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Topographic and Geographic Influences on Near-Surface Temperature Under Different Seasonal Weather Types in Southwestern Alberta

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Topographic and Geographic Influences on Near-Surface Temperature Under Different Seasonal Weather Types in Southwestern Alberta University of Calgary PRISM: University of Calgary's Digital Repository Graduate Studies The Vault: Electronic Theses and Dissertations 2017 Topographic and Geographic Influences on Near-surface Temperature under Different Seasonal Weather Types in Southwestern Alberta Wood, Wendy Helen Wood, W. H. (2017). Topographic and Geographic Influences on Near-surface Temperature under Different Seasonal Weather Types in Southwestern Alberta (Unpublished doctoral thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/28465 http://hdl.handle.net/11023/3686 doctoral thesis University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission. Downloaded from PRISM: https://prism.ucalgary.ca UNIVERSITY OF CALGARY Topographic and Geographic Influences on Near-surface Temperature under Different Seasonal Weather Types in Southwestern Alberta by Wendy Helen Wood A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY GRADUATE PROGRAM IN GEOGRAPHY CALGARY, ALBERTA APRIL, 2017 © Wendy Helen Wood 2017 ABSTRACT Near-surface temperature variability is influenced by geographic and terrain characteristics. My research examines how these influences vary by weather type. This knowledge is used to determine the best methods for modelling temperature in the mountains and prairies in southwestern Alberta, using data collected as part of the Foothills Climate Array (FCA) study. A weather classification system was developed for the area using multivariate statistical analysis, and six weather patterns were identified. Missing temperature data in the FCA are gap-filled using regression equations generated using the most closely correlated station for each site, where correlations are calculated by seasonal weather type. Seasonal weather type correlations improve estimates by ~7% over monthly correlations. The biggest improvements (10 to 20%) occur for chinook and cool-wet days. Cold Arctic air days and hot anticyclonic days in summer show the lowest improvement, indicating strong within- type variability for these weather types. These weather types also show the most variable temperature lapse rates, with frequent inversions. Local weighted regression models outperform multivariate regression models by between 4 and 8% in the mountains. Daily temperature and elevation are not always strongly correlated, most notably during Arctic cold spells. This is true for both minimum and maximum temperatures in the mountains. Therefore, regression models using elevation as the only predictor perform poorly, particularly in winter months. Vertical and horizontal separation are the most important factors in choosing local neighbours, with vertical separation being most important for minimum temperatures and for winter months. Relative elevation and slope, as indictors of cold air pooling potential, influence the selection of local neighbours for minimum and mean temperature models. Spatial proximity is the most important factor determining temperature relatedness in the prairies. Minimum temperatures are strongly influenced by urban and relative elevation effects. Sites located within the city of Calgary are warmer than those in the outlying areas, and temperatures are warmer away from low lying areas. Seasonal variability is stronger than weather type variability in the prairies. Therefore, kriging is suggested as an appropriate method for estimating temperature in the prairies, with models parameterised monthly. ii ACKNOWLEDGEMENTS This thesis would not have been possible without the support and encouragement from many people. In particular, I thank both my husband Nick and my supervisor Dr. Shawn Marshall. Nick you are a saint for putting up with me. Shawn it has been a pleasure and privilege to know you as a friend and supervisor. Your quest for sound science is an inspiration. Thank you for your patience and quietly challenging me to do better. Thanks also to my committee members, Dr. Stefania Bertazzon and Dr. John Yackel. Stefania tried hard to instill statistical correctness in both my methods and writing, I tried hard, but can never measure up to her high standards. It was always a pleasure talking about the weather with John, someone who shares my interest in our highly changeable weather here in Alberta. Rick Smith provided technical support and was a good listener for all my problems, as well as being a source of many good ideas. Terri Whitehead did an amazing job of looking after the field work and data management. My life was a lot easier knowing I could go to Terri with questions, and with her good organisational skills she always provided the answers. A host of summer students were responsible for field work and data collection. Geography department staff, in particular Paulina Medori who always kept me informed of degree requirements and deadlines, allowing me to lose myself in data analysis, and Robin Poitras who helped me produce beautiful posters from my random collection of text and images. I am grateful for financial support I received through Shawn Marshall's Canada research chair funding, and scholarships from the Alberta government and University of Calgary Faculty of Graduate studies. iii TABLE OF CONTENTS Abstract ............................................................................................................................... ii Acknowledgements ............................................................................................................ iii Table of Contents ............................................................................................................... iv List of Figures ................................................................................................................... vii List of Tables .................................................................................................................... xii Abbreviations and Symbols ............................................................................................. xvi 1. Introduction ..................................................................................................................1 1.1 Thesis Objectives ................................................................................................. 3 1.2 Thesis outline ....................................................................................................... 5 2. Background ..................................................................................................................6 2.1 Climate processes and temperature ...................................................................... 6 2.1.1 Temperature Lapse Rates ...............................................................................7 2.1.2 Surface Energy Fluxes ...................................................................................9 2.1.3 Terrain Influences ........................................................................................12 2.2 Weather Typing .................................................................................................. 13 2.3 Interpolation and Regression Models ................................................................. 17 3. Study Area and Data Quality Analysis ......................................................................22 3.1 Study Area .......................................................................................................... 22 3.2 Instrument Calibration and Accuracy ................................................................ 27 3.2.1 Site setup and maintenance ..........................................................................27 3.2.2 Instrumentation ............................................................................................28 3.2.3 Instrument calibration ..................................................................................29 3.2.4 Vented calibration tests ................................................................................33 3.2.5 Station relocation .........................................................................................36 3.3 Quality Control ................................................................................................... 37 3.3.1 Field checks .................................................................................................39 3.3.2 Time shifts ...................................................................................................39 3.3.3 Spikes ...........................................................................................................40 3.3.4 Extreme values .............................................................................................41 3.3.5 Snow burial ..................................................................................................42 iv 3.3.6 Neighbourhood consistency .........................................................................42 3.3.7 Field notes manual review ...........................................................................45 3.3.8 Final review .................................................................................................47 3.4 Summary ...........................................................................................................
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