Estimation of Relative Humidity and Dew Point Temperature Using Limited Meteorological Data
Publication: Journal of Irrigation and Drainage Engineering
Volume 143, Issue 9
Abstract
Hydrological processes such as evaporation and evapotranspiration (ET) are affected by air humidity. Air humidity is commonly expressed as relative humidity (RH) or dew point temperature () and is required for the determination of evaporation from water or soil surfaces and ET from cropped areas. However, the availability of humidity data is sometimes an issue. In cases in which RH data are not available, air humidity on a daily basis can be estimated by using daily maximum and minimum temperatures along with the dew point temperature. Guidelines from an international organization recommend the use of a dew point temperature slightly less than the daily minimum temperature for daily computations, when its measurements are not available. In this study, the daily average dew point temperature () was taken as less than the daily minimum temperature. Thus, daily RH data (maximum, minimum, and mean RH) were generated from daily maximum and minimum temperatures for Roorkee Station (India) during 2012–2016. Four different values of (, 1, 2, 3) were used for determining the actual vapor pressure values used in RH estimation. Daily RH values determined using different values of were compared with observed RH data. It was observed that for the nonsummer months, having an average value of daily mean RH greater than 60% (January–March and July–December), resulted in minimum error in RH estimation. However, during the summer months, having an average value of daily mean RH less than 60% (April–June), provided relatively better estimates of RH. During the summer months, large errors occurred in the estimation of maximum and minimum RH values using this approach; hence, mean RH values that are relatively better estimated during these periods should be used for hydrological applications. Further, linear -RH relationships (with and without parabolic correction) have been assessed to determine daily values. These relationships have been found to provide more accurate estimates of and actual vapor pressure on a daily basis than the FAO-56 vapor pressure models when only daily data are available (instead of and data) along with daily temperature data.
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Acknowledgments
The authors would like to acknowledge the financial support of the Ministry of Earth Sciences (MoES) (Government of India)-Natural Environment Research Council (NERC) (United Kingdom) project Mitigating Climate Change Impacts on Indian Agriculture through Improved Irrigation Water Management for carrying out this research work.
References
Ahooghalandari, M., Khiadani, M., and Jahromi, M. E. (2016). “Developing equations for estimating reference evapotranspiration in Australia.” Water Resour. Manage., 30(11), 3815–3828.
Allen, R. G., Pereira, L. S., Raes, D., and Smith, M. (1998). “Crop evapotranspiration: Guidelines for computing crop water requirements.”, Food and Agriculture Organization of the United Nations, Rome.
Allen, R. G., Pereira, L. S., Smith, M., Raes, D., and Wright, J. L. (2005). “FAO-56 dual crop coefficient method for predicting evaporation from soil and application extensions.” J. Irrig. Drain. Eng., 1.
Allen, R. G., Smith, M., Pereira, L. S., and Perrier, A. (1994). “An update for the calculation of reference evapotranspiration.” ICID Bull., 43(2), 35–92.
Allen, R. G., and Wright, J. (2009). “Estimation of evaporation and evapotranspiration during nongrowing seasons using a dual crop coefficient.” World Environmental and Water Resources Congress, ASCE, Reston, VA, 1–14.
Blaney, H. F., and Criddle, W. D. (1950). “Determining water requirements in irrigated areas from climatological irrigation data.”, U.S. Dept. of Agriculture, Soil Conservation Service, Washington, DC, 48.
Boast, C. W., and Robertson, T. M. (1982). “A micro-lysimeter method for determining evaporation from bare soil: Description and laboratory evaluation.” Soil Sci. Soc. Am., 46(4), 689–696.
Bohren, C., and Albrecht, B. (1998). Atmospheric thermodynamics, Oxford University Press, New York.
Bosen, J. F. (1958). “An approximation formula to compute relative humidity from dry bulb and dew point temperatures.” Mon. Weather Rev., 86(12), 486.
Dalton, J. (1802). “On the force of steam or vapour from water and various other liquids, both in a vacuum and in air.” Mem. Lit. Philos. Soc. Manchester, 5, 550–595.
Devitt, D. A., Sala, A., Smith, S. D., Cleverly, J., Shaulis, L. K., and Hammett, R. (1998). “Bowen ratio estimates of evapotranspiration for Tamarix ramosissima stands on the Virgin River in southern Nevada.” Water Resour. Res., 34(9), 2407–2414.
Doorenbos, J., and Pruitt, W. O. (1975). “Guidelines for predicting crop water requirements.”, Food and Agriculture Organization of the United Nations, Rome.
Eccel, E. (2012). “Estimating air humidity from temperature and precipitation measures for modelling applications.” Meteorol. Appl., 19(1), 118–128.
Evett, S. R., Schwartz, R. C., Howell, T. A., Baumhardt, R. L., and Copeland, K. S. (2012). “Can weighing lysimeter ET represent surrounding field ET well enough to test flux station measurements of daily and sub-daily ET?” Adv. Water Resour., 50, 79–90.
Flumignan, D. L., Faria, R. T. D., and Lena, B. P. (2012). “Test of a microlysimeter for measurement of soil evaporation.” Engenharia Agrícola, 32(1), 80–90.
Grismer, M. E., Orang, M., Snyder, R., and Matyac, R. (2002). “Pan evaporation to reference evapotranspiration conversion methods.” J. Irrig. Drain. Eng., 180–184.
Hansen, J. B., Holm, P. E., Hansen, E. A., and Hjelmar, O. (2000). “Use of lysimeters for characterization of leaching from soil and mainly inorganic waste materials.”, Nordtest, Denmark.
Harbeck, G. E., Jr. (1962). “A practical field technique for measuring reservoir evaporation utilizing mass-transfer theory.”, United States Government Printing Office, Washington, DC, 101–105.
Hargreaves, G. H., and Samani, Z. A. (1982). “Estimation of potential evapotranspiration.” J. Irrig. Drain. Div., 108(3), 223–230.
Hargreaves, G. H., and Samani, Z. A. (1985). “Reference crop evapotranspiration from temperature.” App. Eng. Agric., 1(2), 96–99.
Hatiye, S. D., Hari Prasad, K. S., and Ojha, C. S. P. (2016). “Study of deep percolation in paddy fields using drainage-type lysimeters under varying regimes of water application fields using drainage-type lysimeters under varying regimes of water application.” ISH J. Hydraul. Eng., 23(1), 35–48.
Hillel, D. (2004). Introduction to environmental soil physics, Elsevier Academic Press, Amsterdam, Netherlands.
Huang, Y., Zhang, K., Yang, S., and Jin, Y. (2013). “A method to measure humidity based on dry-bulb and wet-bulb temperatures.” Res. J. Appl. Sci. Eng. Technol., 6(16), 2984–2987.
Kottek, M., Grieser, J., Beck, C., Rudolf, B., and Rubel, F. (2006). “World map of the Köppen-Geiger climate classification updated.” Meteorologische Zeitschrift, 15(3), 259–263.
Lawrence, M. G. (2005). “The relationship between relative humidity and the dewpoint temperature in moist air: A simple conversion and applications.” Bull. Am. Meteorol. Soc., 86(2), 225–233.
Liu, C., Zhang, X., and Zhang, Y. (2002). “Determination of daily evaporation and evapotranspiration of winter wheat and maize by large-scale weighing lysimeter and micro-lysimeter.” Agric. For. Meteorol., 111(2), 109–120.
Meyer, A. F. (1915). “Computing runoff from rainfall and other physical data.” Trans. Am. Soc. Civ. Eng., 78(2), 1056–1155.
Mohan, S., and Arumugam, N. (1994). “Irrigation crop coefficient for lowland rice.” Irrig. Drain. Syst., 8(3), 159–176.
Nagler, P. L., Scott, R. L., Westenburg, C., Cleverly, J. R., Glenn, E. P., and Huete, A. R. (2005). “Evapotranspiration on western U.S. rivers estimated using the enhanced vegetation index from MODIS and data from eddy covariance and Bowen ratio flux towers.” Remote Sens. Environ., 97(3), 337–351.
Penman, H. L. (1948). “Natural evaporation from open water, bare soil and grass.” Proc. R. Soc. London, 193(1032), 120–145.
Rohwer, C. (1931). “Evaporation from free water surfaces.”, U.S. Dept. of Agriculture, Washington, DC.
Romanenko, V. A. (1961). “Computation of the autumn soil moisture using a universal relationship for a large area.” Proc., Ukrainian Hydrometeorological Research Institute, Vol. 3, Ukrainian Hydrometeorological Research Institute, Kiev, Ukraine.
Schmidt, C. D. S., Pereira, F. A. C., Oliveira, A. S., Júnior, J. F. G., and Vellame, L. M. (2013). “Design, installation and calibration of a weighing lysimeter for crop evapotranspiration studies.” Water Resour. Irrig. Manage., 2(2), 77–85.
Sellers, W. (1960). “A statistical method for estimating the mean relative humidity from the mean air temperature.” Mon. Weather Rev., 88(4), 155–157.
Singh, V. P., and Xu, C. Y. (1997). “Evaluation and generalization of 13 mass-transfer equations for determining free water evaporation.” Hydrol. Process., 11(3), 311–323.
Stanhill, G. (2002). “Is the class A evaporation pan still the most practical and accurate meteorological method for determining irrigation water requirements?” Agric. For. Meteorol., 112(3), 233–236.
Sumner, D. M., and Jacobs, J. M. (2005). “Utility of Penman-Monteith, Priestley-Taylor, reference evapotranspiration, and pan evaporation methods to estimate pasture evapotranspiration.” J. Hydrol., 308(1–4), 81–104.
Thornthwaite, C. W. (1948). “An approach toward a rational classification of climate.” Geog. Rev., 38(1), 55–94.
Thornthwaite, C. W., and Mather, J. R. (1955). “The water budget and its use in irrigation Water, the Yearbook of Agriculture.” U.S. Dept. of Agriculture, Washington, DC, 346–358.
Upreti, H., Ojha, C. S. P., and Hari Prasad, K. S. (2015). “Estimation of deep percolation in sandy-loam soil using water-balance approach.” Irrig. Drain. Syst. Eng., 4(S1), 002.
Vu, S. H., Watanbe, H., and Takagi, K. (2005). “Application of FAO-56 for evaluating evapotranspiration for simulation of pollutant runoff from paddy rice field in Japan.” Agricul. Water Manage., 76(3), 195–210.
Xu, C. Y., and Singh, V. P. (2000). “Evaluation and generalization of radiation-based methods for calculating evaporation.” Hydrol. Process., 14(2), 339–349.
Xu, C. Y., and Singh, V. P. (2001). “Evaluation and generalization of temperature-based methods for calculating evaporation.” Hydrol. Process., 15(2), 305–319.
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Journal of Irrigation and Drainage Engineering
Volume 143 • Issue 9 • September 2017
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©2017 American Society of Civil Engineers.
History
Received: Dec 28, 2016
Accepted: Apr 6, 2017
Published online: Jul 8, 2017
Published in print: Sep 1, 2017
Discussion open until: Dec 8, 2017
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