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Weather and Evapotranspiration Studies in a Saltcedar Thicket, Arizona

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Weather and Evapotranspiration Studies in a Saltcedar Thicket, Arizona Weather and Evapotranspiration Studies in a Saltcedar Thicket, Arizona G E 0 L 0 G I CAL SURVEY P R 0 FE S S I 0 N A L PAPER 4 9 1-F Weather and Evapotranspiration Studies in a Saltcedar Thicket, Arizona By T. E. A. VAN HYLCKAMA STUDIES OF EVAPOTRANSPIRATION G E 0 L 0 G I CAL SURVEY P R 0 FE S S I 0 N A L PAPER 4 9 1-F U N I T E D STATES G 0 V ERN M EN T P R I N T I N G 0 F F I C E, WAS H I N G T 0 N 1 9 8 0 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard, Director Library of Congress Cataloging in Publication Data Van Hylckama, T. E. A. Weather and evapotranspiration studies in a saltcedar thicket, Arizona. (Studies of evapotranspiration) (Geological Survey professional paper; 491-F) Bibliography: p. F48-F51. 1. Tamarix Chinensis. 2. Evapotranspiration-Arizona-Buckeye region. 3. Vegetation and climate-Arizona-Buckeye region. 4. Microclimatology-Arizona-Buckeye region. 5. Phreatophytes­ Arizona-Buckeye region. I. Title. II. Series. Ill. Series: United States. Geological Survey. Professional paper; 491-F. QE75.P9 no. 491-F [QK495.T35] 557.3s 80-11316 [583'.158] For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Instrumentation-Continued Page Abstract __ ___ __ __ __ __ __ __ __ __ __ __ _ _ _ _ __ __ __ _ __ _ __ __ ____ _ _ _ F1 Radiation ____________________________________ ---_______ F19 Introduction________________________________________________ 1 Soil temperature, heat flow, and soil moisture ____________ 20 Saltcedar and other phreatophytes ______________________ 1 Soil temperature ____________________________________ 20 Literature______________________________________________ 2 Heat-flow plates------------------------------------ 20 Acknowledgments ______________ ________________________ 3 Soil moisture ------~------------------------------- 20 Methods of studying water use ------------------------------ 3 Water-use measurements ________________________________ 21 A bit of history _ __ _ __ _ __ __ __ __ __ _ _______ __ __ _ ___ _______ 3 The microclimate of a saltcedar thicket ---------------------- 22 Hydrologic methods ___ ___ ___ __ _ _ __ _ _ __ __ __ __ _ _____ _ ____ 4 Why the microclimate?---------------------------------- 22 Micrometeorologic methods______________________________ 4 The special observation periods-------------------------- 22 Empirical methods______________________________________ 5 Daily cycles of temperature and humidity ---------------- 23 The Buckeye test site -------------------------------------- 5 Winds ------------------------------------------------ 27 Location, soil, and water ------------------------------ 5 Radiation ---------------------------------------------- 30 Climate________________________________________________ 6 Soil heat flux __ __ _ ____ __ _ ___ __ _ _ _ _ __ ___ ___ __ ______ _____ 30 Vegetation __ _ __ __ _ _ ____ __ __ __ __ _ ___ __ __ _ _ _ _ __ __ ____ __ _ 8 Soil temperatures -------------------------------------- 34 Evapotranspiration and its calculation ______________________ 10 Heat flux and water use -------------------------------- 34 Evaporation____________________________________________ 10 Turbulent transport ___ ___ _ __ __ _ _ __ ____ _ ___ __ _ _ __ ____ _ __ 35 Transpiration ------------------------------------------ 11 Carbon dioxide _ __ __ __ ______ ___ __ _ _ ________ __ _ __ __ _ __ __ 36 Flow resistance ___ __ _ ___ __ ____ __ __ __ __ __ __ __ __ _ ___ __ __ _ 12 Predicting water use________________________________________ 40 Vapor-flow methods ------------------------------------ 12 Use of long-term means -------------------------------- 40 The atmospheric water balance ______________________ 12 Use of daily averages ---------------------------------- 42 The eddy-correlation method ________________________ 13 Short-term predictions ___ __ _ ___ __ ___ ___ __ __ __ __ _____ _ ___ 43 Bulk-aerodynamic methods______________________________ 13 Discussion ------------------------------------------------ 47 The Dalton approach________________________________ 14 References cited __ _ __ __ ____ __ _ _ _ __ ___ _ _ __ __ __ __ __ ____ _______ 48 The aerodynamic or profile approach ________________ 14 Appendices ------------------------------------------------ 53 Energy-budget method _ ____ __ __ __ _ _ _ _ __ __ __ __ ____ __ __ ___ 15 A. Tables Combination methods _ __ __ _ _ __ __ __ __ __ __ __ __ __ __ __ __ _ __ 16 A-1 Hourly averages of windspeeds and wind direction Instrumentation _ __ _ _ __ __ __ _ __ _ __ _____ __ _ __ __ ____ __ _ _ __ __ ___ 17 A-2 Hourly averages of air temperature and vapor pressure The atmosphere: Wind and temperature __________________ 17 A-3 Radiation data Wind---------------------------------------------- 17 A-4 Windspeed, temperature, and water vapor data Air temperature __ _ _ ____ ___ __ _ _ ___ _ __ __ _ _ ____ __ __ ___ 18 B. A nomogram for data reduction Precipitation and water vapor __________________________ 18 C. Symbols and dimensions Rainfall ____________________________________________ 18 Water vapor ________________________________________ 18 ILLUSTRATIONS Page FIGURE 1. A reproduction of plate 1 in Hales' (1727) "Vegetable Staticks" ------------------------------------------------ F4 2. Map showing location of the project site---------------------------------------------------------------------- 5 3. Sketch of the project site, southeast of Buckeye, Ariz., showing position of main features ________________________ 6 4. Aerial photograph of the project site _ __ __ _ _ __ _ _ __ __ _ __ _ _ ___ ____ __ __ __ __ __ _ _ __ _ ___ __ __ __ __ __ __ __ __ _ __ _ __ __ __ _ 6 5. Photograph of the project site from a 4-m-high platform ------------------------------------------------------ 6 6. Graph showing mean monthly temperature __ ___ __________________________ ______ _____________ _________ ____ ___ 7 7. Circular graph showing wind roses ___________________ ______________ ____________ _________ ____ _____ __ ____ _ _ ___ 8 8. Circular graph showing wind directions ___ ____ ________ _________________ _________ _________ ____ __ _______ ____ ___ 8 9-12. Graphs showing: 9. Mean monthly wind speeds__________________________________________________________________________ 8 10. Monthly rainfall____________________________________________________________________________________ 9 11. Solar radiation ------------------------------------------------------------------------------------ 9 12. Dew-pointtemperatures ---------------------------------------------------------------------------­ 9 13. Schematic drawings of leaf stomata__________________________________________________________________________ 11 14. Example of a 16-point strip chart _ _ ___ __ __ __ __ _ _ __ _ _ _ _ _ __ _ __ __ __ __ _ _ __ _ __ _ __ __ _ _ _ ___ __ __ _ __ __ _ __ _ _ __ _ _ __ __ __ _ 17 15. Example of a windspeed record _ __ __ __ __ __ __ __ _ __ _ __ __ _ __ ___ __ __ _ _ __ _ __ _ _ _ __ __ _ __ _ _ _ __ __ __ _ ___ __ __ _ _ __ __ __ __ _ 18 III IV CONTENTS Page FIGURE 16. Sketch of an air-temperature sensing system ______________________________________________ ---------_________ F19 17. Diagram of the ventilation system -------------------------------------------------------------------------- 19 18. Nomogram to compute vapor pressure________________________________________________________________________ 20 19-22. Photographs showing: 19. Radiation mast showing instrument installed -------------------------------------------------------- 21 20. Adjustable nomogram for computing heat flow-------------------------------------------------------- 21 21. Tensiometers installed in one tank ______ __________________ __ ___ ____ __ __ ________ ______ ____________ __ _ 21 22. Reading of tensiometers at night _________ ________________ __________ ____ __ ____ ____ ___ _____ ______ __ 22 23. Sample of an event recording chart -------------------------------------------------------------------------- 22 24. Graph showing microclimate characteristics of the Buckeye project site ---------------------------------------- 23 25. Graph showing the distribution ofwindspeeds within and above a stand of saltcedar ---------------------------- 27 26. Example of a border-punched card used for analyzing wind profiles -------------------------------------------- 28 27-45. Graphs showing: 27. How to determine roughness length, friction velocity, and zero displacement---------------------------- 29 28. Relation between modified roughness length and windspeed ratios ------------------------------------ 30 29. Modified roughness length versus stability ratio ------------------------------------------------------ 30 30. March of radiation and heat flow for seven 3-day periods ---------------------------------------------- 31 31. Methods of computing heat flow in the ~oil ---------------------------------------------------------- 32 32. Heat flow into and out of the ground in an evapotranspirometer near Buckeye, Ariz. ____________________ 33 33. Heat flow into and out of the ground in a lysimeter near Tempe, Ariz.---------------------------------- 33 34. Sinusoidal 24-hour heat flow into and out of soils ---------------------------------------------------- 33 35. Relation between amplitudes of daily temperature waves, damping depths, and depths of 0.05 x amplitudes 35 36. Relation between soil heat flux and water use -------------------------------------------------------- 35 37. Relation between windspeeds, temperatures, and vapor pressures
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