1. An investigation of climatic controls in the upper Laramie River watershed during low stream flow years Josh Heyer with Dr. J. J. Shinker Department of Geography PROPOSED RESEARCH PROJECT The upper Laramie River is located in the drought-prone intermountain west. During low stream flow years climate controls at the surface (e.g. decreased precipitation and soil moisture) and in the atmosphere (e.g. sinking motions in the atmosphere suppressing uplift of moisture) can lead to decreased stream flow in the Laramie River watershed. Insight into how precipitation varies allows for a better understanding of how climatic controls are connected with low stream flow years in this, and potentially other watershed. Acknowledgments: I would like to thank Dr. Jacqueline J. Shinker, the McNair Scholars Program: Zackie Salmon, Susan Stoddard, Pilar Flores, and all my family and friends for their support. References available upon request: jheyer1@uwyo.edu This study will investigate which climate controls suppress precipitation amounts and how these climate controls are connected to low stream flow years in the upper Laramie River. During lower-than-normal stream flow years in the upper Laramie River watershed, large and small scale climatic controls suppress precipitation and regulate drought conditions. Time-series plots of precipitation from the National Oceanic and Atmospheric Administration (NOAA) will be constructed to identify drier-than-normal years from 1950 to 2010. Stream flow data from the United States Geologic Survey (USGS) National Water Information System will be compared to five selected lower-than-normal precipitation years. Based on the selected five years, composite anomalies will be calculated for surface conditions and atmospheric controls using data from the National Center for Environmental Prediction and National Center for Atmospheric Research (NCEP-NCAR) Regional Reanalysis dataset. Analysis of how these climate components control spatial (e.g. local-to- regional) and temporal (e.g. monthly-to-seasonal) variations via composite-anomaly maps will establish how the variables contribute to drought conditions leading to low stream flow. This study is important to water management, agriculturalist, natural resource managers, and populations reliant on the water resources provided by the Laramie River. Furthering our understanding of how climatic controls are associated with low stream flow years and drought is important for improving future water management of the Laramie River. Stream flow data Obtained from USGS Gage Site 06661585, located near Bosler, Wyoming (approximately 30 miles north of Laramie). 2002 Proof of Concept Normal Stream flow (example) 1998 156.9 cfs Low Stream flow (example) 2002 18.9 cfs Figure A. 500 mb Geopotential Height Figure B. 500 mb Omega Figure C displays patterns of low surface soil moisture content, associated with suppressed precipitation amounts (Figure D) in the upper Laramie River watershed for the year 2002. Figure D. Precipitation Amounts at Surface Figure A displays higher-than-normal heights associated with a ridge in the atmosphere over Wyoming and much of the U.S. Composite-anomaly maps for dry/low stream flow year 2002 : Figure D shows lower-than-normal surface precipitation amounts in the upper Laramie River for the year 2002. Introduction Statement of the Problem Hypothesis Methods Data Analysis Importance of Study Precipitation Anomalies Figure B shows patterns of sinking motions in the atmosphere centered around Wyoming, which lead to lower-than-normal precipitation (Figure D). Sinking motions Rising motions Lower than normal Higher than normal Western U.S. Digital Elevation Map Time Series Plot for North Platte River, U.S. Climate Division 10 Figure C. Surface Soil Moisture Lower than normal Higher than normal Lower than normal Higher than normal 2002 Year