Catalyseur Quebecois en observation de la Terre

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EXTERNE : "Satellite Scatterometry: Winds, Vegetation, and Ice"

  • 2021-02-01
  • 10:00
  • En ligne (Voir description)


Évènement de la Geosciences and Remote Sensing Society de l'IEEE

EN ANGLAIS

Remote sensing is the study of the environment from a distance. Recent developments in satellite-based sensors and computer processing techniques offer unique perspectives of our planet. Microwave remote sensing includes active (radars) and passive (radiometers) sensors. This talk focuses on the applications of a class of active microwave remote sensors known as scatterometers. Satellite scatterometers have been built and flown by several nations including, the U.S., ESA, India, and China. Wind scatterometers are satellite radars designed to measure near-surface vector winds over the ocean. The scatterometer does not directly measure the wind. Rather, it measures the normalized radar backscatter (σo) of the surface. Then, from multiple σo measurements, the wind blowing over the ocean's surface is inferred. Scatterometer wind measurements have wide application in air-sea interaction and weather observation. Wind scatterometers typically operate at one of two bands, C (5.4 GHz) or Ku (13.4 GHz). Ku band is more sensitive to wind, but also to the adverse effects of rain. However, this sensitivity can be exploited to simultaneously estimate wind and rain. Scatterometers also collect σo measurements over land and ice. While the low resolution (25 km) of the scatterometer measurements can limit their utility in land and ice studies, reconstruction processing enables the generation of enhanced resolution σo images from past and present scatterometers. Such enhanced resolution scatterometer images have been proven to be useful for high resolution wind/rain estimation as well as in a variety of studies of polar ice and tropical vegetation. In particular enhanced resolution scatterometer observations have been used over land to study deforestation of tropical rain forest and desertification. Over the glaciated regions of Greenland and Antarctica, the radar signal is very sensitive to melting conditions and can thus be used to global warming conditions. The contrast between ocean and ice scattering enables tracking of major Antarctic icebergs in all weather conditions. In this talk, a brief overview of scatterometer remote sensing is provided and a number of applications of microwave remote sensing are described.

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