American Journal of Water Resources
ISSN (Print): 2333-4797 ISSN (Online): 2333-4819 Website: http://www.sciepub.com/journal/ajwr Editor-in-chief: Apply for this position
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American Journal of Water Resources. 2018, 6(6), 212-216
DOI: 10.12691/ajwr-6-6-1
Open AccessArticle

Determining the Effective Distance Spatially for Sharing the Climatic Data Relating to Reference Evapotranspiration

Homayoon Ganji1, and Takamitsu Kajisa1

1Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu City, Mie 514-8507, Japan

Pub. Date: December 09, 2018

Cite this paper:
Homayoon Ganji and Takamitsu Kajisa. Determining the Effective Distance Spatially for Sharing the Climatic Data Relating to Reference Evapotranspiration. American Journal of Water Resources. 2018; 6(6):212-216. doi: 10.12691/ajwr-6-6-1

Abstract

The estimation of reference evapotranspiration (ET0) with the FAO-Penman-Monteith method faces challenges in some places due to its high data demand. To overcome this challenge some methodologies recommended by FAO. However, sharing the nearby station’s data is another way to estimate ET0 more accurate in some cases than that of using the FAO’s recommendation. In this paper, the important matter is the determination of an effective distance (Xc) which is the upper limit of distance for data sharing between the stations. ∆ET0(st) which is the average errors between the two stations given by the measured data is theoretically very small if the distance is zero. ∆ET0(Alt) which is the error produced from the alternative data given by FAO’s recommendation is equal to ∆ET0(st) at Xc. By using the data form 48 metrological stations in Japan, we examined this concept in the case of three kinds of data. The results confirmed, there was Xc exited along the investigated distance at which ∆ET0(st) was smaller than ∆ET0(Alt). This was the case corresponding to the solar radiation and actual vapor pressure. Xc was found smaller than the minimum distance in the case of wind data. It is, therefore, possible to use the FAO’s alternative wind data.

Keywords:
effective distance climatic variables reference evapotranspiration geostatistical technique error theory

Creative CommonsThis work is licensed under a Creative Commons Attribution 4.0 International License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

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References:

[1]  Allen, R.G., Pereira-Luis, S., Dirk, R. and Martin, S, “FAO Irrigation and drainage paper no. 56,” Rome. FAO, 56: 97-156. 1998.
 
[2]  Droogers, P. and Allen R. G, “Estimating reference evapotranspiration under inaccurate data conditions,” J. Irrig. Drain Syst, 16: 33-45. 2002.
 
[3]  Gocic, M. and Trajkovic, S, “Software for estimating reference evapotranspiration using supplementary data,” J. Compu Electron Agric, 71: 158-162. 2010.
 
[4]  Popova, Z., Milena, K. and Luis, S. P, “Validation of the FAO methodology for computing ET0 with supplementary data, Application to South Bulgaria,” J. IRRI DRAIN ENG, 55: 201-215. 2006
 
[5]  Cordova, M., Galo, C. R., Patricio, C., Bradford, W. and Rolando, C, “Evaluation of the Penman-Monteith (FAO-56PM) method for calculating reference evapotranspiration using supplementary data application to the wet Páramo of Ecuador,” J. Mt Res Dev, 35: 230-39. 2015.
 
[6]  Jabloun, M. D., and Sahli, A, “Evaluation of FAO-56 methodology for estimating reference evapotranspiration using limited climatic data: Application to Tunisia,” J. Agric Water Manag., 95: 707-715. 2008.
 
[7]  Sentelhas, P. C., Terry, J. G. and Eduardo, A. S, “Evaluation of FAO Penman-Monteith and alternative methods for estimating reference evapotranspiration with missing data in southern Ontario, Canada,” J. Agric Water Manag, 97: 635-44. 2010.
 
[8]  Ganji, H., Kajisa, T, “Applying the error propagation approach for predicting root mean square error of the reference evapotranspiration when estimated with alternative data,” J. Agri. Eng. (under review).
 
[9]  Warrick, A.W., and Myers, D.E, “Optimization of sampling locations for variogram calculations,” J. Wat. Res. Res, 23: 496-500. 1987.
 
[10]  Garcia, M., Raes, D., Allen, R. G. and Herbas, C, “Dynamics of reference evapotranspiration in the Bolivian highlands (Altiplano),” J. AGR FOREST METEOROL. 125: 67-82. 2004.