Results From Four Years Of Field Research With A C-band (6-cm) Field Microwave Scatterometer In Cultural- And Natural-vegetation Sites
Notice bibliographique
Résumé
From 1984-88, we explored the potential uses of C-band active-microwave sensors by conducting field experiments with a boom-truck mounted C-band (4.75 GHz, 5.3 cm) scatterometer called the Microwave Scatterometer, C-band (MS-C). The experiments, all carried out in test sites in California, covered the following types of land cover ( and conditions): arid-land vegetation (different conditions from place to place and caused by fire or pruning), plum trees (different conditions caused by saline-water treatments and growth during a season), pygmy forests (differences in stand densities from place to place), rice (different conditions of emergent biomass from place to place), and walnuts (different conditions caused by different imgation rates and by growth during a season). The MS-C allows one to measure not only the total backscattering coefficient, denoted by (m2 m-z), of an object of investigation for each polarization combination, but also the distribution of the sources of backscattering with slant range (or height above the surface) in a thick vegetation canopy, denoted by the volumetric backscattering cross section, oV (m2 In some experiments, we cooperated with other investigative teams [e.g., the Earth Observing System (Eos) Synergism Team] to expand the measurements to other microwave frequencies. The purpose of this paper is to report the results of all of these measurement efforts as a whole. The overall purpose of this series of C-band scatterometer experiments was to increase the understanding of the potential uses of related synthetic aperture radar (SAR) imagers such as the first European Remote Sensing Satellite (ERS-I) SAR which will soon be in operation. Many future SAR imagers plan to use C-band (RADARSAT by Canada and the Eos SAR by the U.S.A.). Overall, we found that a consistent set of guidelines for the interpretation of the data set as a whole emerged. First, in many cases, we observed important effects of the angular orientation of stems (e.g., in trees) relative to the plane of polarization. Nearly vertical stems produced relative high magnitudes for the vertical-transmit, vertical-receive (VV) combination. Conversely. horizontal stems produced relatively high HH (horizontalhorizontal) magnitudes. We believe that the stem-angle effect arises from the orientation of those few stems in a canopy which are a right angles to the radar path. Representing the overall structure of the canopy, these effective broad-side'' scatrerers dominate the overall microwave power returned to the sensor. Second, to reduce the effects of stem orientation, we suggest using the average of the backscattering coefficients, 00~~ and @HH, for VV and HH [called the like-polarization (LK) magnitudes]. Third, as an index of stem-angle related canopy structure, we suggest using the normalized difference between 00 and 00~~. Fourth, to differentiate between a rough, surface scatterer and a volume scatterer (both capable of producing moderate levels of like polarization magnitudes), we recommend the use of the ratio of 00~~ and cf'LK,.where the subscript,
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Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».