ELBARA, the ETH L-band radiometer for soil-moisture research

Mätzler, Christian; Weber, D. A.; Wüthrich, M.; Schneeberger, K.; Stamm, C.; Wydler, Hannes; Flühler, H.

doi:10.1109/igarss.2003.1294682

Cited by 22 publications

(21 citation statements)

References 2 publications

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“…The microwave measurements used to validate the model are performed with the ETH L-Band Radiometer (ELBARA) [16] installed above a footprint comprising an area with leaf litter on top of a conducting wire grid.…”

confidence: 99%

“…The L-band radiometer ELBARA [16] was specifically designed for tower-based field-scale experiments. Since 2002, this instrument has been successfully deployed in numerous campaigns which provided information that is important for interpreting L-band radiance in terms of soil moisture and other scene parameters like roughness and vegetation covers [10]- [12], [19]- [23].…”

Section: A Remote Sensing Systemmentioning

confidence: 99%

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Testing a New Model for the L-Band Radiation of Moist Leaf Litter

Schwank

Guglielmetti²,

Mätzler

et al. 2008

IEEE Trans. Geosci. Remote Sensing

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Abstract-The crown vegetation of a deciduous forest is known to be semitransparent at low microwave frequencies, and leaf litter covering the forest soil has been recognized to have a significant impact on ground emission. The proposed approach for modeling the L-band radiative transfer through leaf litter consists of an isotropic effective medium approach for the litter permittivities, a coherent radiative transfer model for computing the coherent reflectivities from dielectric depth profiles, and an averaging procedure for computing the reflectivities determining the field-scale brightness temperatures. Evaluations were performed for the case of leaf litter on top of a conducting wire grid (litter-grid formation) and for litter on underlying soil (litter-soil formation). A model sensitivity analysis was performed with respect to parameters characterizing litter thickness variations and boundary roughness. For the litter-soil formation, the model was rather sensitive to local irregularities at the air-to-litter boundary. Modeled microwave signatures reproduced the major features of the measurements performed on a site comprising a litter-grid formation. Under dry conditions, the investigated litter layer was nearly "invisible." When the same litter layer was wetted, it acted as an important radiation source to be taken into account for the quantitative remote soil moisture detection of forested areas. Under certain conditions, the simulations revealed an increasing brightness when the litter is wetted prior to the underlying soil. Further wetting of the litter-soil system then resulted in a decreasing brightness as expected for increased moisture. Such effects are important to know to avoid misleading interpretations of L-band signatures.

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confidence: 99%

Section: A Remote Sensing Systemmentioning

confidence: 99%

Testing a New Model for the L-Band Radiation of Moist Leaf Litter

Schwank

Guglielmetti²,

Mätzler

et al. 2008

IEEE Trans. Geosci. Remote Sensing

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confidence: 99%

“…ELBARA-II technical specifications and its performance under field conditions are outlined by Schwank et al [17,27]. The first generation ELBARA was designed and constructed in 2001 at the Institute of Applied Physics, University of Bern [28]. A number of ELBARA-II radiometers were produced by the company Gamma Remote Sensing AG (Gümligen, Switzerland) with the main purpose of calibration and validation activities supporting ESA's SMOS mission [18].…”

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confidence: 99%

Davos-Laret Remote Sensing Field Laboratory: 2016/2017 Winter Season L-Band Measurements Data-Processing and Analysis

2017

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Abstract:The L-band radiometry data and in-situ ground and snow measurements performed during the 2016/2017 winter campaign at the Davos-Laret remote sensing field laboratory are presented and discussed. An improved version of the procedure for the computation of L-band brightness temperatures from ELBARA radiometer raw data is introduced. This procedure includes a thorough explanation of the calibration and filtering including a refined radio frequency interference (RFI) mitigation approach. This new mitigation approach not only performs better than conventional "normality" tests (kurtosis and skewness) but also allows for the quantification of measurement uncertainty introduced by non-thermal noise contributions. The brightness temperatures of natural snow covered areas and areas with a reflector beneath the snow are simulated for varying amounts of snow liquid water content distributed across the snow profile. Both measured and simulated brightness temperatures emanating from natural snow covered areas and areas with a reflector beneath the snow reveal noticeable sensitivity with respect to snow liquid water. This indicates the possibility of estimating snow liquid water using L-band radiometry. It is also shown that distinct daily increases in brightness temperatures measured over the areas with the reflector placed on the ground indicate the onset of the snow melting season, also known as "early-spring snow".

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“…The Dicke-type radiometer ELBARA [10] is equipped with a dual-mode Picket horn antenna with 23.5 dB gain and a −3 dB full beamwidth of 12…”

Section: B Instrumentationmentioning

confidence: 99%

L-Band Reflectivity of a Wire Grid Above a Dielectric Surface

Völksch

Schwank

Mätzler

2010

IEEE Geosci. Remote Sensing Lett.

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Abstract-We investigated the influence of a wire grid above a paved ground on thermal brightness at 1.4 GHz. Reflectivities were derived from dual-polarized brightness temperature measurements for different grid orientations and wire spacings between 2.5 and 20 cm. For spacings larger than a quarter of a wavelength (≈5 cm), the grid had no impact on the observed reflectivities. A physical model was used to analyze the experimental results.

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ELBARA, the ETH L-band radiometer for soil-moisture research

Cited by 22 publications

References 2 publications

Testing a New Model for the L-Band Radiation of Moist Leaf Litter

Testing a New Model for the L-Band Radiation of Moist Leaf Litter

Davos-Laret Remote Sensing Field Laboratory: 2016/2017 Winter Season L-Band Measurements Data-Processing and Analysis

L-Band Reflectivity of a Wire Grid Above a Dielectric Surface

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