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network (Global Telecommunication System, GTS) and are available for time-critical 
applications such as weather forecasts. In non-real-time mode, the data are returned from the 
ships to the operator states via meteorological logbooks or electronic data carriers. The 
operator then transmits them via two Global Collecting Centres (GCCs at Bracknell, UK, and 
DWD, Hamburg) to eight regional subcentres for archiving and further evaluation. In this 
process, they are subjected to a minimum quality control and additional correction in the 
subcentres. Moreover, the complete volume of observations is available in this way. The total 
amount of observed data is available at DWD. 
Drifting meteorological buoys 
The VOS data are collected on all world oceans and thus exhibit a global distribution. 
However, it has to be taken into account that they concentrate along the main shipping routes. 
For that reason, meteorological drifting buoys are preferably deployed in such a way that they 
drift into ocean areas with a low data coverage, in order to close data gaps. A programme for 
the North Atlantic is co-ordinated, for example, by the European Group of Ocean Stations 
(EGOS) combining the resources of DWD and eight other European weather services. The 
data quality - atmospheric pressure, air and water temperatures - is high because the buoys 
are subject to permanent monitoring. The data are disseminated via GTS and are available at 
DWD. 
Platforms in the shelf and coastal zone 
In the coastal areas of the North and Baltic Seas, DWD is operating a marine meteorological 
monitoring network comprising coastal stations, automatic weather stations on unmanned 
lightships, lighthouses etc. A high temporal and spatial density of in-situ data is thus achieved 
in the coastal zone which is disseminated via GTS. 
Automated launching units at sea 
In the vast ocean area, far too few direct operational measuring data for the determination of 
current atmospheric pressure, temperature, humidity and wind profiles are available. In order 
to improve the worldwide network of radiosondes above the oceans, the Automated 
Shipboard Aerological Programme (ASAP) has been established which is integrated into the 
WMO programme COSNA (Composite Observing System - North Atlantic). Within the 
framework of this programme, containerized automated launching units are installed on board 
merchant vessels, with two daily radiosonde ascents performed by the ship’s crews. The 
results are transmitted in real-time to GTS. The German Weather Service DWD occupies a 
top position in this programme, operating five out of a total fifteen units. 
Products and services 
DWD-P1 is a permanent operational programme for the collection of marine meteorological 
in-situ data using the systems described above. The data are either exchanged in real-time or 
processed in non-real-time. These services, which form part of DWD’s statutory tasks and are 
integrated into WMO programmes such as WWW (World Weather Watch), are of vital 
importance to the numerous GOOS activities which are based on them, among them the 
GOOS programme contributions DWD P2 and P3. They constitute an important contribution 
to the Global Ocean Observing System.