WHP Ref. No.: IR1W/ISS2 Last updated: 14 December 1994 Cruise report "Sonne" cruise 89 A. Cruise narrative A.1. Highlights a. WOCE designation: IR1W and ISS2 b. Expedition designation:06BE89/1 c. Chief scientist: Prof. Dr. F. Schott Institut für Meereskunde Universitat Kiel Dusternbrooker Weg 20 24150 Kiel, Germany Telephone: +49-431-597-3820 Telefax: +49-431-597-3821 Telex: 17431793 IFMKIEL d. Ship: Sonne e. Ports of call: Colombo, Sri Lanka to Karachi, Pakistan f. Cruise dates: August 4 to August 30, 1993 A.2. Cruise Summary Information a. Geographic boundaries: Stations along IR1W were primarily located along 8¿N (IR1W) between 54¿E and 77¿E. Additional stations that fall both on IR1W and within the ISS2 Special Study area are located between 6¿N and 19¿N from 51¿E to 59¿E. b. Stations occupied: 99 CTD/rosette stations were occupied during the cruise. 62 of these stations fall along IR1W with the other 37 located within the ISS2 area. Water sampling on the cruise included measurements of salinity, both by CTD and bottle sample oxygen determinations, CTD temperature. Tracer analysis were made for F-11 and F-12, but reliable values were gained only for F-11. c. Floats and drifters deployed: None reported. d. Moorings deployed or recovered: None reported. A.3. List of Principal Investigators Parameter/Instrument Sampling group Responsible Investigator CTD/O2 / Rosette IfM Kiel Lothar Stramma Chlorofluorocarbons IfM Kiel Monika Rhein ADCP IfM Kiel Jurgen Fischer Salinity IfM Kiel Lothar Stramma Oxygen IfM Kiel Monika Rhein XBTs IfM Kiel Lothar Stramma A.4. Scientific Programme and Methods SONNE cruise 89 focused on the study of the circulation and water mass of the Arabian Sea. The investigation was carried out in the context of the World Ocean Circulation Experiment (WOCE). Cruise objectives were the study of water mass and heat exchange at the entrance of the Arabian Sea during the summer monsoon, the investigation of the outflow of the Somali Current region to the north and the investigation of upwelling off the Oman coast. SONNE left Colombo, Sri Lanka on 4 August 1993 at 21:00 local time heading towards the southwest Indian coast. A test station was done at 7¿29.8¿N, 78¿14.8¿E. The CTD section along 8¿N started with CTD station 2 at 7¿59.98¿N, 76¿51.97¿E. On 15 August at station 50 at 8¿01¿N, 53¿55.21¿E the 200 miles zone of Somalia was reached. As no research permission for Somalia waters was obtained, some CTD stations were made along the 200 mile zone of Somalia, or within the Yemen waters at the border to the Somalia waters. Although the winds increased due to the summer monsoon off the African continent, CTD measurements were still possible, although sometimes without water bottles, as R/V SONNE showed very good performance during rough weather. In the last week of the cruise, CTD stations were made in the Owens Fracture Zone and off the Omani coast. The ship reached Karachi on 28 August, where the cruise SONNE 89 terminated. A.5. Major Problems and Goals Not Achieved None reported. A.6. Other Incidents of Note None reported.