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The wind energy production estimates are very important to a wind power project. The remote sensing technique has been widely used to retrieve the offshore wind speed and direction which could be used to calculate the wind energy of potential wind farm. However, almost all existing methods focus on wind power density, and the directional wind energy distributions are rarely studied. Before using remote...
Dual-frequency Precipitation Radar (DPR) consists of Ka- and Ku-band radars which operate in scanning mode at low incidence angles. It is installed on the Global Precipitation Measurement (GPM) satellite. Definition of boundary wave number in frameworks of the two-scale model of scattering surface is an important problem for investigation and modelling of radar backscatter from the sea surface. In...
Stepped-Frequency Microwave Radiometer (SFMR) measurements and Precipitation Radar (PR) data on tropical rainfall measuring mission (TRMM) are collocated to acquire the normalized radar cross sections (NRCS) at low incidence angles. At the same time, the whitecap coverages are concluded from averaging previous results. Using the formation of Kudryavtsev et al, the NRCS of whitecap is obtained. The...
As the launch of radars, such as the Precipitation Radar (PR) on Tropical Rainfall Measuring Mission (TRMM)[1] satellite and the Surface Wave Investigation and Monitoring (SWIM) on China France Oceanography SATellite (CFOSAT)[2], that operate in low incident angles, more and more NRCS data at low incident angle will be obtained. In order to retrieve the sea surface wind speed using low incident angle...
The motivation of this work is to investigate the characteristics of Normalized Radar Cross Section (NRCS) of X-band SAR under high winds using a TerraSAR-X (TS-X) image taken in Typhoon Megi in the South China Sea. NRCS derived from TS-X is compared with the simulated NRCS using the C-band GMF CMOD5 and the Ku-band GMF NSCAT4. The wind velocity is ranged from 25 to 36 m s−1 in the analysis. Results...
French-Indo joint mission SARAL/AltiKa is the first space-borne altimeter operating at Ka-band, which is expected to obtain finer resolution ocean surface wind speed and significant wave height (SWH) measurements particularly in coastal areas compared to the traditional Ku-band altimeters. In this paper, we present the preliminary validation results for the SARAL/AltiKa coastal SWH and wind speed...
It is known that the slope probability density function (pdf) of the sea surface is non-Gaussian and can be expressed as a Gram-Charlier to fouth-order expension, including seven parameters: slope variances in upwind and crosswind direction, two skewness coefficients and three peakedness coefficients. Cox and Munk[1] had gotten all the seven parameters varying with the wind speed using optical data...
The SAR-derived wind fields presented the detailed structure of wind fields along the coastal areas, which had heretofore been unobtainable from scatterometer observation. Comparison of the retrieved SAR wind speeds with in-situ buoy wind measurements showed a small difference of less than 1 m/s, which implied that the results of SAR wind retrieval satisfied the limit of accuracy of satellite scatterometry...
The robust wind wave growth functions established with ideal fetch-limited and quasi-steady wind conditions (e.g., [11–13]; and references therein) have been observed to be applicable to wind generated waves under considerably more varying conditions, including hurricanes [1, 3, 4, 14, 15] and rapidly accelerating and decelerating wind fields such as those encountered in mountain gap winds [16–19].
In this talk we introduce the combined active / passive (CAP) data product for the Soil Moisture Active Passive mission. We develop the algorithms for a radiometer-only salinity product, a radar-only vector wind product, and a combined active / passive vector wind and salinity product. We show the radiometer-only salinity product nears the Aquarius salinity accuracy requirements, that the radar-only...
The Global Precipitation Measuring (GPM) was proposed jointly by US and Japan and satellite equipped with a dual-frequency precipitation radar (DPR) and a microwave radiometer (GMI). GPM is partly a follow-on mission of the Tropical Precipitation Mission (TRMM), but GPM will extend the observation to cold regions. Our team has experience in developing of retrieval algorithms for precipitation radar...
In this study, we investigated the accuracies of SSS in the northwest Pacific Ocean for the recent three years (2012–2014) by comparison with in situ salinity measurements from Argo floats, moored buoys, and many of ship CTD measurements. The satellite SSS errors of the northwest Pacific Ocean presented characteristic dependence on latitudes close to the global ocean but were mostly underestimated...
The results of remote sensing, buoy and profile based on measured data indicate that the wind speed, H1/3 and salinity increased, sea surface temperature declined, and wind direction changed greatly during the transit of the Matmo typhoon on July 25. It was found that the typhoon transport the Yellow Sea Cold Water Mass into the the Yellow and Bohai seas mixed zone.
Sea surface salinity (SSS) has a profounding influence on the the exchanges of matter and energy at the air-ocean interface. It is also a driving force for ocean circulations. The capability of accurate measurement of SSS with high spatial and temporal resolution shall be a desirable boost to the global climate models. The scientific missions Soil Moisture and Ocean Salinity (SMOS) [1] and Aquarius...
We report on airborne measurements of the cross-polarized (VH) ocean surface normalized radar crosssection (NRCS) at incidence angles between 15° and 40° obtained at C-band in high-wind (> 30 m s−1) conditions. The present observations were taken in Hurricane Patricia on 23 October 2015 and extend the wind speed range of the existing cross-polarization ocean surface NRCS literature [1]–[4]. The...
Along-Track Interferometric (ATI) SAR has demonstrated through several studies a capability to detect ocean surface currents. One of the most challenging problems in ocean surface current retrieval using SAR is the removal of the wind-wave contribution. The phase difference provided by ATI-SAR technique is directly related to the radial velocity of the moving ocean surface. In order to infer the current-only...
The surface equivalent neutral wind field (ENWF) response to the sea surface temperature (SST) is investigated utilizing the monthly average ENWF acquired by the Quick Scatterometer (QuickSCAT) and the monthly average SST by the Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) from June 2002 to November 2009 in four typical sea areas, i.e. the Kuroshio Extension, the Gulf...
Sea surface temperature (SST) is an essential variable for numerical weather prediction and global climate modeling. Sea surface skin temperature (SSTskin) measurements are required for the validation of satellite SST products. Several radiometers for in situ SSTskin measurements have been developed. The infrared SST autonomous radiometer (ISAR) is a self-calibrating instrument with an accuracy of...
The empirical dependence of the azimuth wavelength cut-off on the significant wave height and on the wind speed have been studied. The azimuth cut-off is estimated on the fitting of a Gaussian function to the azimuth autocorrelation function of the radar cross section. The feasibility of estimating the significant wave height and/or the wind speed has been investigated as well. We use SAR images acquired...
The Bragg scattering theory does not explain the cross-polarized (VH or HV) normalized radar-backscatter cross-sections (NRCSs) from the ocean surface very well. The difference lies in the non-Bragg scatterings mechanisms including specular reflection and quasi-specular reflection or diffraction on the sharp edges of wave breaking. The specular reflection is a function of radar incidence angle and...
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