Climate

The weekly Maps of SST for the North Sea and Baltic are constructed on wednesdays. Data received during the past 7 days are used. The North Sea map is based on both satellite and ship observations. The Baltic map is based solely on satellite measurements. The North Sea map is animated since 1995, the Baltic since 1996. Maps of the Monthly Means and Anomalies are presented dating back to 1968.

Sea ice, next to snow, is the most variable constituent of the Earth´s surface. Small variations in climate forcing are associated with substantial changes in sea ice coverage. Thus sea ice is viewed as a key-indicator for climate change.
All sea ice charts presented here are based on digital sea ice concentrations derived from SSMR and SMMI satellite data (courtesy of National Snow and Ice Data Center, Boulder, CO). The historical evolution since 1978 of the geographical distribution of global sea ice, as well as its seasonal, intraseasonal, and interannual variability, can be explored here easily through an interactive video machine. The actual evolution over the most recent 30 days of global sea ice coverage, and snow cover in the Northern Hemisphere, can be visualized in the same fashion.
Although navigational requirements are accounted for in these products, for general navigation ice conditions in the Baltic and North Sea, as well as American, Norwegian and Russian waters are of special interest. Ice information on these regions is available from BSH's Ice service.

The northward transport of heat in the Atlantic Ocean is very important for the climate conditions in Northern Europe. The amount as well as the variablity of this transport are poorly known. The determination of the meridional fluxes (in German: Meridionale Transporte im Nordatlantik) of heat and freshwater across the line between the English Channel and the Grand Banks of Newfoundland is a major contribution of BSH to Climate Research.

The WOCE Global Hydrographic Climatology WGHC was published in September 2004. It provides a consistent and coherent hydrographic gridded full–depth data set on 45 depth levels with a 0.5° spatial resolution. High quality hydrographic observations from the WOCE one–time and repeat hydrographic cruises with ca. 9000 stations for the period 1990 — 1998 are the modern basis.

As part of the Hamburg Ocean/CLIVAR-projekt: "The changing North Atlantic Ocean: mechanisms of circulation changes" the changes in the thermohaline circulation are quantified on time scales of years to decades. First analyses of the coherent data set along the hydrographic section WOCE/A2 during the Nineties show significant interannual changes in the climate relevant key parameters of the large-scale circulation in the North Atlantic such as heat and freshwater transports. With a phase lag of one year the transport values show an almost linear correlation with changes in the dominant mode of low-frequent atmospheric variability in the North Atlantic, the North Atlantic Oscillation (NAO). The values for two historic cruises from 1957 and 1982 confirm this behaviour.

All hydrographic data of the Atlantic Ocean will be assembled to produce a coherent and consistent data set of the thermohaline status for the WOCE period. This data set will be used to produce a printed and an electronic atlas of all measured and some derived properties in order to describe the thermohaline circulation of the Atlantic Ocean which plays an eminent role for the climate particularly of Northern Europe. The atlas details will follow closely those used by other groups who work on similar projects for the other oceans, i.e. the Pacific, Southern and Indian Ocean. Thus, finally there will be a complete global set of all hydrographic data, including tracers. In addition we will complement the WOCE hydrographic data with data of comparable quality for earlier periods, i.e the pre-WOCE period and earlier to quantify changes in properties and derived properties and to describe their origins on decadal time scales. As a reference period the WOCE period 1990-1997 will be uniformly used.

The WOCE Hydrographic Programme Special Analysis Centre was a joint project between Max-Planck-Instituts für Meteorologie and BSH. The hydrographic dataset of the World Ocean Circulation Experiments were analyzed for consistency and gridded using both optimal interpolation and assimilation into a global LSG (Large Sale Geostrophical) model.