Cumulative Issue #139 June 2006 ISSN 0274-6338

http://www.grss-ieee.org/menu.taf?menu=Publications&detail=newsletter Editor: Adriano Camps

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IEEE Geoscience and Remote Sensing Society Newsletter • June 2006 17

UNIVERSITY PROFILE

CENTRE FOR GEO-INFORMATION, WAGENINGEN UNIVERSITY ANDRESEARCH CENTRE, THE NETHERLANDS

Lammert Kooistra1, Michael Schaepman1,2, Jan Clevers1, Li Jia2, Sander Mucher2, and Allard de Wit2

IntroductionThe Centre for Geo-Information (CGI) of WageningenUniversity and Research Centre is a joint research centrefounded in the year 2000. CGI is a combination of tworesearch entities. On the one hand the Laboratory for Geo-Information Science and Remote Sensing of WageningenUniversity and on the other hand the Geo-Informationgroup of Alterra. Both entities are managed in a joint man-agement team, creating mutual research benefits on bothsides. The Wageningen University based part has beenfounded already in 1994. It was named the Laboratory forGeo-Information Science and Remote Sensing (GRS) andhas been serving as a focal point for geo-information relat-ed academic research and education within WageningenUniversity since then. Applied research in the domain ofgeo-information already has a long tradition within Alterraand its predecessors. As a result research within CGI is typ-ically performed in multidisciplinary teams that offer theopportunity to share and integrate knowledge between bothscientific and applied research, and education in the field ofgeo-information science.

The following research themes delineate the main researchfocus of CGI:• providing geo-information for rural areas: making knowl-

edge and information available to underpin policy deci-sions on natural resources;

• monitoring rural areas; developing GIS-based and RS-based methods for monitoring rural areas, at national aswell as global levels;

• quantitative retrieval of geo-biophysical and –chemicalvariables from spatially distributed data at scales fromlocal to global for environmental management;

• scenario studies: integrating GIS and RS knowledge inprocess models for planning and scenario studies;

• visualization and communication of geo-information:using multimedia technology in developing and underpin-ning policies for the rural areas.

PeopleRemote sensing is one of the main research topics withinCGI. However, there are substantial other fundamental andapplied research activities going on, that include spatial datainfrastructures, spatial data modelling and geo-visualization.In the subsequent part of this section we will put the mainemphasis on remote sensing related research of both, theUniversity and Alterra. The remote sensing team of CGIincludes the following staff:

Wageningen University• Dr. Michael Schaepman, full professor, scientific manager

CGI, quantitative, physical based remote sensing• Dr. Jan Clevers, associate professor, quantitative, statistical

based remote sensing• Dr. Lammert Kooistra, assistant professor, ecology and

remote sensing• Dr. Sytze de Bruin, assistant professor, spatial data quality

and uncertainty• Drs. Harm Bartholomeus, university lecturer remote sensing• Dr. Gabriela Schaepman-Strub, external research fellow

(European Space Agency sponsored), jointly with KNMI,Centre Ecosystems and Centre Water and Climate ofWageningen University; quantitative remote sensing, ter-minology, Albedo.

Alterra• Dr. Li Jia, researcher, physical based multi-angular remote

sensing• Ir. Sander Mucher, researcher, land-use monitoring• Ir. Allard de Wit, researcher, crop monitoring and forecasting• Ir. Gerard Hazeu, researcher, land-use monitoring• Ir. Anne Schmidt, researcher, ecology and remote sensing

The University staff is complemented by the scientific stafffocusing on GIS and visualization as follows:• Dr. Arnold Bregt, full professor, spatial data infrastructures

1Laboratory of Geo-Information Science and Remote Sensing; Wageningen University, Centre for Geo-Information,Droevendaalsesteeg 3, 6708 PB, Wageningen, The Netherlands2Alterra Green World Research, Centre for Geo-Information, Wageningen UR, Droevendaalsesteeg 3, 6708 PB,Wageningen, The Netherlandse-mail: Lammert.Kooistra@wur.nl

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• Dr. Ron van Lammeren, associate professor, geo-visual-ization

• Dr. Joep Crompvoets, assistant professor, spatial datainfrastructures

In total, CGI is home to more than 60 scientists, researchers,technical staff, as well as software engineers (split into approx.50% University staff (http://www.grs.wur.nl/UK/Staff/) and50% Alterra staff). They are working in collaboration with var-ious national and international research institutions and organi-zations, including the government and private sectors to pro-vide university-level education and research in geo-informationscience, in view to support policy development and the designand management of rural areas.

In the following sections, the research focus of the remotesensing activities of the Centre for Geo-Information are out-lined using a number of case studies and research directions.

EducationGRS offers various academic programs and educational train-ing at BSc, MSc, PhD, and PostDoc levels focusing on fourspecializations: i) remote sensing and geospatial imaging, ii)geographical information systems (GIS), iii) geospatial infor-mation and communication technology (Geo-ICT), and iv)geographical information management). At the BSc level,GRS takes care of introductory teaching in geo-informationscience for large groups of students at Wageningen Universityof various backgrounds and disciplines. In average about 30students join our MSc programme on Geo-InformationScience every academic year, which has been fully accreditedto be taught in English and is compliant with the EuropeanCredit Transfer System (ECTS) (www.geo-informatie.nl).Our MSc students originate from over 29 countries world-wide, combining skills of various disciplines relevant in theEarth System Sciences.

University level teaching aims at an end-to-end under-standing of the geo-information cycle, ranging from acquisi-tion and storage, to Earth Observation (remote sensing meth-ods), GIS, analysis (including spatio-temporal modeling andresearch tools), to visualization. The solid training of acade-mic competencies includes approaches to improve scientificwriting and evaluating skills, as well as recognizing innova-tive opportunities within the Geographic InformationSciences. Particular focus is put on a multidisciplinary educa-tional curriculum, where students can apply the gainedknowledge in geo-information to spatial planning, geography,ecology and environmental management applications. Sincerecently, a joint distance learning MSc in Geo-informationManagement and Applications (GIMA) is offered by DelftUniversity, Utrecht University, the International Institute forGeo-information and Earth Observation (ITC) andWageningen University (www.msc-gima.nl).

A multitude of PhD students are working on their PhD dis-sertations usually finalizing their work in a period of fouryears. GRS is member of the C.T. de Wit Graduate School forProduction Ecology and Resource Conservation (PE&RC)(www.dpw.wageningen-ur.nl/peenrc), which is ensuring thequality and coherence of the PhD education. GRS is alsohosting PostDoc’s and research fellows, wanting to pursue afurther specialization of the core research subject.

International embeddingCGI participates and contributes to major international devel-opments in remote sensing through active participation inprogrammes, working groups and steering committees. Theserange from the contribution to the Group on EarthObservations (GEO) work plan to build a Global EarthObservation System of Systems (GEOSS), to drafting the sci-entific challenges for ESA’s (European Space Agency) LivingPlanet Programme, defining the land contribution in the jointESA/EU (European Union) ‘Global Monitoring forEnvironment and Security’ (GMES) programme, amongstothers. Significant input to the further advancement of spec-trodirectional imaging has been made in the form of con-tributing to the ESA Earth Explorer Core Mission definition,namely SPECTRA, as well as providing contributions to newsensor development (ESA APEX), definition (ESA SPEC-TRA, FLEX, Sentinel), as well as calibration (ESAMERIS/ENVISAT and CHRIS/PROBA). CGI’s societal con-tribution is reflected in active roles at ISPRS (Chairing WGVII/1 on fundamental physics and modeling) and EARSeL, aswell as offering and chairing invited sessions at several con-ferences on remote sensing (IEEE, ISPRS, SPIE, EARSeL,ESA). CGI strives for honoring all activities relevant for sci-ence and therefore actively contributes to the peer reviewprocess of most relevant remote sensing journals. GRS is alsoinvolved in several EU-funded activities, such as the HYRES-

18 IEEE Geoscience and Remote Sensing Society Newsletter • June 2006

Figure 1. Aerial view of a part of the WUR campus to the North ofthe city of Wageningen collected by a Vexcel Ultracam D digital cam-era (courtesy: Aerodata).

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IEEE Geoscience and Remote Sensing Society Newsletter • June 2006 19

SA project, aiming at building a European-wide network ofhyperspectral remote sensing facilities.

Research focusRemote sensing research at CGI specializes in the domain ofquantitative, physical and statistical based retrieval of landsurface parameters relevant for earth system modeling withspecial focus on spectrodirectional imaging. Particular atten-tion is paid to the use of radiative transfer models, supportvector machines, data assimilation methods, and linking soil-vegetation-atmosphere transfer models to state-space estima-tion algorithms. This is complemented by our expertise inlinking ecological and dynamic vegetation models to imagingspectroscopy for applications like biodiversity assessment athabitat and ecosystem level as well as modeling CO2-seques-tration. Additional expertise is present in the domain of spa-tial data infrastructures (global inventory of clearinghouses),crop yield forecasting (e.g., CGMS, MARS), National,European and global scale land use mapping (e.g., LGN5,GLC2000, PELCOM), directional thermal and reflectivemeasurements, as well as water and energy balance modeling.Further activities include the definition of user requirementsfor future sensors, including the translation of applicationrequirements into engineering specifications. Extensive labo-ratory and field measurement activities complement theresearch activities. The following sections presents a selectionof recent research advances with emphasis on remote sensing.

Quantitative statistical and physical approachesassessing leaf to canopy propertiesSeveral ongoing projects focus on the application of radiativetransfer (RT) based models to estimate canopy structural andbiochemical properties for different ecosystems. We usequantitative statistical based approaches, which are relativelyeasy to develop but usually are site-specific. Radiative trans-fer modeling takes into account physical processes describingthe interaction of radiation with the various canopy compo-nents at foliage and canopy level. In combination with theabove, we apply multi-angular approaches for parameterretrieval as well. We use all three approaches for the enhancedretrieval of biophysical variables (e.g., Leaf-Area-Index) todetect multiple stress response in Norway spruce forest stand,or assess the ecological relevance of Minnaert’s k in Borealecosystems. The 3-D based DART model is used to simulatehigh spatial and spectral resolution image data (Figure 2). Weinvert models (RPV, SAIL/PROSPECT, DART) using air-borne and spaceborne spectro-directional data. Selectedresults show that the parameterization of the canopy RTmodel must correspond to the spatial and spectral scale of theobserved objects and should consider important eco-physio-logical processes of the studied tree species. The presentedDART parameterization is based on enhancing the model for

eco-physiological processes in combination with extensivefield measurements. The in-situ measurements are sufficient-ly precise, but for large heterogeneous areas they eventuallyshould be replaced using comparable nondestructiveapproaches (e.g. LIDAR – forest structure measurements), aswell as by modeling methods (e.g. PROSPECT – a model ofleaf optical properties). In another application, the seasonalvariability in a boreal forest ecosystem is assessed using spec-tro-directional satellite data (CHRIS/PROBA) and radiativetransfer modeling. We develop methods that combine recentadvances in spectro-directional imaging (e.g. surface andatmosphere anisotropy, laboratory and field directional mea-surements, etc.) with explicit scene modeling of individualtrees and their changing background. Inclusion of the spatial-temporal dynamics of the understory’s seasonal coverageshould decrease the retrieval uncertainty of relevant parame-ters like fPAR and finally Net Primary Production.

Quantitative remote sensing in ecosystem modelingAn important research focus is the application of remotesensing for ecosystem modeling. Recent advances inapplying biogeochemistry based process models provethat their combination with regional scale remote sensingis a very promising approach for testing ecologicalhypotheses and for assessing and forecasting the state of

Figure 2. 3D representation of Norway spruce as used in the DARTmodel (left), and resulting radiative transfer modeling result for sim-ulated forest stand (right)

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20 IEEE Geoscience and Remote Sensing Society Newsletter • June 2006

large landscapes. In particular spatially contiguous dis-tributed input of biophysical (e.g., LAI, fPAR, gap frac-tion) and biochemical parameters (e.g., chlorophyll a/bcontent, the C:N ratio) are of outmost importance. In ajoint Belgian-Dutch project, a combined remote sensing-ecological modeling approach was elaborated for a riverfloodplain in the Netherlands. Directional airborne imag-ing spectrometer data from the HyMap sensor in 2004 andAHS-160 sensor in 2005 were used to derive continuousfields for several biophysical variables (cover figure).Such derived variables were used as input for the ecolog-ical model SMART-SUMO (developed within WUR) tosimulate vegetation development under scenarios ofchanging abiotic conditions and management. Significantsimulation differences in total biomass depending on themanagement approach (agriculture vs. natural reserve)demonstrate the need to develop ‘vegetation’ scenariosanalogous to IPCC atmospheric scenarios. Other ongoingprojects focus on the improved retrieval of Albedo for nat-ural vegetation in arctic regions to reduce uncertainties inregional to global climate modeling; and the spatial-tem-poral modeling of organic carbon in agricultural soil usingimaging spectroscopy.

Monitoring land cover change and habitat qualityCGI is involved in several projects that deal with land usemonitoring at the national (Dutch Land Use Database:www.lgn.nl), European (Corine Land Cover, PELCOM)and global scale (GLC2000). Standardized and validatedclassification methodologies have been developed basedon sources originating from multi-temporal satellite data(e.g., Landsat TM, NOAA-AVHRR, ERS-SAR, LISS) andancillary geographical information (e.g., topography, aeri-al photographs). In addition, several projects focus on nat-ural habitat monitoring over large regions (e.g., EUNatura2000 network). To map all major European habitatsa flexible spatial data infrastructure was developed inwhich existing and new spatial data sets (including remote-ly sensed information) are exploited and (ecological)knowledge rules have been explicitly defined (PEEN-HAB). The resulting European Habitat Map has been vali-dated extensively and is now being used as an indicativemap for the definition of a Pan-European EcologicalNetwork. In addition, a standardized methodology hasbeen developed (Figure 3) linking measures of historicalland cover change to pressures on biodiversity(www.creaf.uab.es/biopress). The method produces esti-mates of land cover change (1950 – 2000) that are statisti-cally representative of change dynamics in the differentbio-geographical regions of Europe. Special attention waspaid to land cover change affected in the vicinity of areasthat are protected for reasons of their biodiversity interest.

Modeling land-atmosphere exchange using multi-angular remote sensingThe study of multi–angular radiometric observations of theterrestrial biosphere from airborne and spaceborne platformsis a major research interest of several projects within CGI.Available water determines how terrestrial vegetationresponds to weather and climate by controlling the allocationof available energy and by modulating the land-atmosphereexchange of water and carbon. The exchange of energybetween land-surface and atmosphere and within terrestrialvegetation canopies is a significant determinant of processesin the atmospheric boundary layer and in terrestrial ecosys-tems. For these processes, it is crucial to determine accurate-ly the partitioning of available energy into sensible heat fluxdensity (heating or cooling of the surface) and latent heat fluxdensity (evaporation from surface) over a wide range of spa-tial and temporal scales. Observations from space of surfacealbedo, temperature and roughness help modeling and under-standing land – atmosphere interactions.

Multi–angular radiometric observations of the terrestrialbiosphere have been adopted to characterize and understandthermal heterogeneity towards better models of heat exchangeat the land – atmosphere interface. At CGI, a modeling sys-tem has been developed that describes radiative and convec-tive processes in the canopy space using a 3D model to dealwith realistic canopy architecture. Based on this sophisticatedmodel, simpler models have been derived and validated toretrieve foliage and soil temperatures using space-bornemulti-spectral imaging radiometers. Models and algorithmshave been evaluated using data collected during field experi-ments in China, USA, France and Spain (Figure 4). At theregional scale, sensible heat flux density was modeled usingbi-angular ATSR-2 observations of exitance and compared

Figure 3. Overview of BIOPRESS methodology: land cover changeanalysis performed using a comparison of aerial photographsfrom1950 and Landsat TM images of 1990 for selected areas in theBelgium and Spain.

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IEEE Geoscience and Remote Sensing Society Newsletter • June 2006 21

with measurements by Large Aperture Scintillometers (LAS)at a spatial scale comparable with the ATSR-2 spatial resolu-tion. The comparison showed a high agreement and was with-in the accuracy of the scintillometers.

Crop yield monitoring and forecastingSeveral projects are ongoing which are developing sophisti-cated applications for crop yield monitoring and forecasting.Information on the outlook of yield and production of cropsover large regions is essential for government services dealingwith import and export of food crops, for agencies with a rolein food relief and for international organizations with a man-date in monitoring the world food production and trade. Ateam from CGI is as consortium leader responsible for pro-viding agricultural crop monitoring services to the JointResearch Centre of the European Commission within theMARS project (Monitoring Agriculture through RemoteSensing techniques). The monitoring system, consist of threemain tasks: providing information on weather(MeteoConsult), processing and visualizing results fromsatellite imagery (Flemish Institute for Technology (VITO))and monitoring of conditions for crop growth and yield fore-casting (CGI). Within these systems, crop models (e.g.,WOFOST) are fed with daily weather variables and comparedto remote sensing derived variables (e.g., SPOT-Vegetation:

NDVI and accumulated dry matter) to provide crop yield andother crop related variables. Time-series of crop simulationresults are used as input in a statistical analysis which fore-casts current years crop yield. The spatial output of the systemis made available through the Crop Growth MonitoringSystem (http://www.marsop.info). Recently, efforts have beenmade to develop a global system for monitoring crop condi-tions based on the so-called Crop Water Satisfaction Index(CWSI). New programming techniques have made it possibleto create an online interactive interface for querying theCWSI database (Figure 5). In this way end-users are facilitat-ed to quickly navigate through global coverage maps forCWSI values for different crops, make comparison betweenyears and with long term averages, and make detailed ana-lyzes of CWSI for specific locations.

A critical aspect is the accuracy of the yield forecasts.Within the Geoland project, five different systems for yieldforecasting from different European research institutes arecompared for three test sites (Poland, Belgium and Spain).Results from this project are essential to improve yield fore-casting system performance at the European and global level.

Field equipment and sensor developmentAt the GRS laboratory, a field equipment pool with state-of-the-art instruments is available to support the above researchprojects. The pool includes 2 ASD FieldSpec Pro spectrora-diometers (including contact probes for soils and leaves; nee-dle optical properties measurement devices; and directionalleaf optical properties measurements using a sphere), hemi-spherical cameras (including various analytical softwarepackages assessing gap fraction, LAI, etc.), DGPS systemsand field digitizing systems (PDA’s). A laboratory-based mea-surement set-up for controlled spectral measurements is avail-able which is also equipped with a calibration facility. Theinstruments are used by staff and students to measure spectralground truth in the field and provide accurate laboratory mea-

Figure 4. Upper panel: Simulated images of brightness temperatureof the Barrax agricultural site (Spain) at nadir and at forward 60degree zenith view angle by using process and radiative transfermodels. Lower panel: retrieved soil and vegetation componentimages using synthetic multi-angular TIR images.

Figure 5. Interface of CWSI database showing the global distribu-tion of rain fall during the last 10 days of June 2005.

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The Specialist Meeting on Microwave Radiometry andRemote Sensing Applications, commonly referred to asMicroRad or simply “µrad,” was conceived to provide a com-mon international forum to report and discuss recent achieve-ments in the field of microwave radiometry for remote sens-ing of the environment. The meetings are also intended tofacilitate interaction between the scientific community andindustry, and to foster the benefits to society of microwaveand millimeter-wave radiometry, both through the applicationof data products in weather prediction, climate analysis, andenvironmental management, and through economic gain. Thefirst MicroRad specialist meeting was held in Rome at “LaSapienza” in 1983, and the second in Florence in 1988. Sincethen, MicroRad has been held approximately every 2.5 years,alternating in venue between the United States and Italy.

MicroRad ‘06 This year at least 125 MicroRad attendees from 15 differentcountries convened in San Juan, Puerto Rico, USA. They pre-sented 130 technical papers in 16 sequential sessions over 4full days, with 5 oral papers per session. These included 34invited talks, half from Europe and half from the U.S. Postersassociated with each session were introduced by sessionchairs preceding each 40-minute coffee break, allowing plen-ty of time for interacting with poster presenters and forrenewing aquaintances. This format continued the successfulstructure of the MicroRad conferences to date.

There were several new aspects of MicroRad in 2006. Onewas audio recordings. Deftly handled by Shane Pearlman of

PM-Networks, MicroRad 06 was the pilot conference foraudio lectures recorded by IEEE GRSS to make available notonly the slide presentations, but also full audio presentationwith a synchronized slide show. The first audio lecture isavailable to the general public at http://www.grss-ieee.org/menu.taf?menu=Conferences&detail=Audio. Onemay also navigate to the IEEE GRSS home page,http://www.grss-ieee.org, select “Conferences” from the topmenu bar, and then select “Audio Lectures.” Additional audiolectures from MicroRad ‘06 are accessible to all IEEE GRSSmembers who log in as such and visit the same web page.

MicroRad ’06 Proceedings will be published on CD-ROMand distributed to all participants after the conference. Anothernew aspect of MicroRad ’06 is that these proceedings will includePDF versions of presentation slides, for those authors who gavepermission to include them. Longer papers have been solicitedfor a Special Issue of TGARS, with a manuscript due date of June1, 2006. See the TGARS web site at http://www.grss-ieee.org/menu.taf?menu=Publications&detail=TGARS or theMicroRad ’06 web site at http://www.microrad06.org (click onTechnical Program) for more information.

Technical ProgramThe conference opened on Tuesday, February 28, with thesensor calibration session featuring presentations on currentand planned radiometer systems given by representatives ofgovernment, federally funded agencies, universities and pri-vate industry. Specifically, correlating systems provideunique calibration challenges as do the long term monitoring

22 IEEE Geoscience and Remote Sensing Society Newsletter • June 2006

surements as required for simulation and modeling. In addi-tion, within the Wageningen University network we haveaccess several laboratory facilities (e.g., spectroscopy, fluo-rescence, soil and plant biochemistry), and several types ofmeteorological equipment (incl. scintillometers). A largelibrary of remote sensing imagery is available in-house, con-sisting of full global cover datasets (NASA GIMMS,Pathfinder, GeoCover), space-borne imaging spectrometerdata (MERIS, CHRIS/PROBA, HYPERION/EO-1, MODIS),and various airborne imaging spectrometer data sets, incl.ground measurements (DAIS7915, CASI, HyMap, AHS160,AISA, AVIRIS, etc.).

Summary and references In this paper we have provided a brief overview of the ongo-ing research activities in the field of remote sensing at theGRS laboratory within the Centre for Geo-information. Moredetailed information about all our research projects within thebroad field of geo-information science, publications, staff andalso the academic educational programs can be found atwww.geo-informatie.nl. If this article has drawn your atten-tion as a potential student, researcher or collaborator, weencourage you to contact the corresponding author(Lammert.Kooistra@wur.nl) such that we can provide youwith more detailed information.

CONFERENCE REPORT

THE 9TH SPECIALIST MEETING ON MICROWAVE RADIOMETRY ANDREMOTE SENSING APPLICATIONS (MICRORAD’06) IN SAN JUAN,PUERTO RICO, USA, FEBRUARY 28 – MARCH 3, 2006.By Steven C. Reising and David B. Kunkee

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