This is the author accepted manuscript. The final version is available from The International Glaciological Society via http://dx.doi.org/10.3189/2015JoG14J123AbstractRepeated measurements of density profiles and surface elevation along a 515 km traverse of the Greenland ice sheet are used to determine elevation change rates and the error in determining mass-balance trends from these rates which arises from short-term fluctuations in mass input, compaction and surface density. Mean values of this error, averaged over 100 km sections of the traverse, decrease with time from the start of observations in 2004, with a half-time of ∼4 years. After 7 years the mean error is less than the ice equivalent mass imbalance.This
project
is
a
contribution
to
the
calibration
and
validation
of
the
European
Space
Agency
(ESA)
CryoSat
satellite
altimeter
and
is
supported
by
ESA
and
by
the
UK
Natural
Environment
Research
Council
(NERC)
Consortium
grant
NER/O/S/2003/00620.
We
are
grateful
to
the
NERC
Geo-
physical
Equipment
Facility
and
the
University
of
Edinburgh
for
the
loan
of
Leica
GPS
systems.
Logistic
support
for
the
traverses
was
provided
by
CH2M
HILL
Polar
Services,
G.
Somers,
J.
Pailthorpe,
H.
Chamberlain,
M.
Hignell
and
J.
Sweeny
gave
invaluable
assistance
in
the
field
and
T.
Benham
provided
Figure
1.
Finally,
we
thank
R.
Arthern
for
useful
discussions
and
our
Scientific
Editor,
H.
Fricker,
and
two
anonymous
reviewers
for
helpful
comments
