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Unfollow Follow Unblock. Other Affiliations:. Publication Date: Remote Sensing. View on adsabs. Save to Library. Ground-based measurements can be performed.

The optics consist of an objective lens and a condenser mounted according to the Koehler principle to provide uniform irradiation over the detector surface. The radiometric signal is treated by a fast thermopile detector characterized by a low noise and a very weak temperature dependence of its responsivity.

The managing system allows either manual or automated measurements. The energy consumption of the instrument is optimized for a maximum autonomy. The optical and electrical units of the instrument are described. Different experimental studies for measuring the sensitivity accuracy, spectral characteristics, thermal behavior and, field of view of the instrument are described. The instrument is dedicated to ground and vegetation on the one hand.

The radiometer is also designed for calibrations or analyses of satellite radiometry data. Some atmospheric measurements obtained with a prototype are presented. Prospects are the development and the qualification of a narrow field-of-view instrument adapted to inhomogeneous targets such as cirrus clouds. Paris-Fog : des chercheurs dans le brouillard more. View on researchgate. The primary purpose of these. View on seadas. Satellite ocean-color algorithms generally use aerosol-mixture models to estimate and remove the atmospheric contribution to the measured signal.

These models, based on aerosol samples, may or may not be realistic. In atmospheric In atmospheric correction, we are more interested in the optical behavior of the aerosols through the entire atmosphere. Comparisons of SeaWiFS-derived and measured aerosol optical thickness have revealed a systematic underestimation of the Angstrom coefficient, suggesting that the reference models may not be representative of actual conditions. To investigate the adequacy of the models and ultimately to improve atmospheric correction, we analyze atmospheric optics data collected by the AERONET project under a wide range of aerosol conditions at coastal and island sites.

Using non-supervised classification techniques self-organized mapping, hierarchical clustering , we determine the natural distribution of retreived aerosol properties of the total atmospheric column, i. These clusters may be used as new aerosols mixtures in radiative transfer algorithms.

We compare the clusters with the SeaWiFS reference models and, through application examples, conclude about their potential to improve atmospheric correction of satellite ocean color. Maritime aerosol optical thickness measured by handheld sun photometers more.

The calibration, processing, quality control, and archival methodology for handheld sun The calibration, processing, quality control, and archival methodology for handheld sun photometers are described here, along with their deployment statistics.

Data processing has been standardized for all instruments by using identical calibration methods, ancillary data, and processing software. A K-means unsupervised classification technique is used to separate these populations. Properties for each class are presented, along with the characteristics of each class by regional oceanic basin.

Results also compare favorably with maritime aerosols measured by land-based AERONET Cimels in island sites, while providing data coverage in previously sparsely sampled regions. A study of the effect of non-spherical dust particles on the AVHRR aerosol optical thickness retrievals more. Multidisciplinary and Particle Shape. Evaluation of a planetary boundary layer subgrid-scale model that accounts for near-surface turbulence anisotropy more.

Atmospheric sciences. Impact of terrain heterogeneity on near-surface turbulence structure more. Brown during the Aerosol Characterization Experiment - Asia more.

SIRTA, a ground-based atmospheric observatory for cloud and aerosol research more. Hourdin , P. Drobinski , Christophe Pietras , and Vincent Noel. Several programs have been successful in establishing global or regional networks dedicated to monitoring a Haeffelin et al.

In the days following the onset of the In the days following the onset of the eruption, this plume was scrutinised for scientific purposes and decision making especially with regard to aviation hazard assessment. This paper complements. Validation of two-channel VIRS retrievals of aerosol optical thickness over ocean and quantitative evaluation of the impact from potential subpixel cloud contamination and surface wind effect more.

Unique data repository facilitates ocean color satellite validation more. Thermal-infrared field radiometer for vicarious cross-calibration: characterization and comparisons with other field instruments more. Analysis of the performance characteristics of the five-channel Microtops II Sun photometer for measuring aerosol optical thickness and precipitable water vapor more.

Regional evaluation of an advanced very high resolution radiometer AVHRR two-channel aerosol retrieval algorithm more. Received 29 May ; revised 20 August ; accepted 10 October ; published 20 January Part I: Characterization of the Instrument more. Long-term study of coherent structures in the atmospheric surface layer more. Dubos and Christophe Pietras. Abstract A long-term study of coherent turbulence structures in the atmospheric surface layer has been carried out using 10 months of turbulence data taken on a m tower under varying meteorological conditions.

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