneau, Randall J.; Hodges, Ben R.; Eaton, David J.
Water resources availability could be affected by alterations of hydrologic processes as a result of climate change. Global projections of climate change indicate negative impacts on water systems with increasing flooding and drought events. This investigation presents the modeling of climate change effects on the hydrology and water resources availability in the Rio Conchos basin, the main tributary of the lower portion of the bi-national Rio Grande/Bravo basin, and its impact on the water treaty signed between the United States of America and Mexico in 1944. One of the problems most relevant to the study basin is the frequent occurrence of long drought periods. Coupled with increased water demands and low irrigation efficiencies, the competition for water resources is high on both sides of the border. Three main parts are addressed in this research. First, a hydrologic model has been developed using the one-dimensional, 2 layer soil moisture accounting scheme embedded in a water evaluation and planning model. Second, downscaled precipitation and temperature data, from five general circulation models for two emission scenarios, A1B and A2, were used as inputs to the Rio Conchos hydrologic model to determine the effect on basin hydrology. A multi-model ensemble is developed and several techniques, such as probability density functions, wavelet analysis, and trend analysis, are used to assess the impacts. Third, a water resources planning model for the basin has been developed, which integrates the hydrologic model and water management modeling, to evaluate the impacts on the entire water system and simulate adaptive strategies to mitigate climate change in the study basin. Skill-weighted multi-model ensemble results show that annual average runoff may be reduced by 12% ± 53% and 20% ± 45% in 2080-2099 relative to 1980-1999 for the A1B and A2 scenarios, respectively. Likewise, results show that reliability and resiliency of the water system will tend to decrease; consequently, the vulnerability of the system increases over time. Proposed adaptation measures could make the system more reliable and less vulnerable in meeting water demands for irrigation and municipal uses.
Plano Setorial de Mitigação e de Adaptação : à mudança do clima na mineração : Plano de Mineração de Baixa Emissão de Carbono (Plano MBC)
(Ministério do Meio Ambiente, Governo Federal Brasil, 2013) Brazil. Secretaria de Geologia, Mineração e Transformação Mineral; Casa Civil (Brazil)