Dynamic Threshold of Carbon Phenology in Two Cold Temperate Grasslands in China

doi:10.3390/rs13040574

	Dynamic Threshold of Carbon Phenology in Two Cold Temperate Grasslands in China
	Xu, Lingling 1,2; Niu, Ben 1; Zhang, Xianzhou 1,3; He, Yongtao 1,3
刊名	REMOTE SENSING
	2021-02-01
卷号	13 期号:4 页码:16
关键词	temperate grasslands satellite-based phenology threshold algorithms eddy covariance (EC)
DOI	10.3390/rs13040574
通讯作者	Niu, Ben(niub@igsnrr.ac.cn)
英文摘要	Plant phenology, especially the timing of the start and the end of the vegetation growing season (SOS and EOS), plays a major role in grassland ecosystem carbon cycles. As the second-largest grassland country in the world, China's grasslands are mainly distributed in the northern cold temperate climate zone. The accuracies and relations of plant phenology estimations from multialgorithms and data resources are poorly understood. Here, we investigated vegetation phenology in two typical cold temperate grasslands, Haibei (HB) and Inner Mongolia (NM) grasslands, in China from 2001 to 2017. Compared to ground vegetation phenology observations, we analyzed the performance of the moderate resolution imaging spectroradiometer MODIS phenology products (MCD12Q2) and two remote sensing-based vegetation phenology algorithms from the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI) time series (five satellite-based phenology algorithms). The optimal algorithm was used to compare with eddy covariance (EC)-based carbon phenology, and to calculate the thresholds of carbon phenology periods (SOSt and EOSt) in each site. Results showed that satellite-based phenology estimations (all five algorithms in this study) were strongly coupled with the temporal variation of the observed phenological period but significantly overestimated the SOS, predicting it to be over 21 days later than the field data. The carbon phenology thresholds of HB grassland (HB_SOSt and HB_EOSt) had a significant upward trend, with the multiyear average values being 0.14 and 0.29, respectively. In contrast, the thresholds of NM grasslands (NM_SOSt and NM_EOSt) also showed a certain upward trend, but it was not significant (p > 0.05), with the multiyear average values being 0.17 and 0.2, respectively. Our study suggested the thresholds of carbon phenology periods (SOSt and EOSt, %) could be simply and effectively estimated based on their significant relationship with the EC-based maximum of gross primary productivity observations (GPPmax) at a specific site and time. Therefore, this study suggested the thresholds of carbon phenology were not fixed even in a specific ecosystem, which also provided simple bridges between satellite-based vegetation phenology and EC-based carbon phenology in similar grasslands.
资助项目	National Natural Science Foundation of China[31700421] ; National Natural Science Foundation of China[41807331] ; National Key Research and Development Program[2017YFA060 4801] ; West Light Foundation of the Chinese Academy of Sciences
WOS研究方向	Environmental Sciences & Ecology ; Geology ; Remote Sensing ; Imaging Science & Photographic Technology
语种	英语
出版者	MDPI
WOS记录号	WOS:000624416600001
资助机构	National Natural Science Foundation of China ; National Key Research and Development Program ; West Light Foundation of the Chinese Academy of Sciences
内容类型	期刊论文
源URL	[http://ir.igsnrr.ac.cn/handle/311030/160639]
专题	中国科学院地理科学与资源研究所
通讯作者	Niu, Ben
作者单位	1.Chinese Acad Sci, Inst Geog Sci & Nat Resources Res, Key Lab Ecosyst Network Observat & Modeling, Lhasa Plateau Ecosyst Res Stn, Beijing 100101, Peoples R China 2.Natl Meteorol Ctr, Beijing 100081, Peoples R China 3.Univ Chinese Acad Sci, Coll Resources & Environm, Beijing 100190, Peoples R China
推荐引用方式 GB/T 7714	Xu, Lingling,Niu, Ben,Zhang, Xianzhou,et al. Dynamic Threshold of Carbon Phenology in Two Cold Temperate Grasslands in China[J]. REMOTE SENSING,2021,13(4):16.
APA	Xu, Lingling,Niu, Ben,Zhang, Xianzhou,&He, Yongtao.(2021).Dynamic Threshold of Carbon Phenology in Two Cold Temperate Grasslands in China.REMOTE SENSING,13(4),16.
MLA	Xu, Lingling,et al."Dynamic Threshold of Carbon Phenology in Two Cold Temperate Grasslands in China".REMOTE SENSING 13.4(2021):16.