Permafrost zonation index map and statistics over the Qinghai–Tibet Plateau based on field evidence

Permafrost is prevalent over the Qinghai–Tibet Plateau (QTP), but mapping its distribution is challenging due to the limited availability of ground‐truth data sets and strong spatial heterogeneity in the region. Based on a recently developed inventory of permafrost presence or absence from 1475 in s...

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Bibliographic Details
Published in:Permafrost and Periglacial Processes
Main Authors: Cao, Bin, Zhang, Tingjun, Wu, Qingbai, Sheng, Yu, Zhao, Lin, Zou, Defu
Other Authors: National Natural Science Foundation of China
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2019
Subjects:
Online Access:http://dx.doi.org/10.1002/ppp.2006
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fppp.2006
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.2006
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Summary:Permafrost is prevalent over the Qinghai–Tibet Plateau (QTP), but mapping its distribution is challenging due to the limited availability of ground‐truth data sets and strong spatial heterogeneity in the region. Based on a recently developed inventory of permafrost presence or absence from 1475 in situ observations, we developed and trained a statistical model and used it to compile a high‐resolution (30 arc‐seconds) permafrost zonation index (PZI) map. The PZI model captures the high spatial variability of permafrost distribution over the QTP because it considers multiple controlling variables, including near‐surface air temperature downscaled from re‐analysis, snow cover days and vegetation cover derived from remote sensing. Our results showed the new PZI map achieved the best performance compared to available existing PZI and traditional categorical maps. Based on more than 1000 in situ measurements, the Cohen's kappa coefficient and overall classification accuracy were 0.62 and 82.5%, respectively. Excluding glaciers and lakes, the area of permafrost regions over the QTP is approximately 1.54 (1.35–1.66) ×10 6 km 2 , or 60.7 (54.5–65.2)% of the exposed land, while area underlain by permafrost is about 1.17 (0.95–1.35) ×10 6 km 2 , or 46 (37.3–53.0)%.