The results are presented from a technological experiment on computer-based digital transmission of Soviet satellite imagery via telephone lines from Moscow to Helsinki. The images have been used for real time sea ice mapping purposes.Particular features of the specific hardware and software are outlined. Time and cost values of the satellite data transmission via standard common-use telephone lines are given. The assessment for effectivity of experiment technologies for operational purposes in Finland is given. The system has been tested for aiding in the operational ice charting in the Baltic Sea. Also a particular test was performed in connection with the Finnish Antarctic expedition FI"ARPS9.Examples of transmitted images and technology exploitation features are presented. The ways to improve the telephone line image transmission technology are outlined. 829

ABSTRACT. Results are presented from an experiment concerni ng operatio na l space-borne ice charting based on the Russian O cean and R esource sa tellite sys tems. The surface truth consisted of routin e operational data, helicopter-borne reconn aissance, and some ground measurements. Examples of th e satellite im age ry a re given a nd identifica tion of ice types is described. Cluster-a na lysis has been used [or a utomatic im age segmenta tion. The po tential of these satellites in operational ice charting is discussed. A 160 m resolution optical scanner and a 2 km resolution rad ar a re found to be very useful complements to the present routine system.

Preliminary results from the usage of satellite digital ice data transmission technology for the purposes of an experiment over the Gulf of Bothnia, Baltic Sea are presented. The methodology and algorithms for computerized identification of ice types are discussed. The method of cluster-analyses has been used for ice field image segmentation in order to separate regions which are quasi-homogeneous in spectral-textural signatures and belong to particular ice types. The efficiency of this method is analysed. The cluster-analysis method has been used for processing satellite data from moderate spatial resolution scanners to generate ice charts automatically. On the contrary to standard subjective methods for ice chart generation, computer based systems enable to construct more detailed and objective ice classification maps. Examples of multispectral objective clustering of ice fields are given. Results from comparison between such clustering and operational ice maps are discussed.

ABSTRACT. Results are presented from an experiment concerni ng operatio na l space-borne ice charting based on the Russian O cean and R esource sa tellite sys tems. The surface truth consisted of routin e operational data, helicopter-borne reconn aissance, and some ground measurements. Examples of th e satellite im age ry a re given a nd identifica tion of ice types is described. Cluster-a na lysis has been used [or a utomatic im age segmenta tion. The po tential of these satellites in operational ice charting is discussed. A 160 m resolution optical scanner and a 2 km resolution rad ar a re found to be very useful complements to the present routine system.