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Large‐scale InSAR monitoring of permafrost freeze‐thaw cycles on the Tibetan Plateau
Author(s) -
Daout Simon,
Doin MariePierre,
Peltzer Gilles,
Socquet Anne,
Lasserre Cécile
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070781
Subject(s) - permafrost , interferometric synthetic aperture radar , geology , subsidence , plateau (mathematics) , climatology , active layer , forcing (mathematics) , terrain , seasonality , spatial variability , synthetic aperture radar , physical geography , geomorphology , remote sensing , structural basin , oceanography , layer (electronics) , mathematics , mathematical analysis , ecology , chemistry , statistics , organic chemistry , biology , thin film transistor , geography
Abstract Multitemporal interferometric synthetic aperture radar (InSAR) observations are used to characterize spatial variations of the permafrost active layer and its temporal evolution in Northwestern Tibet. We develop a method to enhance InSAR performances for such difficult terrain conditions and construct an 8 year timeline of the surface deformation over a 60,000 km 2 area. The ground movement induced by the active layer's response to climate forcing is limited to Cenozoic sedimentary basins and is spatially variable in both its seasonal amplitude (2.5–12 mm) and multiannual trend (−2 to 3 mm/yr). A degree‐day integrated model adjusted to the data indicates that subsidence occurs when the surface temperature exceeds zero (May to October) over areas where seasonal movements are large (>8 mm). The period of subsidence is delayed by 1–2 months over areas where smaller seasonal movements are observed, suggesting an unsaturated soil where water occurs in the deeper part of the active layer.