Thermal-Infrared Spectral and Angular Characterization of Crude Oil and Seawater Emissivities for Oil Slick Identification

Niclòs, Raquel; Doña, Carolina; Valor, E.; Bisquert, Mar

doi:10.1109/tgrs.2013.2288517

Cited by 30 publications

(20 citation statements)

References 28 publications

(51 reference statements)

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“…For detailed information on the field measurements and the technique for deriving the sea surface emissivity, please refer to Niclòs et al [29,30]. Similar results were obtained using a CE 312 radiometer with six channels placed in the 8-14 µm range [31]. This time a plane sea water sample was measured with the six spectral bands at angles of 15 • , 30 • , 45 • , 50 • , 55 • , 60 • , and 65 • .…”

Section: In Situ Measurementsmentioning

confidence: 54%

A Lookup Table-Based Method for Estimating Sea Surface Hemispherical Broadband Emissivity Values (8–13.5 μm)

Cheng

Liang

et al. 2017

Remote Sensing

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Sea surface hemispherical broadband emissivity (BBE,(8)(9)(10)(11)(12)(13).5 µm) is a vital parameter for calculating surface radiation budgets. Such data are currently unavailable. This paper proposes a lookup table-based method for retrieving sea surface hemispherical BBE values. The physically-based sea surface emissivity model of Wu and Smith, together with the optimal refractive index, were used to generate hemispherical BBE values under wind speeds ranging from zero to 50 m/s. A lookup table of hemispherical BBE values as a function of wind speed was established and used to retrieve sea surface hemispherical BBE values under foam-free conditions. The accuracy of the estimates of hemispherical BBE was 0.003, given a wind speed of zero. The foam effect was explicitly considered. After incorporating the foam effect, hemispherical BBE was expressed as a linear function of the hemispherical BBE values of sea water and foam, weighted by the fraction of foam coverage. With this method, we have produced an hourly sea surface hemispherical BBE product with a resolution of 10 km and global coverage that covers the period from 2003 to 2005, using wind speed data from Modern-Era Retrospective analysis for Research and Applications (MERRA)-2.

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Section: In Situ Measurementsmentioning

confidence: 54%

A Lookup Table-Based Method for Estimating Sea Surface Hemispherical Broadband Emissivity Values (8–13.5 μm)

Cheng

Liang

et al. 2017

Remote Sensing

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“…In order to evaluate the results obtained with the different methodologies, temperature and emissivity values for different surface types measured by Coll et al [21] and Niclòs et al [30] in the field were used.…”

Section: Reference Measurementsmentioning

confidence: 99%

“…This last uncertainty has a value of ±0.37 and was obtained as a result of a MOD28 product validation with in situ measurements. Water emissivity values, shown in Table 4, were measured in [30] for the six CE312-2 bands. A sample of Mediterranean Sea water was used to obtain the emissivity from measurements of the surface and sky radiance with two CE312-2 radiometers and the surface temperature with several Negative Temperature Coefficient (NTC) thermistors (see [30] for more details).…”

Section: Reference Measurementsmentioning

confidence: 99%

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Comparison and Evaluation of the TES and ANEM Algorithms for Land Surface Temperature and Emissivity Separation over the Area of Valencia, Spain

et al. 2017

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Land Surface temperature (LST) is a key magnitude for numerous studies, especially for climatology and assessment of energy fluxes between surface and atmosphere. Retrieval of accurate LST requires a good characterization of surface emissivity. Both quantities are coupled in a single radiance measurement; for this reason, for N spectral bands available in a remote sensor, there will always be N + 1 unknowns. To solve the indeterminacy, temperature-emissivity separation methods have been proposed, among which the Temperature Emissivity Separation (TES) algorithm is one of the most widely used. The Adjusted Normalized Emissivity Method (ANEM) was proposed as a modification of the Normalized Emissivity Method (NEM) algorithm by adjusting the initial emissivity guess using an estimation provided by the Vegetation Cover Method (VCM). In this work, both methods were applied to a set of five ASTER scenes over the area of Valencia, Spain, which were recalibrated and atmospherically corrected using local radiosoundings and ground measurements. These scenes were compared to the ASTER temperature and emissivity standard products (AST08 and AST05, respectively). The comparison to reference measurements showed a better agreement of ANEM LST in low spectral contrast surfaces, with biases of +0.4 K, +0.8 K for TES and +1.4 K for the AST08 product in a rice crop site. For sea surface temperature, bias was −0.1 K for ANEM, +0.3 K for TES and +1.3 K for the AST08 product. The larger differences of the AST08 product could be ascribed mainly to the atmospheric correction based on NCEP profiles in contrast to the local correction used in TES and ANEM and to a lesser extent the Maximum-Minimum Difference (MMD) empirical relationship used by TES. In terms of emissivity, ANEM obtained biases up to ±0.007 (positive over vegetation and negative over water), while TES biases were up to −0.015. The AST05 product showed differences up to −0.050, although for high contrast areas, such as sand surfaces, it showed better accuracy than both TES and ANEM. A comparison between TES and ANEM on four different classes within the scene showed a systematic difference between both algorithms, which was more pronounced for low spectral contrast surfaces. Therefore, ANEM improves the accuracy at low spectral contrast surfaces, while obtaining similar results to TES at higher spectral contrast surfaces, such as urban areas. The combination of both methods could provide a procedure benefiting from the strengths shown by each of them.

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“…The effects diminish for the wet soils since water strongly absorbs in the region of the quartz Reststrahlen bands [21]. Figure 6 also shows the water emissivity values for the flooded soils (December-January and June) at this site obtained from [22] since there is no difference for fresh water and sea water emissivities [23]. A hand-portable Fourier transform infrared (FT-IR) spectrometer, Designs and Prototypes (D&P) Instruments model 102 [24], was used to test the spectral variation observed with the other methods.…”

Section: Ground-truth Lst Retrieval: Emissivity Correctionmentioning

confidence: 99%

An Autonomous System to Take Angular Thermal-Infrared Measurements for Validating Satellite Products

et al. 2015

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An autonomous system for field land surface temperature (LST) measurements taken at different observation angles was developed to be deployed easily at any conventional meteorological tower station. The system permits ground-truth data to be acquired on a continuous basis, and angularly scans land and sky hemispheres with a single thermal-infrared (TIR) radiometer. This paper describes the autonomous angular system and the methodology to assess ground-truth LST and relative-to-nadir emissivity data from system measurements. Ground-truth LSTs were used to validate satellite-retrieved LST products at two experimental sites (rice crop and shrubland areas). The relative-to-nadir emissivity values were used to analyze the anisotropy of surface emissive properties over thermally-homogeneous covers. The EOS-MODIS MOD11_L2/MYD11_L2 LST product was evaluated and shown to work within expected uncertainties (<2.0 K) when tested against the system data. A slight underestimation of around −0.15 K was observed, which became greater for the off-nadir observation angles at the shrubland site. The system took angular measurements for the different seasonal homogeneous covers at the rice crop site. These measurements showed emissivity angular anisotropies, which were in good agreement with previously published data. The dual-view ENVISAT-AATSR data reproduced them, and revealed that the system data collected for thermally-homogeneous surfaces could be used to test future satellite TIR sensors with multi-angular or bi-angular capabilities, like the forthcoming SLSTR on board Copernicus Sentinel-3A.

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Thermal-Infrared Spectral and Angular Characterization of Crude Oil and Seawater Emissivities for Oil Slick Identification

Cited by 30 publications

References 28 publications

A Lookup Table-Based Method for Estimating Sea Surface Hemispherical Broadband Emissivity Values (8–13.5 μm)

A Lookup Table-Based Method for Estimating Sea Surface Hemispherical Broadband Emissivity Values (8–13.5 μm)

Comparison and Evaluation of the TES and ANEM Algorithms for Land Surface Temperature and Emissivity Separation over the Area of Valencia, Spain

An Autonomous System to Take Angular Thermal-Infrared Measurements for Validating Satellite Products

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