- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Methods for LiDAR-based estimation of extensive grassland biomass
摘要： Biomass estimation derived from Terrestrial Laser Scanning (TLS) is already an established technique in forestry, whereas TLS measurements are less well investigated for use in grassland ecosystems. Detailed information provided by survey systems can enhance management strategies and support timely measures. Field measurements were made in the “UNESCO biosphere reserve Rh?n” in Central Germany with a TLS station (Leica P30). Four methods for estimating biomass from 3d point clouds have been applied to the data, which were Canopy Surface Height (CSH), Sum of Voxel, Mean of 3d-grid Heights, and Convex-Hull. The optimum set of model specific parameters to increase model stability and performance was identified. The methods were compared in terms of model performance and calculation speed. For each method the effect of the number of scans used for each point cloud was assessed. The best fit for fresh biomass determination was achieved with a mean CSH value derived from the top 5% of all CSH values (adj. R2 0.72). In all cases, models for dry biomass estimation had less explanatory power than those for fresh biomass. CSH models based on point clouds, which were merged from two opposite scans, achieved the highest average accuracy both for fresh and dry biomass (adj. R2 0.73 and 0.58 respectively).
关键词： Biomass,TLS,Point cloud,Grassland,LiDAR
更新于2025-09-23 15:23:52
-
[IFIP Advances in Information and Communication Technology] Computer and Computing Technologies in Agriculture X Volume 509 (10th IFIP WG 5.14 International Conference, CCTA 2016, Dongying, China, October 19–21, 2016, Proceedings) || Modelling and Predicting of Soil Electrical Conductivity and PH from Semi-arid Grassland Using VIS-NIR Spectroscopy Technology
摘要： The electrical conductivity (EC) and pH value are key indicators for soil physical and chemical properties, which can re?ect the level of soil acid and alkali, furthermore, in?uence the vegetation growth. The spectroscopy technique can estimate and evaluate electrical conductivity and pH value rapidly and ef?ciently, which can provide useful information on the real-time soil management in the semi-arid rangeland or grassland. We picked the semi-arid grassland of northern China covering an area about 200 km2 as the target research area, given that it is highly sensitive to grazing and mining affect. Soil samples were collected from 72 sampling sites in this area, which covered grazing exclusion, over grazing and grassland restoration area. The SVC HR-1024 spectroradiometer was used to acquire soil spectrum. This study aims to indicate the spectral characteristic for soil EC and pH, and propose a predicting modeling method with optimal input spectral region and transformation by comparing the support vector machine (SVM) regression method and partial least squares (PLSR) regression modeling method. Our results showed that: (1) once EC value is larger than 0.10 ls/m, the soil spectral re?ectance decreases with increasing of EC value. The absorption depth, width and area at 1900 nm reduce with increasing of EC value as well; (2) There are positive correlation between EC, pH value and soil spectral re?ectance. The highest correlation coef?cient value of 0.7 between pH and re?ectance is recorded at visible region around 500 nm; (3) The SVM modeling method produce the higher prediction accuracy (RPD = 2.18, RMSE = 0.035, R2 = 0.78 for EC, RPD > 3, RMSE = 0.349, R2 = 0.91 for pH) rather than PLSR methods in soil EC and pH prediction. This study indicated that it was possible to use the spectroradiometer technology to predict EC and pH value for the soil from semi-arid grassland, which would provide the basis for soil acid and alkali detecting using hyper-spectral remote sensing technology.
关键词： Semi-arid grassland,Spectral modeling and predicting,Soil electrical conductivity and pH,Spectral characteristic
更新于2025-09-23 15:22:29
-
Quantitative Estimation of Biomass of Alpine Grasslands Using Hyperspectral Remote Sensing
摘要： In order to promote the application of hyperspectral remote sensing in the quanti?cation of grassland areas’ physiological and biochemical parameters, based on the spectral characteristics of ground measurements, the dry AGB and multisensor satellite remote sensing data, including such methods as correlation analysis, scaling up, and regression analysis, were used to establish a multiscale remote sensing inversion model for the alpine grassland biomass. The feasibility and effectiveness of the model were veri?ed by the remote sensing estimation of a time-space sequence biomass of a plateau grassland in northern Tibet. The results showed that, in the ground spectral characteristic parameters of the grassland’s biomass, the original wave bands of 550, 680, 860, and 900 nm, as well as their combination form, had a good correlation with biomass. Also, the remote sensing biomass estimation model established on the basis of the two spectral characteristics (VI2 and Normalized Difference Vegetation Index [NDVI]) had a high inversion accuracy and was easy to realize, with a ?tting R2 of 0.869 and an F test value of 92.6. The biomass remote sensing estimate after scale transformation had a standard deviation of 53.9 kg/ha from the ?tting model established by MODIS NDVI, and the estimation accuracy was 89%. Therefore, it displayed the ability to realize the estimation of large-scale and long-time sequence remote sensing biomass. The veri?cation of the model’s accuracy, comparison of the existing research results of predecessors, and analysis of the regional development background demonstrated the effectiveness and feasibility of this method.
关键词： biomass,spectral characteristic parameters,alpine grassland,multiscale,hyperspectral remote sensing
更新于2025-09-23 15:21:01
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Crop Mapping for a Future Copernicus Agricultural Service
摘要： The ECoLaSS project: “Evolution of Copernicus Land Services based on Sentinel data” is developing innovative methods and algorithms for next-generation prototypes of improved or novel operational Copernicus Land services from 2020 onwards. This paper introduces the ECoLaSS project and focusses on developments and first results particularly in view of a new pan-European agricultural service. Dense time series of optical (Sentinel-2) and SAR (Sentinel-1) data are analyzed by means of high-volume data processing chains. Prototype crop mask and crop type maps were successfully derived for a test site in Baden-Württemberg, Germany. The agricultural prototype products are compared with the operational Copernicus High Resolution Layer (HRL) 2015 Grassland product. An outlook presents the next steps towards fit-for-purpose prototypes for pan-European roll-out.
关键词： CLMS,time features,time series,Copernicus,grassland,Sentinel,HRL,agriculture,LCLU
更新于2025-09-23 15:21:01
-
Remote sensing equivalent water thickness of grass treated with different fertiliser regimes using resample HyspIRI and EnMAP data
摘要： The aim of this study was to test the spectral settings of the forthcoming EnMAP and HyspIRI hyperspectral imagers in estimating equivalent water thickness of native grass grown under different management practices, using two regression ensembles (partial least squares regression (PLSR) and sparse partial least squares regression (SPLSR)). Results showed that the HyspIRI spectral settings better characterised Equivalent water thickness (EWT) of grass grown under different fertiliser regimes in relation to the EnMAP spectral settings. Specifically, t-test analysis indicated there were significant differences (α = 0.05) between the (pooled) relative root mean square errors derived using the HyspIRI spectral settings when compared to those exhibited by EnMAP. When all data was combined, HyspIRI spectral data settings exhibited relatively higher accuracy in estimating grass EWT with a RMSE of 3.039 g cm?2 (RRMSE = 31.7%) and an R-square of 0.59 when compared to EnMAP which exhibited a RMSE of 3.216 g cm?2 (RRMSE = 33.6%) and an R-square of 0.54. The near infrared and shortwave infrared bands were selected as the most optimally variables in estimating grass water content across different grassland management practices using the SPLSR. These findings are critical for monitoring grasslands condition at landscape scale. Overall this information is critical for determining and understanding their moisture retention capacity across different land management practices and in light of climate variability and change.
关键词： Grassland management practices,Spectral settings,Water content,Grassland health
更新于2025-09-19 17:15:36
-
Cross-task perceptual learning of object recognition in simulated retinal implant perception
摘要： Anthropogenic nitrogen (N) enrichment can significantly alter soil chemical properties in various ecosystems. Previous manipulative N experiments mainly focused on the intensity of N addition on soil properties by changing N input rates. It remains unclear, however, whether frequency of N addition can affect soil chemical properties. We examined the effects of frequency (2 versus 12 applications yr?1) and rate (ranging from 0 to 50 g N m?2 yr?1) of N addition on soil chemical properties of pH, base cations, soil pH buffering capacity (pHBC), and soil available micronutrients in a temperate steppe with and without mowing. Mowing significantly increased the effective cation exchange capacity (ECEC), soil exchangeable Ca and Na, available Fe, and soil pHBC when N was applied at low frequency. Low frequency of N addition significantly decreased soil pH and exchangeable Na but increased soil exchangeable Mg without mowing; however, it increased soil exchangeable Na and available Zn with mowing, while available Fe and Mn increased both with and without mowing. Higher rates of N addition (≥20 g N m?2 yr?1) decreased soil pH, ECEC and exchangeable Ca but increased soil available Fe, Mn and Cu regardless of the mowing treatment and frequency of N addition. Changes in soil organic matter, pHBC and ECEC were the main reasons affecting soil pH across mowing and N application treatments. Our results indicate that frequency of N addition played an essential role in altering soil chemical properties. Simulating N deposition via large and infrequent N additions can underestimate (exchangeable Mg and available Fe and Mn) or overestimate (soil pH and exchangeable Na) changes in soil properties. Our results further suggest that the effects of frequency of N addition on soil chemical attributes in semi-arid grassland ecosystems can be regulated by appropriate mowing management.
关键词： Soil micronutrient,Soil acid buffering capacity,Nitrogen deposition,Base cation,Soil acidification,Semi-arid grassland
更新于2025-09-19 17:15:36
-
[Advances in Ecological Research] Mechanisms underlying the relationship between biodiversity and ecosystem function Volume 61 || Terrestrial laser scanning reveals temporal changes in biodiversity mechanisms driving grassland productivity
摘要： Biodiversity often enhances ecosystem functioning likely due to multiple, often temporarily separated drivers. Yet, most studies are based on one or two snapshot measurements per year. We estimated productivity using bi-weekly estimates of high-resolution canopy height in 2 years with terrestrial laser scanning (TLS) in a grassland diversity experiment. We measured how different facets of plant diversity (functional dispersion [FDis], functional identity [PCA species scores], and species richness [SR]) predict aboveground biomass over time. We found strong intra- and inter-annual variability in the relative importance of different mechanisms underlying the diversity effects on mean canopy height, i.e., resource partitioning (via FDis) and identity effects (via species scores), respectively. TLS is a promising tool to quantify community development non-destructively and to unravel the temporal dynamics of biodiversity-ecosystem functioning mechanisms. Our results show that harvesting at estimated peak biomass—as done in most grassland experiments—may miss important variation in underlying mechanisms driving cumulative biomass production.
关键词： functional diversity,functional identity,ecosystem functioning,Biodiversity,species richness,grassland,terrestrial laser scanning
更新于2025-09-11 14:15:04
-
[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Assessing the Ecological Value of Grasslands from Sentinel 2: A Case Study in Flanders
摘要： Grasslands are of great ecological importance in Western Europe, mainly because they harbor a wide variety of (endangered) fauna and flora. However, not all grasslands are equally valuable. All grasslands in Flanders can be assigned to one of six ‘restoration phases’ of increasing ecological value. In this paper, we assessed how well these different phases can be distinguished from an intra-seasonal time series of Sentinel 2 satellite images. We found that the phases at the low and high extremes are very distinctive in the spectro-temporal domain of our Sentinel 2 acquisitions. The intermediate phases however are more similar spectrally, making them more difficult to discern. Most phases can however be separated at minimum one acquisition date. This is an encouraging result as we aim at developing a monitoring system for grassland restoration at the parcel scale.
关键词： grassland restoration,spectro-temporal separability,ecology,Sentinel 2
更新于2025-09-10 09:29:36