Marine climate
Dansk version

Climate of Greenland

A research project has been performed in coorporation with the Danish Climate Centre with the aim to establish a data and knowledge base on the expected climate changes in the Greenland and the surrounding seas. DMI's regional climate model was used to calculate a scenario of the climate for the period 1960-2050. The contribution of DMI was simulations with a regional ocean model forced with the climate scenario. One purpose of the ocean fields, besides the analysis of the hydrography, is to provide a background for studies of the Greenland ocean environment. The fields can thus be used to drive ocean biological, and chemical models which depends on the physical paramters of the ocean.

Read more about the project on: klimagroenland.dmi.dk.


Contact: Nicolai Kliem nk@dmi.dk, Mads Hvid Ribergaard mhri@dmi.dk


Oceanographic investigations off West Greenland

The West Greenland area is the commercial most important for fishery. These waters are strongly affected by incoming water masses from both Polar and temperate regions, which have large impacts on the marine productivity over the Greenland shelf area. It is the strength of these currents that determine the hydrographic conditions around the Southeast and West Greenland fishing banks. Thereby changes in the North Atlantic circulation have large impact on the distribution of species and thereby the fishery.

Every year in June/July, the Danish Meteorological Institute, preforms oceanographic investigations off West Greenland as part of a contract with the Greenland Institute for Natural Resources. In the last several years, the Danish Naval Defence has supported shiptime onboard their inspection-cutters for this work.

Temperature and salinity is measured on 30 stations on 6 sections from Cape Farewell in south to Sisimiut in north. Some of these measurements has been taken regularly from 1950, which is unique for the area. This gives the opportunity for studying the oceanographic climate fluctuations and its relation on the local fishery. The results form these investigations is taken into consideration by the Greenland Institute for Natural Resources when they give their recommendation for the regulation of the fishery.

 In the past few years, DMI has also taken hygrographic measurements inside different West Greenlandic fjords. The reason is an increaded fishery on snow craps, which growth is largely influenced by the bottom temperature, which is very different in between fjords – mainly determined by the sill depth – but also by runoff, the hydrography outside the fjord, etc.

Scientific reports is found here.


Contact: Mads Hvid Ribergaard mhri@dmi.dk


Transport of fry in Greenland waters

The transport of Halibut from eggs, to larvae and finally as they settle at the bottom is studied using oceanographic modelling. The time from spawning to hatching is made dependent on temperature, which is determined by empirical relations. Moreover the eggs is supposed to be found near the pycnocline. Likewise, the growth of halibut larvae is made exponential dependent on temperature and they are assumed to settle from the surface when reaching a fixed weight.

Further information here.

 

Historical, the cod fishery has been the most important industry for Greenland, but a collapse around 1970 forced the fishermen to search for alternatives. One of the most important spawming grounds is found southwest of Iceland. The cod eggs and larvaes are mainly tranported north of Iceland, but a minor fraction ends up in Greenland. In the 1950s and the early 1960s this transport were important in maintaining the Greenland cod stock, but since it was reduced. In the last couple of years the Greenland cod stock has increased likely due to this transport. The transport of cod eggs and -larvae are studied using oceanographic models and observations.

Source: report.


Contact: Mads Hvid Ribergaard mhri@dmi.dk

 

Exchange of water masses between the Atantic and the Nordic Seas

The Nordic Seas, situated between Greenland and Norway, is an important part of the global thermohaline circulation, which brings warm water northwards to the northwestern european coast and gives us our relatively mild climate. In the Nordic Seas, the water masses have become so dense that they sink to great depth and return sourthwards.

COI apply global ocean models to investigate changes and other characteristics of this circulation. This is not an easy task because the topography of the sea floor in the area is complex. The most important obstacle to the free exchange of water masses is the undersea ridge extending from southern Greenland via Iceland and the Faroes to Scotland.

There have been considerations about rising temperatures and more precipitation in the Nordic Seas would slow down the sinking and thereby the entire thermohaline circulation, which would influence the climate of western Europe. Our model calculations show that the slow down has been at minimum during the past half century. 

Contact: Steffen Olsen, smo@dmi.dk, Torben Schmith, ts@dmi.dk


Slow climate variations

The temperature of the atmosphere have risen by app. 0.8 degrees since the beginning of the previous century. This has not been a steady rise: the temperature rose rapidly intil around 1940, from when it was constant or slightly decreasing to about 1970 and from then again rising. This means that our emission of greenhouse gasses from burning of coal, oil and petrol can not be the whole explanation – there must be additional factors causing the climate to vary slowly.

A closer analysis shows that the warming in the 1940es was particularly strong in the North Atlantic and the Arctic. DMI have contributed to the understanding of these variations by reconstructing the export of sea ice from the Arctic Ocean through the Fram Strait along the east coast of Greenland. We have also used global ocean and climate models to understand the variations. These model studies show that the ocean ‘by itself’ is able to produce climate variations with a period between 50 and 100 years.

 

Contact: Steffen Olsen, smo@dmi.dk, Torben Schmith, ts@dmi.dk








October 16, 2007