SOUTHAMPTON OCEANOGRAPHY CENTRE CRUISE REPORT No. 24 RRS DISCOVERY CRUISE 233 23 APR - 01 JUN 1998 A Chemical and Hydrographic Atlantic Ocean Survey: CHAOS Principal Scientist D Smythe-Wright 1999 George Deacon Division for Ocean Processes Southampton Oceanography Centre Empress Dock European Way Southampton S014 3ZH UK Tel: +44 (0)1703 596439 Fax: +44 (0)1703 596204 Email:
[email protected] DOCUMENT DATA SHEET AUTHOR: SMYTHE-WRIGHT, D et al PUBLICATION DATE: 1999 TITLE: RRS Discovery Cruise 233, 23 Apr-01 Jun 1998. A Chemical and Hydrographic Atlantic Ocean Survey: CHAOS. REFERENCE: Southampton Oceanography Centre Cruise Report, No. 24, 86pp. ABSTRACT RRS Discovery Cruise 233, CHAOS (Chemical and Hydrographic Atlantic Ocean Survey) combined a long meridional section notionally along 20°W from 20°N to Iceland with a detailed survey of the Rockall Trough. The meridional section was designed to i) establish the sources and sinks of halocarbons in subtropical and subpolar waters during spring bloom conditions; ii) to examine the decadal scale variability in the eastern Atlantic over the last 40 years by repeating the northern part of the WOCE A16 line first occupied in 1988 and again in 1993 (NATL 93), and parts of other sections occupied in 1957, 1973, 1983 and 1991; iii). to study the spreading mixing and ventilation rates of Labrador Sea Water, Mediterranean Water, and waters of Southern Ocean origin (Antarctic Intermediate Water and Antarctic Bottom Water) which extend into the northeast Atlantic. The detailed survey of the Rockall Trough comprised 4 zonal sections notionally at 57°N, 56°N, 54°N and 52°N in order to i) make a detailed study of the water masses in the Rockall Trough with particular emphasis on their circulation/recirculation patterns ii) to re-occupy stations along the Ellett line (57°N) to continue the time series dating from 1975.