干旱区生态环境知识资源中心(Arid): Mapping fractional woody cover in an extensive semi-arid woodland area at different spatial grains with Sentinel-2 and very high-resolution data

Arid

DOI	10.1016/j.jag.2021.102621
	Mapping fractional woody cover in an extensive semi-arid woodland area at different spatial grains with Sentinel-2 and very high-resolution data
	Shafeian, Elham; Fassnacht, Fabian Ewald; Latifi, Hooman
通讯作者	Shafeian, E (corresponding author), Karlsruhe Inst Technol KIT, Inst Geog & Geoecol, Kaiserstr 12, D-76131 Karlsruhe, Germany.
来源期刊	INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION
ISSN	1569-8432
EISSN	1872-826X
出版年	2021
卷号	105
英文摘要	Woody canopy cover is an essential variable to characterize and monitor vegetation health, carbon accumulation and land-atmosphere exchange processes. Remote sensing-based global woody and forest cover maps are available, yet with varying qualities. In arid and semi-arid areas, existing global products often underestimate the presence of woody cover due to the sparse woody cover and bright soil background. Case studies on smaller regions have shown that a combination of collected field data and medium-to-high resolution free satellite data (e.g., Landsat / Sentinel-2) can provide woody cover estimates with practically-sufficient accuracies. However, most earlier studies focused on comparably small regions and relied on costly field data. Here, we present a fully remote sensing-based work-flow to derive woody cover estimates over an area covering more than 0.5 million km2. The work-flow is showcased over the Zagros Mountains, a semi-arid mountain range covering western Iran, the northeast of Iraq and some smaller fraction of southeast Turkey. We use the Google Earth Engine to create homogeneous Sentinel-2 mosaics of the region using data from several years. These data are combined with reference woody cover values derived by a semi-automatic procedure from Google (R) and Bing (R) very high resolution (VHR) imagery. Several random forest (RF) models at different spatial grains were trained and at each grain validated with iterative splits of the reference data into training and validation sets (100 repetitions). Best results (considering the trade-off between model performance and spatial detail) were obtained for the model with 40 m spatial grain which showed stable relationships between the VHR-derived reference data and the Sentinel-2 based estimates of woody cover density. The model resulted in median values of coefficient of determination (R2) and RMSE of 0.67 and 0.11, respectively. Our work-flow is potentially also applicable to other arid and semi-arid regions and can contribute to improve currently available global woody cover products, which often perform poorly in semi-arid and arid regions. Comparisons between our woody cover products with common global woody or forest-cover products indicate a clear superiority of our approach. In future studies, these results may be further improved by taking into account regional differences in the drivers of woody-cover patterns along the environmental gradient of the Zagros area.
英文关键词	Semi-arid woodlands Zagros Woody cover Sentinel-2 VHR imagery Land cover
类型	Article
语种	英语
开放获取类型	gold
收录类别	SCI-E
WOS记录号	WOS:000724264800002
WOS关键词	FOREST BIOMASS ESTIMATION ; CANOPY COVER ; TEXTURE ANALYSIS ; SATELLITE DATA ; TRAINING DATA ; OAK FORESTS ; TREE COVER ; LANDSAT 8 ; VEGETATION ; CLASSIFICATION
WOS类目	Remote Sensing
WOS研究方向	Remote Sensing
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/374149
作者单位	[Shafeian, Elham; Fassnacht, Fabian Ewald] Karlsruhe Inst Technol KIT, Inst Geog & Geoecol, Kaiserstr 12, D-76131 Karlsruhe, Germany; [Latifi, Hooman] KN Toosi Univ Technol, Fac Geodesy & Geomat Engn, Dept Photogrammetry & Remote Sensing, Tehran 1543319967, Iran; [Latifi, Hooman] Univ Wurzburg, Dept Remote Sensing, Oswald Kulpe Weg 86, D-97074 Wurzburg, Germany
推荐引用方式 GB/T 7714	Shafeian, Elham,Fassnacht, Fabian Ewald,Latifi, Hooman. Mapping fractional woody cover in an extensive semi-arid woodland area at different spatial grains with Sentinel-2 and very high-resolution data[J],2021,105.
APA	Shafeian, Elham,Fassnacht, Fabian Ewald,&Latifi, Hooman.(2021).Mapping fractional woody cover in an extensive semi-arid woodland area at different spatial grains with Sentinel-2 and very high-resolution data.INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION,105.
MLA	Shafeian, Elham,et al."Mapping fractional woody cover in an extensive semi-arid woodland area at different spatial grains with Sentinel-2 and very high-resolution data".INTERNATIONAL JOURNAL OF APPLIED EARTH OBSERVATION AND GEOINFORMATION 105(2021).