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Journal of Arid Land
Journal of Arid Land  2026, Vol. 18 Issue (5): 735-751    DOI: 10.1016/j.jaridl.2026.05.001     CSTR: 32276.14.JAL.20250338
Research article     
Spatiotemporal dynamics and driving factors of carbon sinks across ecosystems in Northwest China
CHEN Xueye1, SHI Ying2, BIE Qiang2,*(), Mujib ADEAGBO3
1 Key Laboratory of Urban Land Resources Monitoring and Simulation, Ministry of Natural Resources, Shenzhen 518000, China
2 School of Geomatics, Lanzhou Jiaotong University, Lanzhou 730070, China
3 School of Engineering, Cardiff University, Cardiff CF243AA, UK
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Abstract  

Net ecosystem productivity (NEP) is a key indicator for estimating carbon sink dynamics in terrestrial ecosystems. Existing studies on carbon sink dynamics in Northwest China have uncertainties in quantifying spatiotemporal variations of NEP and their driving factors. This study estimated NEP across ecosystems in Northwest China during 2000-2020 using multi-model integration, and analyzed its spatiotemporal patterns and drivers. Results showed that the annual average NEP was 97.98 g C/(m2∙a), with higher values at eastern and western margins and lower values in central hinterland. Strong carbon sink areas included the Yili River Basin and northern slope of Tianshan Mountains, while low carbon sink areas concentrated in eastern Xinjiang Uygur Autonomous Region (Eastern Xinjiang) and Alxa-Ejin Plateau. NEP trended upward from 79.22 g C/(m2∙a) in 2000 to 109.03 g C/(m2∙a) in 2020 with low variability and strong persistence, suggesting continuous growth. NEP significantly and positively correlated with near-infrared reflectance of vegetation (NIRv), weakly with climate factors, and negatively with socio-economic density indicators. Topographically, NEP peaked at 2.0-2.4 km elevation, 15°-25° slopes, and north-facing aspects. Changes in ecosystem type significantly influenced NEP, with bare land conversion into grassland/cropland enhancing carbon sinks. Results of this study highlight the need for ecological restoration and rational land use to boost carbon sequestration in this ecologically sensitive region.

Key words： near-infrared reflectance of vegetation      net ecosystem productivity      carbon sink      driving factors      Northwest China     
Received: 23 July 2025      Published: 31 May 2026
Corresponding Authors: *BIE Qiang (E-mail: bieq@lzjtu.edu.cn)
About author: Author contributions

Methodology, formal analysis, and conceptualization: CHEN Xueye; Writing - review and editing, methodology, formal analysis, and conceptualization: SHI Ying; Supervision, funding acquisition, and conceptualization: BIE Qiang; Methodology and data curation: Mujib ADEAGBO. All authors approved the manuscript.

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CHEN Xueye
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Cite this article:

CHEN Xueye, SHI Ying, BIE Qiang, Mujib ADEAGBO. Spatiotemporal dynamics and driving factors of carbon sinks across ecosystems in Northwest China. Journal of Arid Land, 2026, 18(5): 735-751.

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http://jal.xjegi.com/10.1016/j.jaridl.2026.05.001     OR     http://jal.xjegi.com/Y2026/V18/I5/735

Fig. 1 Schematic map and eight sub-regions of in Northwest China. Eastern Xinjiang: eastern Xinjiang Uygur Autonomous Region. Note that the figure is based on the standard map (GS(2023)2767) of the National Geomatics Center of China (https://www.ngcc.cn/), and the boundary of the standard map has not been modified.
Ecosystem type Site name Latitude Longitude Elevation (m)
Forest land Sidaoqiao 42°00′00′′N 101°08′24′′E 873
Sidalong 38°25′48′′N 99°55′48′′E 3146
Dayekou Guantan Forest 38°31′48′′N 100°15′00′′E 2835
Hunhelin 41°59′24′′N 101°07′48′′E 874
Grassland Zhangye 38°58′48′′N 100°27′00′′E 1460
Cropland Linze 39°19′48′′N 100°08′24′′E 1440
Daman 38°51′36′′N 100°22′12′′E 1556
Yingke Irrigation District Oasis 38°51′36′′N 100°24′36′′E 1519
Nongtian 42°00′00′′N 101°07′48′′E 875
Barren land Guazhou 41°24′36′′N 95°40′12′′E 2014
Huazhaizi 38°46′12′′N 100°19′12′′E 1731
Huangmo 42°06′36′′N 100°59′24′′E 1054
Luodi 42°00′00′′N 101°07′48′′E 878
Minqin 39°12′36′′N 103°40′12′′E 1020
Shenshawo Desert 38°47′24′′N 100°29′24′′E 1594
Table 1 Information of the 15 ecosystem sites
Fig. 2 Comparison of estimated gross primary production (GPP) from near-infrared reflectance of vegetation (NIRv) and measured GPP
Fig. 3 Comparison of estimated GPP from MOD17A2H and measured GPP
Vegetation parameter Evergreen forest Deciduous forest Mixed forest Other forests
SLA (m2/kg) 10 25 17 25
Rm,1 (g C/(m2∙a)) 0.0020 0.0060 0.0040 0.0080
Rm,2 (g C/(m2∙a)) 0.0010 0.0010 0.0010 0.0010
Rm,3 (g C/(m2∙a)) (coarse root) 0.0010 0.0010 0.0010 0.0015
Rm,3 (g C/(m2∙a))
(fine root)		 0.0030 0.0030 0.0030 0.0015
Q10,1 2.1 2.1 2.1 2.1
Q10,2 1.7 1.3 1.5 1.5
Q10,3 1.9 1.9 1.9 1.9
M2 (kg/m2) 10.1 8.8 8.1 1.0
M3 (kg/m2) 0.2317M2 $\mathrm{e}^{0.359} M_{2}^{0.639}$ $0.5\left(0.2317 M_{2}+\mathrm{e}^{0.359} M_{2}^{0.639}\right)$ 0.2
Table 2 Vegetation parameters
Parameter Cropland Grassland Forest land Barren land and others
R0 (kg SOC/(m2∙a)) 4.63±2.14 9.62±6.70 1.34±0.17 1.55±0.17
Q (°C) 0.004±0.015 0.023±0.007 0.029±0.004 0.031±0.003
K (m) 1.94±0.98 5.16±3.89 0.59±0.14 0.68±0.12
Ψ (kg C/m2) 4.27±1.21 3.99±1.66 1.43±0.33 2.23±0.34
Table 3 Specific parameters of estimating Rs
Fig. 4 Comparison of estimated net ecosystem productivity (NEP) and measured NEP
Fig. 5 Spatial distribution of annual average NEP during 2000-2020
Fig. 6 Cluster analysis of annual average NEP during 2000-2020. NS, non-significant cluster; HH, high-high; HL, high-low; LH, low-high; LL, low-low.
Fig. 7 Spatial variation of annual average NEP during 2000-2020
Fig. 8 Stability of annual average NEP during 2000-2020
Fig. 9 Persistence of average annual NEP during 2000-2020
Fig. 10 Spatial distribution of monthly average NEP during 2000-2020. (a), January; (b), February; (c), March; (d), April; (e), May; (f), June; (g), July; (h), August; (i), September; (j), October; (k), November; (l), December.
Fig. 11 Interactive detector of influencing factors. X1-X10 represent evapotranspiration, precipitation, temperature, NIRv, aspect, elevation, slope, ecosystem type, gross domestic product (GDP), and population density, respectively.
Fig. 12 Annual average NEP, total NEP, and area percentage of different types of ecosystem during 2000-2020
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