Scientific Goals

Some Basic Facts:

• The South Patagonia Ice Cap is a poorly understood region with no accurate maps.
• Remote sensing is a powerful analysis tool. However, good ground control is essential for improving map information; enabling researchers to conduct further studies using improved maps.
• There is one glacier in the study area at its Neoglacial maximum: the Pio XI (Bruggen) Glacier. This is the only glacier in the world with this condition.
• Overall the ice cap has shrunk by 4% over the last 40 years
• Of the 23 glaciers monitored by Forster, et al. using SAR, many showed no change between 1992 and 1997, seven showed obvious retreat (of up to 1 km on Upsala Glacier), and four showed oscillating behavior of both advance and retreat during that time, eg. Greve Glacier.

Our Scientific Goals:

• We intend to provide the first accurate basemap of the region that will be tied to the WGS84 datum horizonatally and GEOID96 vertically using at least 10 control points. We will use the ERDAS SAR RADAR module to accomplish this for the radar imagery.
• We will climb to Cerro Lautoro and survey its summit using GPS. This is one of the highest points on the ice cap and has been climbed several times despite being an active volcano.

• We will attempt to photograph, collect spectrometer and GPS data for areas representative of Forster et al's four "radar glacier zones":

1. (zone A) a relatively dry snow zone with dominant C band returns;
2. (zone B) a moderately wet snow zone with dominant L band returns;
3. (zone C) a wet snow zone with weak returns in all bands; and
4. (zone D) bare ice and/or heavily crevassed surfaces with strong returns in all bands.

• We will attempt to ground verify the existence of 3 C-band radar signatures visible in the RADARSAT Imagery.

1. melting wet snow (low C-band return),
2. cold dry snow (dominated by C-band volume scatter),
3. rough bare ice (strong C-band).

• Finally, we hope to provide some useful data to help answer the fundamental question: How much of the recent change seen in these glaciers is an indication of global warming and climatic change?

References:

1. Forster, R.R., B.L. Isacks, and S.B. Das, 1996, Spaceborne imaging radar (SIR-C/X-SAR) reveals near-surface properties of the South Patagonian Icefield, J. Geophys. Res. (Planets), 101, 23,169-13,180.

 2. Forster, R..R., L.C. Smith, and B. L. Isacks, 1997, Effects of Weather Events on X-SAR Returns from Icefields: A Case study of the Hielo Patagonico Sur, in press, Ann. Glaciology.

3. Smith, L.C., R.R. Forster, and B.L. Isacks, 1997, Seasonal climatic forcing of alpine glaciers revealed by orbital synthetic aperture radar, in press, J. Glaciology.