exist that reach
back to early 19th century but most series are much shorter (Hamlington and Thompson, 2016). In
contrast, satellite altimetry has only been available since the early 1990’
s. Satellite altimetry mea-
sures the sea surface height, namely the sea level compared to a fixed reference frame (the center of
the earth, the geoid or a reference ellipsoid) for latitudes up to 66 N and
S (ESA
/media/vedurstofan-utgafa-2020/VI_2020_005.pdf