Abstract:

Net Ecosystem Productivity (NEP) is an important indicator for quantitatively assessing carbon sink functions in terrestrial ecosystems. Spatial and temporal distribution patterns of the vegetation carbon sink in the Fenhe River Basin and prediction of the vegetation carbon sink in the Fenhe River Basin over the next 30 years. Based on Digital Elevation Model (DEM), Normalized Difference Vegetation Index (NDVI), Land Use, and meteorological data, the vegetation carbon sink in the Fenhe River Basin from 1999 to 2023 was quantitatively estimated by the improved CASA model using a combination of model simulation and remote sensing techniques. The gray GM(1, 1) model was applied to predict the carbon sink of vegetation in the Fenhe River Basin from 2024 to 2053. The results show: 1) Vegetation mean annual Net Ecosystem Productivity (NEP) showed a significant upward trend over time, with an average annual growth rate of 8.05%, with larger fall and summer multiyear mean NEP of C 45.33 g∙m⁻²∙a⁻¹ and 44.23 g∙m⁻²∙a⁻¹, respectively, and smaller spring and winter NEP of C 21.41 g∙m⁻²∙a⁻¹ and 19.70 g∙m⁻²∙a⁻¹, respectively. 2) The overall spatial distribution of vegetation NEP was characterized by “low in the middle and high in the two wings”. In 2006, the high-carbon sink area moved southward to the southern part of the Fenhe River Basin, with an average increase of nearly C 100 g∙m⁻²∙a⁻¹ compared to 2005. And the high carbon sink area similarly migrates southward in 2019-2023, increasing by C 46.05 g∙m⁻²∙a⁻¹ compared to 2018. 3) The vegetation carbon sink in Fenhe River Basin will continue to grow over the next 30 years, with an average annual growth rate of 2.68%. It is expected to reach C 200 g∙m⁻²∙a⁻¹ by 2032 and C 300 g•m⁻²∙a⁻¹ by 2048. The vegetation carbon sink in the Fen River Basin shows an overall increasing trend over the next 30 years, which provides a scientific basis for ecological environmental protection, the formulation of carbon emission reduction policies, and the planning of sustainable development in the region.

Key words: Net Ecosystem Productivity (NEP), ecosystem carbon sink, vegetation carbon sink, CASA model, Gray GM(1, 1) model, Fenhe River basin

摘要：

净生态系统生产力（Net Ecosystem Productivity，NEP）是定量评估陆地生态系统碳汇功能的重要指标。为了探究汾河流域植被碳汇量的时空分布规律并预测未来30年汾河流域植被碳汇量。基于数字高程模型（DEM）数据、归一化植被指数（NDVI）数据、土地利用数据和气象数据，运用改进的CASA模型定量估算了汾河流域1999－2023年的植被碳汇量，用灰色GM(1, 1)模型预测了2024－2053年汾河流域植被碳汇量。结果显示，1）植被年均NEP随时间呈明显上升趋势，年均增长率为8.05%，其中，秋季和夏季多年平均NEP较大，分别为C 45.33 g∙m⁻²∙a⁻¹和44.23 g∙m⁻²∙a⁻¹，而春季和冬季较小，分别为C 21.41 g∙m⁻²∙a⁻¹和19.70 g∙m⁻²∙a⁻¹。2）植被NEP在空间上整体分布特点为“中部低，两翼高”。植被碳汇量发生显著时空迁移，2006年高碳汇区南移至汾河流域南部，较2005年平均增长近C 100 g∙m⁻²∙a⁻¹。2019－2023年高碳汇区同样向南迁移，较2018年增加C 46.05 g∙m⁻²∙a⁻¹。3）未来30年汾河流域植被碳汇量将持续增长，年均增长率为2.68%。预计到2032年将达到C 200 g∙m⁻²∙a⁻¹，2048年有望达到C 300 g∙m⁻²∙a⁻¹。汾河流域目前及未来30年植被碳汇量总体呈上升趋势，研究结果为该区域生态环境保护、碳减排政策制定和可持续发展规划提供科学依据。

关键词: 净生态系统生产力（NEP）, 生态系统碳汇, 植被碳汇量, CASA模型, 灰色GM(1, 1)模型, 汾河流域