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This paper presents a new design of an X-band imaging interferometric radiometer needed for wind vector, precipitation and vegetation measurement with acceptable complexity, light weight and low power consumption. It introduces polarimetric capability to conventional 1D imaging interferometer by employing a polarimetric patch antenna. Conical beam is generated by beam squint. Novel 2-point calibration...
In this presentation, the polarization ratios were calculated from AIRSAR polarimetric SAR data and ENVISAT ASAR dual-polarization data; and their empirical CC parameters which depend on incidence angle were obtained. Five C band HH polarization RADARSAT-1 SAR images are used to validate these polarization ratios and we found that the empirical parameter alpha = 0.5 is superior to other possible parameter...
The IEM proposed in 1992, for rough surface scattering has been extensively applied for microwave remote sensing of terrain. Model validation has been made by experimental measurements and by numerical simulations. However, estimation accuracy was verified mostly for like-polarizations in the monostatic configuration. Since then, much effort has been devoted to improving the model performance. A recent...
The presence of vegetation in the radio channel could affect the coverage areas of cellular mobile phone systems. The different components of a tree have influence in the performance of the radio system. Whereas the trunk is commonly in a fixed and stable location, the leaves could be in continuous movement forced by the wind. This time variation, which can be correlated with the wind speed and direction,...
The sea ice in polar region has been shrunk and thinned considerably with the rampant global temperature during the last few decades. It has already shown dramatic effects on regional water balance, ocean circulation and global climate. Nowadays, an extensive investigation and understanding of the environmental change in polar region becomes a crucial task. However, difficulties resulting from transportation,...
On October 3-5, 2005 a smog advisory was issued for southern Ontario,Canada, due to high ground-level ozone and fine particulate matter (particles less than 2.5 microns in diameter - PM 2.5). Warm temperatures up to 28 C, high humidity and gentle winds contributed to a build-up of pollutants locally. In addition, southerly winds transported pollutants from the neighbouring United States northward...
In a paper the acoustic method of measurement of speed and a direction of moving of turbulent air is discussed. It is proposed to increase resolution measuring device with shifting of frequency of heterodyne signal on 1%. For supervising of weak air turbulence it is suggested to measure phase difference of signal with respect to reference one.
Distributed networks of short-range radars offer the potential to observe winds and rainfall at high spatial resolution in volumes of the troposphere that are unobserved by today's long-range weather radars. One class of potential distributed radar network designs includes Off-the-Grid (OTG) weather radar networks. These are short-range radar nodes designed to be deployed as part of an ad-hoc network...
In an ERS-SAR image of the sea off Kii Peninsula on 30 March 1996, we found an atmospheric front formed by the sheltering effect of land topography and swell modulation in the sheltered/non-sheltered areas. From the SAR image, high- resolution wind speed and SAR-wave spectrum are retrieved. In the frequency range higher than the peak frequency, the SAR- spectra of the non-sheltered area have energy...
Since the pioneering work of Cox & Munk , who first investigated the probability distribution of liquid surface facets using the analysis of aerial photographs of the Sun glitter, it has been widely recognized that the dominant parameter that determines the sea surface roughness is the mean square slope (MSS) of the sea surface which is mainly related to short wind waves and other surface effects...
The Imaging Wind and Rain Airborne Profiler (IWRAP) and Simultaneous Frequency Microwave Radiometer have been flown aboard the NOAA WP-3D "Hurricane Hunter" aircraft for the past five (2002-2006) hurricane seasons. IWRAP is a conically scanning, high resolution C- and Ku-band Doppler radar that profiles from the aircraft to ocean at four incidence angles. The microwave return from the ocean...
Retrieval of wind speed using L-band synthetic aperture radar (SAR) is both an old and new endeavor. Although the Seasat L-band SAR in 1978 was not well calibrated, early results indicated a strong relationship between observed SAR image intensity and wind speed. The JERS-1 L-band SAR had limited usefulness over the ocean. Most recent wind retrievals from spaceborne SARs have been at C-band for ERS-1/2,...
Bora events over the Adriatic Sea and Black Sea are investigated by using synthetic aperture radar (SAR) images acquired by the Advanced Synthetic Aperture Radar (ASAR) onboard the Envisat satellite, optical and infrared images acquired by the MODIS sensor onboard the Terra satellite, and sea surface wind data acquired by the scatterometer onboard the Quikscat satellite. Quantitative information on...
In 2005 and 2006, we mounted an X- band Doppler radar on ships that operated in the South China Sea and off the coast of New Jersey, respectively. The measurements were made only at W polarization in 2005 but at both HH and W polarization in 2006. On average, VV normalized radar cross sections, sigma0(VV), behaved at grazing angles between 1 and 2 degrees in much the same manner that they do at higher...
Radar backscatter data are collected using a coherent, dual-polarized radar from a fixed tower in the ocean. Statistical analysis is performed to investigate the 1D and 2D probability density functions of backscatter intensity, Doppler frequency, coherence function and polarization ratio. The fraction of sea spike coverage generally increases with wind speed but the trend of increase is modified by...
In scatterometry, the wind vector retrieval problem is ambiguous, i.e., the inversion procedure does not result in a unique wind solution. To remove such ambiguity, a spatial filter is applied over the ambiguous wind field. Such filtering methods succeed in most of the cases. However, as the resolution increases both the noise and the direction ambiguity in retrieved winds increases, leading to arbitrary...
We present a case study of low-level wind jets induced in sequence by orographic effects off the Pacific coast of northern Japan during 7-11 June 2003, and demonstrate that the transition of the wind jets causes areal differences of the wave height variations along the coast. First, we analyze SeaWinds scatterometer wind measurements. Under the easterly wind, a strong wind jet formed after passing...
Based on polarization ratio from ENVISAT ASAR, we compared the wind vectors retrieved from CMOD5 with alpha= 0.6, alpha = 0.5, our polarization ratio,VV HWGMF with our polarization ratio and HH HWGMF with results from QuikSCAT and buoy, respectively. We found that CMOD5 with alpha= 0.5 polarization ratio is best one for retrieving high wind speed from RADARSAT SAR; and error between QuikSCAT and HH...
Both atmospheric and oceanic processes play an important role in the dynamics of tropical cyclones. Due to the relatively small amount of in situ data available for extreme events like hurricanes or typhoons remote sensing techniques play an important role in the measurement of the relevant geophysical parameters. In this paper some recent results on SAR observation of extreme wind conditions are...
The relationship between ocean wind vectors and L-band normalized radar cross sections (NRCS) is examined using the Phased-Array L-band Synthetic Aperture Radar (PALSAR). We used PALSAR ScanSAR images with a wide range of incidence angles from 17deg to 43deg. More than 6,000 match-ups, each consisting of the NRCS, incidence angles, wind speeds and wind directions, were collected. The NRCS exhibits...
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