Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model
Under the influence of climate change and human activities, the southern boundary of the permafrost region in Northeast China, which is located at the southern edge of the permafrost area of Eurasia, has moved north, the surface temperature has increased, and the thickness of the frozen layer has de...
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MDPI AG
2022-07-01
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| Series: | Remote Sensing |
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| Online Access: | https://www.mdpi.com/2072-4292/14/13/3185 |
| _version_ | 1827619315100155904 |
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| author | Wei Shan Chengcheng Zhang Ying Guo Lisha Qiu |
| author_facet | Wei Shan Chengcheng Zhang Ying Guo Lisha Qiu |
| author_sort | Wei Shan |
| collection | DOAJ |
| description | Under the influence of climate change and human activities, the southern boundary of the permafrost region in Northeast China, which is located at the southern edge of the permafrost area of Eurasia, has moved north, the surface temperature has increased, and the thickness of the frozen layer has decreased. At present, there is a lack of classification standards or a map of the thermal state of permafrost that can reflect the dynamic change characteristics of permafrost in Northeast China. A vegetation impact factor consisting of normalized difference vegetation index and forest canopy closure was introduced into MODIS LST products, in order to improve the applicability of products in Northeast China. Based on the improved MODIS LST data, this study analyzed the distribution and change of the mean annual surface temperature and the surface frost number (<i>SF</i><i>nc</i>) from 2003 to 2019. <i>S</i><i>Fnc</i> was used as the standard to classify the thermal state of permafrost, and a map of the thermal state distribution and changes of permafrost in Northeast China, with a spatial resolution of 1 km, was produced. Compared with the observation data of meteorological stations and field monitoring data, the reliability of classification results was nearly 95%. The map showed that there was no area of extremely stable permafrost (<i>SFnc</i> ≥ 0.667), the area of stable permafrost (0.55 ≤ <i>SF</i><i>nc</i><i><</i> 0.667) changed from 14.9 × 10<sup>4</sup> km<sup>2</sup> to 6.5 × 10<sup>4</sup> km<sup>2</sup>, the <i>S</i><i>Fnc</i> reduced from 0.564 to 0.557, the area of semi-stable permafrost (0.51 < <i>SFnc</i> < 0.55) changed from 17.68 × 10<sup>4</sup> km<sup>2</sup> to 17.77 × 10<sup>4</sup> km<sup>2</sup>, the <i>S</i><i>F</i><i>Nc</i> reduced from 0.529 to 0.528, and the area of transitional or unstable permafrost (0.49 ≤ <i>S</i><i>Fnc</i> ≤ 0.51) changed from 8.67 × 10<sup>4</sup> km<sup>2</sup> to 9.56 × 10<sup>4</sup> km<sup>2</sup>. The thermal state of permafrost decreased and the distribution of stable permafrost shrank, due to continuous rising air temperature. The overall change characteristics of the thermal state distribution of permafrost were that the southern boundary of the permafrost region moved northward, the regional permafrost thermal state decreased, and there was an increased region of semi-stable, transitional or unstable permafrost from the frozen soil thawed at the edge of the permafrost region with higher stability. The permafrost region in Northeast China has lush vegetation, and the continuous degradation of permafrost will change the vegetation growth environment and affect the global carbon cycle process. This work will provide important data support for climate change feedback, natural disaster process research, and an early warning and prevention of terrestrial ecosystem response in the permafrost region of Eurasia. |
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| spelling | doaj.art-ae3194586f70416ea6a801b01b7aa1ad2023-12-01T21:41:02ZengMDPI AGRemote Sensing2072-42922022-07-011413318510.3390/rs14133185Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number ModelWei Shan0Chengcheng Zhang1Ying Guo2Lisha Qiu3Institute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin 150040, ChinaInstitute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin 150040, ChinaInstitute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin 150040, ChinaInstitute of Cold Regions Science and Engineering, Northeast Forestry University, Harbin 150040, ChinaUnder the influence of climate change and human activities, the southern boundary of the permafrost region in Northeast China, which is located at the southern edge of the permafrost area of Eurasia, has moved north, the surface temperature has increased, and the thickness of the frozen layer has decreased. At present, there is a lack of classification standards or a map of the thermal state of permafrost that can reflect the dynamic change characteristics of permafrost in Northeast China. A vegetation impact factor consisting of normalized difference vegetation index and forest canopy closure was introduced into MODIS LST products, in order to improve the applicability of products in Northeast China. Based on the improved MODIS LST data, this study analyzed the distribution and change of the mean annual surface temperature and the surface frost number (<i>SF</i><i>nc</i>) from 2003 to 2019. <i>S</i><i>Fnc</i> was used as the standard to classify the thermal state of permafrost, and a map of the thermal state distribution and changes of permafrost in Northeast China, with a spatial resolution of 1 km, was produced. Compared with the observation data of meteorological stations and field monitoring data, the reliability of classification results was nearly 95%. The map showed that there was no area of extremely stable permafrost (<i>SFnc</i> ≥ 0.667), the area of stable permafrost (0.55 ≤ <i>SF</i><i>nc</i><i><</i> 0.667) changed from 14.9 × 10<sup>4</sup> km<sup>2</sup> to 6.5 × 10<sup>4</sup> km<sup>2</sup>, the <i>S</i><i>Fnc</i> reduced from 0.564 to 0.557, the area of semi-stable permafrost (0.51 < <i>SFnc</i> < 0.55) changed from 17.68 × 10<sup>4</sup> km<sup>2</sup> to 17.77 × 10<sup>4</sup> km<sup>2</sup>, the <i>S</i><i>F</i><i>Nc</i> reduced from 0.529 to 0.528, and the area of transitional or unstable permafrost (0.49 ≤ <i>S</i><i>Fnc</i> ≤ 0.51) changed from 8.67 × 10<sup>4</sup> km<sup>2</sup> to 9.56 × 10<sup>4</sup> km<sup>2</sup>. The thermal state of permafrost decreased and the distribution of stable permafrost shrank, due to continuous rising air temperature. The overall change characteristics of the thermal state distribution of permafrost were that the southern boundary of the permafrost region moved northward, the regional permafrost thermal state decreased, and there was an increased region of semi-stable, transitional or unstable permafrost from the frozen soil thawed at the edge of the permafrost region with higher stability. The permafrost region in Northeast China has lush vegetation, and the continuous degradation of permafrost will change the vegetation growth environment and affect the global carbon cycle process. This work will provide important data support for climate change feedback, natural disaster process research, and an early warning and prevention of terrestrial ecosystem response in the permafrost region of Eurasia.https://www.mdpi.com/2072-4292/14/13/3185Northeast Chinapermafrost thermal stateMODIS LSTsurface frost numbernormalized difference vegetation index |
| spellingShingle | Wei Shan Chengcheng Zhang Ying Guo Lisha Qiu Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model Remote Sensing Northeast China permafrost thermal state MODIS LST surface frost number normalized difference vegetation index |
| title | Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model |
| title_full | Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model |
| title_fullStr | Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model |
| title_full_unstemmed | Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model |
| title_short | Mapping the Thermal State of Permafrost in Northeast China Based on the Surface Frost Number Model |
| title_sort | mapping the thermal state of permafrost in northeast china based on the surface frost number model |
| topic | Northeast China permafrost thermal state MODIS LST surface frost number normalized difference vegetation index |
| url | https://www.mdpi.com/2072-4292/14/13/3185 |
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