Specifications

Field procedures

Ablation and velocity stakes

A network of 14 ablation and surface velocity stakes distributed along the central flow

line has been established in spring 2008 on the outlet glacier of the A.P. Olsen ice cap

and along three transects at elevations of approximately 675, 900 and 1300 m (figure 1

and table. 1) respectively. Each 6 m long stake was assembled from 2 m lengths of

aluminium tube. A Kovacs drill was used with success, allowing very fast drilling

operations.

ID LAT LONG

01 N7437.1293 W02121.8890

02 N7437.4536 W02123.0806

05 N7438.3637 W02125.6941

04 N7437.9356 W02123.9705

03 N7437.6633 W02122.1934

06 N7438.5687 W02125.3384

08 N7438.9168 W02128.2411

07 N7438.5616 W02129.0397

10 N7439.6703 W02133.1732

09 N7439.2688 W02130.5855

12 N7439.7398 W02136.0492

11 N7439.0492 W02136.2686

13 N7440.5023 W02136.3062

14 N7439.8511 W02140.4234

Tab. 1 – Position of the ablation and displacement stakes.

The stakes must be measured and re-drilled every year following this procedure

(assuming the current planning of only one visit per year in springtime):

1. upon approaching an existing stake, take a picture documenting the undisturbed

site

2. measure the length of the stake above the snow surface

3. place the GPS antenna on top of the existing stake and start a measurement with

the most accurate survey mode available (see GPS section)

. If tilted, note attitude.

4. take a note of stake number, date, time, picture number, air temperature, GPS

survey mode being used for the precision survey and GPS fix from the handheld

5. probe with an avalanche probe the snow depth in the immediate surroundings of

the stake and record all measurements, not just the average