Determination of mean areal rainfall in the Gaza Strip using geographic information system (gis)‎ technique

الملخص EN

Three practical methods or models, Thiessen polygons, Isohyets and Inverse Distance Weight (IDW), were applied for computing individual station weights and Mean Areal Rainfall (MAR) over the entire the Gaza Strip area.

This study offers three graphic models for estimating MAR over a period of 25 years recorded in 10 observation stations in the Gaza Strip.

GIS is used to interpolate annual rainfall totals between gauging station to produce regional estimates of MAR.

Both areas and mean values over a given area (Gaza Strip) are standard GIS computations.

The MAR was computed by applying each model separately to find out the effect of the method applied as well as the regional and geographic coordinates.

The results show that the MAR in the Gaza Strip are between 335.7 mm, 338.3 mm and 345.4 mm according to IDW method, Thiessen polygons and Isohyetal method respectively.

The accuracy of these methods has a little variation (less than 10 mm).

Based on MAR, the annual volume of the rainfall over the area of the Gaza Strip will be 121, 122, and 124 million cubic meters according to the three methods.

The Isohyetal method is the most precise method in simulating monthly and yearly rainfall.

Therefore, these results must be considered in the climatic and water studies such as application of GIS for map preparation.