1. Scientist, Christian Michelsen Research AS, Fantoftvegen 38, Bergen 5072, Norway.
2. Department Manager and Scientist, Christian Michelsen Research AS, Fantoftvegen 38, Bergen, Norway (corresponding author).
3. Scientist, KTN AS, Gravdalsveien 262, Laksevåg 5165, Norway.
4. Senior Scientist, Christian Michelsen Research AS, Fantoftvegen 38, Bergen, Norway.