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Sy, A. et al. (2002): Upper Ocean Climate Ship-of-Opportunity Programme of BSH - A Status Report 
1. Overview of upper ocean climate monitoring activities 
The ship-of-opportunity programme (SOOP) managed by "Bundesamt fur Seeschifffahrt und 
Hydrographie" (BSH) focuses on the North Atlantic Ocean, and on the North and Baltic Seas. Its 
main contribution, the Atlantic XBT programme along the TOGA-WOCE-IGOSS (TWI) lines 
AX-3 and AX-11, which was originally planned in the late 80s as a contribution to WOCE (World 
Ocean Circulation Experiment) and IGOSS (Integrated Global Ocean Services System, now 
JCOMM) (Sy and Ulrich, 1989; Sy 1993a), has been continued and developed. Almost 15,000 
temperature profiles from expendable bathythermographs (XBT) have been obtained so far 
covering the Atlantic Ocean from the North Pole to the Equator. Within the framework of BSH’s 
SOOP, research and merchant vessels equipped with thermosalinographs or contact 
thermometers participate in near-surface temperature and salinity measurements. 
The thermohaline circulation (THC) of the North Atlantic is subject to strong natural variability on 
time scales ranging from years to decades which are correlated somehow with the atmospheric 
North Atlantic Oscillation (NAO) (e.g. Dickson et al., 1996; Sy et al., 1997a; Koltermann et al., 
1999; Curry and McCartney, 2001) and thus influence European climate. In particular 
occurrences of rapid and sustained THC changes severely affect the European climate, as has 
been shown by palaeo-climate records and model studies (e.g. Dansgaard et al., 1993; 
Rahmsdorf, 1994; 1995; Manabe and Stouffer, 1994; 1995; IPCC, 2001). Therefore, and 
because all observations indicate that global warming is continuing (IPCC, 2001), the risk of 
such changes must be better assessed. However, this is hampered by lack of observation data. 
For that reason, BSH's plans to upgrade its commercial vessel-based upper ocean thermal 
programme to an enlarged upper ocean climate programme (in particular TWI line AX-3) by 
using more sophisticated measurements were translated into action in 1998. As a contribution 
to GOOS (Global Ocean Observing System) and CLIVAR (Climate Variability and 
Predictability), BSH combined the AX-3 XBT programme with occasional XCTD measurements 
and with repeats of research vessel-based full-depth hydrographic sections in order to operate a 
well designed and cost-effective climate related monitoring programme in the GOOS A2- 
corridor of the North Atlantic (BSH, 1999), a key region for both ocean climate and European 
climate change investigation. 
As BSH acts as the German input and output GTS hub for real-time oceanographic data, all 
SOOP data are inserted as BATHY, TESAC or TRACKOB coded bulletins onto GTS (Global 
Telecommunication System of WMO) with a delay of about 1 day to 1 week. Real-time data 
from various Atlantic ocean areas have been contributed by the German Navy which accounted 
for some 20 % of a total of more than 15,000 German BATHY data circulating on the GTS in 
2000 and 2001, respectively. Since 2001, however, the Navy’s data contribution has decreased 
almost to zero due to changes in its declassifying policy. Further BATHY data are contributed in 
real-time by BSH's stationary "Marine Environmental Monitoring Network in the North and Baltic 
Seas" (MARNET). 
The scientific rationale, current technical and organizational status, and some preliminary results 
of the operational programme and other related operational data activities are described briefly 
in this report.