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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Validation of Wave and Wind Product of the New Phase Saral Using Buoys Data
摘要： Since July 4th 2016, the SARAL/Altika has been moved in a new orbit, and it has continuously provided wave height measurements for more than 1 year. Before using these data, the measurements need to be validated. Based on the in-situ buoys from the National Data Buoy Center (NDBC), the SARAL Ka-band significant wave height (SWH) and Sea Surface Wind (SSW) measurements were validated and have been corrected using a linear regression with in-situ measurements. Compared with NDBC data, the validation results of SARAL show a RMS (Root Mean Square) of 0.28 m for SARAL SWH measurements and RMS of 1.30m/s for SARAL SSW speed indicating capability of AltiKa providing SWH and wind speed products with reliable accuracy. Therefore the accuracy of SARAL SWH products is higher than that of Jason-1/2 SWH data, and does not require any correction.
关键词： Sea Surface Wind,SARAL/AltiKa,Validation,Root Mean Square,Significant Wave Height
更新于2025-09-23 15:22:29
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - A New Azimuth Cut-Off Procedure to Retrieve Significant Wave Height Under High Wind Regimes
摘要： In this study, the azimuth cut-off approach, which is typically adopted to estimate wind speed from Synthetic Aperture Radar (SAR) imagery collected under nominal wind conditions, is discussed with respect to high wind regime cases. First, the key roles played by the pixel spacing, the size of the boxes used to partition the SAR imagery and the image texture (homogeneity) are discussed in terms of their effects on the azimuth cut-off (λc) estimation. Then, the reliability of the λc estimation is analyzed by measuring the distance between the measured and fitted autocorrelation functions (ACFs). This analysis shows that it is of paramount importance to filter unfeasible/unreliable λc values. To identify those values in an objective way a criterion is proposed that is based on the χ2 test performed over a large dataset of Sentinel-1 SAR imagery. The effectiveness of the χ2 test is verified by correlating the accepted estimates against auxiliary significant wave height data.
关键词： SAR,significant wave height,wind speed,azimuth cut-off
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Assessment of Reprocessed SSH and SWH Measurements Derived from HY-2A Radar Altimeter
摘要： This paper assesses the reprocessed sea surface height (SSH) and significant wave height (SWH, or Hs) measurements derived from Haiyang-2A (HY-2A) radar altimeter using Jason-2 and buoy observations. The mean standard deviations of the SSH crossover differences for HY-2A and Jason-2 are 5.123 cm and 5.202 cm, respectively. The mean standard deviation of the SSH crossover differences between HY-2A and Jason-2 is 5.23 cm. Compared with the National Data Buoy Center (NDBC) SWH measurements, the reprocessed HY-2A SWH measurements show a root-mean-square error (RMSE) of 0.221 m with a positive bias of 0.149 m. After calibrated with the two-branched corrections, the RMSE for the reprocessed HY-2A SWH measurements is reduced to 0.160 m, which is even lower than that for Jason-2 (0.228 m). Therefore, the reprocessed HY-2A SSH and SWH measurements are of high accuracy.
关键词： radar altimeter,HY-2A,sea surface height,significant wave height
更新于2025-09-09 09:28:46