气候变化领域集成服务门户(CCPortal): An Upscaling Algorithm to Obtain the Representative Ground Truth of LAI Time Series in Heterogeneous Land Surface

CCPortal

DOI	10.3390/rs71012887
	An Upscaling Algorithm to Obtain the Representative Ground Truth of LAI Time Series in Heterogeneous Land Surface
	Shi, Yuechan; Wang, Jindi; Qin, Jun; Qu, Yonghua
通讯作者	Wang, JD (通讯作者)
发表日期	2015
EISSN	2072-4292
起始页码	12887
结束页码	12908
卷号	7 期号:10
英文摘要	Upscaling in situ leaf area index (LAI) measurements to the footprint scale is important for the validation of medium resolution remote sensing products. However, surface heterogeneity and temporal variation of vegetation make this difficult. In this study, a two-step upscaling algorithm was developed to obtain the representative ground truth of LAI time series in heterogeneous surfaces based on in situ LAI data measured by the wireless sensor network (WSN) observation system. Since heterogeneity within a site usually arises from the mixture of vegetation and non-vegetation surfaces, the spatial heterogeneity of vegetation and land cover types were separately considered. Representative LAI time series of vegetation surfaces were obtained by upscaling in situ measurements using an optimal weighted combination method, incorporating the expectation maximum (EM) algorithm to derive the weights. The ground truth of LAI over the whole site could then be determined using area weighted combination of representative LAIs of different land cover types. The algorithm was evaluated using a dataset collected in Heihe Watershed Allied Telemetry Experimental Research (HiWater) experiment. The proposed algorithm can effectively obtain the representative ground truth of LAI time series in heterogeneous cropland areas. Using the normal method of an average LAI measurement to represent the heterogeneous surface produced a root mean square error (RMSE) of 0.69, whereas the proposed algorithm provided RMSE = 0.032 using 23 sampling points. The proposed ground truth derived method was implemented to validate four major LAI products.
关键词	LEAF-AREA INDEX ESSENTIAL CLIMATE VARIABLES ACCURACY ASSESSMENT GLOBAL PRODUCTS RESOLUTION LAI SENSOR WEB GEOV1 LAI PART 2 VALIDATION MODIS
英文关键词	upscaling algorithm; leaf area index (LAI); in situ measurement; ground truth; Heihe River basin
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Geology ; Remote Sensing ; Imaging Science & Photographic Technology
WOS类目	Environmental Sciences ; Geosciences, Multidisciplinary ; Remote Sensing ; Imaging Science & Photographic Technology
WOS记录号	WOS:000364328600013
来源期刊	REMOTE SENSING
来源机构	中国科学院青藏高原研究所
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/258444
推荐引用方式 GB/T 7714	Shi, Yuechan,Wang, Jindi,Qin, Jun,et al. An Upscaling Algorithm to Obtain the Representative Ground Truth of LAI Time Series in Heterogeneous Land Surface[J]. 中国科学院青藏高原研究所,2015,7(10).
APA	Shi, Yuechan,Wang, Jindi,Qin, Jun,&Qu, Yonghua.(2015).An Upscaling Algorithm to Obtain the Representative Ground Truth of LAI Time Series in Heterogeneous Land Surface.REMOTE SENSING,7(10).
MLA	Shi, Yuechan,et al."An Upscaling Algorithm to Obtain the Representative Ground Truth of LAI Time Series in Heterogeneous Land Surface".REMOTE SENSING 7.10(2015).