Assessment of spatial and temporal variability of rainfall data using Kriging, Mann kendall test and the Sen?s slope estimates in Jordan from 1980 to 2007

This study aims to examine the spatial and temporal variability of the mean annual rain in Jordan during a 28-year period (1980-2007). The used meteorological datasets are the monthly rainfall amounts (mm) and the annual rainfall recorded at twenty five meteorological stations of the Jordan Meteorological Department. The stations are uniformly distributed over Jordan territory. Various spatial and statistical tools were used to display and analyze the spatial and temporal variability of rainfall data. ArcGIS was used to produce the spatially distributed rainfall data by using Kriging interpolation method. The non-parametric Mann-Kendall test was used to determine whether there is a positive or negative trend in data with their statistical significance. Sen?s method was also used to determine the magnitude of the trends. The findings of the analysis show that statistically significant negative trends (95% confidence level) appear mainly in three areas, while no significant trends (95% confidence level) are found in the remnant areas. Further analysis concerning the seasonal Rain Intensity (RI) is needed, because there are different seasonal patterns, taking into account that, convective rain in Jordan occurs mainly within the winter season.