Tuesday, September 17, 2019

PhD defense about permafrost phenomena in artic and alpine environments

Helena Bergstedt impressively defended her PhD Thesis “Spatial and temporal patterns of microwave scattering mechanisms across scales in cold terrestrial environments”.

Over the last four years, Helena investigated permafrost phenomena in artic and alpine environments. These landscapes undergo annual thawing and refreezing of the ground surface. These freeze/thaw cycles occur at different time scales from daily variations to seasonal changes in surface state. Helena’s research focused on spatial heterogeneity within grid cells of satellite scatterometer data in highly complex terrain in cold regions. She identified and quantified different microwave scattering mechanisms that negatively influence the accuracy of surface state information derived from satellite based microwave sensors.

Through five major publications, she mainly addressed landscape type specific differences between surface state information, dependencies of frozen and thawed season backscatter variations, possibilities of deriving mean annual ground temperature and permafrost extent from freeze/thaw information and the possibility of deriving a frozen fraction capable of describing gradual freeze-up and thaw processes on a landscape scale.

This research work contributed to the improvement of accurate representation of freeze/thaw processes in complex landscapes within future surface state data sets, especially with respect to permafrost applications. Here you can find more about her research.

We wish Helena all the best on her future road of life!

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