6 Matching Annotations
  1. Apr 2019
  2. Dec 2018
    1. This image shows what appears to be a large patch of fresh, untrodden snow – a dream for any lover of the holiday season. However, it’s a little too distant for a last-minute winter getaway: this feature, known as Korolev crater, is found on Mars, and is shown here in beautiful detail as seen by Mars Express.

      P Martian permafrost. The outer world seen from a very short distance. The inner life of the Red Planet.

  3. May 2017
    1. slope instability

      Slope instability occurs when mass-movement of rock, snow, or oil move downward due to gravity (Heritage). The types of slope instability are avalanches, landslides, rock fall, and rock slip, Slope instability can be detrimental depending on the infrastructure in that region. Water movement significantly contributes to slope instability. Water from snow or permafrost melt soaks into the soil, replacing air pockets and making the soil heavier (Nelson). Heavy soil on a steep slope can cause the soil to become dislodged and cause slope instability. The amount of water in the soil can also determine the slope angle. Too little water keeps the slope shallow, but some water can allow for a steeper slope due to changes in surface tension. Too much water caused a landslide because the excess water turns the soil into a fluid. Additional, unexpected permafrost melt can put too much water in the soil and lead to slope instability. Cold mountainous regions are often at risk for slope instability (Gruber). Permafrost exists in steep bedrock, which is categorized by a slope angle greater than 37 degrees. Ridges, spurs, and peaks are subject to increased permafrost melt that can lead to slope instability. Heat transfer by advection, or horizontal convection, is unpredictable and can occur through nearby ground water movement. This heat transfer leads to an increased rate of permafrost melt and can cause greater slope instability that heat transfer through the soil itself. Slope instability due to permafrost is directly influenced by climate change effects and could be detrimental to nearby populations and communities.

      References: "Slope Instability." Heritage-Newfoundland and Labrador. Accessed May 06, 2017. http://www.heritage.nf.ca/articles/environment/slope-instability.php.

      Nelson, Stephen A. "Slope Stability, Triggering Events, Mass Movement Hazards." Tulane EENS 3050. December 10, 2013. Accessed May 06, 2017. http://www.tulane.edu/~sanelson/Natural_Disasters/slopestability.htm.

      Gruber, S., and W. Haeberli. "Permafrost in steep bedrock slopes and its temperature-related destabilization following climate change." JOURNAL OF GEOPHYSICAL RESEARCH 112, no. F02S18 (June 8, 2007). http://onlinelibrary.wiley.com/store/10.1029/2006JF000547/asset/jgrf280.pdf;jsessionid=4ACF5A28370C79D8882CD5745BE13C0B.f02t03?v=1&t=j2dliru8&s=9d3e555adabe5cef09dd53635b4830823d3afa9d.

    2. permafrost

      Permafrost is ground that is permanently frozen. Permafrost contains soil, sand, and gravel, which are held together by ice (National Geographic). Permafrost can extend deep into the Earth, ranging in depths from 1 to 1000 meters. Frozen ground can be considered permafrost if it is frozen continuously at a temperature less than 0 degrees Celsius for two or more years (International Permafrost Association). Permafrost is common to places where temperatures stay below freezing, such as Siberia, Canada, Alaska, Greenland, among others (National Geographic). Permafrost can be continuous or discontinuous. Continuous permafrost is a solid sheet of permafrost, like in Siberia. Discontinuous permafrost exists when some permafrost areas remain frozen all year, but other areas of permafrost melt for a brief period of time during the summer. Such discontinuous permafrost exists in Canada. The melting of permafrost can be dangerous due to increased water levels and levels of erosion when the soil, gravel, and sand are no longer held together by ice. Measuring the temperature of deep permafrost can provide information about temperature changes in a region due to climate change (International Permafrost Association). In the 21st century, permafrost research had focused on monitoring the boundaries of permafrost and identifying melt regions. When permafrost melts, it melts from the top and bottom simultaneously. Areas of discontinuous permafrost create the most concern when considering climate change effects. Areas of continuous permafrost are not expected to melt for a very long period. Current permafrost research focuses on areas where permafrost is thin, as these areas are most likely to create issues for infrastructure.

      References: "What is Permafrost?" International Permafrost Association. Accessed May 04, 2017. http://ipa.arcticportal.org/publications/occasional-publications/what-is-permafrost.

      "Permafrost." National Geographic Society. October 09, 2012. Accessed May 04, 2017. https://www.nationalgeographic.org/encyclopedia/permafrost/.

    3. thermal degradation of the permafrost

      Thermal degradation is the process of the breaking of molecules due to heating (Zeus). In Arctic regions, thermal degradation can occur to permafrost. This can lead to uneven snowmelt and ground instability (Grandpre). The ground instability affects any infrastructure built on permafrost, including roads, buildings, or piping systems. Uneven melting of the permafrost can create holes or indentations in roadways. A study by the Canadian Journal of Earth Sciences in 2011 showed that heat transfer from groundwater movement can increase the rate of thermal degradation of permafrost. In areas where wildfires are prevalent, thermal degradation of permafrost is an even greater issue (Jafarov). Climate change effects change the patterns and prevalence of forest fires. A study performed for Environmental Research Letters found that under conditions of severe fire in an upland forest where no other climate change effects are present, 18 meters of permafrost can degrade in 120 years. In lowland forests, permafrost is more resilient to thermal degradation and these effects were not found. Wildfires affect permafrost because they burn the organic layer of soil and the rate of permafrost melt is directly impacted by how much of the organic layer is burned. If a thick organic soil layer is present and the fire is short-lived, the permafrost may not melt. Climate change also increases the rate of thermal degradation in permafrost. Temperatures in northern high latitude regions are expected to rise by 2.5 to 7 degrees Celsius. The thermal degradation of permafrost is important not only due to increased carbon emissions in the air and oceans, but also for its negative effects of infrastructure.

      References: Grandpré, Isabelle De, Daniel Fortier, and Eva Stephani. "Degradation of permafrost beneath a road embankment enhanced by heat advected in groundwater." Canadian Journal of Earth Sciences. August 01, 2012. Accessed May 06, 2017. http://cjes.geoscienceworld.org/content/49/8/953.

      Jafarov, E. E., V. E. Romanovsky, H. Genet, A. D. McGuire, and S. S. Marchenko. "The effects of fire on the thermal stability of permafrost in lowland and upland black spruce forests of interior Alaska in a changing climate." Environmental Research Letters 8, no. 3 (August 27, 2013). Accessed May 06, 2017. http://iopscience.iop.org/article/10.1088/1748-9326/8/3/035030/pdf.

      "Thermal Degradation of Plastics." Zeus Industrial Products Inc. 2005. Accessed May 06, 2017.

  4. Apr 2017
    1. Pointed Mountain pipeline

      The Pointed Mountain Pipeline is a 34.2-mile long natural gas pipeline that connects a dehydration plant at Beaver River in British Columbia, with another plant at Pointed Mountain in the Northwest Territories (Landeen, Brandt). The pipeline extends across British Columbia, the Yukon, and the Northwest Territories. The pipeline crosses the Kotaneelee and La Biche Rivers. Construction on the pipeline began January 24, 1972 and the pipeline was completed in March of 1972, but was not in operation. Throughout the construction of the pipeline, scientists worried about the environmental factors of the pipeline, such as permafrost melting, bank instability, and siltation of rivers. The pipeline was built through a permafrost region. Because the natural gas has the ability to melt the permafrost, weights were attached to the pipe to prevent it from surfacing. Scientists were concerned about bank instability due to erosion when the pipeline crossed the Kotaneelee River. Sandbags supported the pipeline in order to increase stability. Drainage pipes were also added to prevent erosion. Scientists were also concerned about the high water levels in the rivers during spring thaw. The pipes were placed in a deep trench, surrounded by concrete to prevent rising of the pipes during flooding. The trench then fills in with water to prevent river overflow. A map showing the installation of the pipeline can be found below:

      Landeen, B. A., and W. C. Brandt. "Impressions on the construction of the Pointed Mountain Gas Pipeline." Environment Canada Fisheries and Marine Service, November 1975. Accessed April 06, 2017. http://www.dfo-mpo.gc.ca/Library/15011.pdf