Anomalous glacier responses to 20th century climatic changes in Darwin Cordillera, southern Chile

Abstract

BSTRACT, Th ere is a n as ymm etri c pa ttern res ponse o f g lac iers in Darwin C ordill e ra (54-55° S, 69-71 ° \ \') to th e clim a te o f th e 20 th ce n t ur)" Thi s asy mm e try is suggested he re as a ca use of a n in c reased wind ac ti\'ity II'hi c h has a pro no unced OJ'ogra phi c effec t. Altho ug h clim a ti c reco rd s for th e las t 50 yea rs show a warming trend , as we ll as no trend in prec ipitation in th e a rea, so me glac ie rs a re ad\'a ncing , Th e a rea is cha rac te ri zed by stro ng clim a ti c g radi e nts, with hi gh ra tes o f prec ipita tion on th e so uthwes te rn sid e of th e ra nge a nd dry co nditi o ns on th e no rth e rn sid e, Glaciers on th e north ern a nd eas tern sid es shO\\' a ge nera l tre nd of recedin g fro nts, " 'ith a fe w exce pti ons, th ese g lac iers ha \'e g ra duall y a nd uninterruptedl y bee n shrinking sin ce th e turn of th e ce ntury, On th e so uth ern rim, th e prese nt extents o f som e glaciers are simil a r to th eir 20th ce ntury m ax imum extents, Th ese a re, in turn , simil a r or close to th e H oloce ne maximum, Th e m os t extrem e sites a re th e g lac ie rs o n eith er sid e of :do unt D a r\\'in , II'hich is 2469 m hi g h, Th e no rth -fac ing glacie r V e nti squ ero :'1a rinelli has retrea ted se\'e ra l hundred m e tres per yea r o \, er th e las t twO d ecades, \\'hile th e so uth-fac ing g lac iers in th e Pa hi a Pi a bas in ha \'e ach'a nced durin g th e sa me peri od ,In thi s stud y, th e fro nta l c h a nges o\'e r th e las t 50 years of 20 g laciers ha \'e b ee n a na lysed , A e ri a l ph o togra ph s (\'e rti ca ls) fr om 194 3 a nd 1984 ha ve bee n used , as w ell as obliqu e a e ri a l ph otog ra ph s fr o m ]993 , Th e ge neral res ult is th a t glac iers with acc umula ti o n a reas fac ing so uth a ndll'es t sho \\' so m e\\'ha t sta bl e fr o nts, \\'hil e g lacie rs fac ing eas t a nd no rth sho\\' receding front,

Synchronous acceleration of ice loss and glacial erosion, Glaciar Marinelli, Chilean Tierra del Fuego

“…The dramatic recession of Glaciar Marinelli in the latter half of the 20th century is in stark contrast to the general pattern of standstill or minor recession of calving and non-calving glaciers around the Cordillera Darwin (Holmlund and Fuenzalida, 1995), and in particular to the slow advance of the south-facing glaciers of Bahia Pia, which drain the other side of Monte Shipton (personal communication from C. Porter, 2006). Holmlund and Fuenzalida (1995) first documented the exceptional retreat of Glaciar Marinelli, noting that a relatively warm 20th century may have caused significant thinning of the glacier tongue through ablation, while the glacier continued to be grounded on the terminal moraine.…”

“…Climate records at Bahia Felix and Punta Arenas, 220 km and 180 km to the west and northwest of Marinelli fjord, show a slight decrease in annual precipitation starting in 1920 (Holmlund and Fuenzalida, 1995), but no significant change in seasonality. Records from Punta Arenas and Puerto Williams (135 km to the southeast) also indicate a sustained regional warming since 1915 and a relatively dry period around Tierra del Fuego in the mid-1960s (Porter and Santana, 2003).…”

“…Meteorological gradients across the Cordillera Darwin are steep, with heavy precipitation and solid cloud cover being typical over the southern and western fjords, and drier conditions to the north and east (Holmlund and Fuenzalida, 1995;Porter and Santana, 2003). Automated weather stations recently deployed by the University of Magallanes show annual precipitation averages of 1600 mm at Bahia Pia, in the southern part of the range, dropping to 800 mm at Seno Almirantazgo, just north of Marinelli fjord (personal communication from A. Santana, 2005).…”

“…Holmlund and Fuenzalida (1995) first documented the exceptional retreat of Glaciar Marinelli, noting that a relatively warm 20th century may have caused significant thinning of the glacier tongue through ablation, while the glacier continued to be grounded on the terminal moraine. When the glacier front thinned sufficiently in the latter half of the century, the ice broke up quickly and the front retreated rapidly.…”

Glacial retreat in the Baspa basin, Himalaya, monitored with satellite stereo data

“…Meltwater from these glaciers forms an important source of run-off in northern India during the summer months. This run-off is likely to change, as extensive glacier retreat is reported in the Himalaya and other parts of the world (Dhobal and others, 1995;Holmlund and Fuenzalida, 1995). Himalayan glacier retreat is normally difficult to study due to the rugged, mountainous terrain, but remote sensing offers a useful tool that can be used to assess information about glacier features such as accumulation area, snowline and moraine-dammed lakes (Kulkarni,1991).…”