Continued northward expansion of the Ross Ice Shelf, Antarctica

The last major calving event along the Ross Ice Shelf (RIS, Antarctica) front occurred a decade ago, following a substantial increase in the rate of ice-front advance in the few years preceding the event. This "B-9" event, on the eastern part of the front between Edward VII Peninsula and Roosevelt Island, removed approximate to 5100 km(2) of ice, about 100 years of advance in that sector, but reduced the ice-shelf area by only 1 %. Since 1987 the entire ice front has continued to advance, more than regaining the area lost during the B-9 event. The western front is now well north of any position recorded during the last 150 years, and it has not experienced major calving for at least 90 years. Ice-front heights generally decrease from east to west, but local variability is high. Elevations are relatively low from 171 degrees to 177 degrees W; the location of "warm" Modified Circumpolar Deep Water circulation beneath the outer ice shelf. Modern heights considerably exceed historical heights between 179 degrees Wand 178 degrees E and are lower west of 174 degrees E, probably due to recent dynamic changes such as rifting and the western advance. The general advance of the RIS front and the period of several decades to more than a century that elapses between major calving events is consistent with a relatively stable ice front. This contrasts with several smaller ice shelves along the Antarctic Peninsula and McMurdo Ice Shelf in the Ross Sea which have retreated substantially during the past few decades.