Existing observations and models show that under the background of climate warming, the thickness of permafrost active layer in Qinghai Tibet Plateau increases, the annual average ground temperature rises and the hot-melt karst landform is widely developed. Ground deformation is an important indicator of permafrost degradation. However, at present, the research on ground deformation mostly focuses on the research on small spatial scale, and the spatio-temporal heterogeneity of freezing and thawing process in permafrost area is not considered enough, and the spatial characteristics and control factors of large-scale and large-scale surface deformation are still unclear.
Wu Tonghua, a research team of Golmud station, State Key Laboratory of Cryosphere science, Northwest Institute of ecological environment and resources, Chinese Academy of Sciences, developed an InSAR remote sensing inversion method for ground deformation in permafrost areas on a large spatial scale, and applied it to an area of about 140000 square kilometers in the middle of the Qinghai Tibet Plateau.
Based on sentinel-1 SAR remote sensing image data and MODIS surface temperature and soil data analysis, this method fully considers the spatio-temporal heterogeneity of freezing and thawing process in permafrost area, and can effectively separate the ground seasonal deformation related to the freezing and thawing process of active layer and the ground long-term deformation caused by thawing of permafrost, The results show that the central Qinghai Xizang Plateau has experienced obvious ground seasonal deformation and long-term deformation.
The results can provide reliable technical methods for monitoring the surface deformation of permafrost land in the Qinghai Tibet Plateau and even the Arctic, further deepen the understanding of the relationship between ground deformation, surface freezing and thawing process and permafrost degradation in permafrost areas, and provide important scientific support for plateau ecological environment protection and engineering construction and maintenance.
1. MODIS dataset comes from: https://ladsweb.modaps.eosdis.nasa.gov/search
2. Sentinel-1 SAR remote sensing image data comes from: https://search.asf.alaska.edu/#
Based on sentinel-1 SAR remote sensing image data, using the method of small baseline set and combined with MODIS surface temperature and soil data analysis, this method fully considers the spatio-temporal heterogeneity of freezing and thawing process in permafrost area, and can effectively separate the ground seasonal deformation related to the freezing and thawing process of active layer and the ground long-term deformation caused by permafrost melting, The results show that the central Qinghai Xizang Plateau has experienced obvious ground seasonal deformation and long-term deformation. The geo detector method and correlation analysis are also introduced to reveal the control factors of ground deformation.
We combined Stefan one-dimensional heat conduction model with modis-lst and solved it by SBAS InSAR method to quantify the ground deformation of permafrost in Qinghai Tibet Plateau. We have successfully described the amplitude and spatial patterns of large-scale linear and seasonal deformation. With the help of modis-lst and soil information, our method can be easily extended to the whole Qinghai Tibet Plateau scale.
If more accurate data are available in the future, all external temperature and soil parameters can be easily replaced. In the Arctic, due to the influence of snow cover, only SAR images obtained in summer are available. In addition, there are modis-lst data products with a resolution of 1km and soil information with a resolution of 250m in the Arctic. Therefore, we believe that our method can also be widely used in the Arctic permafrost region.
| # | number | name | type |
| 1 | 41690142 | Research on Cryosphere Process and Ecological Service Function | National Natural Science Foundation of China |
| 2 | 41771076 | Study on the Influence Mechanism of Permafrost Degradation in the Source of the Yangtze River on Groundwater and Surface Runoff | National Natural Science Foundation of China |
| 3 | 42001072 | Research on Temporal and Spatial Changes of Surface Deformation in Permafrost Regions of Qinghai-Tibet Plateau Based on Multi-te | National Natural Science Foundation of China |
| 4 | 2020D08 | Research on Ground Deformation in Permafrost Regions of Qilian Mountains Based on Multi-temporal InSAR Technology | other |
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CSTR:11738.11.ncdc.NIEER.2021.1977
10.12072/ncdc.NIEER.db0125.2021