EUROSPEC: at the interface between remote-sensing and ecosystem CO2 flux measurements in Europe

Abstract. Resolving the spatial and temporal dynamics of gross primary productivity (GPP) of terrestrial ecosystems across different scales remains a challenge. Remote sensing is regarded as the solution to upscale point observations conducted at the ecosystem level, using the eddy covariance (EC) technique, to the landscape and global levels. In addition to traditional vegetation indices, the photochemical reflectance index (PRI) and the emission of solar-induced chlorophyll fluorescence (SIF), now measurable from space, provide a new range of opportunities to monitor the global carbon cycle using remote sensing. However, the scale mismatch between EC observations and the much coarser satellite-derived data complicate the integration of the two sources of data. The solution is to establish a network of in situ spectral measurements that can act as a bridge between EC measurements and remote-sensing data. In situ spectral measurements have already been conducted for many years at EC sites, but using variable instrumentation, setups, and measurement standards. In Europe in particular, in situ spectral measurements remain highly heterogeneous. The goal of EUROSPEC Cost Action ES0930 was to promote the development of common measuring protocols and new instruments towards establishing best practices and standardization of these measurements. In this review we describe the background and main tradeoffs of in situ spectral measurements, review the main results of EUROSPEC Cost Action, and discuss the future challenges and opportunities of in situ spectral measurements for improved estimation of local and global estimates of GPP over terrestrial ecosystems.

[1]  K. Sakowska.  Modelling the Spatial Distribution of CO 2 Fluxes in a Subalpine Grassland Plateau of the Italian Alps Using Multiple Airborne AISA Eagle Hyperspectral Sensor Observations and Sentinel-2 Simulated Data. , 2015 .

[2]  Gustau Camps-Valls,et al.  Uncertainty analysis of gross primary production upscaling using Random Forests, remote sensing and eddy covariance data , 2015 .

[3]  John A. Gamon,et al.  Reviews and Syntheses: optical sampling of the flux tower footprint , 2015 .

[4]  John A. Gamon,et al.  Monitoring seasonal and diurnal changes in photosynthetic pigments with automated PRI and NDVI sensors , 2015 .

[5]  M. Rossini,et al.  Continuous and long-term measurements of reflectance and sun-induced chlorophyll fluorescence by using novel automated field spectroscopy systems , 2015 .

[6]  Lars Eklundh,et al.  In Situ Calibration of Light Sensors for Long-Term Monitoring of Vegetation , 2015, IEEE Transactions on Geoscience and Remote Sensing.

[7]  Eyal Ben-Dor,et al.  Supervised Vicarious Calibration (SVC) of Multi-Source Hyperspectral Remote-Sensing Data , 2015, Remote. Sens..

[8]  P. Cox,et al.  Observing terrestrial ecosystems and the carbon cycle from space , 2015, Global change biology.

[9]  Micol Rossini,et al.  A Method for Uncertainty Assessment of Passive Sun-Induced Chlorophyll Fluorescence Retrieval Using an Infrared Reference Light , 2015, IEEE Sensors Journal.

[10]  John A Gamon,et al.  The photochemical reflectance index provides an optical indicator of spring photosynthetic activation in evergreen conifers. , 2015, The New phytologist.

[11]  Kelly K. Caylor,et al.  Photosynthetic seasonality of global tropical forests constrained by hydroclimate , 2015 .

[12]  R. Colombo,et al.  Red and far red Sun‐induced chlorophyll fluorescence as a measure of plant photosynthesis , 2015 .

[13]  Julitta.  Optical proximal sensing for vegetation monitoring , 2015 .

[14]  Javier Pacheco-Labrador,et al.  Characterization of a Field Spectroradiometer for Unattended Vegetation Monitoring. Key Sensor Models and Impacts on Reflectance , 2015, Sensors.

[15]  G. Manca,et al.  Net ecosystem carbon balance of an apple orchard , 2015 .

[16]  Larry Leigh,et al.  The Ground-Based Absolute Radiometric Calibration of Landsat 8 OLI , 2015, Remote. Sens..

[17]  Damiano Gianelle,et al.  WhiteRef: A New Tower-Based Hyperspectral System for Continuous Reflectance Measurements , 2015, Sensors.

[18]  J. Ardö,et al.  Ecosystem properties of semiarid savanna grassland in West Africa and its relationship with environmental variability , 2015, Global change biology.

[19]  J. M. Krijger,et al.  Potential of the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor for the monitoring of terrestrial chlorophyll fluorescence , 2014 .

[20]  Gilberto Pastorello,et al.  Retrieval of the photochemical reflectance index for assessing xanthophyll cycle activity: a comparison of near-surface optical sensors , 2014 .

[21]  Javier Pacheco-Labrador,et al.  Characterizing integration time and gray-level-related nonlinearities in a NMOS sensor. , 2014, Applied optics.

[22]  Markus Reichstein,et al.  Linking plant and ecosystem functional biogeography , 2014, Proceedings of the National Academy of Sciences.

[23]  Damiano Gianelle,et al.  Monitoring of carbon dioxide fluxes in a subalpine grassland ecosystem of the Italian Alps using a multispectral sensor , 2014 .

[24]  R. Fensholt,et al.  An automated field spectrometer system for studying VIS, NIR and SWIR anisotropy for semi-arid savanna , 2014 .

[25]  L. Eklundh,et al.  A physically based vegetation index for improved monitoring of plant phenology , 2014 .

[26]  C. Frankenberg,et al.  Linking chlorophyll a fluorescence to photosynthesis for remote sensing applications: mechanisms and challenges. , 2014, Journal of experimental botany.

[27]  WhiteheadKen,et al.  Remote sensing of the environment with small unmanned aircraft systems (UASs), part 1: a review of progress and challenges1 , 2014 .

[28]  Damiano Gianelle,et al.  On the relationship between ecosystem-scale hyperspectral reflectance and CO2 exchange in European mountain grasslands. , 2014 .

[29]  C. Frankenberg,et al.  Prospects for Chlorophyll Fluorescence Remote Sensing from the Orbiting Carbon Observatory-2 , 2014 .

[30]  E. Nikinmaa,et al.  A temperature-controlled spectrometer system for continuous and unattended measurements of canopy spectral radiance and reflectance , 2014 .

[31]  K. Soudani,et al.  Remote sensing: A green illusion , 2014, Nature.

[32]  David J. Harding,et al.  Amazon forests maintain consistent canopy structure and greenness during the dry season , 2014, Nature.

[33]  Javier Pacheco-Labrador,et al.  Nonlinear Response in a Field Portable Spectroradiometer: Characterization and Effects on Output Reflectance , 2014, IEEE Transactions on Geoscience and Remote Sensing.

[34]  Erle C. Ellis,et al.  High spatial resolution three-dimensional mapping of vegetation spectral dynamics using computer vision , 2013 .

[35]  Jan G. P. W. Clevers,et al.  Remote estimation of crop and grass chlorophyll and nitrogen content using red-edge bands on Sentinel-2 and -3 , 2013, Int. J. Appl. Earth Obs. Geoinformation.

[36]  B. Poulter,et al.  Evaluating the potential of large-scale simulations to predict carbon fluxes of terrestrial ecosystems over a European Eddy Covariance network , 2013 .

[37]  P. Alton,et al.  From site-level to global simulation: Reconciling carbon, water and energy fluxes over different spatial scales using a process-based ecophysiological land-surface model , 2013 .

[38]  M. Lomas,et al.  Evaluation of terrestrial carbon cycle models for their response to climate variability and to CO2 trends , 2013, Global change biology.

[39]  R. DeFries,et al.  Current systematic carbon-cycle observations and the need for implementing a policy-relevant carbon observing system , 2013 .

[40]  Natascha Kljun,et al.  Effect of spatial heterogeneity on the validation of remote sensing based GPP estimations , 2013 .

[41]  P. Zarco-Tejada,et al.  Spatio-temporal patterns of chlorophyll fluorescence and physiological and structural indices acquired from hyperspectral imagery as compared with carbon fluxes measured with eddy covariance , 2013 .

[42]  Pablo J. Zarco-Tejada,et al.  Spatial Resolution Effects on Chlorophyll Fluorescence Retrieval in a Heterogeneous Canopy Using Hyperspectral Imagery and Radiative Transfer Simulation , 2013, IEEE Geoscience and Remote Sensing Letters.

[43]  Micol Rossini,et al.  Analysis of within- and between-day chlorophyll-a dynamics in Mantua Superior Lake, with a continuous spectroradiometric measurement , 2013 .

[44]  Miina Rautiainen,et al.  Sensitivity of narrowband vegetation indices to boreal forest LAI, reflectance seasonality and species composition , 2013 .

[45]  Philip A. Townsend,et al.  Disentangling the contribution of biological and physical properties of leaves and canopies in imaging spectroscopy data , 2013, Proceedings of the National Academy of Sciences.

[46]  M. Rossini,et al.  Inter-comparison of hemispherical conical reflectance factors (HCRF) measured with four fibre-based spectrometers. , 2013, Optics express.

[47]  Andreas Hueni,et al.  Spectral Information System Development for Australia , 2012, GSR.

[48]  Philip Lewis,et al.  Hyperspectral remote sensing of foliar nitrogen content , 2012, Proceedings of the National Academy of Sciences.

[49]  Fredrik Lagergren,et al.  Modeling GPP in the Nordic forest landscape with MODIS time series data—Comparison with the MODIS GPP product , 2012 .

[50]  Nicholas C. Coops,et al.  Characterizing spatial representativeness of flux tower eddy-covariance measurements across the Canadian Carbon Program Network using remote sensing and footprint analysis , 2012 .

[51]  P. Ciais,et al.  Carbon Cycle Uncertainty in REgional Carbon Cycle Assessment and Processes (RECCAP) , 2012 .

[52]  Christian Götze,et al.  Overview of Experimental Setups in Spectroscopic Laboratory Measurements - the SpecTour Project , 2012 .

[53]  E. Davidson,et al.  Using model‐data fusion to interpret past trends, and quantify uncertainties in future projections, of terrestrial ecosystem carbon cycling , 2012 .

[54]  Michele Meroni,et al.  Remote sensing-based estimation of gross primary production in a subalpine grassland , 2012 .

[55]  A. Gitelson,et al.  Remote estimation of crop gross primary production with Landsat data , 2012 .

[56]  Albert Porcar-Castell,et al.  Physiology of the seasonal relationship between the photochemical reflectance index and photosynthetic light use efficiency , 2012, Oecologia.

[57]  Timothy J. Malthus,et al.  The Fields of View and Directional Response Functions of Two Field Spectroradiometers , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[58]  J. Moncrieff,et al.  Carbon dioxide exchange of a Sitka spruce plantation in Scotland over five years , 2012 .

[59]  Anatoly A. Gitelson,et al.  Remote estimation of gross primary productivity in soybean and maize based on total crop chlorophyll content , 2012 .

[60]  Stuart E. Marsh,et al.  Feasibility of Invasive Grass Detection in a Desertscrub Community Using Hyperspectral Field Measurements and Landsat TM Imagery , 2011, Remote. Sens..

[61]  Quan Wang,et al.  Calibration and validation of salt-resistant hyperspectral indices for estimating soil moisture in arid land , 2011 .

[62]  James J. Butler,et al.  SWIR calibration of Spectralon reflectance factor , 2011, Remote Sensing.

[63]  C. Frankenberg,et al.  New global observations of the terrestrial carbon cycle from GOSAT: Patterns of plant fluorescence with gross primary productivity , 2011, Geophysical Research Letters.

[64]  A. Arneth,et al.  Global patterns of land-atmosphere fluxes of carbon dioxide, latent heat, and sensible heat derived from eddy covariance, satellite, and meteorological observations , 2011 .

[65]  Jennifer L. Dungan,et al.  On the reproducibility of field-measured reflectance factors in the context of vegetation studies , 2011 .

[66]  Rebecca N. Handcock,et al.  Ground-Based Optical Measurements at European Flux Sites: A Review of Methods, Instruments and Current Controversies , 2011, Sensors.

[67]  Lars Eklundh,et al.  An Optical Sensor Network for Vegetation Phenology Monitoring and Satellite Data Calibration , 2011, Sensors.

[68]  Daniel Schläpfer,et al.  Correction of cirrus effects in Sentinel-2 type of imagery , 2011 .

[69]  M. Rossini,et al.  The hyperspectral irradiometer, a new instrument for long-term and unattended field spectroscopy measurements. , 2011, The Review of scientific instruments.

[70]  Jonas Ardö,et al.  Exploring the potential of MODIS EVI for modeling gross primary production across African ecosystems , 2011 .

[71]  Tong Sun,et al.  Temperature and nonlinearity corrections for a photodiode array spectrometer used in the field. , 2011, Applied optics.

[72]  A. Karnieli,et al.  Exploring field-of-view non-uniformities produced by a hand-held spectroradiometer , 2011 .

[73]  D. Baldocchi,et al.  Testing the performance of a novel spectral reflectance sensor, built with light emitting diodes (LEDs), to monitor ecosystem metabolism, structure and function , 2010 .

[74]  J. Grace,et al.  Determination of leaf pigment content in Calluna vulgaris shoots from spectral reflectance , 2010 .

[75]  H. Jones,et al.  Remote Sensing of Vegetation: Principles, Techniques, and Applications , 2010 .

[76]  N. Coops,et al.  A NEW, AUTOMATED, MULTIANGULAR RADIOMETER INSTRUMENT FOR TOWER-BASED OBSERVATIONS OF CANOPY REFLECTANCE (AMSPEC II) , 2010 .

[77]  Jadunandan Dash,et al.  The potential of the MERIS Terrestrial Chlorophyll Index for carbon flux estimation , 2010 .

[78]  M. Rossini,et al.  High resolution field spectroscopy measurements for estimating gross ecosystem production in a rice field , 2010 .

[79]  F. Woodward,et al.  Terrestrial Gross Carbon Dioxide Uptake: Global Distribution and Covariation with Climate , 2010, Science.

[80]  M. Nilsson,et al.  Estimating northern peatland CO2 exchange from MODIS time series data , 2010 .

[81]  Weixing Cao,et al.  Exploring hyperspectral bands and estimation indices for leaf nitrogen accumulation in wheat , 2010, Int. J. Appl. Earth Obs. Geoinformation.

[82]  W. Oechel,et al.  A continuous measure of gross primary production for the conterminous United States derived from MODIS and AmeriFlux data , 2010, Remote Sensing of Environment.

[83]  Damiano Gianelle,et al.  SpecNet revisited: bridging flux and remote sensing communities , 2010 .

[84]  Thomas Hilker,et al.  An assessment of photosynthetic light use efficiency from space: Modeling the atmospheric and directional impacts on PRI reflectance , 2009 .

[85]  Luis Alonso,et al.  Remote sensing of solar-induced chlorophyll fluorescence: Review of methods and applications , 2009 .

[86]  Zhao-Liang Li,et al.  Scale Issues in Remote Sensing: A Review on Analysis, Processing and Modeling , 2009, Sensors.

[87]  Jens Nieke,et al.  The spectral database SPECCHIO for improved long-term usability and data sharing , 2009, Comput. Geosci..

[88]  J. Peñuelas,et al.  Remote estimation of carbon dioxide uptake by a Mediterranean forest , 2008 .

[89]  T. A. Black,et al.  The use of remote sensing in light use efficiency based models of gross primary production: a review of current status and future requirements. , 2008, The Science of the total environment.

[90]  T. A. Black,et al.  Separating physiologically and directionally induced changes in PRI using BRDF models , 2008 .

[91]  K. Soudani,et al.  Calibration and validation of hyperspectral indices for the estimation of broadleaved forest leaf chlorophyll content, leaf mass per area, leaf area index and leaf canopy biomass , 2008 .

[92]  Andrew E. Suyker,et al.  Synoptic Monitoring of Gross Primary Productivity of Maize Using Landsat Data , 2008, IEEE Geoscience and Remote Sensing Letters.

[93]  T Vesala,et al.  Flux and concentration footprint modelling: state of the art. , 2008, Environmental pollution.

[94]  D. Baldocchi.  ‘Breathing’ of the terrestrial biosphere: lessons learned from a global network of carbon dioxide flux measurement systems , 2008 .

[95]  J. Peñuelas,et al.  Normalized difference spectral indices for estimating photosynthetic efficiency and capacity at a canopy scale derived from hyperspectral and CO2 flux measurements in rice , 2008 .

[96]  G. Georgiev,et al.  Long-term calibration monitoring of Spectralon diffusers BRDF in the air-ultraviolet. , 2007, Applied optics.

[97]  Lars Eklundh,et al.  Estimation of absorbed PAR across Scandinavia from satellite measurements. Part II: Modeling and evaluating the fractional absorption , 2007 .

[98]  L. Gómez-Chova,et al.  Estimation of solar‐induced vegetation fluorescence from space measurements , 2007 .

[99]  N. Coops,et al.  Instrumentation and approach for unattended year round tower based measurements of spectral reflectance , 2007 .

[100]  Andreas Hueni,et al.  Spectroradiometer data structuring, pre‐processing and analysis – an IT based approach , 2006 .

[101]  Ranga B. Myneni,et al.  The impact of gridding artifacts on the local spatial properties of MODIS data : Implications for validation, compositing, and band-to-band registration across resolutions , 2006 .

[102]  M. Schildhauer,et al.  Spectral Network (SpecNet)—What is it and why do we need it? , 2006 .

[103]  Benoit Rivard,et al.  Comparison of spectral indices obtained using multiple spectroradiometers , 2006 .

[104]  W. Oechel,et al.  Parallel adjustments in vegetation greenness and ecosystem CO2 exchange in response to drought in a Southern California chaparral ecosystem , 2006 .

[105]  T. Painter,et al.  Reflectance quantities in optical remote sensing - definitions and case studies , 2006 .

[106]  Nigel P. Fox,et al.  Progress in Field Spectroscopy , 2006, 2006 IEEE International Symposium on Geoscience and Remote Sensing.

[107]  Alejandro Ferrero,et al.  Apparent violation of the radiant exposure reciprocity law in interline CCDs. , 2006, Applied optics.

[108]  Cheng-I Hsieh,et al.  Estimating the uncertainty in annual net ecosystem carbon exchange: spatial variation in turbulent fluxes and sampling errors in eddy‐covariance measurements , 2006 .

[109]  A. Viña,et al.  Relationship between gross primary production and chlorophyll content in crops: Implications for the synoptic monitoring of vegetation productivity , 2006 .

[110]  Edward J. Milton,et al.  Calibration of dual‐beam spectroradiometric data , 2006 .

[111]  José J. San José,et al.  Productivity and carbon fluxes of tropical savannas , 2006 .

[112]  T. A. Black,et al.  A MODIS-derived photochemical reflectance index to detect inter-annual variations in the photosynthetic light-use efficiency of a boreal deciduous forest , 2005 .

[113]  Eric D. Kolaczyk,et al.  On the choice of spatial and categorical scale in remote sensing land cover classification , 2005 .

[114]  Richard J. Murphy,et al.  Estimation of surface chlorophyll‐a on an emersed mudflat using field spectrometry: accuracy of ratios and derivative‐based approaches , 2005 .

[115]  Maosheng Zhao,et al.  Improvements of the MODIS terrestrial gross and net primary production global data set , 2005 .

[116]  Lars Eklundh,et al.  Net primary production and light use efficiency in a mixed coniferous forest in Sweden , 2005 .

[117]  F. Baret,et al.  Effect of senescent leaves on NDVI-based estimates of fAPAR: Experimental and modelling evidences , 2004 .

[118]  Alfredo Huete,et al.  A multi-scale analysis of dynamic optical signals in a Southern California chaparral ecosystem: A comparison of field, AVIRIS and MODIS data , 2004 .

[119]  Jing Chen,et al.  Spatial scaling of net primary productivity using subpixel information , 2004 .

[120]  Maosheng Zhao,et al.  A Continuous Satellite-Derived Measure of Global Terrestrial Primary Production , 2004 .

[121]  S. Wofsy,et al.  Modeling gross primary production of temperate deciduous broadleaf forest using satellite images and climate data , 2004 .

[122]  E. Davidson,et al.  Satellite-based modeling of gross primary production in an evergreen needleleaf forest , 2004 .

[123]  Daniel Schläpfer,et al.  SPECCHIO: a spectrum database for remote sensing applications , 2003 .

[124]  Evanthia Karpouzli,et al.  Underwater light characterisation for correction of remotely sensed images , 2003 .

[125]  Hans Peter Schmid,et al.  Footprint modeling for vegetation atmosphere exchange studies: a review and perspective , 2002 .

[126]  A. Huete,et al.  Overview of the radiometric and biophysical performance of the MODIS vegetation indices , 2002 .

[127]  A. Arneth,et al.  Remote sensing of photosynthetic-light-use efficiency of a Siberian boreal forest , 2002 .

[128]  Kurt Thome,et al.  Bi-directional calibration results for the cleaning of SpectralonTM reference panels , 2002, SPIE Optics + Photonics.

[129]  G. Roberts.  A review of the application of BRDF models to infer land cover parameters at regional and global scales , 2001 .

[130]  Stephen Sitch,et al.  Global warming feedbacks on terrestrial carbon uptake under the Intergovernmental Panel on Climate Change (IPCC) Emission Scenarios , 2001 .

[131]  R. Kormann,et al.  An Analytical Footprint Model For Non-Neutral Stratification , 2001 .

[132]  M. Goulden.  Carbon assimilation and water-use efficiency by neighboring Mediterranean-climate oaks that differ in water access. , 1996, Tree physiology.

[133]  C. Field,et al.  Relationships Between NDVI, Canopy Structure, and Photosynthesis in Three Californian Vegetation Types , 1995 .

[134]  R. Myneni,et al.  On the relationship between FAPAR and NDVI , 1994 .

[135]  Gérard Dedieu,et al.  Methodology for the estimation of terrestrial net primary production from remotely sensed data , 1994 .

[136]  C. Field,et al.  A narrow-waveband spectral index that tracks diurnal changes in photosynthetic efficiency , 1992 .

[137]  C. Tucker.  Red and photographic infrared linear combinations for monitoring vegetation , 1979 .

[138]  F. E. Nicodemus,et al.  Geometrical considerations and nomenclature for reflectance , 1977 .

[139]  J. A. Schell,et al.  Monitoring the Vernal Advancement and Retrogradation (Green Wave Effect) of Natural Vegetation. [Great Plains Corridor] , 1973 .

[140]  J. Monteith.  SOLAR RADIATION AND PRODUCTIVITY IN TROPICAL ECOSYSTEMS , 1972 .

[141]  M. P. Martín,et al.  Relaciones espacio-temporales entre datos ópticos adquiridos por el sensor hiperespectral CASI y flujos de carbono en un ecosistema de dehesa , 2015 .

[142]  Michele Meroni,et al.  emote estimation of grassland gross primary production during xtreme meteorological seasons , 2014 .

[143]  C. Hugenholtz,et al.  Remote sensing of the environment with small unmanned aircraft systems ( UASs ) , part 1 : a review of progress and challenges 1 , 2014 .

[144]  M. Rossini,et al.  A dual-field-of-view spectrometer system for reflectance and fluorescence measurements (Piccolo Doppio) and correction of etaloning , 2014 .

[145]  L. Corp,et al.  Measurement of regional-scale chlorophyll fluorescence , 2010 .

[146]  K. Hudson-Edwards,et al.  Characterisation of the environmental impact of the Rodalquilar mine, Spain by ground-based reflectance spectroscopy , 2009 .

[147]  Arnaud Carrara,et al.  Biogeosciences Quality control of CarboEurope flux data – Part 1 : Coupling footprint analyses with flux data quality assessment to evaluate sites in forest ecosystems , 2008 .

[148]  T. Vesala,et al.  Quality control of CarboEurope flux data , 2007 .

[149]  J. G. Ferwerda,et al.  A free online reference library for hyperspectral reflectance signatures , 2006 .

[150]  Prasad S. Thenkabail,et al.  Evaluation of Narrowband and Broadband Vegetation Indices for Determining Optimal Hyperspectral Wavebands for Agricultural Crop Characterization , 2002 .

[151]  Ü. Rannik,et al.  Estimates of the annual net carbon and water exchange of forests: the EUROFLUX methodology , 2000 .

[152]  J. Maranville,et al.  Photosynthesis Light Sensor and Meter , 1971 .