River ice

Participating scientists

  • Tom Kokkonen

In fall 2011 a research project of the River Kymijoki ice conditions was commenced. The whole ice season is covered and the river is examined trough all its length, from the central lake district to the Gulf of Finland. The estuary area is examined in our Baltic Sea research.

Research goals

The aim of this study is to increase the understanding of ice conditions and the ice season of the River Kymijoki. The main interests in this research are ice cover formation and structure, frazil ice, influence of the ice cover on the river discharge, mixing and water quality.

Study site

River Kymijoki is located in southeast Finland and it freezes annually. It is the fourth largest river in Finland by its discharge and catchment area. The catchment area is 37 107 km² which is 11 % of the area of Finland. The lake percentage of the river catchment is 19 %. The river divides into two different main branches, and both of them further divide into two different branches before the river reaches the Gulf of Finland, Baltic Sea. The length of the river is approximately 200 km and it drops 78.5 m across this distance.


The research is made by field trips to the River Kymijoki during the ice season. Field measurements include sounding by CTD and ac-9 spectrophotometer. Also water and ice samples are taken for the further analyses of the crystal structure of ice and the chemical properties of water and ice. Measurement points are selected so that there are points in every divided branch and several in the main branch. That way we can have a good overall understanding of the River Kymijoki ice conditions.

Field measurements at the River Kymijoki

Field measurements at the River Kymijoki, 12th March 2012

Crystal structure of River Kymijoki ice

Crystal structure of River Kymijoki ice cover