• Climate change affects landscape freeze-

    From ScienceDaily@1:317/3 to All on Wed Apr 13 22:30:44 2022
    Climate change affects landscape freeze-thaw but not in the same way everywhere

    Date:
    April 13, 2022
    Source:
    Concordia University
    Summary:
    Researchers have use new statistical framework and analysis
    of datasets to demonstrate how increasing air temperatures and
    decreasing snow cover work in tandem to increase the effects of
    climate change in a non-linear fashion, meaning that they work to
    amplify the overall impact felt on the ground.



    FULL STORY ==========================================================================
    As any resident of northern climates knows, a seasonal thaw is never straightforward. The freeze-thaw process can last over a period of months
    and historically was mitigated by predictable air temperature and snow
    cover depth.


    ========================================================================== Climate change, however, warms the air and thins the snow, and therefore
    can affect this cycle. According to a new study by Concordia researchers published in the Nature journal Scientific Reports, this can have major
    impacts on greenhouse gas emissions in the north and urban infrastructure
    in the south.

    Using a new statistical framework and by analysing datasets from the
    National Snow and Ice Data Center, Princeton University and the Dorval, Quebec-based Canadian Meteorological Centre, the researchers demonstrate
    how increasing air temperatures and decreasing snow cover work in tandem
    to increase the effects of climate change in a non-linear fashion,
    meaning that they work to amplify the overall impact felt on the ground.

    Furthermore, they affect Quebec's distinct ecological regions differently, presenting policy makers and residents with unique problems.

    "The historical data shows there is a vivid divide between Quebec's
    northern areas and the southern parts of the province, where the majority
    of Quebec's population and assets reside," says Ali Nazemi, an associate professor in Concordia's Department of Building, Civil and Environmental Engineering, and the principal investigator of the project and co-author
    of the paper. The paper's lead author is Concordia graduate Shadi Hatami,
    PhD 21, currently a postdoctoral fellow at McGill.

    Compounding problems The researchers note that air temperature, snow
    cover and freeze-thaw cycles are closely linked. A thick layer of snow
    acts as a blanket for frozen soil in winter. As the snow cover decreases,
    the warmer air penetrates the ground and thaws begin earlier.



    ==========================================================================
    In the far northern regions of the province, such changes result in fewer
    days of frozen soil, meaning that there is an increased likelihood of a
    release of thousands of tons of greenhouse gases like carbon and methane
    into the atmosphere.

    These added gases will act to intensify the effects of climate change.

    Further south, in the more densely populated areas around the St. Lawrence river valley, there will be more transitional days during the winter
    season, when the soil experiences a thaw and a freeze, with water
    repeatedly expanding and contracting as temperatures rise and drop. This
    will pose an added strain on already fragile road, bridge and water infrastructure.

    "By calculating these non-linear responses, we can try to quantify
    how many fewer frozen days we will see in the north and how many more transitional days we will see in the south under changes in temperature
    and snow depth conditions," says Nazemi.

    "This provides us with a way to approximate how many more tons of gases
    will be released into the atmosphere and how much more deterioration of
    our infrastructure we can expect." A quick reversion is also possible


    ==========================================================================
    Just as rising temperatures and thinner snow cover leads to amplified
    thawing across the province's ecological zones, the authors point out
    that the reverse is also true, although with less intensity than warming.

    In fact, lower air temperatures and more snow cover can also lead to
    amplified freezing and faster rebound, where the number of frozen days in
    the north and the number of transitional days in the south would revert
    closer to the historical average.

    Nazemi believes this paper's strength depends on its powerful mathematics
    and the amount of data made available through various technologies such
    as satellite remote sensing.

    Many previous studies have predicted a rise in greenhouse gas emissions
    from thawing permafrost, but these were often based on attempts to
    replicate the physics of the phenomenon in small areas with many
    assumptions.

    The new method relies on the probability theory and statistical function
    based on data gathered from 25km x 25 km scale pixels of Quebec's
    territory.

    "We brought this newer mathematical analysis to quantify some factors that
    had not been quantified before," he says. "We are now in the process of upscaling this methodology to cover the entire area of Canada and Alaska."

    ========================================================================== Story Source: Materials provided by Concordia_University. Original written
    by Patrick Lejtenyi. Note: Content may be edited for style and length.


    ========================================================================== Journal Reference:
    1. Shadi Hatami, Ali Nazemi. Compound changes in temperature and
    snow depth
    lead to asymmetric and nonlinear responses in landscape freeze-thaw.

    Scientific Reports, 2022; 12 (1) DOI: 10.1038/s41598-022-06320-6 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220413130821.htm

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