Greenhouse gases (GHGs) released from permafrost regions may have a positive feedback to climate change, but there is much uncertainty about additional warming from the permafrost carbon cycle. One of the main reasons for this uncertainty is that the observation data of large-scale GHG concentrations are sparse, especially for areas with rapid permafrost degradation. We selected the Mongolian Plateau as the study area. We first analyzed the active layer thickness and ground temperature changes using borehole observations. Based on ground observation data, we assessed the applicability of Greenhouse Gases Observing Satellite (GOSAT) carbon dioxide (CO2) and methane (CH4) datasets. Finally, we analyzed the temporal and spatial changes in near-surface CO2 and CH4 concentrations from 2010 to 2017 and their patterns in different permafrost regions. The results showed that the Mongolian permafrost has been experiencing rapid degradation. The annual average near-surface CO2 concentration increased gradually between 2.19 ppmv/yr and 2.38 ppmv/yr, whereas the near-surface CH4 concentration increased significantly from 7.76 ppbv/yr to 8.49 ppbv/yr. There were significant seasonal variations in near-surface CO2 and CH4 concentrations for continuous, discontinuous, sporadic, and isolated permafrost zones. The continuous and discontinuous permafrost zones had lower near-surface CO2 and CH4 concentrations in summer and autumn, whereas sporadic and isolated permafrost zones had higher near-surface CO2 and CH4 concentrations in winter and spring. Our results indicated that climate warming led to rapid permafrost degradation, and carbon-based GHG concentrations also increased rapidly in Mongolia. Although, GHG concentrations increased at rates similar to the global average and many factors can account for their changes, GHG concentration in the permafrost regions merits more attention in the future because the spatiotemporal distribution has indicated a different driving force for regional warming. (C) 2021 Elsevier B.V. All rights reserved.

Methane (CH4) is the second most significant driver of global warming, following carbon dioxide. However, the spatial-temporal variation of CH4 and its driving factors largely remain unclear. Here we selected the Northern Hemisphere as the study area. We used the data from the Total Column Carbon Observing Network (TCCON) to assess the accuracy of the Greenhouse Gases Observing Satellite (GOSAT) Proxy XCH4 (column-averaged dry air mixing ratio of CH4) data. We then analyzed the spatial-temporal distribution of XCH4 in the Northern Hemi-sphere, and further quantified the influencing factors using geographic detectors. The results showed that during 2009-2021, the annual mean XCH4 increased from 2009 (1775.19 ppb) to 2021 (1872.71 ppb), with an increasing rate of 7.50 ppb/year. The monthly average value was the lowest in May (1805.65 ppb) and the highest in September (1825.63 ppb). The XCH4 in the low-latitude region was higher than that in the high-latitudinal region. The geographic detector showed that anthropogenic activities were the main factors affecting the XCH4. Our results revealed the spatial-temporal patterns XCH4 and their driving factors in the Northern Hemisphere, and thus provided a scientific basis for the management of this greenhouse gas in the future.