The American Geophysical Union (AGU) annual Fall Meeting later this month is one of the biggest earth science meetings of the year. This year the student research projects from the Juneau Icefield Research Program (JIRP) have each prepared a poster on their scientific projects and findings to be presented t this meeting by a student representative of the group. Its a great achievement and I hope those who can attend the meeting have a great time there. If you are visiting the AGU please try to visit the posters being presented by our teams of students, which I have listed below. The name of the person presenting the poster is given in brackets after the poster title although the posters were prepared by a whole team, whose names can be found my following the title link to the abstract.
Many JIRP faculty are also presenting at the AGU Fall Meeting, including Jason Amundson, Anthony Arendt, Billy Armstrong, Matt Beedle, Kiya Riverman, Eric Klein, Jeremy Littell, Brad Markle, Chris McNeil, Twila Moon, Allen Pope, Shad O’Neel and Martin Truffer. Have a talk to any of our former students of these faculty members to learn more about the program. Or indeed, check out the JIRP blog, which continues to post students reflections and continuing news on the website.
In April this year, Costanza and I went to try and download some data from a water level guage on the Dudh Kosi Phanka and Nha, in front of the Ngozumpa glacier, operated by the Department of Hydrology and Meteorology. Unfortunately, we found that it had been dismantled – looks like someone decided they could make better use of the solar panel and the battery. To be fair, that is likely to be true!
Anyway it made me think about what data was ever collected from this guage and all I could find was data from 2007, though there may well be more. I don’t know the full history of its installation, maintenance and data download history.
You can see some of the data below but first some information on the sensor and some caveats.
The sensor is a sonic ranger so it measures a distance to the water level, by using the speed of soun, and the travel time for a sonic pulse to bounce back from the water surface to the sensor.
This will obviously be noisy as the water surface is choppy and variable, even though its mounted over a backwash pool.
Readings were saved for 15 minute, 60 minute and daily values – I have not seen the program for this but I assume these are averaged values in order to filter out some of the noise.
This location captures runoff from the connected lakes and cathcments on the west side of the glacier, as well a the glacier.
First, I wanted to remove some of the outliers as there are some big jumps in the apparent water level in the dataset which are unlikely to be true. So, I made a very crude filter by determining the mean distance to the water level (calculated on all data including those that I think are probably erroneous), which was 2.01m, and removed all data points that deviated from this by more than 1.50m. I chose this threshold just by eyeballing the data and its a pretty generous filter in that it definitely lets through some remaining noise, but I thought thats better that excluding some valid data.
Here is the daily mean water level for the available data bracketed by the daily maximum and minimum in grey. Clearly there are still some values that are most probably errors and they will be affecting the calculated mean values, but you can see the general pattern of peak water level during the core monsoon months which is as expected.
Then I used the 15 minute data to plot the hour of the day when the high and low water occurred. Becasue of limitations in the size of the memory of teh datalogger (which overwrites its data once its full), this covers only the latter part of 2007. I think the plot is kind of interesting as it looks like during the core summer monsoon months of July, August and September that the river level is highest around the middle of the night, whereas outside of these three summer monsoon months the river is highest in the middle of the day.
To be honest I’m not totally sure how to interpret this. Is this because the monsoon rain comes in the afternoon/evening here and by the time it all comes downstream its late into the night? Or does this tell us something about the efficiency of the glacier drainage system varying between these two seasons? I’d need to analyse the precipitation data at the same time to start exploring this, and I do not have that data to hand just now. Watch this space.
Allie Strel is studying cartography and is one of the staff partly responsible for the student mass balance measurements of the Juneau Icefield during JIRP each summer. She has made this infographic of the Juneau icefield mass balance measurement program:
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I recently spent a delightful few days wandering around Grindelwald with my friend (and paleclimatologist) Brad Markle. Isn’t it nice?
On one particularly fine sunny day we got to talking about websites, blogging, tweeting and so on. I am quite a proponent of this actually, even though initially it seems its going to take way too much time away from the more important science activities that we actually are judged on, get jobs on, and feel pressured to produce more of.
That is writing papers of course.
I have mixed feelings about this heavy weighting of success on the number of papers published by scientists, as I think it has some negative consequences for the integrity of the science being produced, as well as being responsible for making a glut of incremental papers instead of a smaller number of more complete, well thought out, and well-reviewed papers. However, that topic is not for this blog, and also its a hard thing for me to take a stance on as my own publication list is generally too short, low impact, and of marginal interest, so I need to be careful not to sound bitter and like I am just making excuses for my own shortcomings.
So, on to the business at hand. Let me first tell you a story about how I began to develop my own small web presence, then I will follow up with what I get out of it, and why I have grown to appreciate what it offers far more than I did at my cynical outset.
I made this website as I thought it might increase my chances of getting a grant from the FWF. I googled what would be the easiest way to do this, and concluded: WordPress. I decided if I could not make a webpage in half a day then it was too much time to invest. With WordPress I managed to meet this tight time constraint and had the bare bones of my website by 11am. I was however a bit annoyed to see that (at least at that time) you could not avoid having a blog page with WordPress. I thought “Curses! I’ve not time for that! I can’t even get my own papers written”. But I was stuck, as to start again with a package that did not require a blog component would mean going over my half-day time rule. For some months before this, a friend of mine who works in sustainability had been trying to get be to join Twitter. She advised me that you can use it as a filtered news feed to keep up to data on thing of interest to you. I realised that I could link a Twitter feed onto my website thereby making some updates to the page even if I was too lazy to write real blogs. So I joined Twitter as well.
Yes, I was pretty cynical. But now I like it a lot, and here are some reasons why.
I chose my website content to serve my own interests. It helps me:
Keep a clean record of my achievements in my online CV, which saves me time when I need to do annoying tasks like complete my annual achievement reports to my own University, apply for jobs, find my own papers/posters if I want to share them with colleagues
Have a feed of journal contents of potential interest to me in one place (admittedly this partly broke when the EGU changed their RSS feed and it took me more than half a day to try and fix it so it is not fixed – sorry, but it was really useful to me for a while)
Easily provide useful background on me and my work if I am contacted by colleagues, media or anyone else, and also if I am approaching someone for help I use it to offer background on me
My blog helps me in even more ways:
I write up the small bits of analysis that we all have to do to check quality, process out data, understand its meaning. The kind of things that take 3 days of data analysis and then become one or two lines in a publication, like how do my measurements compare to earlier or other measurements. These posts are super-useful when colleagues come with questions about the basic science of my projects. Many times I have avoided a long email answer to a valid questions by being able to say: “Check out this blog which answers all your questions”. I find this useful as its like keeping an online lab book of the small analysis step we make, s it costs little time to do and saves lots of time if someone asks you details about something you did months ago (and you can’t remember everything off the top of your head, so would have to spend time going back to your analysis notes). I see these types of blog as saving me time in the long run.
I also write some opinion pieces. These blogs help me clear up my thinking on a certain topic and help me develop a (hopefully) clear, straightforward writing style.
Also some days when everything is going wrong, I write a short, fun blog post just to trick myself into believing I have achieved something. I see these types of blog as serving an important role in making me feel I can round off a hitherto unsatisfactory work day on a positive note.
I guess the outreach impact of my blogging is very small as I do not ‘advertize’ the things I write via other channels and I suppose the traffic to my site is low. I feel uncomfortable with self-promotion, so I am happy with this, but it means I cannot really assess the potential impact of blogging. Certainly, I do try and use my blog if I am contacted by the media, in my face-to-face outreach, my teaching, and my research partners are glad to have something to put in a web outreach box in the annual reports to the funding agencies.
Tweeting helps me in different ways:
I tweet things that I’ve read, and find valuable sources of information that I might need to look up later – so basically its like a public internet reading list for my own personal use. How selfish. But at least I share it, right? It might be useful to you too?
It makes it look like I update my website even if I’m too lazy/ have no time to write a blog post. I guess this actually fools no-one.
The people I follow give me filtered news on imprint glaciological topics that I am not directly involved in. For example, I do no research on the large icesheets, and these are a hot bed for new glaciological understanding, are of great relevance to understanding past climate, and future sea levels, and I think its important that I know whats going on in this sphere. However, I’ve hardly the time to read all the papers on icesheets as well as all the papers coming out each week on mountain glaciers and topics I am actually engaged in researching in. So. Twitter gives me soundbite updates and points me towards things that I really must make the time to read. In doing this it makes me a better, broader, scientist.
Linking Twitter to a Facebook page lets me update my community page on research on glaciers in the Khumbu Himal, without actually having to look at Facebook very often. Phew! Dodged a procrastination bullet there! Yes, thats right, I actually have TWO webpages, twitter accounts and Facebook pages. Never thought that would happen.
So there you have it. My first rule of my web and social media presence is that I don’t let it take too much of my time. That means if its hard to do something technical with the webpage, or some potentially interesting blog topic would take a weeks worth of otherwise un-necessary research, then it won’t get done. My second rule is that I don’t let Twitter get me depressed by the onslaught of achievement that it delivers to my screen. Rule #1 is easier than rule #2, but I hope this blog helps convince some people to get involved. The public deserve that we learn to communicate our science better. Have fun!
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There are always so many things to do and learn about! Its fun having Jordan Mertes here in Innsbruck for a while, as he is expert in using Structure from Motion tools to develop surface terrain models. I’ve dabbled in this a fair bit but usually feel a bit out of my depth and am not always sure if I have generated models of the best possible quality.
The principle is that you take a bunch of photos of an object or surface of interest, from a variety of angles and distances and specialized software can be used to identify a large number of common features in the images, perform a suite of positional calculations on these and determine where the photos was taken from and also the 3D form of the surface being photographed. Its pretty cool stuff. Anyone can do it! Like many colleagues of mine, I use Agisoft Photoscan software, which you must pay for, but there are other freeware versions using the same principles such as Visual Structure from Motion. All you need is a camera and a computer and a natty idea …
Ben Partan and I took a bunch of images and videos in 2013/2014 to see how well we could use this kind of photogrammetry and software to create surface models of snow penitentes in Chile to compare with the models we generated using the Microsoft Kinect as a close range 3D camera (see Nicholson et al., 2016).
Penitentes are a hard challenge for terrestrial photography as the contrast is poor and the surface is complex and shadowed. It was a very good learning ground for us – we could see how well different configurations of photo vantage points compared to extracting frames from videos, and we tried both cheap and high quality cameras.
Below is an example model of snow penitentes in a river bed, where we tested all our equipment and set up. The image is a screenshot from Agisoft Photoscan software. You can see from the camera positions indicated in blue that we were trying two approaches: (1) taking an array of photos from a single location and moving on to do the same at another, and (2) taking a single photo, and then moving along a meter to take the next one.
You can read much more about Structure from Motion (SfM) applications in earth science in this new book: Structure from Motion in the Geosciences by Jon Carrivick, Mark Smith and Duncan Quincey, and in Westoby and others (2012). A very timely publication indeed as these techniques are booming in earth science and perhaps especially in glaciology at present. You can read more about the penitentes we measured in our publication in the Cryosphere.
Westoby, M. J., Brasington, J., Glasser, N. F., Hambrey, M. J., & Reynolds, J. M. (2012). “Structure from-Motion” photogrammetry: A low-cost, effective tool for geoscience applications. Geomorphology, 179, 300–314. doi:10.1016/j.geomorph.2012.08.021
Nicholson, L. I., Petlicki, M., Partan, B., and MacDonell, S. (2016) 3D surface properties of glacier penitentes over an ablation season, measured using a Microsoft Xbox Kinect, The Cryosphere, 10, 1897-1913, doi:10.5194/tc-10-1897-2016, 2016.
I like to follow the work of my colleagues and office mates, and both Ben Marzeion and Kristin Richter were recently involved in publishing a paper in Nature Climate Change that demonstrates that human activities dominate the recent sea level rise.
The key findings are that in the first half of the 20th century, only about 15 % of sea-level rise were of anthropogenic origin, but human emissions caused about 70 % of sea-level rise between 1970 and 2005, as summarized in the infographic below.
Interesting times at the Imja lake in 2016. The Nepali Army are lowering the water level by 3m. The thought behind this is that is a lot of water hemmed in behind an ice cored moraine, and that this poses a flood threat as (i) an ice cored dam is fundamentally not very reliable and is expected to be less so under continued regional climate change and (ii) ongoing glacier retreat causes the lake to keep expanding. A nice clear summary is given on the From a Glaciers Perspective blog written by Mauro Pelto.
This photo of the lake, looking upglacier is by Jeff Kargel. I took it from an article on www.scitechdaily.com so unfortunately I don’t know the exact date of it, but as its from the air it gives the best view! Note the bright blue of some of the lakes that are not turbid as the water is still within them and the sediment is settling to the bottom of the waterbody.
According to what I’ve read in the news the army has airlifted a lot of heavy equipment up to do this engineering work at just over 5000m. Quite a feat already.
From the Kathmandu Post: “The DHM in technical and financial support from the United Nations Development Programme and the Global Environment Facility is implementing the $7.2 million Community Based Flood and Glacial Lake Outburst Risk Reduction Project (CFGORRP) that aims to reduce possible loss of human lives and infrastructure from a glacial lake outburst flooding in Solukhumbu and the downstream Tarai and Churia districts of Mahottari, Siraha, Saptari and Udaypur.“
The risk assessment of glacier lakes such as the Imja is a tricky business (e.g. Emmer and Vilimek, 2013). They are considered more dangerous if (a) the moraine dam is narrow, and if (b) ice or rock avalanches into the lake are likely, as these trigger waves that can overtop the moraine dam and in the process of doing so instigate a rapid erosion of the dam which could ultimately cause an outburst to occur. The Imja lake was previously being drained by a narrow spillway that meandered across 100s of metres of moraine dam to enter the downvalley river flow, deeming it relatively stable. Furthermore, the Glaciersonline site about the Imja lake notes that geophysical data collected by Reynolds International shows that much of the moraine dam is not ice cored and therefore is much more stable than some moraine lake dams. However, this lake, which is more than 1.5km long, 600m wide and 90m deep in places, is currently the fastest growing lake in Nepal, expanding at over 40m/year, and a series of lakes are expanding around this spillway. If these small lakes within the moraine dam continue to expand, the effective width of the moraine dam will be reduced over time. At the same time, as the lake expands upglacier, eating away at the ice which is no longer replenished by sufficient from accumulation from above the upglacier expansion of the main lake might eventually mean that the lakewaters will be overlooked by steep slopes from which avalanches are likely.
Thus clip from the forthcoming movie Outburst illustrates some of the main risk criteria that are causes for concern regarding glacier lake outburst floods, using the example of an un-named lake in the Hongu valley:
The Imja lake, and the threat it may or may not present has been a cause of tension between the local community and researchers and media outlets that emphasize, and are alleged to exaggerate, the catastrophic likelihood of a flood. For example, it was sad for me to hear stories of how residents of Namche, which lies 100s of metres above the river in the valley below, were so panicked about the threat of a flood from the Imja lake occurring during the earthquake of April 2015, that some people were fleeing uphill, even though even if all of the water from the Imja lake were to escape, Namche itself would certainly not be affected directly. This seems to indicate a failure to communicate the threat accurately and effectively, despite the ongoing efforts of groups such as ICIMOD and The Mountain Institute and the HiMAP project. Hopefully their continued efforts, and wider community collaboration will change this over time.
Imja lake GLOF risk has in the past been assessed as moderate, and on this basis I guess (not very scientific I know, but I have not had time to really dig into the limited number of high quality hazard assessments made on some of these lakes!) there might be glacier lakes in the Himalaya that are more likely to be the sources of outburst floods in the near future. However, as the fastest growing glacier lake in Nepal, the government recently identified it as one of the 6 most dangerous lakes in the country, and, as this region is so important for tourism in Nepal, and downstream communities are concerned about potential flooding, the decision to act has been taken. Given the size of the lake and how it is developing it may be a timely intervention, although of course the catch with averted disasters is that its never clear if there would have been a disaster without the intervention.
To my knowledge, the most comprehensive survey of glacier lakes in the Himalaya is that carried out by ICIMOD, which is freely available to download here, and is well worth a read for its balanced view on our current knowledge, risk assessment and communicating risk.
Here is the flowchart used to identify the lakes posing a critical risk:
Here are the lakes identified as dangerous according to this criteria:
Emmer, A. and Vilimek, V (2013) Review Article: Lake and breach hazard assessment for moraine-dammed lakes: an example from the Cordillera Blanca (Peru). Nat. Hazards Earth Syst. Sci., 13, 1551–1565
ICIMOD (2011) Glacier lakes and glacial lake outburst floods in Nepal. Kathmandu: ICIMOD.
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Debris-covered glaciers are a particularly large component of the mountain cryosphere in the eastern Nepalese Himalaya:
NASA Earth observatory image of the day 17th October 2010, showing the debris-covered glaciers near Mt Everest.
The Ngozumpa glacier is a debris covered glacier (just out of the image above to the west) and also the largest glacier in Nepal. It was the target of our fieldwork in April. As you can see in the photo below it presents pretty challenging terrain to work on. Access to the glacier is made difficult because of high upstanding moraines around it. Nevertheless we wanted to get onto this glacier and measure how thick the ice is.
View looking roughly northwards up the Ngozumpa glacier towards Gyachung Kang, showing the lumpy debris covered glacier surface lying about 100m below the upstanding lateral moraines.
The motivation for this is twofold: Firstly, the total volume of ice in the Himalaya is poorly known so every data point that can be added helps improve estimates of how much water is stored in glaciers there. Secondly, we need to know the ice thickness in order to be able to apply numerical models of how the glacier will behave.
To measure the thickness of the glacier we set out to use ground penetrating radar. This sends out a low frequency radio wave that penetrates the glacier ice and is reflected back from the glacier bed towards the surface. The time it takes to receive the reflected signal can be converted into a representation of ice thickness. We had both Narod and Dolores radar systems with us, and antennae that could span 2-20MHz frequencies. These are long cable antennae that need to be laid out and moved across the glacer surface.
To my knowledge the only previous measurements on this glacier are from Sarah Thompsons PhD thesis, in which she measured ice thicknesses of 80m just above what is called the Spillway lake, so about 1km from the terminus. This is quite interesting as the maximum depth of this lake is about 30m suggesting that its might still be underlain with lots of ice.
The map on the left shows the Ngozumpa glacier ouline, with the approximate locations of the ground penetrating radar lines measured shown in red (we also did some down-glacier long profiles between these cross-profile lines to help generate a more comprehensive 3D model of the ground beneath the glacier), and the location of the Spillway lake, which is shown in detail on the right with the depths in 2010 (Thompson et al., 2012).
Hamish Pritchard is leading the charge in analysing the ice thickness data as he has already collected similar data from the Langtang region of central Nepal. The radar data from these glaciers is generally quite noisy and it can be difficult to see a strong bed reflector, but by taking a lot of measurements and by measuring extended profiles, the bed is easier to identify.
Thompson, S., Benn, D. I., Dennis, K., Luckman, A. (2012) A rapidly growing moraine-dammed glacial lake on Ngozumpa Glacier, Nepal.Geomorphology,145–146, 1–11
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