A 21-year record is presented of surface mass balance measurements along the K-transect. The series covers the period 1990-2011. Data are available at 8 sites along a transect over an altitude range of 390 - 1850 m at approximately 67° N in West Greenland. The surface mass balance gradient is on average 3.8 x 10**-3 m w.e./m, and the mean equilibrium line altitude is 1553 m a.s.l. Only the lower 3 sites within 10 km of the margin experience a significant increasing trend in the ablation over the entire period.

Supplement to: van de Wal, Roderik S W; Boot, Wim; Smeets, Paul C J P; Snellen, Henk; van den Broeke, Michiel R; Oerlemans, Johannes (2012): Twenty-one years of mass balance observations along the K-transect, West-Greenland. Earth System Science Data, 4(1), 31-35