Spatial distribution and changes of Xing'an permafrost in China over the past three decades

摘要

Climate warming causes profound consequences on permafrost distribution throughout the high-latitude regions of the globe. Xing'an permafrost in China is the southernmost part of high-latitude permafrost and is constantly changing. However, understanding on this change process of permafrost is limited. On the basis of digital elevation model (DEM) data, meteorological station, survey data and the meteorological forcing dataset in the northern northeast area in China, we calculated the mean annual ground surface temperature (MAGST), the frost number (Fn) of air temperature (Ta), and the ground surface temperature (GST) with the Fn model. The change in permafrost were analyzed from 1980 to 2010 by statistical and empirical/semi-empirical models. Comparison of the calculated results with the published frozen ground map and survey data, the description on permafrost distribution was more accurate using the Fn of GST than Ta. Permafrost zoning was performed using Fn of GST results and continuous coefficient. The area of permafrost changed from 2.21 x 10(5) Km(2) to 4.87 x 10(5) Km(2). The degradation trend was from low-to high-altitude areas and from continuous to discontinuous permafrost. The permafrost was significantly degraded from the 1980s to the 1990s. The degradation rate slowed down from the 2000s, and some areas have been developed. This work provides basic data and reference for regional permafrost research and project in cold areas.