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Scatterometric wind retrieval based on HH- or VV-pol. radar backscatter experiences saturation at high winds, whereas recent measurements demonstrated that the cross-polarized signal, VH- or HV-pol. at high winds shows a strong dependence on wind speed. Explanation of such a behavior of the cross-polarized microwave radar from a theoretical standpoint represents a challenge. A classical composite...
The Dual-frequency Precipitation Radar (DPR) installed on the Global Precipitation Measurement (GPM) core satellite is being developed by JAXA and NICT. This paper describes objectives, technical performance, resource allocation, preliminary design, development model test, critical design and proto-flight test (PFT) of the DPR instrument. The DPR system PFT will be completed in 2011. After completion...
The planned Soil Moisture Active Passive (SMAP) mission1 will use both active radar and passive radiometer instruments at L-Band to measure and monitor both soil moisture and freeze/thaw state globally. The frequency band allocated for the SMAP radar is shared with the Global Navigation Satellite Systems and ground-based radiolocation services. Signals from those users present significant sources...
A rain cell model is used to simulate effects of spatial gradients and vertical structure in rain rate on spaceborne radar observations. The Ku-band radar data is subject to substantial attenuation for rain rates > 10 mm/hr and the nominal field-of-view (FOV) is 5 km. A theoretically based method to correct for attenuation in the measured radar reflectivity factor was tested for these conditions:...
Mesoscale cyclonic activity is one of the characteristics of the cold season in the Japan Sea. High winds and precipitation accompanying intense mesoscale cyclones (MCs) disturb transport and fishery operations in the sea and small sizes and fast development hinders their forecast and detection. Satellite data of visible, infrared, passive and active microwave sensors serve as a valuable source of...
Soil moisture is an import parameter for high latitude research focusing on carbon exchange and permafrost issues. This paper reviews requirements, constrains and possibilities of satellite derived soil moisture data for high latitude applications. Major points are freezing and thawing, and landscape heterogeneity. Special focus is on data derived from ENVISAT ASAR. The different ScanSAR modes (wide...
The polarimetric radar backscatters of a soybean field were measured using the ground-based X-band polarimetric scatterometer (HPS) in an angular range from 20° to 60° in 2009 and 2010. The backscattering coefficients were also obtained using the COSMO-SkyMed (Spotlight mode, HH-mode) from July to October 2010. The backscattering coefficients of the soybean field were computed using the first-order...
Accurate observations of high winds over the oceans are important for analyses of phenomena that range from regional (tropical and extratropical storms) to global scales (air-sea exchanges, ocean circulation). However, so far a lack of in-situ observations of winds above 20 m/s posed severe limitations to the accuracy of satellite-retrieved high winds as insufficient data were available for training...
Marine surface wind vectors observed by the Advanced Scatterometer (ASCAT) on the MetOp-A satellite were evaluated by assessing their self-consistency. Global statistics on wind speeds and directions were calculated from the data for a period of one year. The wind speed histograms exhibited a clear dependence on the cross-track wind vector cell location, which corresponds to the incidence angle. The...
The ADVANCED Wind Scatterometer (ASCAT) instrument is now the principal resource for oceanographers and meteorologists needing timely observations of ocean vector winds across the globe, using an active microwave sensor. This is one of the instruments operated by the European Space Agency (ESA)/European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), on the METOP-A satellite...
SAR-derived wind measurements are in the process of being implemented for operational production within NOAA's National Environmental Satellite, Data, and Information Service. For C-band ENVISAT and RADARSAT-1/2 data, the CMOD5 algorithm is being used; for ALOS data, a special L-band wind algorithm is employed. Comparisons of both C-band and L-band winds with ASCAT scatterometer wind measurements...
Scatterometry is an important means of global wind measurements in the ocean. The standard spatial resolution of scatterometers is typically about 25 km, and because of the contamination from the much stronger land scatter of antenna side lobes, ocean wind sensing in the coastal regions within several tens of kilometers from the shoreline are effectively excluded. However, recent development of ultrahigh...
A dual Ka-band radar system is developed by the Japan Aerospace Exploration Agency (JAXA) for the Global Precipitation Measurement (GPM) dual-wavelength radar (DPR) algorithm development. The usage of the system is to measure backscattering and extinction cross sections by precipitation separately, and to provide testbed data for DPR algorithm. The parameters required in the DPR algorithm are raindrop...
In this paper, a conceptual design for a dual-frequency Rotating Fanbeam SCATterometer (RFSCAT) to fly onboard the future satellite (e.g. FY-3) with altitude of 836km is studied. System configurations of the studied C-band Ku-band RFSCAT are introduced respectively. Then an end-to-end simulation process is adopted to analyze the backscatter measurement accuracy, ant to assess the wind retrieval quality...
Rotating fan-beam scatterometer (RFSCAT) is a new kind of spaceborne scatterometer for ocean surface vector wind (OSVW) measurement. In this paper, some consideration about the calibration of a Ku-band RFSCAT is presented. Both internal calibration and external calibration are described. Preliminary analyses about the internal calibration precision and external calibration accuracy are presented....
A novel ground based multi bistatic interferometric radar sensor has been realized in order to measure the three dimensional displacement vector of civil structures as buildings, bridges and towers.
In this paper a detail description of ArtAr-C&Ku, two frequency (at C-, and Ku-band), multi-polarization, combined, short-pulse scatterometer-radiometer system is presented, for short (from low altitude platforms), middle (from vessels) and long (from aircrafts) distance remote sensing applications for water surface, soil and land snow cover's microwave reflective and emissive characteristics...
In this paper, the status and progress of the scatterometer (SCAT) of the Chinese-French Oceanography Satellite (CFOSAT) will be reported. SCAT/CFOSAT will be the first rotating fan-beam scatterometer (RFSCAT) ever flown on a satellite for global ocean vector wind measurement. The mission schedule, some design and development status and simulation results of its performances will be presented. It...
A transponder system is developed to fulfill the in-orbit calibration of the HY-2 satellite altimeter (ALT) and scatterometer (SCAT). The interaction of a calibration transponder and radar (altimeter / scatterometer) is rather complicated. After a brief description of the two active payloads on HY-2 satellite, several key issues are investigated in detail, including time arrangement and power budget...
We have analyzed rainfall data observed by Precipitation Radar (PR) on board Tropical Precipitation Measuring Mission (TRMM) to compare with the data from AMeDAS ground rain gauge network in Japan. PR has observed latitudes of 35°N–35°S and visited Japan a few times a day. Annual rainfall amounts of 1998–2008, excluding 2001, are calculated in boxes of area size of 0.5°×0.5° – 3°×3° and more. It is...
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