M. Aniya et al., THE USE OF SATELLITE AND AIRBORNE IMAGERY TO INVENTORY OUTLET GLACIERS OF THE SOUTHERN PATAGONIA ICEFIELD, SOUTH-AMERICA, Photogrammetric engineering and remote sensing, 62(12), 1996, pp. 1361-1369
A Landsat TM mosaic of the Southern Patagonia Icefield (SPI), South Am
erica, was utilized as an image base map to inventory its outlet glaci
ers. The SPI is South America's largest ice mass with an area of appro
ximately 13,000 km(2). The icefield does not have complete topographic
map coverage. With the aid of stereoscopic interpretation of aerial p
hotographs and digital enhancement of the Landsat TM image, glacier di
vides were located and glacier drainage basins were delineated, giving
a total of 48 outlet glaciers. Employing a supervised classification
using Landsat TM bands 1, 4, and 5, glacier drainage basins were furth
er divided into accumulation and ablation areas, thereby determining t
he position of the transient snow line (TSL). After comparing with exi
sting data, it was found that the TSL could be taken, for practical pu
rposes, as the equilibrium line (EL). The position of the TSL was then
compared with topographic maps, where available, to determine the equ
ilibrium line altitude (ELA). Altogether, 11 parameters relating prima
rily to glacier morphology were inventoried. Pio XI Glacier (1265 km(2
)) is found to be the largest outlet glacier in South America, and may
also be its longest. The average accumulation area ratio of 0.75 is l
arger them those of the Northern Patagonia Icefield and European glaci
ers. All but two outlet glaciers calve into fords or proglacial lakes.