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Change in water surface area northern Sweden

Pijcke, Femke LU (2017) In Student thesis series INES NGEK01 20171
Dept of Physical Geography and Ecosystem Science
Abstract
Changes in water surface area (w.s.a.) in Arctic regions have been linked to climate warming and permafrost degradation (Briggs et al. 2014). As permafrost thaws, thermokarst lakes are formed. This causes the surface to get wetter. Although, a drying of the surface has often been observed in areas of discontinuous permafrost. As the climate warms, permafrost starts to thaw from underneath the lakes, causing drainage from below to be possible. The permafrost around lake Torneträsk, northern Sweden, has been degrading over the past few decades (Akerman and Johansson 2008), and a change in surface wetness has been observed (Christensen et al. 2004b).

In this thesis, the change in w.s.a. of the Torneträsk region, as well as its relation... (More)
Changes in water surface area (w.s.a.) in Arctic regions have been linked to climate warming and permafrost degradation (Briggs et al. 2014). As permafrost thaws, thermokarst lakes are formed. This causes the surface to get wetter. Although, a drying of the surface has often been observed in areas of discontinuous permafrost. As the climate warms, permafrost starts to thaw from underneath the lakes, causing drainage from below to be possible. The permafrost around lake Torneträsk, northern Sweden, has been degrading over the past few decades (Akerman and Johansson 2008), and a change in surface wetness has been observed (Christensen et al. 2004b).

In this thesis, the change in w.s.a. of the Torneträsk region, as well as its relation to air temperature, precipitation, snow depth and active layer thickness has been investigated by analysing satellite images taken between 1990 to 2015. The w.s.a. in the Torneträsk region has been declining over the past 25 years. This decline however has only been observed in the permafrost free zones and the areas with sporadic permafrost. The areas underlain by continuous and discontinuous permafrost observed an increase in w.s.a. However, no significant relationships were found between the change in w.s.a. and climatic factors, since the study was too short. (Less)
Popular Abstract
The Arctic region has experienced a rapidly changing climate and this has major influences on the characteristics of this region. Air temperatures have been rising in most areas of the Arctic region since the 1960’s, with an acceleration in rising air temperatures measured since the 1980’s (Serreze and Walsh 2000; Smith et al. 2005). The warming of the Arctic triggered changes in the cryosphere, including a warming and degradation of the permafrost, as well as a thickening of the active layer above the permafrost (Hinzman et al. 2005). This causes changes in the water surface area (w.s.a.) of Arctic regions, as this have been linked to climate warming and permafrost degradation (Briggs et al. 2014).
Climate warming causes the permafrost,... (More)
The Arctic region has experienced a rapidly changing climate and this has major influences on the characteristics of this region. Air temperatures have been rising in most areas of the Arctic region since the 1960’s, with an acceleration in rising air temperatures measured since the 1980’s (Serreze and Walsh 2000; Smith et al. 2005). The warming of the Arctic triggered changes in the cryosphere, including a warming and degradation of the permafrost, as well as a thickening of the active layer above the permafrost (Hinzman et al. 2005). This causes changes in the water surface area (w.s.a.) of Arctic regions, as this have been linked to climate warming and permafrost degradation (Briggs et al. 2014).
Climate warming causes the permafrost, in areas underlain with ice-rich permafrost to thaw and degrade, resulting in the formation of thermokarst landscapes. Permafrost is soil, rock, sediment, or any other earth material with a temperature that has remained below 0 ºC for two or more consecutive years (Walsh et al. 2005), and as temperatures rises, the ice within the ice-rich permafrost melts resulting in collapses and subsides of the surface, forming a thermokarst landscape.
Thermokarst lakes are found within a thermokarst landscape. They are formed after the ground subsides due to the thaw of ice-rich permafrost (Luo et al. 2015). The size of the lakes can change over time due to a continuation of permafrost thaw, variations in climate such as precipitation and evapotranspiration, or due to lake drainage caused by taliks (an area of unfrozen ground surrounded by permafrost) and eroding gullies (Yoshikawa and Hinzman 2003; Smith et al. 2005; Karlsson et al. 2012; Luo et al. 2015). The development of thermokarst lakes causes the surface to get wetter. However, a drying of the surface has often been observed in areas of discontinuous permafrost. As the climate warms, permafrost starts to thaw from underneath the lakes, causing drainage from below to be possible.
In this thesis, the change in w.s.a. of the Torneträsk region, northern Sweden, as well as its relation to air temperature, precipitation, snow depth and active layer thickness has been investigated by analysing satellite images taken between 1990 to 2015. The analysis was split up in three regions; areas underlain by sporadic permafrost (coverage of 0-50%), discontinuous permafrost (50-90%) and continuous permafrost (>90%). As each permafrost type responds differently to climate change.
The w.s.a. in the Torneträsk region has been declining over the past 25 years. This decline however has only been observed in the permafrost free zones and the areas with sporadic permafrost. The areas underlain by continuous and discontinuous permafrost observed an increase in w.s.a. However, no significant relationships were found between the change in w.s.a. and climatic factors, since the study was too short. (Less)
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author
Pijcke, Femke LU
supervisor
organization
course
NGEK01 20171
year
type
M2 - Bachelor Degree
subject
keywords
Permafrost, thermokarst lakes, climate change, northern Sweden, remote sensing
publication/series
Student thesis series INES
report number
423
language
English
id
8917623
date added to LUP
2017-06-21 23:20:52
date last changed
2017-06-21 23:20:52
@misc{8917623,
  abstract     = {Changes in water surface area (w.s.a.) in Arctic regions have been linked to climate warming and permafrost degradation (Briggs et al. 2014). As permafrost thaws, thermokarst lakes are formed. This causes the surface to get wetter. Although, a drying of the surface has often been observed in areas of discontinuous permafrost. As the climate warms, permafrost starts to thaw from underneath the lakes, causing drainage from below to be possible. The permafrost around lake Torneträsk, northern Sweden, has been degrading over the past few decades (Akerman and Johansson 2008), and a change in surface wetness has been observed (Christensen et al. 2004b). 
 
In this thesis, the change in w.s.a. of the Torneträsk region, as well as its relation to air temperature, precipitation, snow depth and active layer thickness has been investigated by analysing satellite images taken between 1990 to 2015. The w.s.a. in the Torneträsk region has been declining over the past 25 years. This decline however has only been observed in the permafrost free zones and the areas with sporadic permafrost. The areas underlain by continuous and discontinuous permafrost observed an increase in w.s.a. However, no significant relationships were found between the change in w.s.a. and climatic factors, since the study was too short.},
  author       = {Pijcke, Femke},
  keyword      = {Permafrost,thermokarst lakes,climate change,northern Sweden,remote sensing},
  language     = {eng},
  note         = {Student Paper},
  series       = {Student thesis series INES},
  title        = {Change in water surface area northern Sweden},
  year         = {2017},
}