TY  - JOUR
A1  - Nitze, Ingmar
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Arp, Christopher D.
A1  - Ulrich, Mathias
A1  - Fedorov, Alexander
A1  - Veremeeva, Alexandra
T1  - Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions
JF  - Remote sensing
N2  - Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here, we present a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM, ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e., upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.
KW  - lake dynamics
KW  - lake change
KW  - permafrost region
KW  - Landsat
KW  - Alaska
KW  - Siberia
KW  - thermokarst
KW  - trend analysis
KW  - machine-learning
Y1  - 2017
U6  - https://doi.org/10.3390/rs9070640
SN  - 2072-4292
VL  - 9
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Strauss, Jens
A1  - Schirrmeister, Lutz
A1  - Grosse, Guido
A1  - Fortier, Daniel
A1  - Hugelius, Gustaf
A1  - Knoblauch, Christian
A1  - Romanovsky, Vladimir E.
A1  - Schadel, Christina
A1  - von Deimling, Thomas Schneider
A1  - Schuur, Edward A. G.
A1  - Shmelev, Denis
A1  - Ulrich, Mathias
A1  - Veremeeva, Alexandra
T1  - Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability
JF  - Earth science reviews : the international geological journal bridging the gap between research articles and textbooks
N2  - Permafrost is a distinct feature of the terrestrial Arctic and is vulnerable to climate warming. Permafrost degrades in different ways, including deepening of a seasonally unfrozen surface and localized but rapid development of deep thaw features. Pleistocene ice-rich permafrost with syngenetic ice-wedges, termed Yedoma deposits, are widespread in Siberia, Alaska, and Yukon, Canada and may be especially prone to rapid-thaw processes. Freeze-locked organic matter in such deposits can be re-mobilized on short time-scales and contribute to a carbon-cycle climate feedback. Here we synthesize the characteristics and vulnerability of Yedoma deposits by synthesizing studies on the Yedoma origin and the associated organic carbon pool. We suggest that Yedoma deposits accumulated under periglacial weathering, transport, and deposition dynamics in non-glaciated regions during the late Pleistocene until the beginning of late glacial warming. The deposits formed due to a combination of aeolian, colluvial, nival, and alluvial deposition and simultaneous ground ice accumulation. We found up to 130 gigatons organic carbon in Yedoma, parts of which are well-preserved and available for fast decomposition after thaw. Based on incubation experiments, up to 10% of the Yedoma carbon is considered especially decomposable and may be released upon thaw. The substantial amount of ground ice in Yedoma makes it highly vulnerable to disturbances such as thermokarst and thermo-erosion processes. Mobilization of permafrost carbon is expected to increase under future climate warming. Our synthesis results underline the need of accounting for Yedoma carbon stocks in next generation Earth-System-Models for a more complete representation of the permafrost-carbon feedback.
KW  - Perennial frozen ground
KW  - Thermokarst
KW  - Arctic
KW  - Late Pleistocene
KW  - Greenhouse gas source
KW  - Climate feedback
Y1  - 2017
U6  - https://doi.org/10.1016/j.earscirev.2017.07.007
SN  - 0012-8252
SN  - 1872-6828
VL  - 172
SP  - 75
EP  - 86
PB  - Elsevier
CY  - Amsterdam
ER  -