Metadata file for sea-ice topographic data.

The surface topography (elevation of ice or snow surface 
above sealevel or a reference water level, depth of melt 
ponds) has been determined along two profiles at regular 
time intervals (roughly once every ten days) during the 
ablation season in 1998. Profile 1 was located in level 
second-year ice parallel to the ocean hut line towards 
Sediment City. Profile 2 was located in deformed multi-
year ice extending at a right angle from The Pass (through 
the active ridge separating the Des Groseilliers from the 
location of the main camp) towards the logistics huts. At the 
endpoints of both profiles marker poles had been installed 
and the profile itself was left undisturbed during the entire 
time period (no drilling of holes, no foot or vehicle traffic 
except for measurements). The maximum co-location error 
between measurement points along the profile at different 
time intervals is estimated at <0.5 m along-profile and <2 m 
across-profile. 
Pond depth measurements were carried out with a meter 
stick (error <10 mm). Surface elevation of the ice or pond 
surface was determined with a laser levelling device 
(maximum error <10 mm). Surface elevation has been 
measured relative to the water level in core holes or ponds 
in communication with the free water column (data have not 
been corrected for density structure of water column in hole 
or pond). For the data compilation, no effort has been made 
to distinguish between melting snow and melting ice 
surfaces. Stable-isotope data indicate, however, that only 
traces of snow were present along the profiles after day 
175, such that surface elevation data collected after this date 
reflect the elevation of the ablating ice surface relative to the 
reference water level.
Data files indicate the day of the year in 1998 during which 
measurements were taken (digits 2-4) and the profile 
number (digits 5-6).
The first column indicates the location of the measurement 
point along the profile in meters. The second column gives 
the depth of melt ponds at that location in meters (if present, 
lack of data in this column indicates that no melt pond was 
present at this location). The third column gives the surface 
elevation of either the snow/ice surface or the melt pond 
water surface in meters.
The data block is preceded by a header of two lines
indicating the location and day (line 1) and identifying
the column variables and units (line 2).
Note that in file T166P1, the water depth (at all locations 
where meltwater is present) indicates the depth of the 
meltwater table in the snow cover. The same holds for 
water depth data in file T173P1 at locations 24 to 26 m, 66 
to 71 m, 77 to 79 m, at 84 m and at 89 m along the profile, 
as well as in File T170P2 at locations 54 to 57 m along the 
profile. In all these cases, the surface elevation refers to the 
top surface of the snow cover.