Earth and Planetary Sciences ETDs

Publication Date

Summer 6-14-2019

Abstract

As climate has warmed over the past half century, the strength of the covariance between interannual snowpack and streamflow anomalies in the Rio Grande headwaters has decreased. This change has caused an amplification of errors in seasonal streamflow forecasts using traditional statistical forecasting methods, based on the diminishing correlation between peak snow water equivalent (SWE) and subsequent snowmelt runoff. Therefore, at a time when water resources in south-western North America are becoming scarcer, water supply forecasters need to develop prediction schemes that account for the dynamic nature of the relationship between precipitation, temperature, snowpack and streamflow. We quantify temporal changes in statistical predictive models of streamflow in the upper Rio Grande basin using observed data, and interpret the results in terms of processes that control runoff season discharge. We then compare these observed changes to corresponding statistics in downscaled global climate models (GCMs), to gain insight into which GCMs most appropriately replicate the dynamics of interannual streamflow variability represented by the hydro-climate parameters in the headwaters of the Rio Grande. We quantify how the correlations among temperature, precipitation, SWE, and v streamflow have changed over the last half century within the local climatic and hydrological system. We then assess different long-term GCM-based streamflow projections by their ability to reproduce observed relationships between climate and streamflow, and thereby better constrain projections of future flows as climate warms in the 21st century. In the Rio Grande system, we find that spring season precipitation increasingly contributes to the variability of runoff generation as the contribution of snowpack declines.

Degree Name

Earth and Planetary Sciences

Level of Degree

Masters

Department Name

Department of Earth and Planetary Sciences

First Committee Member (Chair)

Dr. David Gutzler

Second Committee Member

Dr. Peter Fawcett

Third Committee Member

Dr. Joseph Galewsky

Language

English

Document Type

Thesis

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