Analysis of climatic conditions leading to low streamflows in the headwaters of the Colorado River
Fredrickson, Joshua A. E.
Fredrickson, Joshua A. E.
Abstract
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The purpose of my research was to examine the climatic variables associated with recent low streamflows in the headwaters of the Green River in Wyoming. My objectives were: 1) identify years with lower-than-normal streamflows and 2) examine and determine the climatic conditions that led to low streamflows. The climatic variables examined for this study represent surface conditions, atmospheric conditions, and precipitation mechanisms. I examined precipitation rate, temperature, and specific humidity. I also looked at uplift mechanisms—vertical velocity—that enhance or suppress precipitation. The methods I used for my project included: 1) the selection of low-flow years from USGS streamflow data, 2) calculation of composite-anomaly values for low-flow years, 3) creation of composite-anomaly maps of the selected variables for low-flow years, and 4) an analysis and explanation of the composite anomalies. The recent lower-than-normal streamflows in the Green River are the result of varying surface and atmospheric conditions and uplift mechanisms. In general, there was a lack of precipitation during winter months and those dryer-than-normal conditions persisted through spring and into summer/fall. During every season, when there was sufficient moisture available in the atmosphere to allow for precipitation, sinking motions were dominant and suppressed precipitation; and when rising motions were dominant there was not enough moisture in the atmosphere to allow for precipitation, even though the mechanism was present.
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University of Wyoming Libraries