Estimating Air Vapor Pressure in a Semiarid Region Using FAO-56 Methodology
Publication: Journal of Irrigation and Drainage Engineering
Volume 137, Issue 8
Abstract
This paper presents three models for the estimation of vapor pressure from temperature and humidity data as suggested by Food and Agriculture Organization (FAO) Irrigation and Drainage Paper No. 56 (FAO-56) that have been compared for their performance using daily data from 2002 through 2007 for a semiarid climatic region of Udaipur in Rajasthan, India. Vapor pressure data obtained from dew-point temperature has been used as actual vapor pressure. Model 1 performed better than the remaining two models. Lower values of vapor pressure are better modeled by the three models than higher values. The average absolute error of Model 1 varied from 5.09 to 15.59%, of Model 2 from 5.59 to 19.73%, and that of Model 3 from 5.62 to 37.21%. Estimates of vapor pressure obtained from the three models were also used to estimate open-water evaporation determined by the modified Penman method; the results were compared. Errors in vapor pressure data did not significantly affect estimates of evaporation, indicating that other factors such as energy budget played a much more significant role than mass transfer influence for this arid basin. Errors in evaporation estimation were for Model 1, for Model 2, and for Model 3. Even for Models 2 and 3 they were for most months. In general, Model 1 was found to be the best model of vapor pressure estimation and also caused the fewest errors in estimation of evaporation.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The writers are very much grateful to the Head, Department of Soil and Water Engineering, College of Technology and Engineering, Maharana Pratap University of Agriculture and Technology, Udaipur, for supplying the required meteorological data of Udaipur. Also, financial support of INCOH, Ministry of Water Resources, Government of India Grant No. UNSPECIFIED23/53/2006-R & D/312-24 is gratefully acknowledged.
References
Allen, R. G., Pareira, L. S., Raes, D., and Smith, M. (1998). “Crop evapotranspiration: Guidelines for computing crop water requirements.” Irrigation and Drainage Paper No. 56, Food and Agriculture Organization of the United Nations, Rome.
Burman, R. D., Jensen, M. E., and Allen, R. G. (1987). “Thermodynamic factors in evapotranspiration.” Proc., Irrigation Systems for the 21st Century, L. G. James and M. J. English, eds., ASCE, Portland, OR, 28–30.
Dingman, S. L. (1994). “Evapotranspiration.” Chapter 7, Physical hydrology, McMillan, New York, 256–265, 516.
Gangopadhyay, M., Datar, S. V., and George, C. J. (1970). “On the global solar radiation, climate and evapotranspiration estimates in India.” Indian J. Meteorol. Geophys., 23, 48–57.
Gianniou, S. K., and Antonopoulos, V. Z. (2007). “Evaporation and energy budget in Lake Vegoritis, Greece.” J. Hydrol. (Amsterdam), 345, 212–223.
Glover, J., and Mc Cullough, J. S. J. (1958). “The empirical relation between solar radiation and hours of bright sunshine in the high altitude tropics.” Q. J. R. Meteorol. Soc., 84, 56–60.
Howell, T. A., and Dusek, D. A. (1995). “Comparison of vapor pressure deficit calculation methods-southern high plains.” J. Irrig. Drain Eng., 121(2), 191–198.
Jensen, M. E., Burman, R. D., and Allen, R. G. (1990). “Evapotranspiration and irrigation water requirements.” ASCE Manuals and Reports on Engineering Practice No. 70, New York.
Jobson, H. E. (1972). “Effect of using averaged data on the computed evaporation.” Water Res. Res., 8(2), 513–518.
Koberg, G. E. (1964). “Methods to compute long-wave radiation from the atmosphere and reflected radiation from a water surface.” USGS Professional Paper No. 272-F, Washington, DC.
Lenters, J. D., Kratz, T. K., and Bowser, C. J. (2005). “Effect of climate variability on lake evaporation: Results from a long term energy budget study of Sparkling Lake, northern Wisconsin (USA).” J. Hydrol. (Amsterdam), 308, 168–195.
Linsley, R. K., Kohler, M. A., and Paulhus, J. L. H. (1975). “Evaporation and transpiration.” Chapter 5, Hydrology for engineers, McGraw-Hill, New York.
Nokes, S. E. (1995). “Evapotranspiration.” Chapter 4, Environmental hydrology, A. D. Ward and W. J. Elliot, eds., Lewis Publishers, London, 91–132.
Rosenberry, D. O., Winter, T. C., Buso, D. C., and Likens, G. E. (2007). “Comparison of 15 evaporation methods applied to a small mountain lake in the northeastern USA.” J. Hydrol. (Amsterdam), 340, 149–166.
Sadler, E. J., and Evans, D. E. (1989). “Vapor pressure deficit calculations and their effect on the combination equation.” Agric. For. Meteorol., 49, 55–80.
Saxton, K. E. (1975). “Sensitivity analysis of the combination evapotranspiration equation.” Agric. For. Meteorol., 15(3), 343–353.
Shuttleworth, W. J. (1993). “Evapotranspiration.” Handbook of hydrology, D. R. Maidment, ed., McGraw-Hill, New York, 4.1–4.53.
Singh, V. P., and Xu, C. Y. (1997a). “Sensitivity of mass transfer based evaporation equations to errors in daily and monthly input data.” Hydrol. Processes, 11, 1465–1473.
Singh, V. P., and Xu, C. Y. (1997b). “Evaluation and generalization of 13 mass transfer equations for determining free water evaporation.” Hydrol. Processes, 11(3), 311–323.
Suleiman, A. A., and Hoogenboom, G. (2007). “Comparison of Priestley-Taylor and FAO-56 Penman-Monteith for daily reference evapotranspiration estimation in Georgia.” J. Irrig. Drain Eng., 133(2), 175–182.
Sturrock, A. M., Winter, T. C., and Rosenberry, D. O. (1992). “Energy budget evaporation from Williams Lake: A closed lake in north central Minnesota.” Water Resour. Res., 28(6), 1605–1617.
Tanner, C. B., and Sinclair, T. R. (1983). “Efficient water use in crop production: Research or re-search?” Limitation to efficient water use in crop production, H. M. Taylor, W. R. Jordon, and T. R. Sinclair, eds., American Society of Agronomy, Madison, WI, 1–27.
Trewartha, G. T., and Horn, L. H. (1980). “Atmospheric moisture and precipitation.” An introduction to climate, 5th Ed., McGraw-Hill, New York, 41–53.
Warnaka, K., and Pochop, L. (1988). “Analysis of equations for free water evaporation estimates.” Water Resour. Res., 24(7), 979–984.
Weiss, A. (1977). “Algorithm for the calculation of moist air properties on a hand calculator.” Trans. ASAE, 20(6), 1133–1136.
Winter, T. C. (1981). “Uncertainties in estimating the water balance of lakes.” Water Resour. Bull., 17(1), 82–115.
Winter, T. C., Rosenberry, D. O., and Sturrock, A. M. (1995). “Evaluation of 11 equations for determining evaporation for a small lake in north central United States.” Water Resour. Res., 31(4), 983–993.
Xu, C. Y., and Singh, V. P. (1998). “Dependence of evaporation on meteorological variables at different time-scales and intercomparison of estimation methods.” Hydrol. Processes, 12, 429–442.
Yoder, R. E., Odhiambo, L. O., and Wright, W. C. (2005). “Effects of vapor pressure deficit and net irradiance calculation methods on accuracy of standardized Penman-Monteith equation in a humid climate.” J. Irrig. Drain Eng., 131(3), 228–237.
Information & Authors
Information
Published In
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Apr 27, 2010
Accepted: Nov 4, 2010
Published online: Nov 8, 2010
Published in print: Aug 1, 2011
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.