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Timothy G. Fisher - One of the best experts on this subject based on the ideXlab platform.
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megaflooding associated with Glacial Lake agassiz
Earth-Science Reviews, 2020Co-Authors: Timothy G. FisherAbstract:Abstract Significant baseline and episodic megaflooding from Glacial Lake Agassiz was routed to the south, east and north coasts of North America over the Lake’s nearly 6000 year history. The five phases of Lake-level change were controlled by which outlet was active, which in turn was controlled by ice margin position and glacioisostatic adjustment. The southern outlet is the oldest and best understood outlet, while successively younger outlets are progressively less understood. Eastern drainage synchronous with the Younger Dryas chronozone had been assumed by most studies, but a spillway to accommodate the ∼90 m drop in Lake level is yet to be described. With the south and east outlets unable to accommodate the necessary Lake level drawdown, the northwest outlet has become the default outlet with Arctic Ocean Core data supporting it. However, extant terrestrial data from the continent only provides data for a large flood from the Fort McMurray area closer to the end of the Younger Dryas, coinciding with the timing of the Preboreal Oscillation. The challenge remains to find agreement between the marine and terrestrial records. Uncontroversial is the geomorphic and sedimentologic evidence for flooding into and out of the Lake consisting of large spillways, large boulders, and in places giant current ripples composed of boulders. Flood discharge estimates into and out of the Lake range from 0.04 to ∼1 Sv, with final subGlacial drainage into the Tyrell Sea estimated at ∼5 Sv, sufficient to raise global sea level by 0.18 m and initiate the 8.2 ka stadial.
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what caused the low water phase of Glacial Lake agassiz
Quaternary Research, 2013Co-Authors: Thomas V. Lowell, Timothy G. Fisher, Patrick J Applegate, Kenneth LepperAbstract:First-order modeling suggests that a low-water phase in late-Glacial Lake Agassiz can be explained through changes in the balance between evaporation, precipitation, and runoff, rather than drainage. The low-water Moorhead Phase is often attributed to drainage through outlets opened by isostatic depression and retreat of the Laurentide ice margin. However, new data indicate that the proposed outlets were ice-covered during the Moorhead Phase. Instead, the Lake water levels dropped to the Moorhead Phase before the start of the Younger Dryas chronozone and remained there until 11.3 ka. Thus, drainage seems to be an implausible explanation for Younger Dryas-aged low water levels in Lake Agassiz. An alternative explanation is that evaporation equaled or exceeded water inputs from the adjacent ice margin and the deglaciated parts of the drainage basin. To evaluate whether this hypothesis is plausible, we constructed a simple model that considers the paleo-basin geometry, hydrology, and meltwater production from the adjacent ice margin. Modest hydrologic changes (within the range of present-day variability), coupled with low meltwater production, produce a closed basin. Shifts in the location of the polar jet, driven by increased Arctic albedo, may explain our inferred hydrologic changes.
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a chronology for Glacial Lake agassiz shorelines along upham s namesake transect
Quaternary Research, 2013Co-Authors: Kenneth Lepper, Alex W Buell, Timothy G. Fisher, Thomas V. LowellAbstract:Abstract Four traditionally recognized strandline complexes in the southern basin of Glacial Lake Agassiz are the Herman, Norcross, Tintah and Campbell, whose names correspond to towns in west-central Minnesota that lie on a linear transect defined by the Great Northern railroad grade; the active corridor for commerce at the time when Warren Upham was mapping and naming the shorelines of Lake Agassiz (ca.1880–1895). Because shorelines represent static water planes, their extension around the Lake margin establishes time-synchronous Lake levels. Transitions between shoreline positions represent significant water-level fluctuations. However, geologic ages have never been obtained from sites near the namesake towns in the vicinity of the southern outlet. Here we report the first geologic ages for Lake Agassiz shorelines obtained at field sites along the namesake transect, and evaluate the emerging chronology in light of other paleoclimate records. Our current work from 11 sampling sites has yielded 16 independent ages. These results combined with a growing OSL age data set for Lake Agassiz's southern basin provide robust age constraints for the Herman, Norcross and Campbell strandlines with averages and standard deviations of 14.1 ± 0.3 ka, 13.6 ± 0.2 ka, and 10.5 ± 0.3 ka, respectively.
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ages for the big stone moraine and the oldest beaches of Glacial Lake agassiz implications for deglaciation chronology
Geology, 2007Co-Authors: Kenneth Lepper, Timothy G. Fisher, Irka Hajdas, Thomas V. LowellAbstract:Glacial Lake Agassiz has been implicated as the trigger for numerous episodes of abrupt climate change at the close of the last ice age, yet the beginning age of the Lake has never been determined. Here we report the fi rst numerical age data on the Big Stone Moraine and the oldest beaches of Glacial Lake Agassiz. Organic remains from Lakes, bogs, and channels distal to, and inset to, the Big Stone Moraine require that Glacial activity at this moraine ceased prior to 12,000 14 C yr B.P. (13,950 cal [calendar] yr). A site near New Effi ng ton, South Dakota (United States), implies full Glacial recession north of the topographic divide prior to 11,810 14 C yr B.P. (13,670 cal yr), synchronous with the beginning of Glacial Lake Agassiz. Lake Agassiz shorelines inset to the moraine yield optically stimulated luminescence (OSL) ages from 14,200‐12,600 yr cal. Lower strandlines are younger, but the similarity of ages suggests that initial Lake lowering was faster than OSL ages can currently resolve. Nevertheless, the OSL ages represent the fi rst numerical age assignments for the Herman, Norcross, and Upham beach ridges, setting the stage for future numerical age assignments within the Lake Agassiz basin. These two dating methods yield strongly consistent results within stated uncertainties. The age of the Big Stone Moraine implies an interval of rapid retreat for the Des Moines lobe of the Laurentide Ice Sheet during the Bolling-Allerod warm interval. The overlapping ages for the uppermost beach levels and abandonment of the highest Lake Agassiz spillway indicate a rapidly evolving Lake until at least 13,500 yr cal.
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abandonment chronology of Glacial Lake agassiz s northwestern outlet
Palaeogeography Palaeoclimatology Palaeoecology, 2007Co-Authors: Timothy G. FisherAbstract:Abstract Spillway scour Lakes and basins in northwestern Saskatchewan were cored to determine when the spillways were abandoned. The cores contained the target contact of organic muck (gyttja) overlying inorganic sand or silty-clay rhythmites. New AMS radiocarbon dates on terrestrial macrofossils, in conjunction with previously published and unpublished data from the area, indicate that the spillways were abandoned between 9.07 and 9.59 14C kyr BP (10,220–10,810 cal yr BP). Of great interest is whether the channels are associated with northwestern drainage from Glacial Lake Agassiz. The radiocarbon ages recording spillway abandonment are consistent with previous work, which claims that overflow through the northwestern outlet ended ∼ 9.5 14C kyr BP (10,700 cal yr BP); this is consistent with shifting drainage to the southern outlet at this time. The scarcity of dates from the northwestern outlets and other outlets of Lake Agassiz underscores the need to establish a tighter chronological control on outlet switching before outburst flooding from Lake Agassiz can be assumed to be the trigger for abrupt climate change.
Ariane Walz - One of the best experts on this subject based on the ideXlab platform.
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unchanged frequency of moraine dammed Glacial Lake outburst floods in the himalaya
Nature Climate Change, 2019Co-Authors: Georg Veh, Oliver Korup, Sebastian Specht, Sigrid Roessner, Ariane WalzAbstract:Shrinking glaciers in the Hindu Kush–Karakoram–Himalaya–Nyainqentanglha (HKKHN) region have formed several thousand moraine-dammed Glacial Lakes1–3, some of these having grown rapidly in past decades3,4. This growth may promote more frequent and potentially destructive Glacial Lake outburst floods (GLOFs)5–7. Testing this hypothesis, however, is confounded by incomplete databases of the few reliable, though selective, case studies. Here we present a consistent Himalayan GLOF inventory derived automatically from all available Landsat imagery since the late 1980s. We more than double the known GLOF count and identify the southern Himalayas as a hotspot region, compared to the more rarely affected Hindu Kush–Karakoram ranges. Nevertheless, the average annual frequency of 1.3 GLOFs has no credible posterior trend despite reported increases in Glacial Lake areas in most of the HKKHN3,8, so that GLOF activity per unit Lake area has decreased since the late 1980s. We conclude that learning more about the frequency and magnitude of outburst triggers, rather than focusing solely on rapidly growing Glacial Lakes, might improve the appraisal of GLOF hazards. Melting glaciers are increasing Himalayan Glacial Lakes and potentially the risk of outburst floods. An advanced automated algorithm identifies Glacial Lake outburst floods from Landsat images since the late 1980s to improve understanding of these events and trends in their frequency.
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detecting himalayan Glacial Lake outburst floods from landsat time series
Remote Sensing of Environment, 2018Co-Authors: Georg Veh, Oliver Korup, Sigrid Roessner, Ariane WalzAbstract:Abstract Several thousands of moraine-dammed and supraGlacial Lakes spread over the Hindu Kush Himalayan (HKH) region, and some have grown rapidly in past decades due to glacier retreat. The sudden emptying of these Lakes releases large volumes of water and sediment in destructive Glacial Lake outburst floods (GLOFs), one of the most publicised natural hazards to the rapidly growing Himalayan population. Despite the growing number and size of Glacial Lakes, the frequency of documented GLOFs is remarkably constant. We explore this possible reporting bias and offer a new processing chain for establishing a more complete Himalayan GLOF inventory. We make use of the full seasonal archive of Landsat images between 1988 and 2016, and track automatically where GLOFs left shrinking water bodies, and tails of sediment at high elevations. We trained a Random Forest classifier to generate fuzzy land cover maps for 2491 images, achieving overall accuracies of 91%. We developed a likelihood-based change point technique to estimate the timing of GLOFs at the pixel scale. Our method objectively detected ten out of eleven documented GLOFs, and another ten Lakes that gave rise to previously unreported GLOFs. We thus nearly doubled the existing GLOF record for a study area covering ~ 10% of the HKH region. Remaining challenges for automatically detecting GLOFs include image insufficiently accurate co-registration, misclassifications in the land cover maps and image noise from clouds, shadows or ice. Yet our processing chain is robust and has the potential for being applied on the greater HKH and mountain ranges elsewhere, opening the door for objectively expanding the knowledge base on GLOF activity over the past three decades.
Donald I Siegel - One of the best experts on this subject based on the ideXlab platform.
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HYDROLOGICAL PROCESSES Hydrol. Process. (in press) Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/hyp.6239 Heat transport in the Red Lake Bog, Glacial Lake Agassiz
2015Co-Authors: Jeffrey M Mckenzie, Paul H Glaser, Donald I Siegel, Donald O Rosenberry, Clifford I VossAbstract:We report the results of an investigation on the processes controlling heat transport in peat under a large bog in the Glacial Lake Agassiz Peatlands. For 2 years, starting in July 1998, we recorded temperature at 12 depth intervals from 0 to 400 cm within a vertical peat profile at the crest of the bog at sub-daily intervals. We also recorded air temperature 1 m above the peat surface. We calculate a peat thermal conductivity of 0Ð5 W m1 °C1 and model vertical heat transport through the peat using the SUTRA model. The model was calibrated to the first year of data, and then evaluated against the second year of collected heat data. The model results suggest that advective pore-water flow is not necessary to transport heat within the peat profile and most of the heat is transferred by thermal conduction alone in these waterlogged soils. In the spring season, a zero-curtain effect controls the transport of heat through shallow depths of the peat. Changes in local climate and the resulting changes in thermal transport still may cause non-linear feedbacks in methane emissions related to the generation of methane deeper within the peat profile as regional temperatures increase. Copyright 2006 John Wiley & Sons, Ltd. KEY WORDS Glacial Lake Agassiz Peatlands; heat transfer; thermal conductivity; SUTR
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heat transport in the red Lake bog Glacial Lake agassiz peatlands
Hydrological Processes, 2007Co-Authors: Jeffrey M Mckenzie, Paul H Glaser, Donald I Siegel, Donald O Rosenberry, Clifford I VossAbstract:We report the results of an investigation on the processes controlling heat transport in peat under a large bog in the Glacial Lake Agassiz Peatlands. For 2 years, starting in July 1998, we recorded temperature at 12 depth intervals from 0 to 400 cm within a vertical peat profile at the crest of the bog at sub-daily intervals. We also recorded air temperature 1 m above the peat surface. We calculate a peat thermal conductivity of 0·5 W m−1 °C−1 and model vertical heat transport through the peat using the SUTRA model. The model was calibrated to the first year of data, and then evaluated against the second year of collected heat data. The model results suggest that advective pore-water flow is not necessary to transport heat within the peat profile and most of the heat is transferred by thermal conduction alone in these waterlogged soils. In the spring season, a zero-curtain effect controls the transport of heat through shallow depths of the peat. Changes in local climate and the resulting changes in thermal transport still may cause non-linear feedbacks in methane emissions related to the generation of methane deeper within the peat profile as regional temperatures increase. Copyright © 2006 John Wiley & Sons, Ltd.
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regional ground water flow modeling of the Glacial Lake agassiz peatlands minnesota
Journal of Hydrology, 2001Co-Authors: A S Reeve, J Warzocha, Paul H Glaser, Donald I SiegelAbstract:Abstract Three-dimensional ground-water modeling experiments were done to test the hypothesis that regional ground-water flow is an important component of the water budget in the Glacial Lake Agassiz Peatlands of northern Minnesota. Previous data collected from the Glacial Lake Agassiz Peatlands suggest that regional ground-water flow discharges to these peatlands, maintaining saturation, controlling the peat pore-water chemistry, and driving ecological change. To test this hypothesis, steady-state MODFLOW models were constructed that encompassed an area of 10,160 km 2 . Data used in this modeling project included surface-water and water-table elevations measured across the study area, digital elevation data, and well logs from scientific test wells and domestic water wells drilled in the study area. Numerical simulations indicate that the Itasca Moraine, located to the south of the peatland, acts as a recharge area for regional ground-water flow. Ground water recharged at the Itasca Moraine did not discharge to the Red Lake Peatlands, but rather was intercepted by the Red Lakes or adjacent rivers. Simulations suggest that ground-water flow within the peatlands consists of local-flow systems with streamlines that are less than 10 km long and that ground water from distant recharge areas does not play a prominent role in the hydrology of these peatlands. Ground-water flow reversals previously observed in the Red Lake Peatlands are either the result of interactions between local and intermediate-scale flow systems or the transient release of water stored in Glacial sediments when the water-table is lowered.
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87sr 86sr as a tracer of groundwater discharge and precipitation recharge in the Glacial Lake agassiz peatlands northern minnesota
Water Resources Research, 2000Co-Authors: James F Hogan, Donald I Siegel, Joel D Blum, Paul H GlaserAbstract:A contrast in the 87Sr/86Sr ratio of atmospherically derived Sr (∼0.710) and Sr from regional bedrock (>0.730) allows quantification of the proportions of precipitation recharge and groundwater discharge into peat columns of bogs and fens in the Glacial Lake Agassiz Peatlands. Two contrasting bog-fen pairs were studied: the Lost River peatland located over a regional groundwater discharge zone and the Red Lake peatland situated atop a hydrologic divide where recharge is expected to occur. Bog pore waters consist of 90–100% precipitation in the upper 2 m, below which they mix with groundwater. Adjacent fens consist mostly of groundwater, ranging from ∼30% near the surface to ∼100% with depth. At the Red Lake peatland, mixing relations suggest an additional Sr source that may be peat mineralization. Distinct 87Sr/86Sr and [Ca]/[Sr] ratios for groundwater discharging into bog and fen sites are indicative of distinct groundwater sources and are likely indicative of flow paths at two different length scales.
Yong Nie - One of the best experts on this subject based on the ideXlab platform.
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a regional scale assessment of himalayan Glacial Lake changes using satellite observations from 1990 to 2015
Remote Sensing of Environment, 2017Co-Authors: Yongwei Sheng, Shiyin Liu, Qiao Liu, Yong Nie, Linshan Liu, Yili Zhang, Chunqiao SongAbstract:Abstract The Himalaya, the world's highest mountain ranges, are home to a large group of glaciers and Glacial Lakes. Glacial Lake outburst floods (GLOFs) in this region have resulted in catastrophic damages and fatalities in the past decades. The recent warming has caused dramatic Glacial Lake changes and increased potential GLOF risk in the Himalaya. However, our knowledge on the current state and change of Glacial Lakes in the entire Himalaya is limited. This study maps the current (2015) distribution of Glacial Lakes across the entire Himalaya and monitors the spatially-explicit evolution of Glacial Lakes over five time periods from 1990 to 2015 using a total of 348 Landsat images at 30 m resolution. The results show that 4950 Glacial Lakes in 2015 cover a total area of 455.3 ± 72.7 km2, mainly located between 4000 m and 5700 m above sea level. Himalayan Glacial Lakes expanded by approximately 14.1% from 1990 to 2015. The changing patterns of supraGlacial Lakes and proGlacial Lakes are rather complex, involving both Lake disappearance and emergence. Many emergent Glacial Lakes are found at higher elevations, especially the new proGlacial Lakes, which have formed as a result of glacier retreat. Spatially heterogeneous changes of Himalayan Glacial Lakes are observed, with the most significant expansion occurring in the southern slopes of the central Himalaya. Increasing glacier meltwater induced by the Himalayan atmospheric warming is a primary cause for the observed Lake expansion. This study provides primary data for future GLOF risk assessments. A total of 118 rapidly expanded Glacial Lakes are identified as potential vulnerable Lakes for the priority of risk assessment.
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Glacial Lake evolution in the southeastern tibetan plateau and the cause of rapid expansion of proGlacial Lakes linked to Glacial hydrogeomorphic processes
Journal of Hydrology, 2016Co-Authors: Chunqiao Song, Yongwei Sheng, Yong Nie, Jida WangAbstract:Abstract Glacial Lakes, as an important component of the cryosphere in the southeastern Tibetan Plateau (SETP) in response to climate change, pose significant threats to the downstream lives and properties of people, engineering construction, and ecological environment via outburst floods, yet we currently have limited knowledge of their distribution, evolution, and the driving mechanism of rapid expansions due to the low accessibility and harsh natural conditions. By integrating optical imagery, satellite altimetry and digital elevation model (DEM), this study presents a regional-scale investigation of Glacial Lake dynamics across two river basins of the SETP during 1988–2013 and further explores the Glacial-hydrogeomorphic process of rapidly expanding Lakes. In total 1278 and 1396 Glacial Lakes were inventoried in 1988 and 2013, respectively. Approximately 92.4% of the Lakes in 2013 are not in contact with modern glaciers, and the remaining 7.6% includes 27 (1.9%) debris-contact Lakes (in contact with debris-covered ice) and 80 (5.7%) cirque Lakes. In categorizing Lake variations, we found that debris-contact proGlacial Lakes experienced much more rapid expansions (∼75%) than cirque Lakes (∼7%) and non-glacier-contact Lakes (∼3%). To explore the cause of rapid expansion for these debris-contact Lakes, we further investigated the mass balance of parent glaciers and elevation changes in Lake surfaces and debris-covered glacier tongues using time-series Landsat images, ICESat altimetry, and DEM. Results reveal that the upstream expansion of debris-contact proGlacial Lakes was not directly associated with rising water levels but with a geomorphological alternation of upstream Lake basins caused by melting-induced debris subsidence at glacier termini. This suggests that the hydrogeomorphic process of glacier thinning and retreat, in comparison with direct Glacial meltwater alone, may have played a dominant role in the recent Glacial Lake expansion observed across the SETP. Our findings assist in understanding the expansion mechanism of debris-contact proGlacial Lakes, which facilitates early recognition of potential Glacial Lake hazards in this region.
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recent glacier and Glacial Lake changes and their interactions in the bugyai kangri southeast tibet
Annals of Glaciology, 2016Co-Authors: Qiao Liu, Wanqin Guo, Yong Nie, Shiyin LiuAbstract:Glaciers in the Bugyai Kangri are located in a transition zone from southeast Tibet, where monsoonal temperate glaciers dominate, to inner Tibet, where continental glaciers dominate. Here we analyze glacier and Glacial Lake changes in this region using multi-year inventories based on Landsat images from 1981-2013. Results show that the total area of 141 glaciers in the region decreased by 30.44 +/- 0.89 km(2) from 198.35 +/- 9.54km(2) (1980s) to 167.93 +/- 4.52 km(2) (2010s). The annual area shrinkage rate (-0.48% a(-1)) is lower than that reported for southeastern Tibet but higher than that of inner Tibet. Both the number and total area of Glacial Lakes increased between 1981 and 2013. Among all Lakes, proGlacial Lakes contribute most (similar to 81%) to the expansion. The total area of ten proGlacial Lakes increased by 150.3 +/- 13.17% and of these ten Lakes the four that expanded most sharply showed increased calving at their upper margins, resulting in more rapid retreat of Lake-terminating glaciers than land-terminating glaciers. Owing to rapid calving, several Lakes may undergo further growth in the near future, increasing the potential risk of Glacial Lake outburst floods.
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Glacial Lake expansion in the central himalayas by landsat images 1990 2010
2014 AGU Fall Meeting, 2014Co-Authors: Yong Nie, Qiao Liu, Shiyin LiuAbstract:Glacial Lake outburst flood (GLOF) is a serious hazard in high, mountainous regions. In the Himalayas, catastrophic risks of GLOFs have increased in recent years because most Himalayan glaciers have experienced remarkable downwasting under a warming climate. However, current knowledge about the distribution and recent changes in Glacial Lakes within the central Himalaya mountain range is still limited. Here, we conducted a systematic investigation of the Glacial Lakes within the entire central Himalaya range by using an object-oriented image processing method based on the Landsat Thematic Mapper (TM) or Enhanced Thematic Mapper (ETM) images from 1990 to 2010. We extracted the Lake boundaries for four time points (1990, 2000, 2005 and 2010) and used a time series inspection method combined with a consistent spatial resolution of Landsat images that consistently revealed Lake expansion. Our results show that the Glacial Lakes expanded rapidly by 17.11% from 1990 to 2010. The pre-existing, larger Glacial Lakes, rather than the newly formed Lakes, contributed most to the areal expansion. The greatest expansions occurred at the altitudinal zones between 4800 m and 5600 m at the north side of the main Himalayan range and between 4500 m and 5600 m at the south side, respectively. Based on the expansion rate, area and type of Glacial Lakes, we identified 67 rapidly expanding Glacial Lakes in the central Himalayan region that need to be closely monitored in the future. The warming and increasing amounts of light-absorbing constituents of snow and ice could have accelerated the melting that directly affected the Glacial Lake expansion. Across the main central Himalayas, Glacial Lakes at the north side show more remarkable expansion than those at the south side. An effective monitoring and warning system for critical Glacial Lakes is urgently needed.
Georg Veh - One of the best experts on this subject based on the ideXlab platform.
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unchanged frequency of moraine dammed Glacial Lake outburst floods in the himalaya
Nature Climate Change, 2019Co-Authors: Georg Veh, Oliver Korup, Sebastian Specht, Sigrid Roessner, Ariane WalzAbstract:Shrinking glaciers in the Hindu Kush–Karakoram–Himalaya–Nyainqentanglha (HKKHN) region have formed several thousand moraine-dammed Glacial Lakes1–3, some of these having grown rapidly in past decades3,4. This growth may promote more frequent and potentially destructive Glacial Lake outburst floods (GLOFs)5–7. Testing this hypothesis, however, is confounded by incomplete databases of the few reliable, though selective, case studies. Here we present a consistent Himalayan GLOF inventory derived automatically from all available Landsat imagery since the late 1980s. We more than double the known GLOF count and identify the southern Himalayas as a hotspot region, compared to the more rarely affected Hindu Kush–Karakoram ranges. Nevertheless, the average annual frequency of 1.3 GLOFs has no credible posterior trend despite reported increases in Glacial Lake areas in most of the HKKHN3,8, so that GLOF activity per unit Lake area has decreased since the late 1980s. We conclude that learning more about the frequency and magnitude of outburst triggers, rather than focusing solely on rapidly growing Glacial Lakes, might improve the appraisal of GLOF hazards. Melting glaciers are increasing Himalayan Glacial Lakes and potentially the risk of outburst floods. An advanced automated algorithm identifies Glacial Lake outburst floods from Landsat images since the late 1980s to improve understanding of these events and trends in their frequency.
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detecting himalayan Glacial Lake outburst floods from landsat time series
Remote Sensing of Environment, 2018Co-Authors: Georg Veh, Oliver Korup, Sigrid Roessner, Ariane WalzAbstract:Abstract Several thousands of moraine-dammed and supraGlacial Lakes spread over the Hindu Kush Himalayan (HKH) region, and some have grown rapidly in past decades due to glacier retreat. The sudden emptying of these Lakes releases large volumes of water and sediment in destructive Glacial Lake outburst floods (GLOFs), one of the most publicised natural hazards to the rapidly growing Himalayan population. Despite the growing number and size of Glacial Lakes, the frequency of documented GLOFs is remarkably constant. We explore this possible reporting bias and offer a new processing chain for establishing a more complete Himalayan GLOF inventory. We make use of the full seasonal archive of Landsat images between 1988 and 2016, and track automatically where GLOFs left shrinking water bodies, and tails of sediment at high elevations. We trained a Random Forest classifier to generate fuzzy land cover maps for 2491 images, achieving overall accuracies of 91%. We developed a likelihood-based change point technique to estimate the timing of GLOFs at the pixel scale. Our method objectively detected ten out of eleven documented GLOFs, and another ten Lakes that gave rise to previously unreported GLOFs. We thus nearly doubled the existing GLOF record for a study area covering ~ 10% of the HKH region. Remaining challenges for automatically detecting GLOFs include image insufficiently accurate co-registration, misclassifications in the land cover maps and image noise from clouds, shadows or ice. Yet our processing chain is robust and has the potential for being applied on the greater HKH and mountain ranges elsewhere, opening the door for objectively expanding the knowledge base on GLOF activity over the past three decades.