50 years of ice-front changes between the Ade¨ lie and Banzare Coasts, East Antarctica Massimo Frezzotti ,Marco Polizzi ENEA, Centro Ricerche Casaccia, P.O. Box 2400, I-00100 Rome, Italy ABSTRACT . Ice-front change may well be a sensitive indicator of regional climate change. We studied the coastal sector of Wilkes Land, East Antarctica, along the Ade¨ lie and Banzare Coasts, extending from Buchanan Bay (6705’ S, 14430’ E) to Porpoise Bay (67 S, 128E). The glaciers in this area drain the northern part of Dome C (area 270000km 2 ). A comparison of maps, photographs and satellite images, dated several years apart, led to an estimation of the fluctuations of 18 ice fronts over the 50 years 1947^97.The area of the floating glaciers in 1963 was 3035 km 2 , and in 1989, 2785 km 2 .The main glaciers in the area are Ze¨ le¨ e, Astrolabe, du Franc° ais, Commandant Charcot and Pourquoi Pas for the Ade¨ lie Coast, and Dibble, May, Sandford and Frost Glaciers for the Clarie and Banzare Coasts. Most of the floating glaciers have shown cyclical behaviour without a marked trend, but a general reduc- tion since 1947. The reduction in the area of floating glaciers since the 1950s may be linked to changes in ice^ocean interaction, as noted for the floating glaciers of the GeorgeV Coast and the CapeAdare area, and sea-ice extent.The calvingbehaviourof the main glacier tongues is characterized by an accumulation of icebergs projecting from the coast to form iceberg tongues, held in place by grounding and joined together by annual or perennial fast ice. INTRODUCTION The effects of global climate change may prove to be more pronounced in Antarctica than at mid-latitudes (Weller, 1993). Floating glaciers (ice shelves, ice tongues and glacier tongues) are sensitive to atmospheric warming, as shown by the recent spectacular break-up of ice shelves around the Antarctic Peninsula (Rott and others, 1996; Vaughan and Doake,1996), which demonstrates the existence of an abrupt thermal limit on ice-shelf viability associated with regional atmospheric warming (Skvarca and others,1998).Vaughan and Doake (1996) and Frezzotti (1997) have pointed out that the extent of floating glaciers may well be a sensitive indicator of regional climate change. The uncertainty still existing about iceberg-calving processes makes it difficult to determine the present ice-sheet mass balance (Jacobs and others,1992). In this research we studied 18 glaciers that drain along Wilkes Land (Fig. 1). The coastal study area includes: the Ade¨ lie Coast, the Clarie Coast, the part of the George V Coast extending from Buchanan Bay (6705’ S, 14430’ E) to Point Alden (6648’ S, 14202’ E), which was not examined in a previous paper by Frezzotti and others (1998), and the por- tion of the Banzare Coast between Cape Morse (6615’ S, 13010’ E) and Frost Glacier (6705’ S, 129 E). The Ade¨ lie Coast is the portion of Wilkes Land lying between Point Alden and Pourquoi Pas Point (6612’ S,13611’ E).The Clarie Coast is the portion of Wilkes Land lying between Pourquoi Pas Point and Cape Morse. The Ade¨ lie and Clarie Coasts were discovered inJanuary 1840 by Capt. J. Dumont d’Urville, and named, respectively, for his wife Ade¨ lie and for the wife of the captain of his second ship, Clarie. The Banzare Coast was seen from the air by the 1929^31 British^Australian^New Zealand Antarctic Research Expedition (BANZARE) under Sir D. Mawson. The study area is approximately 1200 km in length. The ice shelves and glacier tongues of this area are fed from glaciers that drain the northern part of Dome C (7506’ S,12323’ E). A description of coastline changes since 1947 is provided in this paper. Satellite image analysis of ice- berg-calving frequency and ice-front change along the coast Annals of Glaciology 34 2002 # International Glaciological Society Fig. 1. Sketch map of Wilkes Land. 235