Specific Humidity Correlation with North Atlantic Oscillation Using NCEP Reanalysis Data over Iraqi-Kurdistan Region

Abstract

North Atlantic Oscillation (NAO) in the Northern hemisphere is a large teleconnection pattern affect on the climate of the Mediterranean countries. The aim of this research is to investigate the effect of NAO on specific humidity over Iraqi-Kurdistan region at different pressure levels using NCEP/NCAR reanalysis data. It’s concluded that there is a negative correlation coefficients between NAO and specific humidity at all pressure levels. The correlation coefficients are high at high pressure levels and low at low pressure levels in Jan and Dec, no obvious behaviour for the correlations at the other months. Maximum correlations obtained in winter are in the range of pressure levels 925-1000 mb, in the pressure level range 300-600 mb at spring ,in the rage 500-600 mb for summer and at 400- 600 mb in autumn , thus the NAO cause to increase the specific humidity at the mentioned pressure levels due to reach a moist air from the Atlantic to the Mediterranean and then to the region of study, also the NAO affect the specific humidity of the region at the relatively cold season more than the relatively hot season because the NAO has more activity in Cold seasons than the hot seasons .