M.E. Schaepman

• University of Zurich

The common European beech ( F. sylvatica ) is sensitive to prolonged droughts, and its natural distribution is expected to shift with climate change. To persist in novel environments, young trees rely on the capacity to express diverse response phenotypes. Several methods exist to study drought effects on trees and their diverse adaptive mechanisms...

Numerous biodiversity–ecosystem functioning (BEF) experiments have shown that plant community productivity typically increases with species diversity. In these studies, diversity is generally quantified using metrics of taxonomic, phylogenetic, or functional differences among community members. Research has also shown that the relationships between...

Surface reflectance is an important data product in imaging spectroscopy for obtaining surface information. The complex retrieval of surface reflectance, however, critically relies on accurate knowledge of atmospheric absorption and scattering, and the compensation of these effects. Furthermore, illumination and observation geometry in combination...

Spectral Information Systems provide a framework to assemble, curate, and serve spectral data and their associated metadata. This article documents the evolution of the SPECCHIO system, devised to enable long-term usability and data-sharing of field spectroradiometer data. The new capabilities include a modern, web-based client-server architecture,...

This volume presents a broad overview of the requirements, capabilities, challenges and future directions of spaceborne imaging spectroscopy to explore the Earth’s surface for a range of application domains. These include mine exploration, soil mapping, vegetation monitoring, mapping of pollution and hazardous materials, inland and coastal water mo...

Natural floodplains are characterized by a complex habitat mosaic. However, damming, water storage, and hydropower production affect many floodplains by altering their natural habitat diversity. Field sampling data and imaging spectroscopy are used in combination with statistical models to assess resource allocation strategies of willow stands in p...

Healthy vegetation function supports diverse biological communities and ecosystem processes, and provides crops, forest products, forage, and countless other benefits. Vegetation function can be assessed by examining dynamic processes and by evaluating plant traits, which themselves are dynamic. Using both trait-based and process-based approaches,...

Shifts of center wavelengths (CWLs) and related changes of full-widths at half-maximums (FWHMs) occur during in-flight data acquisitions of push-broom imaging spectrometers such as the airborne prism experiment (APEX). Combined with the spectrally changing properties of the dichroic coating that acts as a beam splitter between the visible and near...

Sun-induced chlorophyll fluorescence (SIF) is a radiation flux emitted from chlorophyll molecules and is considered an indicator of the actual functional state of plant photosynthesis. The remote measurement of SIF opens a new perspective to assess actual photosynthesis at larger, ecologically relevant scales and provides an alternative approach to...

Imaging spectroscopy (IS) provides an efficient tool to assess vegetation status and functioning at ecologically relevant scales. Reliable extraction of vegetation information from spatial and spectral high resolution spectroscopy data requires accurate retrieval schemes to account for the complex radiative transfer in the coupled vegetation-atmosp...

This document provides general insights into diverse aspects of soil related remote sensing, including DSM, remote sensing technologies and soil properties. In this context, we present the underlying concept of DSM and introduce approaches to predict the spatial distribution of soil properties. Furthermore, we introduce remote and proximal sensing...

Physically-based radiative transfer modeling is the key to remote sensing of forest ecosystems. To scale spectral information from the leaf to the sensor level, the canopy architecture of a forest, illumination conditions and the viewing geometry have to be taken into account. Therefore, a new airborne image simulation approach is being developed f...

Sun-induced chlorophyll fluorescence (Fs) is the radiation flux emitted from chlorophyll molecules and can be used as a remote sensing (RS) observable to be linked to plant photosynthesis. Recently, significant progress has been made to quantify Fs from RS data, but both retrieval and interpretation of Fs remain challenging. In the case of airborne...

The physical-based geometric-optical Li-Strahler model can be inverted to retrieve forest canopy structural variables. One of the main input variables of the inverted model is the fractional component of sunlit background (K g). K g is calculated by using pure reflectance spectra (endmembers) of the viewed surface components. In this paper, the fea...

Accurate mapping of forest species composition is an important aspect of monitoring and management planning related to ecosystem functions and services associated with water refinement, carbon sequestration, biodiversity, and wildlife habitats. Although different vegetation species often have unique spectral signatures, mapping based on spectral re...

Adequate assessment and management of landscape patterns and processes need proper representation and quantification of gradients of ecosystem biochemical and structural properties. Discrete land cover mapping approaches represent landscapes as classified entities with “hard” boundaries. On the other hand, continuous field representations of land c...

Directional effects in airborne imaging spectrometer (IS) data are mainly caused by anisotropic reflectance behavior of surfaces, commonly described by bi-directional reflectance distribution functions (BRDF). The radiometric and spectral accuracy of IS data is known to be highly influenced by such effects, which prevents consistent comparison of p...

The MEdium Resolution Imaging Spectrometer (MERIS) can be used to monitor vegetation dynamics at regional to global scales. However, the spatial resolutions provided by this sensor (300 or 1200 m) might not be appropriate to monitor fragmented landscapes. This is why the synergistic use of MERIS full resolution (300 m) and Landsat TM (25 m) data is...

Anthropogenic land use activities are significantly contributing to the ecological degradation of the Earth system. Therefore, having actual and reliable land cover information is fundamental to study the impact of such an ecological degradation on our future welfare. High spatial resolution sensors, such as Landsat TM, are typically used to derive...

Monitoring and forecasting of natural vegetation succession is essential for optimal management of river floodplain ecosystems in Western Europe. For example the development of woody vegetation types (e.g., softwood forest) increases the hydraulic resistance of the floodplain and can have negative effects on the discharge capacity of the river. How...

In this paper we evaluate the potential of ENVISAT–Medium Resolution Imaging Spectrometer (MERIS) fused images for land-cover mapping and vegetation status assessment in heterogeneous landscapes. A series of MERIS fused images (15 spectral bands; 25 m pixel size) is created using the linear mixing model and a Landsat Thematic Mapper (TM) image acqu...

Recently, a laboratory measurement facility has been realized for assessing the anisotropic reflectance and emittance behaviour of soils, leaves and small canopies under controlled illumination conditions. The facility consists of an ASD FieldSpec 3 spectroradiometer covering the spectral range from 350 – 2500 nm at 1 nm spectral sampling interval....

Remotely sensed vegetation indices are widely used to detect greening and browning trends; especially the global coverage of time-series normalized difference vegetation index (NDVI) data which are available from 1981. Seasonality and serial auto-correlation in the data have previously been dealt with by integrating the data to annual values; as an...

The four articles in this special section are devoted to the deployment of analytical data models for geospatial user communities.

The Compact High Resolution Imaging Spectrometer (CHRIS) mounted onboard the Project for Onboard Autonomy (PROBA) spacecraft is capable of sampling reflected radiation at five viewing angles over the visible and near-infrared regions of the solar spectrum with high spatial resolution. We combined the spectral domain with the angular domain of CHRIS...

The Airborne Prism EXperiment (APEX) is an airborne pushbroom imaging spectrometer for Earth observation. Its products will become available in 2011. APEX is currently prepared for final acceptance configuration completing final hardware upgrades, refined calibration methodologies and test flights. APEX is composed of an airborne dispersive pushbro...

Traditionally, the estimation of forest parameters using physically-based canopy radiative transfer models (RT) requires correcting the remote sensing data to top-of-canopy (TOC) level by inverting an atmosphere RT model. By coupling the same canopy and atmosphere models, it is possible to simulate the top-of-atmosphere (TOA) radiance and to work d...

The four papers in this second part of this special issue focus on heterogeneous data access and use for geospatial user communities. The first two papers relate to satellite remote sensing data and the second two are from the hydro-meteorological domain

Hyperspectral remote sensing has demonstrated great potential for accurate retrieval of canopy water content (CWC). This CWC is defined by the product of the leaf equivalent water thickness (EWT) and the leaf area index (LAI). In this paper, in particular the spectral information provided by the canopy water absorption feature at 970 nm for estimat...

CHRIS/PROBA is capable of sampling reflected radiation at five viewing angles over the visible and near-infrared regions of the solar spectrum with a relatively high spatial resolution (~17m). We exploited both the spectral and angular domain of CHRIS data in order to map the surface heterogeneity of an Alpine coniferous forest during winter. In th...

Leaf optical properties (LOPs) are a key input parameter for vegetation canopy radiative transfer models. The uncertainty introduced in the measurement and/or the simulation of this spectral information determines a final reliability of the modelled canopy reflectance. The broad-leaf radiative transfer model PROSPECT version 3.01 has been previousl...

The canopy and atmosphere radiative transfer models SLC and MODTRAN were coupled to simulate top-of-atmosphere (TOA) radiance data for 3 Norway spruce stands in Eastern Czech Republic. The simulations fitted the near-nadir CHRIS radiance data well. A sensitivity analysis based on the singular value decomposition of the Jacobian matrix provided usef...

ESA APEX (Airborne Prism EXperiment) is a project for the realisation of an airborne dispersive pushbroom imaging spectrometer, a dedicated data Processing and Archiving Facility (PAF, hosted at VITO) and a Calibration Home Base (CHB, hosted at DLR) for instrument calibration operation. It has been developed by a joint Swiss-Belgian consortium. The...

Sun-induced chlorophyll fluorescence (Fs) is a promising parameter for remote measuring plant photosynthesis. It has been demonstrated that Fs at cell and leaf level is strongly related to photosynthesis. The transfer of the Fs approach to canopy level remains challenging as the canopy Fs signal is not fully understood yet. Several factors influenc...

Anisotropic reflectance behavior is typical for all natural surfaces. The target- and wavelength-specific characteristics of this physical phenomenon may be expressed by the conceptual quantity of the Bidirectional Reflectance Distribution Function (BRDF). On the one hand, characterization of the BRDF may enable to better estimate biophysical and b...

An at-sensor radiance simulation environment based on Hydrolight and MODTRAN-5 was set up for the evaluation of arbitrary combinations of sensors, methods and targets for the investigation of inland water quality. Each Ls simulation requires three MODTRAN- 5 runs, whereas two runs are needed for the calculation of the specular reflectance. Simulati...

Since content development is growing rapidly, it is very important to follow with this speed especially for students in developing country. International partnerships and cooperation in education will help them to get knowledge about new developments. It will also make possible the integration or exchange of learning material for sharing and reuse...

Rice is the staple food in Iran. More than 80 percent of rice area is distributed in the two northern provinces of Mazandaran and Gilan, so that investment in increasing the quantity and quality can impact an effective role in economic independence and sustainable agriculture. Increased efficiency in rice production is possible through varietal tec...

This work uncovers the spectral trajectory of the unique structurally-related information content that is embedded in the angular domain of multi-angular remote sensing data. CHRIS (Compact High Resolution Imaging Spectrometer) mounted onboard the PROBA (Project for On-board Autonomy) spacecraft is capable of sampling terrestrial reflectance anisot...

An important bio-indicator of actual plant health status, the foliar content of chlorophyll a and b (Cab), can be estimated using imaging spectroscopy. For forest canopies, however, the relationship between the spectral response and leaf chemistry is confounded by factors such as background (e.g. understory), canopy structure, and the presence of n...

Spectral performance of an airborne dispersive pushbroom imaging spectrometer cannot be assumed to be stable over a whole flight season given the environmental stresses present during flight. Spectral performance monitoring during flight is commonly accomplished by looking at selected absorption features present in the Sun, atmosphere, or ground, a...

In this study we combine the spectral domain with the directional domain of hyperspectral CHRIS (Compact High Resolution Imaging Spectrometer) data to map 3D heterogeneity of an Alpine coniferous forest during wintertime. CHRIS mounted onboard the PROBA (Project for On-board Autonomy) spacecraft is capable of sampling terrestrial reflectance anisot...

Monitoring vegetation dynamics is fundamental for improving Earth system models and for increasing our understanding of the terrestrial carbon cycle and the interactions between biosphere and climate. Medium spatial resolution sensors, like MERIS, exhibit a significant potential to study these dynamics over large areas because of their spatial, spe...

The science of spectroscopy has existed for more than three centuries, and imaging spectroscopy for the Earth system for three decades. We first discuss the historical background of spectroscopy, followed by imaging spectroscopy, introducing a common definition for the latter. The relevance of imaging spectroscopy is then assessed using a comprehen...

This paper reviews developments in the science of field spectroscopy, focusing on the last twenty years in particular. During this period field spectroscopy has become established as an important technique for characterising the reflectance of natural surfaces in situ, for supporting the vicarious calibration of airborne and satellite sensors, and...

Life on Earth depends on photosynthesis. Photosynthetic systems evolved early in Earth history and have been stable for 2.5 billion years, providing prima facie evidence for the significance of pigments in plant functions. Photosynthetic pigments fill multiple roles from increasing the range of energy captured for photosynthesis to protective funct...

The Hyperspectral Imaging Network (HYPER-I-NET) is a four-yearMarie Curie Research Training Network project designed to build an interdisciplinary European research community focusing on hyperspectral imaging activities. The network is currently formed by a multidisciplinary team composed of fifteen highly experienced European partner organizations...

Rice cultivated areas and yield information is indispensable for sustainable management and economic policy making for this strategic food crop. Introduction of high spectral and special resolution satellite data has enabled production of such information in a timely and accurate manner. Knowledge of the spectral reflectance of various land covers...

Canopy water content (CWC) is important for understanding the functioning of terrestrial ecosystems. Biogeochemical processes like photosynthesis, transpiration and net primary production are related to foliar water. The first derivative of the reflectance spectrum at wavelengths corresponding to the left slope of the minor water absorption band at...

Three radiative transfer models were coupled to simulate forest radiances at the top-of-atmosphere (TOA) level: 1) the PROSPECT leaf model, 2) the 4SAIL2 canopy model which includes the hotspot and clumping effects, and 3) the MODTRAN atmospheric radiative transfer model. The output of the coupled model can be compared to radiances measured at sate...

The success of radiative transfer model (RTM) inversion strongly depends on various factors, including the choice of a suited radiative transfer model, the followed inversion strategy, and the band configuration of the remote sensing system. Current study aims at addressing the latter, by investigating the influence of band configuration on the aut...

The physical-based geometric-optical Li-Strahler model can be inverted to retrieve forest canopy structural variables. One of the main input variables of the inverted model is the fractional component of sunlit background (K g). K g is calculated by using pure reflectance spectra (endmembers) of the viewed surface components. In this paper, the fea...

Hyperspectral remote sensing is the definitive optical tool for increasing knowledge and understanding of the Earth's surface. Contiguous high-resolution spectrometry provides a new dimension in mapping capability because of the potential for quantitative measurement of surface biogeochemistry. Alexander Goetz provided the vision and leadership tha...

vTwo FP6 initiatives i) HYRESSA, hyperspectral remote sensing in Europe specific support action, and ii) EUFAR, European Facility for Airborne Research in Environmental and Geo-sciences, have joined forces in FP7. The FP7 Integrating Activity EUFAR (including HYRESSA) is now a network of 33 European airborne data providers and experts in airborne m...

Programmable imaging spectrometers can be adjusted to fit specific application requirements that differ from the instrument initial spectral design goals. Sensor spectral characteristics and its signal-to-noise ratio (SNR) can be changed by applying customized online binning patterns. We present a software utility that generates application driven...

Shifts in the timing of spring phenology are a central feature of global change research. Long-term observations of plant phenology have been used to track vegetation responses to climate variability but are often limited to particular species and locations and may not represent synoptic patterns. Satellite remote sensing is instead used for contin...

In this paper, four unique information sources of the Compact High Resolution Imaging Spectrometer (CHRIS) onboard the Project for On-Board Autonomy (PROBA-1) are exploited, namely, the spectral, directional, spatial, and temporal dimensions. Based on the results of three case studies in Switzerland, the use of multi-angular CHRIS-PROBA data for mo...

Canopy water content (CWC) is important for mapping and monitoring the condition of the terrestrial ecosystem. Spectral information related to the water absorption features at 970 nm and 1200 nm offers possibilities for deriving information on CWC. In this study, we compare the use of derivative spectra, spectral indices and continuum removal techn...

Land degradation is always with us but its causes, extent and severity are contested. We define land degradation as a long-term decline in ecosystem function and productivity, which may be assessed using long-term, remotely sensed normalized difference vegetation index (NDVI) data. Deviation from the norm may serve as a proxy assessment of land deg...

An unmixing-based data fusion technique is used to generate images that have the spatial resolution of Landsat Thematic Mapper (TM) and the spectral resolution provided by the Medium Resolution Imaging Spectrometer (MERIS) sensor. The method requires the optimization of the following two parameters: the number of classes used to classify the TMimag...

Forest type maps play a significant role in sustainable forest management. For many years aerial photos and satellite data were a primary data source supporting forest type mapping. Recent developments in remote sensing provide opportunities to further enhance forest type maps by introducing variations of spectral, biochemical and biophysical prope...

Foliar concentration of the main photosynthetic pigments chlorophyll a and b (Cab) is widely regarded as a generic bioindicator of the actual plant status. However, when the scale moves up to stand level, relationships between the spectral response and leaf chemistry tend to break down due to confounding factors such as canopy structure, woody elem...

The spatial distribution of vegetation in the Qilian Mountain area was quantified with remote sensing data. The MODIS NDVI values for June, July, August and September are the best indicators for the vegetation growth during a year in this area and thus were used in this study. The results obtained by analyzing the NDVI data for seven years from 200...

A forest canopy is a complex system with a highly structural multi-scale architecture. Physical based radiative transfer (RT)modelling has been shown to be an effective tool for retrieval of vegetation canopy biochemical/physical characteristics from optical remote sensing data. A high spatial resolution RT through a forest canopy requires several...

The physical based Li-Strahler geometric-optical model can be inverted to retrieve forest canopy structural variables. One of the main input variables of the inverted model is the fractional component of sunlit background (Kg). Kg is calculated by using pure reflectance spectra (endmembers) of the viewed surface components. To detect the forest can...

The spaceborne ESA-mission CHRIS (Compact High Resolution Imaging Spectrometer) on-board PROBA-1 (Project for On-board Autonomy) delivers multi-directional data sets that contain spectral, directional, spatial and multi-temporal information. CHRIS/PROBA data have been acquired over two well documented test sites in Switzerland (Swiss National Park...

View angle effects present in spectral vegetation indices can either be regarded as an added source of uncertainty for variable retrieval or as a source of additional information, enhancing the variable retrieval; however, the magnitude of these angular effects remains for most indices unknown or unquantified. We use the ESA-mission CHRIS-PROBA (Co...

We investigated 40 samples from nine different soil types, originating from several climatic zones and a large variety in SOC content (0.06–45.1%). Spectral measurements for all soil samples were performed in a controlled laboratory environment. We tested the performance of several spectral indices which have been developed to detect biochemical co...

Peatlands accumulated large carbon (C) stocks as peat in historical times. Currently however, many peatlands are on the verge of becoming sources with their C sequestration function becoming sensitive to environmental changes such as increases in temperature, decreasing water table and enhanced nitrogen deposition. Long term changes in vegetation c...

We use the Li-Strahler geometric-optical model combined with a scaling-based approach to detect forest structural changes in the Three Gorges region of China. The physical-based Li-Strahler model can be inverted to retrieve forest structural properties. One of the main input variables for the inverted model is the fractional component of sunlit bac...

Signatures from five remote sensing domains—spectral, spatial, angular, temporal and polarization—provide the basis for the description and discrimination of Earth surfaces and their variability. These signatures have been used for a wide range of terrestrial applications. In this chapter, we review the measurements, modelling and applications of t...

We compare the inversion of two canopy reflectance models to estimate forest crown closure (CC) using an EO-1 Hyperion image: the Kuusk¿Nilson forest reflectance and transmittance (FRT) model, and the Li¿Strahler geometric¿optical model. For predicting CC on a per-pixel basis, the FRT model inversion is carried out by minimizing a merit function th...

In this paper, four unique information sources of the Compact High Resolution Imaging Spectrometer (CHRIS) onboard the Project for On-Board Autonomy (PROBA-1) are exploited, namely, the spectral, directional, spatial, and temporal dimensions. Based on the results of three case studies in Switzerland, the use of multi-angular CHRIS-PROBA data for mo...