| Summary: | Surface albedo has a great influence on Earth's energy balance, because it determines the relation between reflected and absorbed solar radiation on the ground. Therefore it is important to examine the factors which have a high influence on the surface albedo. One of these factors is snow cover. The albedo difference between snow covered and snow free ground in tundra areas is usually around 0.6. Therefore, by slowing or delaying the snowmelt process, it is possible to decrease the amount of absorbed solar energy on the earth surface. The main goal in this study is to examine the influence of vegetation on snowmelt timing and through this on the surface albedo in Northern tundra areas. This is done by studying first the vegetation on the ground using Corine Land Cover 2006, Globcover 2009 and Landsat products. Then, statistical analyses of different time series remote sensing products such as MODIS, Globsnow and Landsat, considering the vegetation, snowmelt and surface albedo are done. The test site is located in the Northern parts of Norway and Finland, where tundra vegetation is the most common land type. A comparison of NDVI, fractional snow cover and albedo between the Finnish and the Norwegian side of the test area is done, based on a presumption, that vegetation on the Norwegian side is denser than on the Finnish side. The results of this work indicate that indeed vegetation is more abundant, and also snow melts faster on the Norwegian side. This of course has an affect also on surface albedo, which is lower on the Norwegian side during the melting season. Lower albedo causes higher solar energy absorption on the Norwegian side. The magnitude of this difference in the absorbed energy between the Norwegian and the Finnish side is calculated in this study. Pinta-albedo vaikuttaa suuresti maapallon energiatasapainoon, koska se määrittää maan pinnalta heijastuneen ja pinnalla imeytyneen auringon säteilyn välisen suhteen. Tämän takia on tärkeää tutkia niitä tekijöitä, jotka vaikuttavat olennaisesti maan ...
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