Ice dynamics (Movie)

This ERS-1 SAR image has been acquired on 5-2-1994 over the Gulf of Finland.
A series of images have been gathered over the same area between 5-2-1994 and 25-3-1994.
At the beginning of the video
, the part of the Gulf of Finland that is visible is almost completely covered with ice. The only major open water area is in the coast of Estonia. The ice cover has lately broken in large areas showing white stripes of open water.
The ice mass moves then mainly eastwards (5-8. Feb) and open water areas are covered with black new ice.
Open water areas appear again in the coast of Estonia but they are closed by ice movement quite soon in the middle of February.
The direction of ice movement changes in the end of February causing more rafting and reshaping of the ice fields. Leads (white) have been formed between new (black) and old (grey) ice areas 20-23. Feb).
Larger areas of deformed ice start to form in the beginning of March and look textured light grey. The ice field breaks again into smaller areas with new ice patches in between.
The ice mass moves then northwards and a lead opens between the drift ice and the fast ice in the Estonian coast (7 Mar). Ridging takes place close to the fast ice in the Finnish coast at the same time.
Further deformation occurs when the ice edge in the Estonian coast moves towards North East. The main drift ice field moves then again southwards thereby closing the open water area.
In the end of March (25. Mar) a large lead opens between the drift ice and the fast ice in the Finnish coast and freezes directly.
In the last frame it is possible to detect in the middle of the image on top of each other two darkish areas surrounded by deformations. These are very smooth level iceareas with only few ridges. The light textured areas West of the two dark areas contain heavily deformed rubble fields. The ice deformed is very old and in places more than 50 cm thick. The long and narrow light lines seen in several images are ship tracks.
Einar-Arne Herland VTT Space technology (Finland)

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry