دراسة مقارنة لطرق تقدير البخر-نتح للمنطقة الوسطى و الشرقية في المملكة العربية السعودية باستخدام العديد من النماذج المناخية

Abstract EN

In this paper, the reference evapotranpiration (ET) covering the period of 1995,1996, and 1997 was estimated over the Centeral and Eastern regions of the Kingdom of Saudi Arabia (Riyadh, Qassim, Eastern and Hail).

Data of this study were extracted from the records of the Presidency of Meteorology and Environmental Protection Agency (PMEP), Jeddah, Saudi Arabia.

Then the reference evapotranspiration rates were evaluated for nine meteorological stations beloning to PMEP, representing different climatic regions of the study area, together with data of agricultural stations belonging to the Ministry of Agriculture, using Pan evaporation method, as a possible evapotranspiration index.

Six different methods were investigated using different available empirical formulae such as: Blaney and Criddle, SCS, FAO, Linacre, Hargreave, Thorngreaves, Thornthwaite, and Pan Evaporation methods.

The class A Pan rates were used as an index of reference ET.

Statistical analysis for the estimated ET for reference crop was performed from meteorological data records for three-years-duration.

Meanwhile, comparisons between ET estimated by pan method and ET estimated by other methods were also statistically performed to find the significant differences.

Analysis of Variance showed a high significant differences among methods used and between months and their interaction on the values of ET.

Moreover, the least square difference analysis (LSD) showed that the FAO method was more realastic and representative method than the others.

The study showed that the annual rate value of ET during the period of the study was high in the Eatern and in the Hail regions, whereas, the rate of ET showed low values in Riyadh region.

Finally, the results of this study are considered very valuable in future planning of water utilization for different agricultural practices in the Kingdom of Saudi Arabia.