Spatiotemporal Characteristics of NPP Changes in Frozen Ground Areas of the Three-River Headwaters Region, China: A Regional Modeling Perspective

• Published in: Frontiers in Earth Science
• Main Authors: Hu, Jianan, Nan, Zhuotong, Ji, Hailong
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media SA 2022
• Subjects: General Earth and Planetary Sciences; permafrost
• Online Access: http://dx.doi.org/10.3389/feart.2022.838558; https://www.frontiersin.org/articles/10.3389/feart.2022.838558/full

Permafrost degradation triggered by climate warming can disturb alpine ecosystem stability and further influence net primary productivity (NPP). Known as the “water tower of China”, the Three-River Headwaters Region (TRHR) on the eastern Qinghai-Tibet plateau (QTP), is characterized by a fragile alpine meadow ecosystem underlain by large areas of unstable permafrost and has been subject to rapid climate change in recent decades. Despite some site-specific studies, the spatial and temporal changes in NPP in the different frozen ground zones across the TRHR associated with climate change remain poorly understood. In this study, a physically explicit Noah land surface model with multi-parameterization options (Noah-MP) was employed to simulate NPP changes on the TRHR during 1989–2018. The simulation was performed with a spatial resolution of 0.1° and a temporal resolution of 3h, and validated at two sites with meteorological and flux observations. The results show that the average NPP was estimated to be 299.7 g C m −2 yr −1 in the seasonally frozen ground (SFG) zone and 198.5 g C m −2 yr −1 in the permafrost zone. NPP in the TRHR increased at a rate of 1.09 g C m −2 yr −2 during 1989–2018, increasing in 1989–2003 and then decreasing in subsequent years. The NPP in permafrost area increased at a rate of 1.43 g C m −2 yr −2 during 1989–2018, which is much higher than the rate of change in NPP in the SFG area (0.67 g C m −2 yr −2 ). Permafrost degradation has complicated ecosystem implications. In areas where permafrost degradation has occurred, both increasing and decreasing changes in NPP have been observed.