[Estimation of net primary productivity in arid region based on coupling model.]

Area of Science:

• Ecology
• Environmental Science
• Remote Sensing

Background:

• Net primary productivity (NPP) is crucial for understanding terrestrial ecosystem matter and energy flow.
• Arid regions' NPP is sensitive to environmental and climate changes, serving as an eco-environmental indicator.

Purpose of the Study:

• To estimate vegetation NPP in the Manas River Watershed using integrated models.
• To analyze NPP's spatial patterns and its relationship with terrain factors like elevation and slope.

Main Methods:

• Coupled the Surface Energy Balance Algorithm for Land (SEBAL) model with the light utility efficiency model.
• Utilized remote sensing (RS) data (Landsat 8, MODIS), meteorological data, and eddy covariance data.
• Employed geographic information system (GIS) for spatial analysis.

Main Results:

• The coupled model provided reasonable NPP estimates for the Manas River Watershed.
• Total annual NPP was 7066.72 Tg C·a⁻¹, with a mean of 278.06 g C·m⁻²·a⁻¹ in 2013.
• NPP exhibited a distinct increase-decrease-increase-decrease pattern from south to north, influenced by land cover and geomorphology.

Conclusions:

• NPP demonstrated significant spatial and temporal variations, with peak productivity in July and August (52.2% of annual total).
• Mean annual NPP generally decreased with increasing elevation and slope, though land cover caused fluctuations.