7/14/2023 0 Comments Indirection bandThe backscattered signal varies according to the wind speed and its effects on ocean roughness. Scatterometers are radars and send pulses of radiation at the surface. The only exception is 'RapidSCAT', which is a scatterometer on the international space ship (ISS). Nowadays scatterometer data is operationally used especially for data assimilation and for marine nowcasting.įigure 8 shows an overview of the current and proposed satellite missions carrying scatterometers.įigure 8: Overview of finished, current and proposed satellite missions with scatterometeres onboard. However, widespread usage of scatterometers started in the 1990s. Scatterometry started in the 1970s – the first satellite with a scatterometer onboard was Seasat-A (NASA). It took some 20 more years to discover that this noise was related to wind velocity. Sensitive to rain, coastal coverage - Land contaminationĭuring World War 2 it was discovered that radars also picked up some kind of clutter over the oceans. Less detection in the higher wind range (> 60 kt), sea ice, coastal coverage - Land contamination Table 2: Comparison of C-band and Ku-band scatterometers. Thus, Ku-band radars with a wavelength of about 2 cm are sensitive to rain. The wavelength of the radar is chosen according to the sampling scale. The two radar types are compared with each other in Table 2. A Geophysical Model Function (GMF) provides the radar cross section as a function of the equivalent neutral wind vector at 10 m anemometer height (not the actual wind!), incidence angle, relative azimuth angle, radar frequency, and polarization.ĭepending on the wavelength of the radiation a distinction can be made between C-band and Ku-band scatterometers. Scatterometers measure the radar cross section of the ocean surface. It has become an increasingly important tool for monitoring climate, forecasting (marine) weather and studying the atmosphere-ocean interactions. Spaceborne wind scatterometry is an indirect method of measurement. They are used by low Earth orbiting satellites and act like radars: they transmit electromagnetic pulses and detect the backscattered signals. Scatterometers are active remote sensing instruments for deriving wind direction and speed from the roughness of the sea.
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