Variability of Wintertime Surface Air Temperature over the Kingdom of Saudi Arabia

Abstract

Variability of wintertime surface air temperature (SAT) in the Kingdom of Saudi Arabia (KSA) is studied. The study is based on time series over thirty one years in length (1978-2008). For the analysis, we use the coefficient of variability (COV) Mann-Kendal statistical test, running mean and cumulative annual mean (CAM). The coefficient of variability (COV) for wintertime SAT decreases gradually from the north to the south of KSA. The higher values for COV occur in northern and northeastern KSA; there are due to the effect of the traveling Mediterranean depressions and their interaction with the inverted-V shape trough of the Sudan low. The relationship between COV and latitude is highly significant, while with longitude it is not significant. The Mann-Kendal statistical test illustrates that positive trends (warming) in wintertime SAT series occurs over the all stations, and that the trends are significant at middle and southern regions of KSA. Recent warming has only occurred during the last two decades at most stations. While cooling in the wintertime SAT appears for the short period of about 5 years, 1978-1983 and 1988-1992. These trends are consistence with trends in the global mean SAT. The results obtained from CAW lead to the conclusion that the thermic regime is modifying in the KSA. This dramatic enhancement, occurred at the beginning of the year 1993, is reflected in net modification in the SAT time series. The analysis of the SAT also shows a significant warming trend after the year 1997 with a rate of 0.03?C/year.