Due to climate warming and increased precipitation, the permafrost of the Tibet Plateau (TP) has undergone serious degradation along with obvious lake expansion in recent decades. Model simulation is often used to analyze the contribution of permafrost melting to lake expansion, which may have many limitations. Taking Hohxil Lake (HL) basin over north TP as an example, this study makes full use of Sentinel-1 images by an improved small baseline subset interferometric technique (SBAS-InSAR), monitors the permafrost deformation from 2015 to 2020, and estimates its contribution to the lake expansion. The results show that the permafrost settlements mainly occur in the flat terrain around HL. The average line of sight (LOS) de-formation rate of permafrost is -3.59 ± 0.001 cm/yr, where there existed many obvious funnel-shaped thawing areas around the lake, indicating a close relationship between lake expansion and permafrost under-ground ice melting. The long-term linear deformation rate of underground ice is inverted by the traditional linear model, and the melting rate is estimated to be (31.17 ± 0.0054) ×106 m3/yr with 9.3% contribution to the HL expansion. This study takes full advantage of Interferometric Synthetic Aperture Radar (InSAR) to quantitatively analyze the contribution of permafrost to lake expansion, which provides a new insight into the study of permafrost hydrological process and the proposed method can be easily extended to analyze lake water budget for underground ice in other watershed over the TP.
KEYWORDS: Optimization (mathematics), Transplantation, Data transmission, Parallel computing, Field programmable gate arrays, Data storage, Data processing, Computer programming, Associative arrays, Algorithm development
In order to further improve the execution efficiency of the SM3 cryptographic hash algorithm, give full play to the advantages of the mainstream heterogeneous platform of CPU+GPU, SM3 algorithm message is filled, expanded and iterative compression part on the device end, by reasonably dividing thread blocks to make the full use of thread block resources, use loop unrolling to increase independent memory operation, use shared memory to hide the delay of visiting instructions. Experiments on files of different sizes on NVIDIA Tesla P100, the data show that the SM3 algorithm for GPU achieves an acceleration ratio of 0.593611 to 1.207481 compared with the CPU serial implementation, and the acceleration effect becomes faster with the file size, providing a reference for the implementation of the national secret algorithm on the GPU platform.
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