Spatial and temporal patterns of climate variables in Iraq

Temporal and spatial changes in Iraq total precipitations, maximum and minimum temperatures in the period of 1980–2011 are analyzed using 28 meteorological stations data distributed throughout the country. The Mann–Kendall and Spearman’s Rho test statistics for annual and seasonal Kendall and Sen’s T tests for monthly total precipitation and temperature series are calculated and plotted on maps to display any spatial trend patterns. Serial correlation structure in the data series and homogeneity of trends in monthly series were tested before applying the methods. Non-parametric methods using annual and monthly data over 32 years show almost same temporal and spatial patterns in trends of precipitation (P), maximum and minimum temperature (Tmax, Tmin) but some are not statistically significant at the 5 % level. While observation shows decreasing trends in precipitation except for two stations when using monthly data, increasing trend is detected in both temperature series. The Sen’s and seasonal Kendall slope estimator are also used to estimate linear trend magnitudes for annual and monthly data to determine the change per unit time in a time series, respectively. The six tests provide the same results about trend in most cases. As a conclusion, all of the study results show that there are not differences in the geographic location of trends (statistically significant or not) in the meteorological variables implying that climatic impacts are spatially uniform in this region. The effect of the North Atlantic Oscillation (NAO) on temporal patterns of climate data in Iraq is also investigated, since it has been suggested that it affects the northern hemisphere climate system. Our study shows that NAO has no detectable influences on climate of this region. This paper is the first comprehensive studies for evidence of climate change with applying tests in this region.