A Landsat-assisted study of the aquatic areas of the Lake Kemijärvi region,Northern Finland

Landsat MSS imagery is employed to assess the aquatic complexes of the regulated Lake Kemijärvi and the adjoining small natural lakes in Northern Finland.Ground data were collected from within the hydrolittoral areas to allow the evaluation and revision of the computer-aided Landsat MSS classification. The major developments reported here are: (1) the utilization of the computer-aided technique for surveying natural and regulated aquatic areas, (2) the recognition of different aquatic units and complexes defined by depth relations, bottom quality, vegetation coverage or flooding stage, and (3) the presentation of the lower limit of satellite data applicability for mapping small-sized and complicated areas.Although the low spectral and ground resolution levels place restrictions on the use of computeraided Landsat MSS data remote sensing for the parametric mapping of all aquatic phenomena, such data are still of value under circumstances in which ground data collected from a small number of reference areas can be extrapolated to apply to the surrounding lakes and aquatic areas within a single MSS frame. Studies of this kind also facilitate the multitemporal inspection of changing regulated lake environments, due to the long-term nature of the Landsat project.