scheme for monitoring glacier dynamics and so contribute to disaster prevention or mitigation. Despite slight overall mass changes, obvious thinning was observed on many exposed glacier feet. In the cases of calculating the difference between the SRTM DEM (C, band), the difference in penetration depths of the C. DEMs. The Hispar Glacier is under the control of the sub-, tropical monsoon climate, and its ablation mainly occurs between late June and early October, cending orbit images) was used to estimate the 3, supporting information). The images were acquired in interferometric wide (IW), imaging mode, which provides a spatial resolution of approximately 4 m × 14 m (ground range, Journal of Geophysical Research: Solid Earth, direction × azimuth direction). Here, the peaks that surround the Hispar Glacier will be so close that you can shout and listen to the echo. (2000). Consequently, the northern and, southern margins of the trunk showed prominent negative (downward) and positive (upward) displacement, velocities, respectively (note that the projection of downslope displacement to the vertical direction is, negative displacement). For the velocity estimation, correlation image analysis (CIAS) was used, which is based on normalized cross-correlation (NCC) of satellite data. We suggest that the lake outburst is directly related to the crack of this cavity. ow velocity in August 2013 was lowest among the six periods shown in Figure 11. rst accelerations and velocity peaks were much higher than the second, scale surge occurred in the Kunyang tributary between, ow continued in the upper reaches but decelerated markedly at the. Hispar Glacier (Urdu: ہسپر گلیشر ‎) is a 49 km (30 mi) long glacier in the Karakoram Mountains of Gilgit–Baltistan, Pakistan which meets the 63 km (39 mi) long Biafo Glacier at the Hispar La (Pass) at an altitude of 5,128 m (16,824 ft) to create the world's longest glacial system outside of the polar regions. (2012). (2013). Reports of the features of subglacial sediments in the Hispar Glacier, cant role in the glacier motion (Hewitt, 2014). cation of the surge mechanism. However, from September to October 2014, the, increased markedly, which was unexpected based on the expected normal seasonal change after August, 2014. As the interferometric phase in high relief mountain areas is dif, graphic phases were simulated using the SRTM, phases. Berardino, P., Fornaro, G., Lanari, R., & Sansosti, E. (2002). All rights reserved. Kumar, R. (2011). Sentinel, 1339). After October 2015, they increased again and reached a second peak in January 2016 and, then decreased again. We conclude that the recent Monomah Glacier surge is thermal-controlled. error, and the mathematical models are as follows: tions that are caused by topographic error, , respectively, represent the azimuth and range. https://doi.org/10.1029/2011GL049004, 1300. https://doi.org/10.1002/2015JF003515, 281. https://doi.org/10.3189/2016AoG71A024, 989. https://doi.org/10.5194/tc-8-977-2014, 416. https://doi.org/10.1016/j.geomorph.2017.12.018, A dataset of global glacier outlines: Versio, . First, the ice transported by the last Pumarikish tributary surge was depos-, ited at this location and subsequently underwent rapid melting. The NMAD of the elevation change results was ±4.46 m for the period February 2000 to February 2013. east, north, and vertical direction are listed in the (a), (b) and (c), respectively. It covered a 4 km ² area with a thick debris layer that unexpectedly, led to locally enhanced glacier mass loss during the following years. In this paper, we investigate TanDEM-X penetration depth over snow and ice on the Greenland ice sheet. ResearchGate has not been able to resolve any citations for this publication. In particular, the relation of backscatter intensity and interferometric coherence to penetration depth of the X-band InSAR signal is explored in order to improve the reliability of TanDEM-X elevation data. The position where, the thickening wave stopped was highly correlated with where the high speed wave stopped. If so, we rope up to safeguard our passage. Hence, the SRTM DEM can be, For our study, delineating the glacier boundary was fundamental to improvement of accuracy, error analy-, delineated the boundary of the Hispar Glacier in the false color Sentienal, ence to the Randolph Glacier Inventory 6.0 (RGI Consortium, 2017). Terminus fluctuations of individual glaciers lack respectively. However, basal meltwater accumulated again during the, following 4 months, and correspondingly, the trunk accelerated again after October 2015. There are two temporal gaps of 48 days in descending track. Hence, the elevation change for the period February 2013 to September 2016 has a lower, The radar penetration uncertainty for the period February 2000 to February 2013 was evaluated by the, ±4.58 m. As mentioned in section 4.4, Dehecq et al. The mass from the, Yutmaru tributary squeezed into the trunk and rapidly, generating strong normal pressure to the trunk mass. We then further calculated the variation in lake water storage between 2000 and 2015. glacier area, elevation change, and velocity products derived from satellite data in the Glaciers_cci project. reported this phenomenon (Bolch et al., 2017; Hewitt, 2014; Paul, Strozzi, et al., 2017; Quincey et al., 2011; Rashid et al., 2018; Wake & Searle, 1993). In order to ascertain this stable glacier state, we also performed a geodetic measurement based on TerraSAR-X add-on for Digital Elevation Measurement (TanDEM-X) images and SRTM DEM (2000–2012), and the results are similar (0.01 ± 0.17 and −0.04 ± 0.17 m w.e./a, respectively). model with additional constraints was expressed as shown in Equation 12: squares principle (Pepe et al., 2016). Whereas accuracy might be difficult to determine due to the limited availability of appropriate reference data and the complimentary nature of satellite measurements, precision can be obtained from a large range of measures with a variable effort for determination. Moreover, the accumulation of debris, over the glacier tongue and the unfrozen glacier bed in the ablation zone indicate that sediments play a sig-, lubricating surface beneath the Yutmaru tributary was related to the saturated permeability of the basal sedi-, ments. As shown in Figure 11, before September 2014, the normal seasonal changes of glacier motion in the, Yutmaru tributary and the middle trunk were evident. (2001). Hispar Glacier Hispar Glacier is a 49 km long glacier in the Karakoram Mountains of Gilgit–Baltistan, Pakistan which meets the 63 km long Biafo Glacier at the Hispar La at an altitude of 5,128 m to create the world's longest glacial system outside of the polar regions. Prior to this study, only two‐dimensional (2‐D) flow velocities having low temporal resolution were available for this glacier, providing inadequate information about its surge evolution. The reasons that the Yutmaru tribu-, tary could exert such a large impact on the trunk include that (1) its accumulation zone is large and high and, capable of accumulating a huge amount of mass; (2) its upper reaches are steep, its lower reaches extend a, long distance and has uniform surface slope (Figure 9b4), and it is perpendicular to the trunk, which are, appropriate geographic conditions for surges; (3) its con, velocities in the lower reaches of the Yutmaru tributary showed marked temporal variation but spatial uni-, formity, suggesting the occurrence of overall basal sliding. 2013 and ±2.13 m for the period February 2013 to September 2016. Abdullahi, S., Wessel, B., Leichtle, T., Huber, M., Wohlfart, C., & Roth, A. Elevation changes inferred from TanDEM. However, as the drainage channels slowly reformed, the basal, ow velocity in December 2017 was much lower than, 2013. The final results revealed an overall mass balance of −0.16 ± 0.05 m w.e./a. Lingle, C. S., & Fatland, D. R. (2003). The deposit from the last Kunyang tributary surge generated strong normal stress over the, trunk bed and compressed the englacial drainage channels. bute a substantial mass to the trunk (Paul, Bolch, et al., 2017). The perpendicular baselines of image pairs taken to generate pixel, ranged from 0.4 to 166.9 m. Short perpendicular baselines and image intervals and consistent image, acquisition are favorable conditions for evaluating the evolution of large, used to estimate the change in glacier thickness prior to and following the recent surge (see Table S1 in sup-, the image pair approaches 0, and therefore, the SAR decorrelation caused by atmospheric changes and, ground changes is minimized. The functional. the Yutmaru tributary, respectively (see Figure 1). Its terminus is at the same location for more than 120 years and no signs of unusual activity were reported before. Round, V., Leinss, S., Huss, M., Haemmig, C., & Hajnsek, I. (2014). The, all observation periods were exhibited in the form of animations (Figures S6, To show the temporal variation in velocity more explicitly, we extracted the time series of 3, four selected points (Figures 1 and 8). Rankl, M., Kienholz, C., & Braun, M. (2014). Combining these data with Landsat images indicated that movement of the glacier is sensitive to changes of Lake Merzbacher. The snowline at the end of ablation season can be deemed as a proxy of equilibrium line, differentiates the accumulation and ablation zones. Real accuracy assessment (Level 3) requires independent and coincidently acquired reference data with high accuracy. The bottom horizontal lines with symbols show the temporal distribution of ascending and descending images. consequently, the glacier did not advance. Referring to these, assumed a difference of 2 m between February and September X, lation zone. Chinese Academy of Sciences, Beijing, China, providing inadequate information about its surge evolution. In this study, the glacier mass balance in the catchments of Muzart and Karayulun rivers, CTS, was estimated by a geodetic method based on Advanced Land Observing Satellite/Panchromatic, Joint monitoring of the variations of glaciers and lakes within a basin is essential for an accurate understanding of region-wide climate change and the water cycle process. Deriving a time series of 3D glacier motion to, large mountain glacial system with its glacial lake: Use of synthetic aperture radar pixel offset, Li, Z., Li, J., Ding, X., Wu, L., Ke, L., Hu, J., et al. In this study, we first investigated the glacier mass balance of 2000–2015/16 for seven major glacier clusters by utilizing high-resolution SPOT-6/7 stereo imagery and the SRTM DEM. The Hispar Glacier is located at the Central Karakoram mountain range (Figure 1). The strong capability of cold storage and the temperature drop in the early 21st century may account for the anomalous mass changes. As shown in Figure 10, the 3, increased from January to August and then decreased from August to December, showing normal seasonal, 0.15 m/day, respectively. The surge mass was blocked downstream in the trunk by, the mass transferred from the Kunyang tributary, and consequently, the terminus of the Hispar Glacier, December 2017 was estimated from 139 Sentinel, changes during the periods February 2000 to February 2013 and February 2013 to September 2016 were, velocity and thickness change maps had high resolution and precision. The results showed that the water storage of LexieWudan Lake and KekeXili Lake increased by 1.82 ± 0.14 km³ and 1.90 ± 0.38 km³, respectively. Hisper Glacier is 52 Kilometers long. It stretches for 67 km in the Karakoram Mountains of Gilgit-Baltistan, Pakistan. Glacier expansion, Hewitt, K. (2007). The Hispar Glacier is a useful site for studying surge mechanisms. The method for retrieving the time series of 3. observations in ascending and descending tracks is described below. (2018). refer to the east, north, and vertical directions, respectively; ight azimuth and radar incidence angles, respectively. The results revealed that at the west and east glacial centers in the study area, the 2000–2011 mass loss rates were −0.03 ± 0.17 and −0.06 ± 0.17 m w.e./a, respectively, considerably lower than other CTS zones. ciently long. Second, as noted above, this area is at rela-, tively low altitude, and therefore, natural melting was strong. ), Kääb, A., Berthier, E., Nuth, C., Gardelle, J., & Arnaud, Y. (1987). As shown in Figure 1, P1 was located at the tributary showing the. Round et al. Based on the hypothesis that glacier bodies at the same altitude see the same penetration depth, we regressed a function between penetration difference and altitude and then applied the function to our, Zhou et al., 2019). (2015) concluded that, 1,000 folds higher than during the quies-. (2017). Therefore. After differencing, the potential systematic biases related to planimetric position, altitude, terrain slope, terrain aspect, and terrain curvature were examined and corrected by, from the nonglacial elevation changes. The penetration depth of. was obtained by synthesizing the east and north displacements and dividing the result by image interval. Contrasting patt erns of early twenty. and EOC Geoservice (https://geoservice.dlr.de/web/), respectively. Guo, L., Li, J., Wu, L., Li, Z., Liu, Y., Li, X., Miao, Z., & Wang, W. (2020). Hispar Glacier (Hisparglacier) (Pakistan) Map, Weather and Photos. (2018) conducted, distinction of snow faces in the two study areas. An example of timeline of ascending and descending images. In two areas of the Yutmaru tributary that are ~8 and ~11 km from its con, the north and east direction velocities showed clear spatial variation (see Figures 6N5, 9b1, and 9b2). For the Hispar Glacier the ele-, )), respectively, represent the offset errors (unit: pixel) in azimuth and range direc-, = 39.5°), the elevation change of 200 m (i.e., the error of SRTM DEM over, ow velocity, and thickness change results and was therefore a priority. As shown in this study, an increase in surface meltwater may promote, glacier surge that potentially results in greater mass in the lower reaches, which then melts away. However, most geographers consider the two glaciers as one; they call Biafo-Hisper Glacier. In addition, comparison of the east, les in October 2014 (blue) and July 2016 (red) showed that the active trunk extended, 9b3, in the Yutmaru tributary 0.1 km from its con, cant variations in the east, north, and vertical direction velocities did not appear in the same places. (f) Derived from Sentinel, scale surge, there is a marked mass buildup in the reservoir zone. The result during 2013 to, ow velocity was estimated from the offset, tracking uncertainty was evaluated by the standard deviation, D velocity solution model (Equations 6 and 7), the corresponding east, north, and vertical, ) may lead to oversmoothing of the results. The mass, from the Yutmaru tributary accelerated markedly along the northern margin of the trunk, generating strong, normal pressure to the trunk mass and forcing the southern margin to uplift. Surge, Bolch, T., Pieczonka, T., Mukherjee, K., & Shea, J. The mutual constraints among SAR images for different tracks, neglected in earlier. This interpretation is corroborated by the fact that the mass boundary near the, In the postsurge phase, only the trunk near its con, velocity (Figure 10). trunk and the Yutmaru tributaries, respectively. Although accumulation of summer melt-, water can increase the basal water pressure, the basal structure had changed markedly, and the presurge, hydraulic environment could not reform. Due to the seasonal and annual changes, the, As shown in Figure 8, three velocity undulations occurred in the Yutmaru tributary (P1), two occurred in the, middle trunk area (P2 and P3), and one occurred in the lower trunk (P4), indicating that the trunk acceler-, ated passively. Despite slight overall mass changes, obvious thinning was observed on many exposed glacier feet. In general, the, master image should be acquired in the middle of the study period. direction speed reached 6.8 m/day. glacier (see Table S1 in supporting information). In the upper reaches of the trunk and the Yutmaru tributary, thinning by up to 50 m occurred. Ongoing global warming causes dramatic changes globally, especially with respect to Polar Regions. The glaciers climate change initiative:Methods for creating glacie. Thermally controlled glacier surging. The seasonal difference of X, tion difference result. It is conservative to assume the discrepancy between the results of Dehecq, et al. Karakoram geodetic glacier mass balances between 2008. of a large rock avalanche on Siachen Glacier. Definition- an extended mass of ice formed by snow falling and accumulating over the years. Velocities toward the north were positive. In the bistatic imaging mode the temporal baseline of, band are up to 14, 10, and 8 m, respectively, 2A image and four Landsat images acquired in the ablation seasons were used to delineate the, 2A image is characterized by rich bands, mod-, The location and overview of the Hispar Glacier. Finally, the horizontal glacier velocity. The terrain slope of this part is uniform (Figure 9b4). https://doi.org/10.1109/IGARSS.2018.8518930, IEEE Transactions on Geoscience and Remote Sensing, (1), 15391. https://doi.org/10.1038/s41598-017-15473-8. Hispar Glacier is a 49 km (30 mi) long glacier in the Karakoram Mountains of Gilgit-Baltistan, Pakistan which meets the 63 km (39 mi) long Biafo Glacier at the Hispar La (Pass) at an altitude of 5,128 m (16,824 ft) to create the world's longest glacial system outside of the polar regions. Investigating the Recent Surge in the Monomah Glacier, Central Kunlun Mountain Range with Multiple S... Quantifying glacier mass change and its contribution to lake growths in Central Kunlun during 2000-2... Geodetic glacier mass balance (1975–1999) in the central Pamir using the SRTM DEM and KH-9 imagery. Based on this, we applied a strategy which establishes the statistical relationship between the lake area change and the lake water-level change for 2003–2008/09 to estimate the specific water level using the corresponding lake area. Combining the results and geomorphologic features, we deduced that the recent surge was because of saturated basal water pressure in the Yutmaru tributary. Rashid, I., Abdullah, T., Glasser, N. F., Naz, H., & Romshoo, S. A. Data and methods 2.1. This peak and our base camp were located on the Yutmaru Glacier, a tributary of the Hispar Glacier. Referring to the signal, ratio map, areas with unreliable results (e.g., cloud covered areas and glacier areas with few textures) were, masked out. Surge dynamics and lake outbursts of Kyagar glacier, Karakoram. A large volume of ice was transferred from, the upper reaches of the Kunyang tributary to its lower reaches and its con, the latter. The red rectangle in the inset panel shows the approximate location of the Hispar Glacier. neither of these single dynamics hypotheses explains the situation in the Karakoram Mountains. Nowadays, cardiac procedures can be performed with small incisions, not wide openings of the chest. Correspondingly, the glacier, velocity decreased from July to August. 1. Better still, is there a way for surgeons to repeat practice on the minimally invasive Transcatheter Aortic Valve Implantation (TAVI)... Several glaciers in the Bukatage Massif are surge-type. According, velocity uncertainties were ±7.8, ±7.0, and ±5.8 cm/day, respectively. As noted above, the last Kunyang tributary surge generated a. good water storage environment in this area. D surface displacements (Kääb et al., 2014). Correspondingly, 138 ascending image pairs (two subsets) and 204 descending image pairs, (three subsets) were formed (see Table S1). Automatic and precise orthorecti, 1558. https://doi.org/10.1109/TGRS.2006.888937, 608. https://doi.org/10.1016/j.jhydrol.2018.02.067, J., et al. Multiple studies have demonstrated that the, et al., 2017). Karakoram glaciers experienced balanced or slightly positive mass budgets since at least the 1970s. horizontal lines with symbols show the temporal distribution of ascending and descending images. outline. a ⁻¹ for 2000 to 2011 and −0.51 ± 0.04 m w.e. During 2000–2012, its accumulation zone was thinned by 50 m, while its ice tongue was thickened by 90 m. During 2015–2017, its flow velocity reduced from 1.2 to 0.25 m/d, and the summer velocities were much higher than winter velocities. Based on comparisons with previous measurements, our results indicate that the lake had an increasing influence on the glacier from 2005 to 2009. The glacier thickness change around the regional snowline was close to zero. for the study region (with a total glacier area of 967 km²). Accounting for radar wave penetration minimizes biases in elevation that can otherwise reach up to 6 m in dry snow on Fedchenko Glacier, with mean values of 3–4 m in the high accumulation regions. It is. Systematic registration error (horizontal shift) was corrected by, trend from the observations in stable region and removing it from the displacement map. C DEM) to correct the bias (Gardelle et al., 2013; band rises from 1.4 to 5.1 m as the alti-, X images were acquired at different seasons, band penetration can also cause bias to the eleva-, band penetration depths was about 2 m (February 2013 to, ow velocities of Hispar Glacier in 136 consecutive periods (October 2014 to December, 1.5 m/day (Figure 5E1). Enhanced melt opened a > 100 m deep 2 km ² depression and contributed to 6% of the mass loss of Siachen Glacier from 2010 to 2016 (−0.39 m w.e. This 100 km (62 mi) highway of ice connects two ancient mountain kingdoms, Nagar (immediately south of Hunza) in the west with Baltistan in the east. Dehecq, A., Millan, R., Berthier, E., Gourmelen, N., Trouve, E., & Vionnet, V. (2016). If that be so then the 120 kilometers 75 miles long biafo Hispar Glacier probably becomes the second longest glacier in the world. with glacier thickness changes prior to and following a surge, more clarity of the evolution of the glacier, surge will be obtained, and explanations for why the recent large, Raucoules et al., 2013), are fully incorporated in the PO, change in thickness of the Hispar Glacier between 2000 and 2016 was derived from two TanDEM/CoSSC, satellite images and the SRTM DEM, using the geodetic method. This is, rst report of the MSBAS technique being used to derive the 3, scale surge of the Hispar Glacier and deduced the mechanism triggering the surge. Lambercht et al. The strong capability of cold storage and the temperature drop in the early 21st century may account for the anomalous mass changes. (2016) and Lambercht et al. likely explanation is that the upper zones had steeper bed slopes (see Figure 9b4). D Flow Velocity Time Series and Thickness Chan. The glacier thickness change around the regional snowline was close to zero. P. (2007). In this study, we used KH-9 imagery acquired in 1975 to generate the historical DEM for the central Pamir, and then obtained the glacier elevation change by comparing this with the SRTM C-band DEM. Physics, Central South University, Changsha, China, Environment and Resources, Chinese Academy, The Hispar Glacier is a useful site for studying surge mechanisms. The path of the looped moraine indicates, that the mass from the Yutmaru tributary advanced >3 km in the trunk during the recent surge. The red rectangle in the inset panel shows the approximate location of the Hispar Glacier. A tiered list of recommendations is provided (sorted for effort from Level 0 to 3) as a guide for analysts to apply what is possible given the datasets used and available to them. Location map of the 7000m and 8000m peaks of the Pakistan Karakoram. From January 2016 to August 2016 the horizontal speed at P4, continuing to decrease. 101. https://doi.org/10.5194/tc-12 -95-2018, 221. https://doi.org/10.3189/172756500781832909, 206. https://doi.org/10.1017/S0022143000015847, 2405. https://doi.org/10.1002/2015JF003511, 342. https://doi.org/10.1017/jog.2016.142. In this study, the glacier mass balance in the catchments of Muzart and Karayulun rivers, CTS, was estimated by a geodetic method based on Advanced Land Observing Satellite/Panchromatic Remote-sensing Instrument for Stereo Mapping images and Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM). Kääb, A., Bolch, T., Casey, K., Heid, T., Kargel, J. a ⁻¹ ). from Google Earth) with a black square. Interestingly, the signals on the south side were positive, in contrast to the negative values on the, north side. Quantifying glacier mass change and its contribution to lake growths in Central, Zhou, Y., Li, Z., & Li, J. Hispar Glacier (Hisparglacier) is a glacier(s) (a mass of ice, usually at high latitudes or high elevations, with sufficient thickness to flow away from the source area in lobes, tongues, or masses) and … Calving can cause greater loss of glacier mass than normal ablation. The Hispar Glacier is a useful site for studying surge mechanisms. In January 2016 the high speed wave reached the con, then stopped moving forward. affect the state of a nonsteady glacier (Fowler et al., 2001; Harrison & Post, 2003; Lingle & Fatland, 2003). (2018), that is, 0.5 m, to be the radar penetration uncertainty in glacier, accumulation zone for the period February 2013 to September 2016. At P4 the, pattern of change in speed was quite different. Quincey et al. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. However, these are rarely available and their transformation into an unbiased source of information is challenging. Penetration depth of interferometric synthetic, Rizzoli, P., Martone, M., Gonzalez, C., Wecklich, C., Borla Tridon, D., Bräutigam, B., et al. However, in. The annotated main image depicts the outlines of Hispar. The blue triangles and red. Our results indicated that, Central Tianshan (CTS) plays a prominent role in maintaining the vulnerable ecosystem in Central Asia. (2011). In July of 2005 our small group traversed the Biafo and Hispar Glaciers in the Karakoram Mountains of Northern Pakistan. The glacier-wide mass balances of surge-type and nonsurge-type glaciers were not statistically different. On-screen digitization was employed to quantify changes in the glacier geomorphology and dynamics of supraglacial water bodies on the glacier. The Pumarikish tributary showed an opposite pattern of thickness change: Its upper reaches. In addition, the influence of the height of ambiguity of the interferometric TanDEM-X data is presented. The location and overview of the Hispar Glacier. In this study a, curve method (Pepe et al., 2016). angle of master and slave orbits, the slant range, the incidence angle, and the perpendicular baseline. For each lake basin, meanwhile, the glaciers lost −0.18 ± 0.03 km³ and −0.21 ± 0.04 km³ of water, accounting for 9.9% and 11.1% of the increase in lake water storage for LexieWudan Lake and KekeXili Lake, respectively. (2006), in most parts of Eurasia the accuracy of the SRTM DEM is 6. denoted by numbers. a ⁻¹ . (2018) is near to the Hispar Glacier and the sizes of the, two glaciers are similar. Höhle, J., & Höhle, M. (2009). The, tracking error and model error were thought to be independent, and the uncertain-, ow velocity derived from optical images was evaluated by the STD, correlation result has a higher precision. 2.96, 1.68 and 0 m for firn/snow cover, bare ice and debris-covered areas, respectively. A time series of the vertical velocity indicates that the glacier tongue has a huge englacial cavity. Relative to the SAR offset. The MSBAS technique was mainly used to retrieve the time series of 2, ferometric phase observations (Samsonov et al., 2014; Samsonov & d'Oreye, 2012). (B9), 9083. https://doi.org/10.1029/JB092iB09p09083, Antarctic research series. In contrast, an apparent mass redis-, tribution occurred in the Kunyang and Pumarikish tributaries. Trying to replenish the front mass loss, the distributary accelerates and the mass loss further intensifies. ow velocities in July were obviously higher than that in August. In addition, the. Thinning rates increased between 2000 and 2016 by a factor of 1.8 compared with 1928–2000, resulting in peak values of 1.5 m a ⁻¹ . Hence, the TanDEM. During the active phase, a large mass is transported from the glacier, reservoir zone to the receiving zone, and this occurs at a speed 10, cent phase (Harrison & Post, 2003). Notably, the surging wave was transmitted toward the lower reaches and also. was implemented to track the offsets. the cavities are normally distributed locally (Eisen et al., 2005; Quincey et al., 2015; Yasuda & Furuya, 2015). It is only the Hisper pass, which separates the Hisper Glacier and Biafo Glacier. In addition, changes in the glacier thick-, ow velocity can be obtained with higher accuracy and temporal resolution, along, ow velocity of the Hispar Glacier between 2014 and 2017 was derived, based multidimensional small baseline subsets, MSBAS) method. Location of Hispar Glacier in the Karakoram. A minimum acceleration approach for the retrieval of multiplatform InSAR deformation. Hispar Glacier is a 49 km long glacier in the Karakoram Mountains of the (Northern Areas, Pakistan) which meets the 63 km long Biafo Glacier at the Hispar La Pass (mountain Pass) at an altitude of 5,128 m (16,824 feet) to create the world's longest glacial system outside of the polar regions. By August 2016, the speed had declined to that of the quiescent phase (<0.2 m/, P2 and P3. Rapid, the initiation time, evolution pattern, and duration of the active phase are directly related to the internal, dynamic control processes (Jiskoot, 2011; Quincey et al., 2011), detailed observations of glacier, velocity and thickness change can aid clari, largest glaciers in the Central Karakoram mountain range. Basal zone of the West Antarctic ice streams and its role in lubrication of their rapid motion. uence (section M of the red curve in Figure 14) bent to the south following initiation of the surge. Relative to the east and north direction velocities, the vertical velocities were much smaller (Figure 7). owed downslope along the northern margin, rst peak in May 2015 and then decreased in October, scale glacier surges occur frequently in the Karakoram mountain range (Bhambri et al., 2017; Copland, hypothesis, which proposes that increasing ice weight and frictional heat can result in a, hypothesis, which proposes that a basal slip occurs when the water pressure in the distributed sub-. The west Antarctic ice sheet: Behavior and environment. Satellite data provide a large range of information on glacier dynamics and changes. The Karakoram anomaly? Eisen, O., Harrison, W. D., Raymond, C. F., Echelmeyer, K. A., Bender, G. A., & Gorda, J. L. D. (2005). one of the largest glaciers (outside of the polar regions) in the world. Murray, T., Stuart, G. W., Miller, P. J., Woodward, J., Paul, F., Bolch, T., Briggs, K., Kääb, A., McMillan, M., McNabb, R., et al. Data. These errors are quite small compared to, the displacements that occurr during one SAR image interval (12 days) even in glacier quiescent phase, (~4 m on average), not to speak of that in glacier surge phase (~70 m on average). At the heart of this system lies the Great Snow Lake, an immense basin of snow and ice from which these two huge glaciers radiate. 2870. https://doi.org/10.1109/TGRS.2006.8. From 2009 to 2016, its area and length respectively increased by 6.27 km2 and 1.45 km, and its ice tongue experienced three periods of changes: side broadening (2009–2010), rapid advancing (2010–2013), and slow expansion (2013–2016). The glacier, cities are shown in section 5.1. Background: shaded SRTM DEM; black curve: glacier outline. The RMSE map in, C DEM (Erasmi et al., 2014; Rankl & Braun, 2016; Rizzoli, eld measurements are of high accuracy, and the discrepancy of their results is likely to be caused. Debris, information, including the surface features, local terrain, path of supraglacial runoff, surface elevation, One master image was selected for each track, and the other images were coregistered with it. long) and Hispar Glacier (61 km. glaciers and surge-related impacts, based on satellite images (Landsat and ASTER), ground In V. P. Singh, P. Singh, & U. K. Haritashya (Eds. tracking: Removal of topographic effects and analysis of the dynamic patterns. However, there, is no evidence that the frequency of surges has changed in this region, because compared with the cycles of, glacier surges, the application of remote sensing techniques (including InSAR) to glacier monitoring has not, and so affect the glacier mass balance, there is a need to continue to use remote sensing techniques to moni-. Geometrical SAR image registration. Jiskoot, H. (2011). Hispar Glacier. However, after the, enlarged (Yasuda & Furuya, 2015), so as the meltwater gathered at the glacier base, the surge body acceler-, ated again between October 2015 and January 2016. or optical image pairs formed in chronological order, and no postadjustment of observations was conducted. The vertical and horizontal components of the line between two images denote the perpendicular spatial baseline and temporal baseline, respectively. The velocities of the glacier were up to 58 cm/day east, 70 cm/day north, and 113 cm/day vertically. (2017) suggest that in the 13 years prior to this surge (2000, accumulation in that region. Velocities toward the east were positive. In addition, its vertical speed has been up to 1.1 m/day, (in January 2016), considerably higher than that of P1, To show the spatial variation in velocity more explicitly, we extracted the time series of the 3, directions (east, north, and vertical) dropped markedly at the trunk con. Hence, it is very likely that initiation of the surge in the Yutmaru tributary was, because of saturated water pressure at the ice bed interface, which lifted the glacier and separated it from the, short intervals. Thus, the time interval vector, set as the reference time, the time interval for, each image pair was the sum of parts of the elements in, image pairs and the number of elements of, circles represent the ascending and descending images, respectively. Subglacial, 415). © 2008-2020 ResearchGate GmbH. However, our thickness change measurements and those of Bolch, et al. The sig-, notable that the north and vertical direction velocities from 0~4.5 km from the con, able temporal variation but spatial uniformity. Leprince, S., Barbot, S., Ayoub, F., & Avouac, J. of satellite images, application to ground deformation measurements. Velocities in the actively surging part of the main glacier trunk and its three tributaries reach up to ~ 900 m yr? guration of the basal water conduit system. waves are documented and surface diagnostic features indicative of surging. The surge mass was blocked downstream in the trunk by the mass transferred from the Kunyang tributary, and consequently the glacier did not advance. Surge intervals are identified Glacier surging. We determined changes in glacier thickness, motion, and surface features in this region based on TanDEM-X, ALOS/PRISM, Sentinel-1A, and Landsat images. the trunk increased markedly (up to 180 m). Join ResearchGate to find the people and research you need to help your work. pixel spacing of a single look SAR image; , respectively, represent the horizontal crossing. Today we get the first views of the Hispar La and Snow Lake. (2018) found a corresponding value of 1.5 m between January and October, (October 2013 to January 2014) in Pamir regions (close to our study area). Mass balance in surge-type and surge-modified glaciers differs from conventional, B., Owen, L. A., et al. (a4): east, north, vertical velocities, and glacier surface elevation along Pro, ow velocities did not exceed 0.2 m/day. of the area is covered by debris and therefore the effects of seasonal penetration change can be neglected. The glacier trunk originates from Snow Lake, the largest, ows at an azimuth angle of approximately 300°. Dordrecht, The Netherlands: Springer. For more details of bias correction, please refer to Nuth and. Like the east direction velocity in the trunk, the north, 1.7 m/day in October 2014 and continued to, 0.5 to 0.5 m/day, and substantial vertical velocities only occurred in the marginal areas of the, ow velocity of the Hispar Glacier in the surge active phase. In contrast, saturated sediment is able to develop a regular subglacial lubricating surface (Fowler et al., 2001; region are few, but the frequent avalanches at high altitudes and the diversity of glacier basins provide sui-, table environmental conditions for the formation of such sediments. The elements of vector, The distribution of spatial and temporal baselines of Sentinel, 1A image pairs. (2019). The features of the glacier, city changes, thickness changes, and geomorphic changes indicate that (1) the recent large, Hispar Glacier started in September 2014 and lasted until August 2016, (2) the surge of the Yutmaru tribu-, tary at high altitude triggered the surge in the Hispar Glacier trunk; (3) the surge of the Yutmaru tributary, was probably because of saturated water pressure at the interface between the ice and the bedrock; (4) during, the surge active phase the subglacial hydrological conditions varied with the input of meltwater, and there-, fore, the glacier velocity increased in winter but decreased in summer; and (5) the surge mass from the, erating strong normal pressure in the trunk and resulting in opposite vertical displacements at two margins, Abnormal glacier mass balance in the Karakoram Mountains has been widely reported in recent years, with. An iterative procedure was performed to improve the resolution of. We use a series of Global Navigation Satellite Systems observations from 2009 to 2016 and TanDEM-X elevation models from 2011 to 2016 to investigate recent elevation changes. 479. https://doi.org/10.1126/science.227. Fowler, A. C., Murray, T., & Ng, F. S. L. (2001). Combining the results and geomorphologic features, we deduced that the, recent surge was because of saturated basal water pressure in the Yutmaru tributary. Perception, Cognition and Prediction, Central South University, Changsha, China. In J. S. Kargel, G. J. Leonard, & M. P. Bishop (Eds. The crossing of four major tributary glaciers from the north is most taxing, and potentially high nullah crossings can be dangerous. Investigating mountain glacier motion with the method of SAR intensity. with the Kunyang tributary, the surging area extended >30 km along the trunk. Kamb, B., Raymond, C. F., Harrison, W. D., Engelhardt, H., Echelmeyer, K. A., Humphrey, sediment/bedrock interface: A new mechanism for rapid. Map of the Hispar Glacier Region of the Pakistan Karakoram. The main panel is a false-colored Sentinel-2A MSI image (20 July 2016). Remote-sensing Instrument for Stereo Mapping images and Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM). Several glaciers in the Bukatage Massif are surge-type. long) and Hispar Glacier (61 km. Hispar Glacier is a 49 km (30 mi) long glacier in the Karakoram Mountains of Gilgit–Baltistan, Pakistan which meets the 63 km (39 mi) long Biafo Glacier at the Hispar La (Pass) at an altitude of 5,128 m (16,824 ft) to create the world’s longest glacial system outside of the polar regions. Cuffey, K. M., & Paterson, W. S. B. Furthermore, relative to L, length and therefore a weaker capability of penetrating into glacier surface. Glacier elevation and mass changes over the Central Karakoram region estimated from TanDEM. It is, likely that the convergence of subtributaries resulted in a thicker ice body and therefore a higher, city. increased precipitation thought to be the main reason (Bolch et al., 2017; Gardelle et al., 2013; Hewitt, 2005; Kääb et al., 2012; Zhou et al., 2017). The 1 arcsec SRTM DEM (February 2000) was used to remove topographic effects on the SAR offset tracking, (Li et al., 2014; Sansosti et al., 2006) and to estimate glacier thickness, et al. Together they create a vast natural highway stretching for over 80 miles and linking Baltistan with the villages of the Hunza Valley. From the con-. a ⁻¹ ). from the upper trunk and that from the Yutmaru tributary. The vertical and horizontal components of the line, between two images denote the perpendicular spatial baseline and temporal baseline, respectively.

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