气候变化领域集成服务门户(CCPortal): Statistical properties of hybrid estimators proposed for GEDI - NASA's global ecosystem dynamics investigation

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DOI	10.1088/1748-9326/ab18df
	Statistical properties of hybrid estimators proposed for GEDI - NASA's global ecosystem dynamics investigation
	Patterson P.L.; Healey S.P.; Ståhl G.; Saarela S.; Holm S.; Andersen H.-E.; Dubayah R.O.; Duncanson L.; Hancock S.; Armston J.; Kellner J.R.; Cohen W.B.; Yang Z.
发表日期	2019
ISSN	17489318
卷号	14 期号:6
英文摘要	NASA's Global Ecosystem Dynamics Investigation (GEDI) mission will collect waveform lidar data at a dense sample of ∼25 m footprints along ground tracks paralleling the orbit of the International Space Station (ISS). GEDI's primary science deliverable will be a 1 km grid of estimated mean aboveground biomass density (Mg ha-1), covering the latitudes overflown by ISS (51.6 °S to 51.6 °N). One option for using the sample of waveforms contained within an individual grid cell to produce an estimate for that cell is hybrid inference, which explicitly incorporates both sampling design and model parameter covariance into estimates of variance around the population mean. We explored statistical properties of hybrid estimators applied in the context of GEDI, using simulations calibrated with lidar and field data from six diverse sites across the United States. We found hybrid estimators of mean biomass to be unbiased and the corresponding estimators of variance appeared to be asymptotically unbiased, with under-estimation of variance by approximately 20% when data from only two clusters (footprint tracks) were available. In our study areas, sampling error contributed more to overall estimates of variance than variability due to the model, and it was the design-based component of the variance that was the source of the variance estimator bias at small sample sizes. These results highlight the importance of maximizing GEDI's sample size in making precise biomass estimates. Given a set of assumptions discussed here, hybrid inference provides a viable framework for estimating biomass at the scale of a 1 km grid cell while formally accounting for both variability due to the model and sampling error. © 2019 US Government.
英文关键词	Carbon monitoring; forest biomass; lidar
语种	英语
scopus关键词	Ecosystems; NASA; Optical radar; Sampling; Space stations; Above ground biomass; Ecosystem dynamics; Forest biomass; Hybrid estimator; International Space stations; Small Sample Size; Statistical properties; Variance estimators; Biomass
来源期刊	Environmental Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/154550
作者单位	USDA Forest Service, Rocky Mountain Research Station, 240W Prospect, Fort Collins, CO 80526, United States; USDA Forest Service, Rocky Mountain Research Station, 507 25th St, Ogden, UT, United States; Department of Forest Resource Management, Swedish University of Agricultural Sciences, Umeå, Sweden; USDA Forest Service, Pacific Northwest Research Station, Seattle, WA, United States; Department of Geographical Sciences, University of Maryland, College Park, MD, United States; Institute at Brown for Environment and Society, Brown University, Providence, RI, United States; Department of Ecology and Evolutionary Biology, Brown University, Providence, RI, United States; USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR, United States
推荐引用方式 GB/T 7714	Patterson P.L.,Healey S.P.,Ståhl G.,et al. Statistical properties of hybrid estimators proposed for GEDI - NASA's global ecosystem dynamics investigation[J],2019,14(6).
APA	Patterson P.L..,Healey S.P..,Ståhl G..,Saarela S..,Holm S..,...&Yang Z..(2019).Statistical properties of hybrid estimators proposed for GEDI - NASA's global ecosystem dynamics investigation.Environmental Research Letters,14(6).
MLA	Patterson P.L.,et al."Statistical properties of hybrid estimators proposed for GEDI - NASA's global ecosystem dynamics investigation".Environmental Research Letters 14.6(2019).