The hyperspectral irradiometer, a new instrument for long-term and unattended field spectroscopy measurements

Meroni, Michele; Barducci, Alessandro; Cogliati, Sergio; Castagnoli, F.; Rossini, Micol; Busetto, Lorenzo; Migliavacca, Mirco; Cremonese, Edoardo; Galvagno, Marta; Colombo, R.; Cella, Umberto Morra di

doi:10.1063/1.3574360

Cited by 69 publications

(85 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…I o is independent of (θ, φ)), it is possible to model the contribution to the total signal of the radiance coming from a differential annulus by combining Eqs. (1) and (2) (Schwerdtfeger 1976;Meroni et al 2011):…”

Section: Radiometric Footprint On Bare Soilmentioning

confidence: 99%

“…In addition, in situ observations of spectral reflectance are increasingly applied to link surface measurements of energy and carbon fluxes with Earth observations (Gamon et al 2006). The measurements of hyper-spectral surface reflectance at eddy covariance sites is an important step for the spatial extrapolation of in situ measurements with remote sensing retrievals from satellite platforms (Balzarolo et al 2011) and to parameterize light use efficiency models for the up-scaling of gross primary productivity (GPP) (Sims et al 2006;Meroni et al 2009;Meroni et al 2011;Peñuelas et al 2011;Rossini et al 2012).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Geometry of the hemispherical radiometric footprint over plant canopies

Marcolla

Cescatti

2017

Theor Appl Climatol

View full text Add to dashboard Cite

Radiometric measurements of hemispherical surface reflectance and long-wave irradiance are required to quantify the broadband albedo and the outgoing thermal radiation. These observations are typically integrated with eddy covariance measurements of sensible and latent heat fluxes to characterize the surface energy budget. While the aerodynamic footprint has been widely investigated, the geometry of the hemispherical radiometric footprint over plant canopies has been rarely tackled. In the present work, the size and shape of the hemispherical radiometric footprint are formalized for a bare surface and in presence of a vegetation cover. For this purpose, four idealized canopies are analyzed and the dependency of the radiometric footprint on leaf area index and canopy height is explored. Besides, the radiometric footprint is compared with the aerodynamic footprint in conditions of neutral stability. It was observed that almost 100% of the hemispherical radiometric signal originates within a distance of a few radiometer heights, while only about 50-80% of the cumulative aerodynamic signal is generated within a distance of about 20 sensor heights. In order to achieve comparable extensions of the footprint areas, hemispherical radiometric measurements should therefore be taken about 6-15 times higher than turbulent flux ones, depending on the vegetation type. The analysis also highlights that the size of the radiative footprint decreases at increasing leaf area index, whereas the aerodynamic footprint shows an opposite behavior. For the abovementioned reasons, this work may support the interpretation of energy flux measurements and the optimal design of eddy covariance stations located in heterogeneous sites.

show abstract

Section: Radiometric Footprint On Bare Soilmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Geometry of the hemispherical radiometric footprint over plant canopies

Marcolla

Cescatti

2017

Theor Appl Climatol

View full text Add to dashboard Cite

show abstract

“…Moreover the selection of new narrow wavebands in hyperspectral data has demonstrated an increase in the sensitivity of the vegetation indices to different vegetation biophysical variables [45]. Hyperspectral instruments are installed in a limited EC towers for continuous/unattended measurements [10,17,25,32] due to the high start-up costs and the additional complexity of making them weatherproof and automated.…”

Section: Radiometric and Spectral Resolutionmentioning

confidence: 99%

“…The hyperspectral systems currently installed at European EC sites are: the Multiplexer based Radiometer Irradiometer (MRI) [10] and the HyperSpectral Irradiometer (HIS) [32] developed at the University of Milano-Bicocca (Italy). Both of these systems utilize Ocean Optics spectroradiometers.…”

Section: Hyperspectral Sensorsmentioning

confidence: 99%

Ground-Based Optical Measurements at European Flux Sites: A Review of Methods, Instruments and Current Controversies

Balzarolo

Anderson

Nichol

et al. 2011

Sensors

View full text Add to dashboard Cite

This paper reviews the currently available optical sensors, their limitations and opportunities for deployment at Eddy Covariance (EC) sites in Europe. This review is based on the results obtained from an online survey designed and disseminated by the Co-cooperation in Science and Technology (COST) Action ESO903-"Spectral Sampling Tools for Vegetation Biophysical Parameters and Flux Measurements in Europe" that provided a complete view on spectral sampling activities carried out within the different research teams in European countries. The results have highlighted that a wide variety of Sensors 2011, 11 7956 optical sensors are in use at flux sites across Europe, and responses further demonstrated that users were not always fully aware of the key issues underpinning repeatability and the reproducibility of their spectral measurements. The key findings of this survey point towards the need for greater awareness of the need for standardisation and development of a common protocol of optical sampling at the European EC sites.

show abstract

“…In the vast majority of studies, which are conducted at present at the ground level, spectral characteristics are measured using various types of automatic systems (Ide et al, 2010;Meroni et al, 2011;Nakaji et al, 2007Nakaji et al, , 2008Sakowska et al, 2015Sakowska et al, , 2016. In order to facilitate the presentation of optical measurements within more than one spectral range, spectral vegetation indices (VIs) were introduced as algebraic dependencies of reflectance (ρ) at various wavelengths (λ).…”

Section: Introductionmentioning

confidence: 99%

Dependence of spectral characteristics on parameters describing CO2 exchange between crop species and the atmosphere

Uździcka¹,

Stróżecki²,

Urbaniak³

et al. 2017

International Agrophysics

View full text Add to dashboard Cite

'Assessment of a seasonal and spatial variation of plant biophysical and spectral indices in the context of CO 2 , CH 4 , H 2 O gas exchange between wetland, forest and arable ecosystems and the atmosphere', 2010-2013.A b s t r a c t. The aim of this paper is to demonstrate that spectral vegetation indices are good indicators of parameters describing the intensity of CO 2 exchange between crops and the atmosphere. Measurements were conducted over 2011-2013 on plots of an experimental arable station on winter wheat, winter rye, spring barley, and potatoes. CO 2 fluxes were measured using the dynamic closed chamber system, while spectral vegetation indices were determined using SKYE multispectral sensors. Based on spectral data collected in 2011 and 2013, various models to estimate net ecosystem productivity and gross ecosystem productivity were developed. These models were then verified based on data collected in 2012. The R 2 for the best model based on spectral data ranged from 0.71 to 0.83 and from 0.78 to 0.92, for net ecosystem productivity and gross ecosystem productivity, respectively. Such high R 2 values indicate the utility of spectral vegetation indices in estimating CO 2 fluxes of crops. The effects of the soil background turned out to be an important factor decreasing the accuracy of the tested models.

show abstract

The hyperspectral irradiometer, a new instrument for long-term and unattended field spectroscopy measurements

Cited by 69 publications

References 32 publications

Geometry of the hemispherical radiometric footprint over plant canopies

Geometry of the hemispherical radiometric footprint over plant canopies

Ground-Based Optical Measurements at European Flux Sites: A Review of Methods, Instruments and Current Controversies

Dependence of spectral characteristics on parameters describing CO2 exchange between crop species and the atmosphere

Contact Info

Product

Resources

About