Questions related to Glacial Geomorphology
Dear research colleagues,
Is there a method to detect glaciers from out of space with satellite images?
Resolution is of course the bottleneck here. So coarser than 100m image data is not beneficial.
1) What Satellite Images are most beneficial for this task?
2) What type of image data might be suited best? Is a specific choice of bands helpful or do LST provide most promising results?
3) I have encountered this work below. It seems very promising, can someone evaluate?
The final goal is to automatically generate masks in shape of these glaciers. For example with help of unsupervised k-means classification or if necessary supervised classification to recognize and distinguish between glaciers and everything else including snow-covered soil by color (examples attached, as you can see it does not work very well yet.). These masks are further a key element for the test part in a CNN project.
Here is a very nice project with very fine masks from lakes and sea instead of glaciers: https://github.com/JiahuiYu/generative_inpainting/issues/451
Since I work mostly with GEE, here are several LST datasets which I ask you to evaluate if you have more experience than me:
Are there today any easy free GUI software e.g. to do with DEM this: draw a polygon, or select a feature/features/, or (automatically) somehow determine a wider area, and get the length, width and height and so on of (glacial) landform(s), or get morphometric characteristics of the selected area/part of the DEM.
In the increasing heating of the atmosphere due to climate change Glacial Lake Outburst Floods (GLOFs) are becoming more critical in the current century. Last decades GLOFs have already taken thousand of lives.
Does the current demand of research of GLOFs and Geo-Risk-Managment fit into a Master-Thesis in "Applied Geoscience" ?
Our Institute covers Hydrogeology, Georisks and Geological Engineering.
There are some mountaineous areas, where it is still not clear whether they have been glaciated during the late pleistocene. Though there is sometimes no typical glacial geomorphology, the bedrock is often covered by layers that are full of rounded and sharp stones. The altitude is too high to find aeolian sediments (like loess), that would make it easy to determine it as periglacial layer. The area where I found this material is situated in the Harz Mountains (Germany) in an area, that is susceptible of having been glaciated. But it has also been marked by periglacial processes afterwards. How can I clearly identify, whether these layers are periglacial or glacial till? THANKS
MWP-1C (Melt water pulse)was termed in Liu et al.,2004.In western pacific area, rapid sealevel rise occured 9.8-9.0ka BP,with the rate nearly 25mm/a. I am eager to konw are there any other geological evidence of rapid sealevel rise at this timespan?
8.2 sealevel jump was attributed to the abrupt collapse of Laurentied Ice sheet and out burst of glacial lakes(Agassia and Ojibway).
So,What's the difference and connection between MWP-1C and 8.2 sealevel jump? (timespan, amplitude of sealevel rise, sources of meltwater....)
Thank you very much!
From what I see, gemorpohology of proglacial zones of tropical glaciers has not been a major issue of concern. Together with my students, we're planning a small geomorphological project on Zongo glacier in Bolivia (drone, DEM, gemorphological map). Any publications, maps or more ideas for research would be of great use.
Thanks in advance,
The frequency curve is of a clay bed from a valley lake deposit in a mountanous terrain.
extreme care is taken when sampling so mixing of samples may not be the case.
This is a question that’s been asked for decades. There is always some danger in picking who first asked it, but glaciologist John Mercer in 1968 is a strong candidate. Mass changes in the ice sheet translate into changes in sea level, and a lot of people live close enough to sea level to be displaced if the ice sheet were to be lost, while many more enjoy the beaches and ports that would be affected.
Many things affect sea level. For example, more snow on an ice sheet — as we expect on the Antarctic ice sheet and central parts of Greenland in a warming world — tends to lower sea level by taking water that evaporated from the ocean and storing it on top of an ice sheet. But more melt on an ice sheet — as we expect in parts of Greenland with warming — takes water from the ice sheet and puts it back in the ocean, raising sea level. Melting of mountain glaciers has a similar effect as melting the ice sheet, as does pumping of water out of the ground to irrigate crops or for other uses, because most of that water ends up in the ocean rather than back in the ground. Warming the ocean causes expansion of the water and raises sea level. All of these are interesting and important influences, with notable uncertainties, but we don’t think that those uncertainties are huge.
Another way to raise sea level is for ice sheets to spread more rapidly under their own weight, taking ice from above sea level and delivering it to the ocean to make icebergs. This influence on sea level is complicated, and is where various uncertainties arise. Many factors control how rapidly ice flows, and thus how rapidly ice sheets can transfer land ice to the ocean to raise sea level.
Today, around most of Antarctica and parts of Greenland, the ice reaching the ocean does not immediately break off to make icebergs; instead it remains attached while spreading over the ocean, forming an ice shelf. The ice shelves almost all exist in bays or fjords, and thus have friction with their sides; the undersides of many ice shelves also hit local high spots in the seafloor, generating additional friction. Furthermore, the undersides of the ice shelves, where they are in contact with the ocean, are at their melting point. Warming ocean water tends to thin the shelves — a warming of 1 degree Celsius increases melting by about 10 meters per year — reducing the friction, and thus allowing faster flow of the ice that feeds the shelves, raising sea level.
Various features of the geologic record, modern observations, and investigations with models point to the importance of “threshold” behavior. Increasing the ocean temperature increases the ice’s speed, with the potential that at some high-enough temperature, the speed will jump rather abruptly and irreversibly. Such behavior is especially interesting and important, but also difficult to predict. You can undoubtedly think of many questions: What happens if the water temperature stays the same, but the rate of ocean circulation changes? What about warming adding meltwater into crevasses that could wedge them open and remove the friction that way? If an ice shelf is thinned, by how much does the flow speed increase? What are the thresholds?
A large and vigorous community of scientists in the field, remote-sensing experts, and modelers is working to measure, understand, project, and test the projections. And, we’re doing so with some urgency — we want to get answers in time to provide useful guidance to people making decisions about energy and the environment.
I would like to estimate quantification of error during the glaciers area mapping and I need instruction
I'm studying a body of ice with known thickness (60m) and slope (20°) and need to calculate the rate of strain (i.e., downslope velocity). I can calculate the downslope force of the glacier but I don't have the needed constants (k, A) needed to complete the strain rate calculation following the Glen-Nye Flow Law (strain rate = k*stress^n). Perhaps it is listed in Hooke's 'Glacial Mechanics' or Benn and Evans' 'Glaciers and Glaciation' texts? Thanks in advance, -Josh
I have no experience in glaciers modeling, but I think it could be useful in my work. I am considering post LGM deglaciation of subpolar fjord and I have a little information about retreats rates. It would be useful to model deglaciation over ~12 ka in order to get more control points for retreat rates. It is necessary for my numerical experiment with erosion rate (glacier positions are input and are integrated).
Do paramo ecosystems depend on glacial geoforms to exist? or can the exist wherever climate conditions are suitable?
I know that due to the variation on temperature given by glacial-intergacial cycles, two process occurs: an altitudinal variability on the bioclimatic floors, generating that paramo ecosystem goes lower or higher depending on the temperature, going lower when is colder and higher when is warmer, the same happens with glaciar environment, the glaciar goes lower when is colder and higher when is warmer.
It is known that in Colombia the maximum extension of glaciar masses was 2400 meters above sea level, and right now due to the temperature conditions paramo ecosystems are located among 3000 meters above sea level, and 4000 meters above sea level, covering old glacial landforms.
but is this a casual relationship between glacial landforms and paramo ecosystems? or there any posibility that paramos has generated a straight relationship with those glacial geoforms?
Right now I am working on a project with the Bogota Water Company. This company is in charge of water supply for the entire city of Bogotá. The water is taken from Chuza River basin, that is located in Chingaza's paramo. Paramo ecosystems are intertropical montane ecosistems located between 3200 meters above sea level and 4000 meters above sea level, with temperatures ranging between 2C and 17C, the mean annual temperature is 10C. In Colombia, all paramos are located on old glacial landscapes .
The project is about understanding what could happen with the water supply under global warming conditions.
From some fieldwork observations as well as aerial photographs interpretation, I could infer that glacial deposits offer the mot suitable geoforms for water catchment, and water infiltration. Glacial deposits have a high rugosity which is evidenced by the presence of a lot of depressions that concentrates water in small and swallow lakes similar to wetlands. I would like to produce a model, that gives me the water catchment susceptibility and water infiltration susceptibility in terms of geomorphology.
In order to solve this issue, I would like to know if anyone can help me with articles, techniques, methodologies regarding the evolution of glacial and periglacial geoforms under global warming, and regarding the relationship between glacial geoforms and water catchment, as well as glacial geoforms and water infiltration.
I would appreciate any information,
What are the best methods in Remote sensing and GIS to study the energy balance of a high altitude glacier where we have little or no observational data.
Current research suggests the possible existence of sporadic permafrost in relation to several buried ice patches of Picos de Europa, with mean annual temperatures close to 0ºC in the debris that cover these relict ice bodies. But so far it has not been demostrated to 100%.
I work in Svalbard. Proglacial rivers are shallow (usually up to ca. 50 cm), the expected discharge may reach up to 5 m3/second during extreme conditions, with summer averages of 0.5-1 m3/second. The flow is rather turbulent, sediment transfer is high, including rocks up to 10 cm in diameter. No stable ground is to be found at the sites, only gravel, occasionally washed out during higher water levels. Any additional abilities of such equipment (e.g. autosampling etc.) would be great, but I guess I'm asking too much.
If you have not heard of anything suitable for my needs, maybe you have some ideas how to organize manual discharge measurements so they will not become pain in the back very soon? I need to measure discharge in 3-4 streams, at least every 5-10 days, together 15 km of trekking. Again - what kind of equipment can you recommend?
I would appreciate any tips from more experienced colleagues.
Thanks for your time,
I want to know the ice sheet or glacier volume (not area) changes in the Tibetan area. Is there any satellite data or mathematical model to calculate the annual change rate, or is there any products already exist?
The rock was found as an erratic boulder in NE Germany (Usedom Island) and most probably comes from Sweden. SW Finland may also be possible though. The individual components are igneous rocks, mostly granites. the rock is part of an exhibition on glacial erratics (Gesteingarten am Forstamt Neu Pudgla) and we would like to add some more information. Please contact me for more details if you have an idea.
I will be using these instruments on Mt. Everest this spring, to look at albedo changes on snowpack on the ground and comparing from results obtained from orbit. Anticipated range: 6800 - 7500 meters. I'm wondering about battery life, field of view and sensitivity of both instruments.
We mapped bedform fields (drumlins, megalineations, ribbed moraine and hummocky terrain), and flow paths hundreds of kilometers long for most of the Laurentide Ice Sheet. In many cases, flow patterns are coherent over whole fields with pristine subglacial landscapes and little, if any, overprinting. Flow at the lateral margins of fields and paths was parallel to these margins-- if the bedforms were created during orderly retreat of arcuate termini the flowlines would be oblique to the lateral margins. Retreat moraines are extremely rare or absent or relate to extra-flow path glaciers, and there does not seem to be extensive masking of the bedforms by proglacial fans or other deposits. One exception is the appearance in some fields of one or a few very large and extensive glaciofluvial moraines, which do not relate to the patterns of bedforms. Tunnel channels and eskers are common elements of the subglacial landscape. I can only imagine that these characteristics mark bedform creation in a single event (others have made this suggestion), followed by ice-sheet stagnation over areas which may be >100 000 km^2. Any thoughts on this interpretation and its ramifications?
I'm a little confused about the inter-changeability of these terms in a marine sedimentation context. My understanding is as follows:
Glaciogenic sedimentation = sedimentation derived from glaciers (or ice-sheets)
Glacimarine sedimentation = sedimentation derived from glaciers (or ice-sheets) that calve directly into the marine environment.
If this is correct then glacimarine sedimentation is a subset of glaciogenic and either of the terms could be used when referring to an ice-sheet that extends into the sea.
Can anybody provide some clarification?