Category Archives: Our news

UAV surveys in Canadian Rockies

A report by Philip Kraaijenbrink

I am visiting Canmore in the Canadian Rocky Mountains to collaborate with Joe Shea on a new unmanned aerial vehicle study led by the Centre for Hydrology of the University of Saskatchewan. The objective is to monitor snow melt and redistribution throughout the melt season using UAV surveys and in situ measurements of the snow pack. The study site is near Fortress Mountain at about 2300 m elevation and is easily accessible by a combination of car and snowmobile.

Unfortunately, the site is often used by the film industry for winter forest scenes. Miscommunication has had us travel up there last week on snowmobiles to find out we could not fly because of a movie shoot. Additionally, the movie crew considerably disturbed the snow pack of interest…

Therefore, we went off to a new site just a bit further up the ridge today. Of course only after checking the weather and wind conditions using the various self-maintained weather stations at the site. Objective: redo the entire ground control survey that was carried out at the other site and perform some UAV flights.

Conditions on the ridge were a bit windy at first but we had faith it would settle down in the afternoon for the flights. Instead of settling down though, strong wind and heavy gusts came in at lunch time. Besides not being able to fly because of the wind, pounding in ground control poles and measuring them with the DGPS rover was not even possible since the gusts made walking around in the snow with all the gear next to impossible. Turned out to be the worst winds of the whole week. Let’s hope for better luck next time we’re in…

 

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Getting up the ridge with snowmobiles and toboggans.

 

Pannable 360-panorama of the site on Fortress Ridge and the DGPS setup.

 

Onset of the winds while doing the final DGPS setup.

 

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Graph of wind speed measured at Fortress Mountain over the last week.

3-D model of ice cliff backwasting published

Pascal and several team members have just had published their paper, A physically based 3-D model of ice cliff evolution over debris-covered glaciers, in the Journal of Geophysical Research: Earth Surface. They used a new data set of high-resolution observations of cliff evolution over one ablation season to identify patterns of changes over four cliffs on the debris-covered tongue of Lirung Glacier (Nepalese Himalaya). The four cliffs have different shape, dominant orientation and slopes, and different degree and history of coupling to a supraglacial pond. The observations show that cliffs on the same glacier and at short distance from each other can both flatten and recline, remain self-similar, or expand radially. Based on the observations a model accounting for the three main processes controlling cliff evolution was developed: atmospheric melt, pond contact ablation enhancement for the cliff base, and reburial by surrounding debris. This modeling approach is able to simulate the cliff evolution over one melt season in a satisfying way in terms of horizontal and vertical extent as well as mean slope and aspect. Modelled volume losses could be validated and were in agreement with TIN-based observations (Brun et al. 2016, Journal of Glaciology).

Simulated cliff evolution based on the monthly updated outlines.

Simulated cliff evolution based on the monthly updated outlines.

The model is able to capture the main cliff dynamics and geometric transformation. Importantly, the model application has clearly shown that for very high resolution studies, neglecting a dynamic update of the cliff geometry would lead to erroneous results in terms of backwasting patterns and volumes.

Updates from Cambridge: PhD, new OA paper, new project

Evan Miles passes PhD viva

Research team member Evan Miles, based at the University of Cambridge, has recently passed his PhD viva and will now be Dr Miles!  His thesis, titled ‘Spatio-temporal variability and energy-balance implications of surface ponds on Himalayan debris-covered glaciers’ has combined remote sensing, field surveys, and numerical modelling to understand the role of supraglacial ponds.

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Figure 1: Evan Miles and Anna Chesnokova installing thermistor strings and a pressure transducer in a supraglacial pond on Lirung Glacier, May 2014.

 

New OA paper studying spatio-temporal variability of supraglacial ponds

Evan and several other team members have just had an Open Access paper published in the Journal of Glaciology based on one aspect of Evan’s doctoral work, Spatial, seasonal and interannual variability of supraglacial ponds in the Langtang Valley of Nepal, 1999–2013.  The study uses 15 years of Landsat data (172 scenes) to analyse the variability of supraglacial ponds on a set of five debris-covered glaciers.  This is a major advance in several ways, as prior studies have used only a few scenes to assess ponded area for debris-covered glaciers.  The use of such an extensive dataset allowed the authors to also assess the spatial patterns of ponding and interannual changes in pond cover in a more robust way than has been done previously.

 

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Figure 2: Spatial distribution of supraglacial ponds as percent of May–October observations (n =68), also showing results for other lakes outside the debris-covered tongues (orange ellipses), 1999–2013.

 

One of the most important results is the seasonal variability of ponds, which controls the role they can play in a glacier’s mass balance.  Expect more news on that topic soon!

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Figure 3: Seasonal pattern of thawed pond cover as percent of observable debris-covered glacier area, with individual scenes coloured by year of observation (n =172) and dot tails highlighting the effect of a 34% overestimation of pond area. The solid black line is the monthly mean, with dashed lines showing the ± 1σ spread.

 

Evan Miles to start Post-Doc in Leeds

Finally, Evan has accepted a two-year research position at the University of Leeds to work with Dr Duncan Quincey, Dr Bryn Hubbard (Aberystwyth University), and Dr Ann Rowan (Sheffield University) as part of the NERC-funded EverDrill project. This is an exciting and ambitious effort to drill to the bed of Khumbu Glacier and install a sensor suite to understand englacial and subglacial processes, a first for the Himalaya, and a critical need identified by other MountainHydrology team members.  More project info can be found here.  Evan will continue to be peripherally involved in many MountainHydrology projects.

New paper: climate change impacts on upper Indus basin hydrology

The Indus is one of the most meltwater-dependent rivers on Earth, and hosts a large, rapidly growing population and the world’s largest irrigation scheme. Understanding the hydrology of the upper Indus basin is challenging. The Hindu Kush, Karakoram and Himalayan mountain ranges are difficult to access, hampering field measurements of meteorological, glaciological and hydrological processes. These processes are therefore still poorly understood. To make it more complex, climate change projections for the Indus basin show a very large spread. In our recent (open access) paper published in PLoS ONE we present hydrological projections for the 21st century in the upper Indus basin, based on a cryospheric-hydrological model forced with an ensemble of downscaled GCM outputs.

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The Hunza river in front of the Passu cones (upper Indus basin).

 

Three methodological advances are introduced:

  • A new precipitation dataset that corrects for the underestimation of high-altitude precipitation is used.
  • The model is calibrated using data on river runoff, snow cover and geodetic glacier mass balance.
  • An advanced statistical downscaling technique is used that accounts for changes in precipitation extremes.

sources

Our projections indicate decreases in glacier melt contribution in favor of snow melt and rainfall-runoff contribution to stream flow in the upper Indus basin, at the end of the 21st century.

 

The focus of the analysis in our study is not only on changes in sources of runoff and water availability but also on changes in seasonality and hydrological extremes, which are still large unknowns in the upper Indus basin. We conclude that the upper Indus basin faces a very uncertain future in terms of water availability towards the end of the 21st century. Despite the large uncertainties in future climate and water availability, basin-wide patterns and trends of intra-annual shifts in water availability are consistent across climate change scenarios. For the near future these trends mainly consist of minor increases in summer flows combined with increased flows during other seasons. For the far future the trends show decreases in summer flows combined with stronger increasing flows during the other seasons. Furthermore, increases in intensity and frequency of extreme discharges are found for most of the upper Indus basin and for most scenarios and models considered, implying increases in flooding events during the 21st century.

The study is presented at the AGU Fall meeting in San Francisco on Monday, 12 December 09:15 – 09:30, Moscone West – 3005

 

extremes

Analysis of future changes indicates increases in the frequency and magnitude of extreme flows for most of the UIB and most of the climate change scenarios.

New ICIMOD video on our Himalayan research

We know very little about glaciers in the high mountains. We know they’re shrinking and temperatures are rising faster at higher altitudes than anywhere else on the planet. But, due to extreme conditions and inaccessibility, we have much to learn. Detailed field measurements are being made on just twelve out of some 54,000 glaciers in the Himalayas. More measurements are needed because these glaciers feed the rivers people living down below rely on.

 


Directed and produced by Susan Hale Thomas

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