The climatological literature contains considerable evidence that increasing concentrations of atmospheric carbon dioxide will result in global warming. In order to investigate the effects of resultant climatic changes on runoff in the Great Basin, a water balance model based on average monthly precipitation and temperature was applied to four watersheds in the region.

PB - University of Arizona VL - MS ER - TY - THES T1 - Climatic Change and Water Availability in the Rio Grande and Pecos River Basins T2 - Hydrology Y1 - 1982 A1 - Quinlan, Peter Thomas AB - Climatologists have speculated that increasing concentrations of atmospheric carbon dioxide deriving from fossil fuel combustion will result in warmer, drier climate for many parts of the world. One such area which is already facing serious water shortages is the upper Rio Grande Basin. A climatic water balance equation was adopted to model three representative drainages within the basin in order to investigate the effects of this climatic change on streamflow. Results show that a 20 C increase in temperature and 10% decrease in precipitation would result in a 30% decline in streamflow. Since demand already exceeds or approaches supply, such a dimunition in water yield would have serious regional and national ramifications. JF - Hydrology PB - University of Arizona VL - MS ER - TY - THES T1 - Applications of Box-Jenkins Methods of the Time Series Analysis to the Reconstruction of Drought from Tree Rings T2 - Hydrology and Water Resources Y1 - 1981 A1 - Meko, David Michael KW - Hydrology AB - The lagged responses of tree-ring indices to annual climatic or hydrologic series are examined in this study. The objectives are to develop methods to analyze the lagged responses of individual tree-ring indices, and to improve upon conventional methods of adjusting for the lag in response in regression models to reconstruct annual climatic or hydrologic series. The proposed methods are described and applied to test data from Oregon and Southern California. Transfer-function modeling is used to estimate the dependence of the current ring on past years’ climate and to select negative lags for reconstruction models. A linear system is assumed; the input is an annual climatic variable, and the output is a tree-ring index. The estimated impulse response function weights the importance of past and current years’ climate on the current year’s ring. The identified transfer function model indicates how many past years’ rings are necessary to account for the effects of past years’ climate. Autoregressive-moving-average (ARMA) modeling is used to screen out climatically insensitive tree-ring indices, and to estimate the lag in response to climate unmasked from the effects of autocorrelation in the tree-ring and climatic series. The climatic and tree-ring series are each prewhitened by ARMA models, and crosscorrelation between the ARMA residuals are estimated. The absence of significant crosscorrelations implies low sensitivity. Significant crosscorrelations at lags other than zero indicate lag in response. This analysis can also aid in selecting positive lags for reconstruction models. An alternative reconstruction method that makes use of the ARMA residuals is also proposed. The basic concept is that random (uncorrelated in time) shocks of climate induce annual random shocks of tree growth, with autocorrelation in the tree-ring index resulting from inertia in the system. The steps in the method are (1) fit ARMA models to the tree-ring index and the climatic variable, (2) regress the ARMA residuals of the climatic variable on the ARMA residuals of the tree-ring index, (3) substitute the long-term prewhitened tree-ring index into the regression equation to reconstruct the prewhitened climatic variable, and (4) build autocorrelation back into the reconstruction with the ARMA model originally fit to the climatic variable. The trial applications on test data from Oregon and Southern California showed that the lagged response of tree rings to climate varies greatly from site to site. Sensitive tree-ring series commonly depend significantly only on one past year’s climate (regional rainfall index). Other series depend on three or more past years’ climate. Comparison of reconstructions by conventional lagging of predictors with reconstructions of the random-shock method indicate that while the lagged models may reconstruct the amplitude of severe, long-lasting droughts better than the random-shock model, the random-shock model generally has a flatter frequency response. The random-shock model may therefore be more appropriate where the persistence structure is of prime interest. For the most sensitive series with small lag in response, the choice of reconstruction method makes little difference in properties of the reconstruction. The greatest divergence is for series whose impulse response weights from the transfer function analysis do not die off rapidly with time. JF - Hydrology and Water Resources PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=753124981&sid=10&Fmt=2&clientId=43922&RQT=309&VName=PQD ER - TY - THES T1 - Long-term Streamflow Histories of the Salt and Verde Rivers, Arizona as Reconstructed from Tree-Rings T2 - Geoscience Y1 - 1981 A1 - Smith, Lawrence P. AB - Tree-ring samples collected from the Salt and Verde River basins have been used to reconstruct the annual and seasonal flow histories of the Salt River near Roosevelt, above Roosevelt Lake, and the Verde River below Tangle Creek, above Horseshoe Reservoir for the period form 1580 to 1979… JF - Geoscience PB - University of Arizona VL - MS ER - TY - THES T1 - Relationships Among Climate, Tree-Ring Widths and Grass Production on the Santa Rita Experimental Range T2 - Geoscience Y1 - 1976 A1 - Winter, C. Larrabee AB - A relationship between tree-ring widths from a site in the Santa Rita mountains and yearly perennial grass production on pasture 1 of the Santa Rita Experimental Range is investigated… JF - Geoscience PB - University of Arizona VL - MS ER - TY - THES T1 - The Feasibility of Augmenting Hydrologic Records using Tree-Ring Data T2 - Hydrology and Water Resources Y1 - 1971 A1 - Stockton, C. KW - Hydrology AB -Two catchments of diverse hydrologic character were chosen in which to test the hypothesis that tree-ring indices contain information about runoff that is of pertinent interest to the hydrologist…[Bright Angel Creek basin, Arizona and Upper San Francisco River basin, Arizona/New Mexico]

JF - Hydrology and Water Resources PB - University of Arizona VL - PhD UR - http://ezproxy.library.arizona.edu/login?url=http://proquest.umi.com/pqdweb?did=760166291&sid=14&Fmt=1&clientId=43922&RQT=309&VName=PQD ER -