Terminus recession, proglacial lake expansion and 21st century calving retreat of Tasman Glacier, New Zealand

The Tasman Glacier is the largest glacier in New Zealand. Although 20th century warming caused down-wastage, it remained at its Little Ice Age terminus until the late 20th century. Since then, rapid calving retreat (U-r ) has occurred, allowing a large (5.96 x 106 m2) proglacial lake to form (maximum depth similar to 240 m). From sequential satellite image analysis and echo sounding of Tasman Lake, we document (U-r ) from 2000 to 2008. U-r varies temporally, with mean U-r of 54 m/a from 2000 to 2006 and a mean U-r of 144 m/a from 2007 to 2008. Consistent with global data sets, calving rate appears closely associated with lake depth at the calving terminus.