The Impacts of NAO on the Hydrology of the Eastern Mediterranean

The impacts of the NAO on the hydrology of eastern Mediterranean countries, such as Turkey, Iran, Kuwait, Oman, and Israel, are documented here from a general perspective. Results for the eastern Mediterranean countries differ from one location to another in terms of consistent NAO signal. Patterns of precipitation, streamflow, and lake levels in Turkey are discussed to show the NAO impacts. A special attention is devoted to the NAO influences on the formation of streamflow homogeneous region and on the probability distribution functions of critical droughts. The results of all these analyses clearly showed that the NAO signals are quite identifiable in various hydrologic variables in Turkey. For example, the NAO during winter was found to influence precipitation and streamflow patterns. In contrast temperature patterns appeared to be less sensitive to the NAO. The results of wavelet analysis showed that the Tuz, Sapanca, and Uluabat lakes reflect strong NAO influences. In southwest Iran, the October–December season is influenced mostly by the NAO in both dry and wet spells. Positive significant correlation values were found between the NAO and the total rainfall in the centre and southern Israel and with some of the rainfall categories. High correlations between the winter mode of the NAO and temperature and sea level pressure in Israel were also noted. In conclusion, current evidences have shown that the NAO has detectable influences on the hydrology of eastern Mediterranean countries with different magnitudes.