Abstract A large number of multispectral and stereo-image data are expected to become available as part of the Global Land Ice Measurements from Space project. We investigate digital elevation model extraction, anisotropic reflectance correction and selected glacier analysis tasks that must be developed to achieve full utility of these new data. Results indicate that glaciers in the Karakoram and Nanga Parbat Himalaya, northern Pakistan, exhibit unique spectral, spatial and geomorphometric patterns that can be exploited by various models and algorithms to produce accurate information regarding glacier extent, supraglacial features and glacier geomorphology The integration of spectral, spatial and geomorphometric features, coupled with approaches for advanced pattern recognition, can help geoscientists study glacier mass balance, glacier erosion, sediment-transfer efficiency and landscape evolution.
Monitoring glacier variations by our GLIMS (Global Land Ice Measurements from Space) Regional Center for Southwest Asia (Afghanistan and Pakistan) shows unusual fluctuations over a 40-yr period for Batura Glacier. We use multiple field measurements (1984, 1991, 1992, 1993), maps and the work of others (1966, 1974, 1975, 1978, 1980), and satellite imagery (KH-9 Lower Resolution Mapping Camera 4/Aug/1973; Landsat MSS 15/Jul/1979; SPOT 20/ Jun/1990; Landsat 5 TM 15/Oct/1992; Landsat 7 ETM 29/Oct/2000 & 30/ Sep/2001; ASTER 29/Oct/2003 & 13/Sep/2004). The terminus was at the Hunza River in late 19 and first half of 20 century and then retreated rapidly ~800 m by 1966, leaving behind prominent end moraines on the north terminus. Orthorectified declassified KH-9 imagery of 1973 shows variable widths on Batura Glacier that were spurious and the result of preprocessing error. Orthorectification was useful for point-to-point comparisons between multitemporal scenes, but not for within-scene comparisons or measurements. Batura does not surge and kinematic waves have not been detected. An ice cliff had formed at the terminus in 1966, advanced forward 100 m and thickened by 15 m by 1975, and advanced another 33 m by 1978. Then instead of advancing as predicted by Chinese scientists, by 1984 the frontal ice cliff had retreated 50100 m, declined in slope angle, and was covered with debris and vegetation, which makes the slope still visible on recent imagery. Our orthorectified imagery shows that from 1973 – 2004 the front of the white ice stream from the first ice fall on the right (south) side underwent retreat of ~2846 m, (retreat rate of 92m yr), mainly through down-wasting increase of debris cover and new melt-water lakes. Similarly the terminus underwent ~392 m of retreat from 1973 – 1990 (~23 m yr annual retreat rate), ~36 m retreat from 1990-1992, (~18 m yr annual retreat rate), and a ~37 m advance (~3 m yr annual advance rate) from 1992-2004. High-resolution imagery on Google EarthTM acquired in 2007 shows an exposed-ice terminus that has advanced ~50 m from 2004 on. A large new ice cliff has emerged on the southeast side ~ 275 m behind the present ice terminus, even while the parent south white-ice-stream source continued to retreat up-ice. The Chinese Batura Glacier Investigation Group used mass balance and tree-ring data in the 1970s to predict glacier advance from the 1970s, cessation in 1991 – 1997, and retreat for 20 – 30 years thereafter. Global cooling was hypothesized with advances again by 2060, but the actual situations have been otherwise. Glacier massbalance regime change is suggested by apparent increased summer monsoonal precipitation, which falls as snow >~5000 m, and renewed terminus advance from beneath an increasingly protective debris cover, even while the lowermost white-ice stream continues to retreat through increased down-wasting during possible global warming. This map, done for an unpublished summary paper of glacier-terminus changes, shows the 1966 and 1974 ice cliffs mapped by Chinese workers, as well as areas of active ice mapped by us. The changes in the ice portal of the Batura river are shown, as well as other landforms. BI-Buried Ice; M-Moraine. By 1984, the bare ice cliff of 1974 was thinly covered with debris. The outflow channels of 1974, in the foreground of both these pictures, has been invaded by camel thorn bushes and a kettle lake had developed that persists to the present. In 1993, much of the debris-buried ice of 1974 and earlier had been invaded by camel thorn. But from this view high on the valley side, melting ice can be seen in the left center, with the ice portal of the Batura River out of site below the cliff. View of lower Batura Glacier in 1992 showing position of white ice stream that derives from the first ice fall from Batura Muztagh. The up-ice retreat of the front of the white ice stream may reflect down -wasting at lower altitudes. Overview of lower Batura Glacier from ASTER scene acquired 13 September 2004. Lower ice stream ogives pass down-ice into reticulated ice hills before disappearing beneath increasing debris cover. The terminus region is blow up in the adjacent image. ASTER Scene 13 September 2004. 1—Ice cliff. 2– Ice portal and Batura River. 3– Farthest recent ice advance. 4– Red vegetation signature of camel thorn on marginally stabilized terminus. Digital Globe Google Earth image 18 April 2007 of Batura Glacier terminus. Precipitation and temperature reanalysis data for Hunza region (Batura Glacier—2 lat/long) generated using GCM climate simulations (European ERA40 climate model) constrained by regional climate-station data. These data can be produced on a monthly basis that show a new increase in summer monsoonal precipitation that falls as snow >~5000 meters. Note increasing precipitation trend. Terminus retreat of the Batura Glacier from left bank of Hunza River according to Goudie, Jones, and Brunsden (1984) as a result of the 1980 British IKP Expedition to Hunza. Conclusion: Glacier mass-balance regime changes may be occurring as a result of global warming wherein increases in summer precipitation reflect a change from winter westerly storms to summer monsoonal storms. The enigmatic retreat of the white ice stream is perhaps a sensitive indicator of down-wasting but not of terminus changes, which may be more sensitive to overall increases of summer precipitation increase. Glaciers in the Western Himalaya and Karakoram are not melting away as are so many glaciers are in the Eastern Himalaya.
Snow-avalanche debris, talus, and other slope deposits derived from a Tertiary pluton and surrounding Cretaceous and Tertiary sedimentary rock supply rock fragments to 23 rock glaciers on Mount Mestas, Colorado. One prominent ice-cemented rock-glacier complex studied since 1910 has a previously unreported extensive and flow in shale in part of its source region. Movement of this rock-glacier complex since the 15th century is indicated by the 283 trees sampled. Data derived from tree-rings show periods of movement in two directions, one to the northwest down the slump and flow, and the other southwest down the icecemented rock glacier. Movement was caused both by loading at the head of the rock-glacier complex and steepening of the toe by removal of mass during recent excavation.
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