Title
A Satellite-Based Model for Simulating Ecosystem Respiration in the Tibetan and Inner Mongolian Grasslands.
Abstract
It is important to accurately evaluate ecosystem respiration (RE) in the alpine grasslands of the Tibetan Plateau and the temperate grasslands of the Inner Mongolian Plateau, as it serves as a sensitivity indicator of regional and global carbon cycles. Here, we combined flux measurements taken between 2003 and 2013 from 16 grassland sites across northern China and the corresponding MODIS land surface temperature (LST), enhanced vegetation index (EVI), and land surface water index (LSWI) to build a satellite-based model to estimate RE at a regional scale. First, the dependencies of both spatial and temporal variations of RE on these biotic and climatic factors were examined explicitly. We found that plant productivity and moisture, but not temperature, can best explain the spatial pattern of RE in northern China's grasslands; while temperature plays a major role in regulating the temporal variability of RE in the alpine grasslands, and moisture is equally as important as temperature in the temperate grasslands. However, the moisture effect on RE and the explicit representation of spatial variation process are often lacking in most of the existing satellite-based RE models. On this basis, we developed a model by comprehensively considering moisture, temperature, and productivity effects on both temporal and spatial processes of RE, and then, we evaluated the model performance. Our results showed that the model well explained the observed RE in both the alpine (R-2 = 0.79, RMSE = 0.77 g C m(-2) day(-1)) and temperate grasslands (R-2 = 0.75, RMSE = 0.60 g C m(-2) day(-1)). The inclusion of the LSWI as the water-limiting factor substantially improved the model performance in arid and semi-arid ecosystems, and the spatialized basal respiration rate as an indicator for spatial variation largely determined the regional pattern of RE. Finally, the model accurately reproduced the seasonal and inter-annual variations and spatial variability of RE, and it avoided overestimating RE in water-limited regions compared to the popular process-based model. These findings provide a better understanding of the biotic and climatic controls over spatiotemporal patterns of RE for two typical grasslands and a new alternative up-scaling method for large-scale RE evaluation in grassland ecosystems.
Year
DOI
Venue
2018
10.3390/rs10010149
REMOTE SENSING
Keywords
Field
DocType
ecosystem respiration,MODIS,moisture effect,ChinaFLUX,alpine grasslands,temperate grasslands
Common spatial pattern,Arid,Ecosystem respiration,Remote sensing,Grassland,Atmospheric sciences,Spatial variability,Enhanced vegetation index,Temperate climate,Geology,Ecosystem
Journal
Volume
Issue
Citations 
10
1
0
PageRank 
References 
Authors
0.34
1
19
Name
Order
Citations
PageRank
Rong Ge100.34
Honglin He272.02
x ren310.75
Li Zhang42286151.94
Pan Li5245.33
Na Zeng600.34
Guirui Yu773.05
Liyun Zhang800.34
Shi-Yong Yu900.34
Fawei Zhang1000.34
Hongqin Li1101.01
Peili Shi1201.69
Shiping Chen1300.68
Yanfen Wang1402.03
Xiaoping Xin15132.96
Yaoming Ma16124.44
Mingguo Ma1713525.69
Yu Zhang1800.34
Mingyuan Du1901.01