In this paper, the results of Empirical Mode Decomposition analysis of underwater ambient noise data are presented. Noise examples are assembled by means of the "ITU Underwater Ambient Noise Measurement and Recording System" in the Strait of Istanbul. Firstly, the analysis results of the data collected during the "no ship in the line of sight" period are shown. Then the same analysis was repeated for the data gathered during periods of various ships' cruising. Variances and frequency spectra of Intrinsic Mode Functions (IMF) were estimated and the results were compared. It is observed that the first 5 IMFs' variances reveal useful information about ship presence near the recording system.